Kai Cao
email: kai.cao@cug.edu.cn

Philippe Hervé Leloup

Guocan Wang

Wei Liu

Gweltaz Mahéo

Tianyi Shen

Yadong Xu

Philippe Sorrel

Kexin Zhang

Sorrel Philippe

Thrusting, exhumation, and basin fill on the western margin of the South China block during the India-Asia collision

Keywords: 9, Table: 1, Appendixes: 8 India-Asian collision, South China, Jianchuan basin, fold-thrust belt, low temperature thermochronology, lithospheric rheology

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Introduction

The collision between India and Asia, which started since 60-50 Ma (Allègre et al., 1984;[START_REF] Ding | The India-Asia collision in north Pakistan: Insight from the U-Pb detrital zircon provenance of Cenozoic foreland basin[END_REF][START_REF] Hu | The timing of India-Asia collision onset -Facts, theories, controversies[END_REF][START_REF] Najman | Timing of India-Asia collision: Geological, biostratigraphic, and palaeomagnetic constraints[END_REF][START_REF] Rowley | Age of initiation of collision between India and Asia: A review of stratigraphic data[END_REF], has resulted in double-thickness crust and growth of the Tibetan Plateau that stands as a mean elevation of 5 km over a distance of ~2000 km north of the plate boundary. The reconstruction of the appropriate rheology of the Asian continental lithosphere as inferred from geodynamic models is crucial to understand the uplift and growth history of the Tibetan Plateau that have puzzled the earth scientists for a century (see reviews in [START_REF] Yin | Geologic Evolution of the Himalayan-Tibetan Orogen[END_REF] and [START_REF] Kapp | Mesozoic-Cenozoic geological evolution of the Himalayan-Tibetan orogen and working tectonic hypotheses[END_REF]). The prevailing models encompass 1) homogenous shortening and thickening distributed within Tibetan lithosphere analogue to a viscous sheet [START_REF] Dewey | Tibetan, Variscan, and Precambrian basement reactivation: products of continental collision[END_REF][START_REF] England | Finite strain calculations of continental deformation 2. Comparison with the India-Asia collision zone[END_REF], 2) homogenous crustal thickening followed by flow of low-viscosity lower crust driven by topographic load [START_REF] Bird | Lateral extrusion of lower crust from under high topography in the isostatic limit[END_REF][START_REF] Clark | Late Cenozoic uplift of southeastern Tibet[END_REF][START_REF] Clark | Topographic ooze: Building the eastern margin of Tibet by lower crustal flow[END_REF][START_REF] Royden | Surface deformation and lower crustal flow in eastern Tibet[END_REF], and 3) upper crustal shortening and oblique intracontinental subduction between coherent elasto-plastic lithospheric blocks [START_REF] Meyer | Crustal thickening in Gansu-Qinghai, lithospheric mantle subduction, and oblique, strike-slip controlled growth of the Tibet Plateau[END_REF][START_REF] Tapponnier | Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine[END_REF][START_REF] Tapponnier | The Ailao Shan/Red River metamorphic belt; Tertiary left-lateral shear between Indochina and South China[END_REF]. The first two models predict that uplift and deformation of the Tibetan plateau commenced throughout the plateau synchronously with or shortly after the India-Asian collision, while the third one predicts stepwise growth of the plateau from south to north and crustal deformation mostly localized along the boundaries of the lithospheric blocks. The discrimination of the three models largely depends on the quantification of the spatiotemporal evolution of intracontinental deformation resulting from the India-Asian collision and convergence. The middle-late Cenozoic extrusion of the crustal materials to the Tibetan sideways, inferred from plasticine analogue modeling, has been relatively well documented by structural analyses and geo-thermochronology (e.g., [START_REF] Tapponnier | Slip-line field theory and large-scale continental tectonics[END_REF][START_REF] Tapponnier | Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine[END_REF][START_REF] Leloup | Structural, petrological and thermal evolution of a Tertiary ductile strike-slip shear zone, Diancang Shan[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF][START_REF] Cao | Initiation of leftlateral deformation along the Ailao Shan-Red River shear zone: new microstructural, textural, and geochronological constraints from the Diancang Shan metamorphic massif[END_REF][START_REF] Lin | 40 Ar/ 39 Ar dating of the Jiali and Gaoligong shear zones: Implications for crustal deformation around the Eastern Himalayan Syntaxis[END_REF][START_REF] Zhang | Structure, kinematics and ages of transpression during strainpartitioning in the Chongshan shear zone, western Yunnan[END_REF][START_REF] Zhang | Structural feature and its significance of the northernmost segment of the Tertiary Biluoxueshan-Chongshan shear zone, east of the Eastern Himalayan Syntaxis[END_REF][START_REF] Zhang | The Xuelongshan high strain zone: Cenozoic structural evolution and implications for fault linkages and deformation along the Ailao Shan-Red River shear zone[END_REF][START_REF] Zhang | Timing and rate of exhumation along the Litang fault system, implication for fault reorganization in Southeast Tibet[END_REF][START_REF] Zhang | Cooling history of the Gongga batholith: Implications for the Xianshuihe Fault and Miocene kinematics of SE Tibet[END_REF]. In contrast, how the Tibetan plateau crust deformed in the early Cenozoic remains poorly constrained (e.g., [START_REF] Cao | Cenozoic thermo-tectonic evolution of the northeastern Pamir revealed by zircon and apatite fission-track thermochronology[END_REF][START_REF] Clark | Early Cenozoic faulting of the northern Tibetan Plateau margin from apatite (U-Th)/He ages[END_REF][START_REF] Horton | Paleocene-Eocene syncontractional sedimentation in narrow, lacustrine-dominated basins of east-central Tibet[END_REF][START_REF] Leloup | Successive deformation episodes along the Lungmu Co zone west-central Tibet[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF][START_REF] Staisch | Eocene to late Oligocene history of crustal shortening within the Hoh Xil Basin and implications for the uplift history of the northern Tibetan Plateau[END_REF][START_REF] Tong | Paleomagnetism of Eocene red-beds in the eastern part of the Qiangtang Terrane and its implications for uplift and southward crustal extrusion in the southeastern edge of the Tibetan Plateau[END_REF][START_REF] Yin | Geologic Evolution of the Himalayan-Tibetan Orogen[END_REF]. Quantitative data of the geometry and kinematics of the first-order structures that predated the occurrence of the crustal extrusion within the collision belt are lacking. Southeast Tibet is characterized by extrusion tectonics accommodated by large-scale strike-slip fault systems in middle-late Cenozoic times especially along the Ailao Shan-Red River shear zone (ASRR) and Red River fault (e.g., [START_REF] Tapponnier | Slip-line field theory and large-scale continental tectonics[END_REF][START_REF] Tapponnier | Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine[END_REF][START_REF] Tapponnier | The Ailao Shan/Red River metamorphic belt; Tertiary left-lateral shear between Indochina and South China[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF] and is thus an ideal region to address the above question. However, the tectonic configuration of southeast Tibet prior to extrusion remains poorly understood. Deformed Paleogene sediments in southeast Tibet provide an opportunity to study Early Cenozoic sedimentation and deformation. The Jianchuan basin, one of the largest hinterland basins in southeast Tibet (Fig. 1), is proximal to the Red River fault and has been the subject of several recent studies pertaining to its age, deformation, exhumation and paleoelevation [START_REF] Cao | Oligocene-Early Miocene topographic relief generation of southeastern Tibet triggered by thrusting[END_REF][START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]Hoke et al., 2014;[START_REF] Li | Cenozoic paleoaltimetry of the SE margin of the Tibetan Plateau: Constraints on the tectonic evolution of the region[END_REF][START_REF] Sorrel | Wet tropical climate in SE Tibet during the Late Eocene[END_REF][START_REF] Wei | No sedimentary records indicating southerly flow of the paleo-Upper Yangtze River from the First Bend in southeastern Tibet[END_REF][START_REF] Wissink | Temporal and spatial patterns of sediment routing across the southeast margin of the Tibetan Plateau: Insights from detrital zircon: Tectonics[END_REF][START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]Yang et al., 2014). Despite its importance, the geodynamic context of its formation and the subsidence mechanisms are still poorly known. In this study, our field and analytical data provide first quantitative constraints on the geometry, kinematics and timing of the compressive deformation along a fault zone that we termed Ludian-Zhonghejiang fold-thrust belt (LZTB) on the western margins of the South China block, western Yunnan, which preceded sinistral motion of the ASRR. These results allow establishing casual links between Early Cenozoic thrusting-induced rock exhumation within the deformation zone and deposition in the Jianchuan basin. Accordingly, we provide mechanistic interpretations for tectonic deformation and sedimentation in southeast Tibet corresponding to the India-Asian collision.

Geological setting

Regional tectonics

The southeast Tibetan Plateau comprises a collage of several major lithospheric fragments, including the Songpan-Garze, Lanping-Simao, Indochina and South China (Fig. 1a). This region has experienced a protracted tectonic history from Paleozoic amalgamation to Mesozoic Tethys evolution (e.g., [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]Deng et al., 2014a;Jian et al., 2009a, b;[START_REF] Metcalfe | Palaeozoic and Mesozoic tectonic evolution and palaeogeography of East Asian crustal fragments: The Korean Peninsula in context[END_REF], overprinted by significant Cenozoic intracontinental deformation under the compound effects of India-Asian convergence and Pacific-Indonesian subduction (e.g., [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]Deng et al., 2014b;[START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Yin | Cenozoic tectonic evolution of Asia: A preliminary synthesis[END_REF]. Paleozoic-Mesozoic orogenesis in southeast Tibet is largely related to the evolution of the Paleo-Tethys recorded by numerous NS-striking belts of Devonian-Permian ophiolites and accretionary mélange complex [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]Jian et al., 2009a, b). Large volume of Permo-Triassic plutonic and volcanic assemblages between the South China and Lanping-Simao blocks had been produced by westward subduction and final suturing of the Paleo-Tethys along the Jinsha-Ailao Shan suture zone [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]Deng et al., 2014a;[START_REF] Faure | The South China block-Indochina collision: Where, when, and how[END_REF]Jian et al., 2009a, b;[START_REF] Zi | Generation of Early Indosinian enriched mantle-derived granitoid pluton in the Sanjiang Orogen (SW China) in response to closure of the Paleo-Tethys[END_REF][START_REF] Zi | Late Permian-Triassic magmatic evolution in the Jinshajiang orogenic belt, SW China and implications for orogenic processes following closure of the Paleo-Tethys[END_REF]. Since initial collision of the India with Asia at 60-50 Ma (Allègre et al., 1984;[START_REF] Ding | The India-Asia collision in north Pakistan: Insight from the U-Pb detrital zircon provenance of Cenozoic foreland basin[END_REF][START_REF] Hu | The timing of India-Asia collision onset -Facts, theories, controversies[END_REF][START_REF] Najman | Timing of India-Asia collision: Geological, biostratigraphic, and palaeomagnetic constraints[END_REF][START_REF] Rowley | Age of initiation of collision between India and Asia: A review of stratigraphic data[END_REF], the eastern margin of the Tibetan Plateau was strongly deformed, with early Cenozoic crustal shortening [START_REF] Tapponnier | Oblique stepwise rise and growth of the Tibet Plateau[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF][START_REF] Studnicki-Gizbert | Early Tertiary Gonjo basin, eastern Tibet: Sedimentary and structural record of the early history of India-Asia collision[END_REF][START_REF] Tong | Paleomagnetism of Eocene red-beds in the eastern part of the Qiangtang Terrane and its implications for uplift and southward crustal extrusion in the southeastern edge of the Tibetan Plateau[END_REF] followed by southward block extrusion and rotation via large-scale strike slip faults (e.g., the ASSR; Fig. 1; [START_REF] Tapponnier | Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine[END_REF][START_REF] Tapponnier | The Ailao Shan/Red River metamorphic belt; Tertiary left-lateral shear between Indochina and South China[END_REF][START_REF] Cao | Initiation of leftlateral deformation along the Ailao Shan-Red River shear zone: new microstructural, textural, and geochronological constraints from the Diancang Shan metamorphic massif[END_REF][START_REF] Leloup | Structural, petrological and thermal evolution of a Tertiary ductile strike-slip shear zone, Diancang Shan[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF][START_REF] Lin | 40 Ar/ 39 Ar dating of the Jiali and Gaoligong shear zones: Implications for crustal deformation around the Eastern Himalayan Syntaxis[END_REF][START_REF] Tong | New insights into the Cenozoic lateral extrusion of crustal blocks on the southeastern edge of Tibetan Plateau: Evidence from paleomagnetic results from Paleogene sedimentary strata of the Baoshan Terrane[END_REF][START_REF] Zhang | Structure, kinematics and ages of transpression during strainpartitioning in the Chongshan shear zone, western Yunnan[END_REF][START_REF] Zhang | Structural feature and its significance of the northernmost segment of the Tertiary Biluoxueshan-Chongshan shear zone, east of the Eastern Himalayan Syntaxis[END_REF][START_REF] Zhang | The Xuelongshan high strain zone: Cenozoic structural evolution and implications for fault linkages and deformation along the Ailao Shan-Red River shear zone[END_REF][START_REF] Zhang | Timing and rate of exhumation along the Litang fault system, implication for fault reorganization in Southeast Tibet[END_REF][START_REF] Zhang | Cooling history of the Gongga batholith: Implications for the Xianshuihe Fault and Miocene kinematics of SE Tibet[END_REF]. Early Cenozoic crustal deformation in east Tibet has been recorded by magmatism [START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF][START_REF] Wang | A tectonic model for Cenozoic igneous activities in the eastern Indo-Asian collision zone[END_REF][START_REF] Zhang | Structure, kinematics and ages of transpression during strainpartitioning in the Chongshan shear zone, western Yunnan[END_REF], tectonic activity of fold-thrust system [START_REF] Horton | Paleocene-Eocene syncontractional sedimentation in narrow, lacustrine-dominated basins of east-central Tibet[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF], deposition of syn-tectonic Paleogene basins, such as the Yushu-Nangqian and Gonjo basins [START_REF] Horton | Paleocene-Eocene syncontractional sedimentation in narrow, lacustrine-dominated basins of east-central Tibet[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF][START_REF] Studnicki-Gizbert | Early Tertiary Gonjo basin, eastern Tibet: Sedimentary and structural record of the early history of India-Asia collision[END_REF][START_REF] Tang | Paleoelevation reconstruction of the Paleocene-Eocene Gonjo basin[END_REF] and paleomagnetism [START_REF] Tong | Paleomagnetism of Eocene red-beds in the eastern part of the Qiangtang Terrane and its implications for uplift and southward crustal extrusion in the southeastern edge of the Tibetan Plateau[END_REF]Zhang et al., 2018). Recent thermochronological results from two vertical profiles at Deqin and Weixi in southeast Tibet reveal two episodes of rapid exhumation during 120-80 Ma and 60-40 Ma to the northwest of the Jianchuan basin [START_REF] Liu-Zeng | Multiple episodes of fast exhumation since Cretaceous in southeast Tibet, revealed by low-temperature thermochronology[END_REF]. The middle-late Cenozoic crustal deformation in southeast Tibet is characterized by large-scale strikeslip fault system. Amongst them, the nearly-1000 km long ASRR extending from Vietnam to southeast Tibet defines a prominent crustal discontinuity and separates the South China to the northeast from Lanping-Simao/Indochina to the southwest. This shear zone comprises four narrow segments of strongly deformed metamorphic rocks: Day Nui Con Voi, Ailao Shan, Diancang Shan and Xuelong Shan from southeast to northwest (Fig. 1). The onset timing for left-lateral shear of the ASRR remains controversial, ranging between ~34 and 28 Ma [START_REF] Cao | Initiation of leftlateral deformation along the Ailao Shan-Red River shear zone: new microstructural, textural, and geochronological constraints from the Diancang Shan metamorphic massif[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF][START_REF] Leloup | Discussion on the role of the Red River shear zone, Yunnnan and Vietnam, in the continental extrusion of SE Asia[END_REF][START_REF] Palin | A geochronological and petrological study of anatectic paragneiss and associated granite dykes from the Day Nui Con Voi metamorphic core complex, North Vietnam: constraints on the timing of metamorphism within the Red River shear zone[END_REF][START_REF] Zhang | The Xuelongshan high strain zone: Cenozoic structural evolution and implications for fault linkages and deformation along the Ailao Shan-Red River shear zone[END_REF] to ~25 Ma [START_REF] Searle | Structural constraints on the timing of left-lateral shear along the Red River shear zone in the Ailao Shan and Diancang Shan Ranges[END_REF], or even later than 21 Ma [START_REF] Searle | Role of the Red River Shear zone, Yunnan and Vietnam, in the continental extrusion of SE Asia[END_REF]. Cessation of its left-lateral deformation occurred at ~17 Ma [START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF]. Since ~10-5 Ma, the dextral Red River fault almost followed the trace of the ASRR [START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Replumaz | Large river offsets and Plio-Quaternary dextral slip rate on the Red River Fault (Yunnan, China)[END_REF].

Subsidence and uplift history of the Jianchuan basin

The Jianchuan basin is a Paleogene intermontane basin in southeast Tibet on the South China block, mostly standing at an elevation of 3-4 km (Figs. 1 and2). It is bounded to the west by the Qiaohou thrust belt [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. Paleogene sediments are strongly folded in the vicinity of the Ludian-Zhonghejiang fault, the eastern branch of the fold belt (Fig. 2). To the northeast of the basin, basal sediments of the Paleogene Baoxiangsi Fm. (E2b) rest unconformably on the Proterozoic and Paleozoic basement rocks. To the southeast of the basin, Eocene sediments are bounded by the Jianchuan normal fault, which belongs to a releasing bend of the Red River fault system that probably initiated in the Late Miocene [START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF][START_REF] Replumaz | Large river offsets and Plio-Quaternary dextral slip rate on the Red River Fault (Yunnan, China)[END_REF]. The Paleogene sediments in the Jianchuan basin and surrounding areas stand unconformably on folded Triassic and older basement rocks [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]. Basin stratigraphy was recently reappraised based on new results of geological mapping, geochronologic data and fossil assemblages [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF][START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. Revised stratigraphic sequences of the Paleogene basin consist of the Mengyejing Formation "(Fm.)" (E1m), Baoxiangsi Fm. (E2b), Jiuziyan Fm. (E2jz), Shuanghe Fm. (E2s) and Jianchuan Fm. (E2jc) from the bottom to the top (Fig. 3). The Mengyejing Fm. (E1m), outcropping in the southern part of the basin, is dominated by red mudstones and siltstones, with limited presence of sandstone and conglomerate layers (Fig. 2). These sediments are interpreted to be a flood plain environment with local occurrence of alluvial-fan deposits [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The Baoxiangsi Fm. (E2b) having a thickness of up to ~600 m is exposed parallel to the bounding Ludian-Zhonghejiang fault to the west and occupies the greatest volume of basin infill [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]Fig. 3). This formation can be subdivided into two units: E2b1 and E2b2. The sediments of E2b1 are characteristics of basal conglomerates, filling an uneven paleo-relief carved within the Shigu metamorphic schists along the northeast basin margin [START_REF] Studnicki-Gizbert | Deformation, erosion and sedimentation in collisional orogens: case studies from eastern Tibet and southwestern China[END_REF], indicative of an angular unconformable contact of the Baoxiangsi Fm. (E2b) above the Proterozoic to Paleozoic metamorphic rocks (Fig. 2). This suite of sediments (E2b1) also locally appear along the Ludian-Zhonghejiang fault (e.g., at site CD522 and east of site CD144; Figs. 2 and4). Contrary to what was described by [START_REF] Wei | No sedimentary records indicating southerly flow of the paleo-Upper Yangtze River from the First Bend in southeastern Tibet[END_REF], there is no clear field evidence for an angular unconformity between the E2b1 and the underlying E1m [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. Most of the Baoxiangsi Fm. (E2b2) consists of massive red siltstones interbedded with red sandstones, containing parallel and cross bedding and channel-fill conglomerates, consistent with a facies interpretation of a braided river system, while the base of the sedimentary succession is locally made of massive, well-sorted, thick multi-storey channelfill sandstones. There is no precise age control for both the Mengyejing Fm. (E1m) and Baoxiangsi Fm. (E2b). The presence of Paleocene-Early Eocene ostracods in the Mengyejing Fm. (E1m), along with charophyte assemblages and Late Eocene mammalian faunas in the Baoxiangsi Fm. (E2b), allow roughly attributing Paleocene and Eocene ages to these two formations respectively [START_REF] Bgmry | Bureau of Geology and Mineral Resources of Yunnan Province[END_REF]. This timing assignment is supported by the cut-off relationships between 35-36 Ma old intrusive rocks and the sediments of the Mengyejing (E1m) and Baoxiangsi Fms. (E2b) (Fig. 3; [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The overlying deposits of the Jiuziyan Fm.(E2jz), Shuanghe Fm. (E2s) and Jianchuan Fm. (E2jc) appear to be restricted to the eastern part of the Jianchuan basin (Fig. 2). The 0-100 m-thick Jiuziyan Fm. (E2jz) seems limited to the northeastern corner of the basin, mostly resting on the mountain top and isolated by incision of the river network (Fig. 2). The Jiuziyan Fm. ( E2jz) is locally in an erosional basal contact above the red mudstones of the Mengyejing Fm. (E1m), while the sediments show a regular transition without any clear angular unconformity at some spots [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. It consists of multi-storey carbonate successions, including life-position stromatolites interbedded with massive matrix-supported conglomerates and argillaceous calcisiltites, indicative of a palustrine-lacustrine environment (Sorrel et al., 2017). The 0-200 m-thick Shuanghe Fm. (E2s), overlying conformably the Jiuziyan Fm. (E2jz), is composed of poorly consolidated yellow sandstones, interbedded with organic-rich coal levels, as well as few layers of lava, tuff and volcanoclastic sediments. The sediments are commonly cut by intrusions (mostly lamprophyres), often sills in the coals or along sandstones stratifications. The strata are folded under nearly EW-directed contraction [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The 0-300 m thick Jianchuan Fm. (E2jc) overlies the folded sediments of the Shuanghe Fm. (E2s). These strata are dominantly volcanoclastic and relates to Late Eocene intrusion of the Shamao Shan syenite [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The deposition timing of the Shuanghe Fm. (E2s) and Jianchuan Fm. (E2jc) was recently refined to be at ~35.9±0.9 Ma and 35.4±0.8 Ma respectively, from zircon U-Pb and 40 Ar/ 39 Ar dating on interbedded and crosscutting igneous rocks (Fig. 3; [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. This is supported by newly-discovered fossils of chara and ostracod [START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. The age of the Shuanghe Fm. (E2s) is further corroborated by a jaw (found in coal deposits) of a large amynodontid that thrived during the Late Eocene Ergilian interval (37.2-33.9 Ma) [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The elevation history of the Jianchuan basin remains highly debated. Paleoaltimetry reconstructions based on stable isotopes suggest an attainment of modern surface height of ~3.3±0.5 km asl. in the Late Eocene for the Jianchuan basin (Hoke et al., 2014). Similar work on the Shuanghe Fm. (E2s) suggests that the Jianchuan basin had reached ~2.6 km asl. close to modern surface elevation in the Late Eocene [START_REF] Li | Cenozoic paleoaltimetry of the SE margin of the Tibetan Plateau: Constraints on the tectonic evolution of the region[END_REF]. However, the Shuanghe Fm. (E2s) was recently revised to be Late Eocene in age, and basin elevation was also re-evaluated to indicate a lower elevation of ~1.2±1.2 km asl. [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. Recent stable isotope and fossil pollen coexistence data suggest the Jianchuan basin experienced a gradual uplift from between 0.5 km asl. and 2.5±0.7 km asl. during deposition of the Jiuziyan Fm. (E2jz) to between 0.9 km asl and 2.9±0.6 km asl. during deposition of the Shuanghe Fm. (E2s) [START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. Low temperature thermochronology data interpreted in the light of thermal modelling suggest that the Jianchuan basin experienced 2.3-3.2 km of rapid exhumation at a rate of 0.57-0.80 mm yr -1 between ~28 and 20 Ma [START_REF] Cao | Oligocene-Early Miocene topographic relief generation of southeastern Tibet triggered by thrusting[END_REF]. These results allowed us to link pronounced relief generation of southeast Tibet during the Oligocene-Early Miocene to thrusting in the context of regional NW-SE crustal shortening [START_REF] Cao | Oligocene-Early Miocene topographic relief generation of southeastern Tibet triggered by thrusting[END_REF].

Geological mapping

The geometry, kinematics and timing of Cenozoic deformation of the Jianchuan basin and adjacent area have remained debated [START_REF] Burchfiel | Tectonics of the southeastern Tibetan Plateau and its adjacent foreland[END_REF]Deng et al., 2014b;[START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF][START_REF] Leloup | Structural, petrological and thermal evolution of a Tertiary ductile strike-slip shear zone, Diancang Shan[END_REF]Tang et al., 2016;[START_REF] Wang | Late Cenozoic Xianshuihe-Xiaojiang, Red River, and Dali Fault Systems of Southwestern Sichuan and Central Yunnan[END_REF]Yang et al., 2014). New mapping results on the western flank of the Jianchuan basin (Figs. 2 and4) indicate that this area is predominantly affected by NNWstriking, WSW-dipping brittle thrusts separating narrow panels of Permo-Triassic and Paleocene strata. These panels are deformed by upright and tight folds with axes subparallel to the trend of the main faults. These structures define a fold-thrust belt that lacks detailed descriptions and quantitative constraints in Yang et al. (2014) and tentatively named "Qiaohou thrust belt" in [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. In order to avoid confusion with the dextral strike-slip Qiaohou fault that is considered as a part of the active Red River fault system [START_REF] Allen | Red River and associated faults, Yunnan Province, China: Quaternary geology, slip rates, and seismic hazard[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF], we use the new term Ludian-Zhonghejiang fold-thrust belt (LZTB) instead of "Qiaohou thrust belt". The fold-thrust belt consists of two main thrusts: the Tongdian and Ludian-Zhonghejiang faults and several parallel folds (Figs. 2 and4). The following sections present the mapping results that focus on geology of the central and southern portions of the Ludian-Zhonghejiang fold-thrust belt, NE-trending faults and Qiaohou fault, as well as folded lithologic units along three main transects A-B, B'-C and E-F (Fig. 4).

Ludian-Zhonghejiang fold-thrust belt (LZTB)

The LZTB stretches over 120 km between the Xuelong Shan and Diancang Shan metamorphic gneiss belts (Fig. 1) along a zone used to be called "Madeng gap", where no high-grade metamorphic rocks are related to the ASRR [START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF]. The 7-12 km wide deformation zone involves Permo-Triassic sedimentary and volcanic rocks in the hanging wall, as well as Paleogene terrestrial sediments of the Jianchuan basin in the footwall (Fig. 4). The northern part of the fold-thrust belt is poorly defined due to heavy vegetation, but the principal fault still can be identified based on field observations of prominent topographic relief and intensively folded Eocene sediments proximal to the fault trace. In contrast, the central segment of the fold-thrust belt outcrops well and is thus the target of our detailed mapping.

Ludian-Zhonghejiang fault and Paleogene strata

The Ludian-Zhonghejiang fault brings Triassic strata on top of the Eocene Baoxiangsi Fm. (E2b; Figs. 2 and4). To the east of the fault, the Baoxiangsi Fm. (E2b) is dominated by thick-bedded red mediumgrained lithic sandstone interbedded with lenticular layers of conglomerates that are poorly-sorted, grain-supported, sub-rounded, and display scour-and-fill and cross bedding structures. This unit is interpreted as an alluvial fan fed by a braided river proximal to a local topographic gradient [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]. The Ludian-Zhonghejiang fault (LZF) is a NNW-SSE-striking and west-dipping thrust fault (Fig. 2). Folding is more intense on either side of the fault zone than it is further away, indicative of localized deformation along the contact between the Triassic and Paleogene strata. The fault has locally a complex trace (Fig. 4). At sites S277 and S219, a fault striking N92E brings the Triassic rocks on top of the Eocene red beds (Figs. 5a and5m). At site CD335/CD435, faults with various orientations bring the Triassic rocks atop the Eocene sediments (Figs. 5b,5c and 6a). The main fault contact in general trends NW-SE and dips to the SW, but is locally close to horizontal, gently dipping to the south, or even to the SE (Fig. 6a). This results in a complex shape of contact between the Triassic and Paleogene units. The primary fault appears as a low angle thrust nappe affected by latter deformation. The fault contact bears striations (Figs. 5d and5e) but with various orientations, which prevents to define a clear common direction of motion for the thrusting (Fig. 6a). The intrusive relationship of a late Eocene lamprophyre with the main thrust fault is ambiguous (Figs. 5b and5c). However, the intrusion clearly cut across the schistosity parallel to the thrust affecting the Triassic rocks (Fig. 5f), suggesting that the intrusion postdated the thrusting. This observation is also supported by the intrusion of a late Eocene syenite within the LZF at site CD321 (Fig. 4). The Eocene and Triassic sediments are folded and affected by later faults (Figs. 6a-c). Some of these faults are parallel to the main contact, but others are ~N80° to N120° trending dextral faults (Fig. 6c). As this later set of faults cartographically crosscuts the contact between the Eocene and Triassic sediments (Fig. 4), we interpret them as resulting from a SE-NW compression after the thrust motion. At site CD237, Triassic coal-bearing slates above the nearly N-Sstriking thrust are schistosed with S-C fabrics (Figs. 5g,5h and 6b), suggesting top to the NE ductilebrittle thrusting (Figs. 5i-k). In contrast, sandstone beds of stronger competence at site CD333 show less ductile-brittle fabrics but are deformed, forming meter-scale asymmetric necked boudins (Fig. 5n).

Along transect E-F between the observation sites CD237 and CD522 (Fig. 5h), the Eocene strata dip almost vertically at the vicinity of the fault, but dip gradually more gently away from the fault. The vertical clastic layers proximal to the thrust fault are dominated by a mixture of very poorly-sorted, subangular to sub-rounded pebbles and boulders of limestone, sandstone and volcanic origin (Fig. 5l), indicative of debris flow and hyper-concentrated flood flow deposits. In general, the Eocene strata east of the fault are deformed by a set of open synclines with steep axial planes striking N-S to NW-SE (Figs. 2b,6f and 6g). A section across the Paleogene sediments (mostly E1m and E2b) of the Jianchuan basin is typified by long-wavelength folds with one syncline showing a steep western limb adjacent to the thrust front (Fig. 2b). The axial traces of the folds within the E2b2 are sub-parallel to the strike of the LZF (Figs. 6f and6g). The Triassic clastic sediments (T3s) are also strongly folded with fold hinge striking NNW (Fig. 6h), parallel to the fault trace of the LZF. 3.1.2 Tongdian fault and flanking units West of the LZF, the Tongdian fault places folded late Permian clastic deposits over Triassic volcanic sequences (Fig. 4). To the west of the Tongdian fault, the rocks comprise a thick sequence of limestone interlayered with siltstone and mudstone of late Permian ages (Tang et al., 2016) that was originally considered to be Triassic in age [START_REF] Bgmry | Bureau of Geology and Mineral Resources of Yunnan Province[END_REF]. Limestone and marl are most common in the lower part of the unit that shows an overturned anticline at site CD524. In the upper part the strata contain more fine-grained clastic deposits of siltstone and mudstone. East of the Tongdian fault, the early to middle Triassic volcanic rocks (T1-2p) consist of massive rhyolitic lava, dacitic lava, rhyolitic or dacitic breccias and tuff. In the northern end of the mapped area, these rocks are intruded by small bodies of Eocene syenite with irregular intrusive margins (Fig. 4). In general, this volcanic sequence is strongly fractured by discretely-spaced small scale secondary faults and abundant cleavages that trends S115-155° and dips SW60-86°(Fig. 6d). Locally, NE-dipping tuff layers are still distinguished in the lower part of the unit (Tang et al., 2016). The suite of Triassic volcanic rocks shows a nonconformable contact with the overlying Triassic clastic deposits (T3s) to the east. The Tongdian fault is a steeply dipping fault zone that locally strikes S130-160° and dips SW46-80° at sites CD517, CD518 and CD524 (Figs. 4,5o and 5p). Striated surfaces within the fault zone show both top to the NE reverse slip and right slip (Fig. 6d) indicative of transpressional deformation. The late Permian strata are deformed by a set of open to tight, upright-plunging folds that trend NW nearly parallel to the bounding Tongdian fault (Fig. 6i), locally showing overturned limb compatible with a NE vergence (Fig. 4). At distances of <1 km from the Tongdian fault, the fold are recumbent and chevron folds less spaced than further away from the fault (Fig. 4), suggesting that the folds are genetically related to thrusting along the fault. Proximal to the Tongdian fault, the Triassic volcanic unit has well-developed cleavages (Fig. 5d) that strikes parallel to the principal fault planes, indicating localized deformation associated with the transpression. At site CD516 ~500 m to the southwest of the Tongdian fault, a steeply dipping brittle fault strikes S140-180° and dips SW60-80° (Fig. 6d). Striations and chatter marks on the fault surfaces indicate both reverse slip and right slip (Fig. 6d). These suggest this fault to be a transpressional structure, which led to folding of the late Permian strata in its hanging wall (Figs. 4 and 6i). The similarity of geometry and kinematics of this fault to the Tongdian fault suggest that this fault is likely a branch fault of the Tongdian fault.

ENE-trending dextral strike-slip faults

Apart from thrust faults, we observed a set of ENE-trending, steeply dipping, brittle faults at several localities (e.g., CD241, CD320, CD327, CD328 and CD347; Figs. 4 and6c). On the fault planes, nearly horizontal calcite growth striae together with the asymmetric calcite crystallization marks indicate a dextral sense of shear. Besides, meters-scale of right lateral separation of Eocene conglomerate beds near site CD320 attests to dextral strike slip offset on the fault. Although the relationship between these ENE-striking right lateral faults with the fold-trust belt cannot be easily examined in the field, we infer that these faults could postdate the thrust structures based on the observations that the ENE-striking dextral strike slip faults apparently cut all the rocks involved in the LZTB and especially the Eocene Baoxiangsi Fm. (e.g., at site CD320; Fig. 4). More convincing evidences for this relationship would require more work.

Qiaohou fault

The Qiaohou fault was regarded as a part of the Red River fault system [START_REF] Allen | Red River and associated faults, Yunnan Province, China: Quaternary geology, slip rates, and seismic hazard[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF]. In the mapped area, this fault zone consists of two splays, named Qiaohou fault-1 and Qiaohou fault-2 respectively (Fig. 4). The Qiaohou fault-1 separates Eocene volcanic rocks in the west from late Permian siltstone and limestone to the east, between which a prominent topographic step occurs. Field measurements show that it is a NNE-striking, steeply dipping, brittle fault at site CD502 (Figs. 4 and6e). Nearly horizontal striae and chatter marks on the fault planes indicate a sense of dextral strike slip with a minor normal component (Fig. 6e). Likewise, the Qiaohou fault-2 shares a similar geometry and kinematics with the Qiaohou fault-1. This fault splay bounds the eastern margin of the Quaternary Madeng basin and is presumably an active fault. These dextral faults are thus young structures that probably initiated in the Late Miocene or later [START_REF] Allen | Red River and associated faults, Yunnan Province, China: Quaternary geology, slip rates, and seismic hazard[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF]. To sum up, field observations provide relative timing for the Cenozoic deformation in the study area based on cutoffs between the structures and Cenozoic sediments and Eocene magmas. Accordingly, we identified four Cenozoic deformation generations. The LZTB dominated the first deformation phase with top to the NE-directed thrusting that took place prior to the Late Eocene. The exact magnitude of crustal shortening across the LZTB is difficult to restore due to the paucity of constraints on the deep structure of the thrust belt. Subsequently, the Qiaohou fault being a part of the Red River system likely commenced in the Late Miocene or later [START_REF] Allen | Red River and associated faults, Yunnan Province, China: Quaternary geology, slip rates, and seismic hazard[END_REF][START_REF] Leloup | The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina: Tectonophysics[END_REF]. The ENE-trending dextral strike-slip faults offset the fold-thrust belt, indicating that this set of faults postdated the thrusting, but their exact activity timing remains unknown. The latest deformation generation is typified by the Qiaohou fault-2, which could be an active fault controlling the Quaternary Madeng basin. Meanwhile, we do not exclude the existence of Pre-Cenozoic structures in this area, but it seems that they have been modified by Cenozoic deformation. In this paper, we thus concentrate on the geometry, kinematics, timing and implications of the first deformation generation expressed by the LZTB.

Sampling and analytical methods

In order to address the timing of deformation within the LZTB, we employed radiometric dating within the deformation zones (Fig. 2; Tables 1 andS1). On one hand, we collected 8 samples from syenitic plutons and lamprophyres intruding the fold-thrust belt for zircon U-Pb dating. These results will firmly place minimum age for the activity of the thrust belt. We also took 6 samples along a vertical profile in the Ludian pluton in the hanging wall of the LZF for multiple dating techniques, including zircon U-Pb, zircon (U-Th)/He (ZHe), apatite fission track (AFT) and apatite (U-Th)/He (AHe). The zircon U-Pb geochronology with closure temperature of 750±50 °C [START_REF] Cherniak | Pb diffusion in monazite: a combined RBS/SIMS study[END_REF] resolves the crystallization age of the igneous rocks. By contrast, the combination of lower-temperature thermochronological systems of ZHe, AFT and AHe with closure temperatures ranging from ~220 to 40 °C record the cooling path in the upper several kilometers of the crust [START_REF] Reiners | Using thermochronology to understand orogenic erosion[END_REF]. Together, these data analyzed with inverse thermal modeling, are able to constrain a complete thermal history of the rocks in the hanging wall of the LZF and further provide information on the onset, duration and rate of rock exhumation, which can be related to thrusting [START_REF] Reiners | Using thermochronology to understand orogenic erosion[END_REF][START_REF] Turab | Tectonics drives rapid exhumation of the western Himalayan syntaxis: Evidence from low-temperature thermochronometry of the Neelum valley region[END_REF]. Apatite and zircon aliquots were extracted from samples using standard crushing, magnetic and heavy-liquid separation techniques. Detailed analytical procedures for zircon U-Pb geochronology, apatite fission track and zircon and apatite (U-Th)/He are described in the supplementary material S1.

Results and interpretation

The analytical datasets are presented in Fig. 2 and Table 1, as well as supplementary material S1 and Tables S1-S6.

Zircon U-Pb geochronology

The majority of dated zircon grains from Mesozoic igneous rocks with oscillatory zoning have low U/Th ratios of <10 (Table S2), indicative of igneous origin. Two samples CD144 and CD149 were collected from the Ludian granite in the hanging wall of the northern segment of the Ludian-Zhonghejiang fault (Fig. 2a). Most zircon grains yield concordant ages clustering at 208-252 Ma (Tables 1 andS2; Fig. S1a). Fifteen and nineteen age points from samples CD144 and CD149 give weighted mean U-Pb ages of 227.7±4.6 Ma and 234.5±4.7 Ma respectively (Figs. S1a andS1b). These two ages thus represent the crystallization age of the Ludian granite. The sample CD327 is a dacite collected in the Pangtiange Fm. (T1-2p). Several ages are pre-Cenozoic, but the lower intercept defined by the linear regression of 10 ages clusters at two group ages at ~270 Ma and ~235 Ma (Tables 1 andS2; Figs. S1c andS1d). Seven out of ten zircon grains yield a younger weighted mean U-Pb age of 234.4±8.5 Ma, overlapping with published zircon U-Pb ages spanning from ~237 to 250 Ma in the same volcanic unit (Yang et al., 2014; Table S3). Six samples CD316, CD323, CD325, CD330, CD331, CD335/CD435 were collected from some small porphyry dykes intruding in the LZTB in the northern end of the mapped area (Figs. 2 and4). Of them, samples CD316, CD323 and CD331 have a few Cenozoic ages that are sub-concordant at ~34-36 Ma (Tables 1 andS4; Figs. S1e-j). Ten, five and six ages yield weighted mean U-Pb ages of 34.5±1.3 Ma, 34.3±1.6 Ma and 35.3±1.7 Ma for samples CD316, CD323 and CD331 respectively (Fig. S1; Tables 1 andS2). Samples CD335 and CD435 were taken from the same lamprophyre at site CD335, so we combined their zircon U-Pb data sets together. Most zircons from these two samples present large range of pre-Cenozoic ages spanning from 251 Ma to 2273 Ma. Six zircon grains yield a weighted mean U-Pb age of 35.1±0.5 Ma (Figs. S1k andS1l). The other two samples CD325 and CD330 yield much more inherited pre-Cenozoic ages (Figs. S1m-p). Only one grain per sample yield Eocene ages that may represent the intrusion age, but the points fall off the concordant curves and thus do not provide a robust age constraint. Overall, the late Eocene ages recorded by these samples generally overlap with previous zircon U-Pb data for the porphyry, granite and syenite plutons and dykes as well as volcanic clasts in and around the Jianchuan basin (Fig. 3 and Table S4), indicating a major flare-up event occurred from ~35.7 to 34.5 Ma [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF].

Low-temperature thermochronology

Single-grain ZHe ages obtained from the samples CD144, CD145 and CD148 consistently cluster within ~100-140 Ma (Tables 1 andS5; Fig. 7a), significantly younger than the Triassic emplacement age of the Ludian granite. These ages thus reflect later cooling or exhumation event. Single-grain ZHe ages of samples CD145 and CD148 show reverse relationships with the effective uranium concentrations ([eU]=[U]+0.235*[Th]; [START_REF] Guenthner | Helium diffusion in natural zircon: Radiation damage, anisotropy, and the interpretation of zircon (U-Th)/He thermochronology[END_REF]Fig.7a), indicating that radiation damage affected the zircon grains [START_REF] Guenthner | Helium diffusion in natural zircon: Radiation damage, anisotropy, and the interpretation of zircon (U-Th)/He thermochronology[END_REF]. Four single-grain AHe ages from the low-elevation sample CD145 range from 29.4 Ma to 43.6 Ma (Fig. 7b). Five single-grain ages from the high-elevation sample CD148 span from 36.0 Ma to 49.6 Ma. In general, neither positive nor negative relationships between the AHe ages and eU appear in Fig. 7b. The single-grain AHe ages of the sample CD148 overlaps with the AFT ages of CD148 and CD149 within errors at comparable elevations, but much younger than the corresponding ZHe ages, indicating self-consistency of the multiple thermochronology data. Two replicates from samples CD145 and CD148 yield very young ZHe ages probably because of grain loss during the preparation process. These two data were not used for inverse modeling and interpretation. The Eocene cooling ages broadly overlap with AHe ages from the northern part of the Ludian pluton [START_REF] Liu-Zeng | Multiple episodes of fast exhumation since Cretaceous in southeast Tibet, revealed by low-temperature thermochronology[END_REF]. Five samples CD144, CD146, CD147, CD148 and CD149 from an elevation profile along the Ludian granite with sufficiently countable grains and kinetic parameters yield a cluster of Eocene AFT ages ranging from 35.8 Ma to 45.3 Ma (Tables 1 andS6). All ages passed the P(χ 2 ) test with very low dispersion values, indicative of single age populations [START_REF] Galbraith | Estimating the component ages in a finite mixture: International Journal of Radiation Applications and Instrumentation[END_REF]. The mean track lengths span from 13.35 to 14.01 µm (Table S6). AFT age plot against elevation show a general positive correlation (Fig. 7c).

Thermal modeling

The cooling histories of the Ludian granite were further derived by using the Bayesian transdimensional Markov chain Monte Carlo protocol [START_REF] Gallagher | Transdimensional inverse thermal history modeling for quantitative thermochronology[END_REF]. The inverse scheme of this program is preferably designed to reconstruct thermal history from a thermochronological age-elevation profile. The model was set up taking into account all AFT ages, track length distribution and kinetic parameters, as well as acceptable single ZHe and AHe ages, apatite and zircon crystal dimensions and U, Th and Sm concentrations from samples CD144, CD145 and CD148. Fission track annealing and He diffusion algorithms used for ZHe, AFT and AHe modelling refer to [START_REF] Guenthner | Helium diffusion in natural zircon: Radiation damage, anisotropy, and the interpretation of zircon (U-Th)/He thermochronology[END_REF], [START_REF] Ketcham | Improved modeling of fission-track annealing in apatite[END_REF] and [START_REF] Gautheron | Effect of alpha-damage annealing on apatite (U-Th)/He thermochronology[END_REF], respectively. In order to make the modeling informative and convincing, two independent geological boundary conditions were given: 1) samples collected from the Ludian granite are at the surface, and thus between 0 and 10 °C at present day; 2) a loosely constrained condition of a temperature of 300±50 °C at 110±20 Ma was given as a start. This constraint box forces the model to pass through the ZHe partial retention zone during the late Cretaceous based on reported Late Cretaceous rapid cooling event of the same batholith near Weixi ~100 km northwest of our samples [START_REF] Liu-Zeng | Multiple episodes of fast exhumation since Cretaceous in southeast Tibet, revealed by low-temperature thermochronology[END_REF]. We used the default values of 30 °C/km for the paleo and present geothermal gradients and allow the temperature offset to vary over time. Each 1,000,000 iterations were performed as burn-in and post-burn-in iterations. The optimized temperature-time curves present a four-episode cooling history (Fig. 7d). The first cooling stage at~125-110 Ma reflects a rapid exhumation process for the pluton passing through the ZHe partial retention zone (PRZ). The following cooling episode between 110-50 Ma shows the rock resided on the upper boundary of the ZHe PRZ for ~60 Ma. Notably, the subsequent accelerated cooling between ~50 and 39 Ma at a rate of ~9 °C Ma -1 (Fig. 7d) is interpreted as exhumation related to thrusting along the LZTB. Based on the modelled cooling histories, the temperature difference of the highest and lowest samples ranges from ~6 to ~12 °C (Fig. 7d). An elevation difference of ~400 m between these two samples thus infers geothermal gradients between ~15-30 °C km -1 . The cooling rate of the Ludian pluton between ~50-39 Ma translates to an apparent exhumation rate of ~0.3-0.6 mm a -1 . The relatively rapid exhumation ended at ~39 Ma and was followed by a protracted period of extremely slow cooling at a rate of <1.75 °C Ma -1 (Fig. 7d) indicative of the cessation of the deformation in the LZTB.

Discussion

Temporal and spatial constraints on the Ludian-Zhonghejiang fold-thrust belt

Geological crosscutting relationships provide relative chronology for the activity of the LZTB. For example, the intrusion of porphyry dykes of 35-36 Ma within the LZTB (Figs. 4, 5b and 5c) indicates that the LZTB was active prior to ~36 Ma. Likewise, the occurrence of syn-tectonic sediments of Baoxiangsi Fm. (E2b) (see below) older than the Shuanghe Fm. dated at ~35.9±0.9 Ma [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF] suggest that the deformation within the fold-thrust belt occurred no later than 36 Ma. Independently, rapid cooling of the Ludian pluton in the hanging wall of the LZF derived from thermochronology and inverse models are compatible with thrusting activity of the LZTB during 50-39 Ma. The existence of syn-tectonic sediments of the Baoxiangsi Fm. (E2b) in the footwall of the thrust belt rules out regional uplift at that time span (See the detailed discussion in the next section), and thus implies NE-oriented crustal shortening initiated at 50 Ma and continued until 39 Ma on the western margin of the South China block. This robust temporal constraint is consistent with geological crosscutting observations. Since 39 Ma, the quiescence of the LZTB is supported by the deposition of sediments in low-lying and flat alluvial to palustrine and fluvial systems of the Jiuziyan and Shuanghe Fms. (Figs. 2 and 3;[START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF][START_REF] Sorrel | Wet tropical climate in SE Tibet during the Late Eocene[END_REF] in the eastern part of the Jianchuan basin. In space, this fold-thrust system may extend to the northwest near Weixi county, where the onset of rapid exhumation during 60-40 Ma was interpreted as relating to the reactivation of local structures [START_REF] Liu-Zeng | Multiple episodes of fast exhumation since Cretaceous in southeast Tibet, revealed by low-temperature thermochronology[END_REF]. Further investigations on the fault extent and correlation are still needed.

Syn-tectonic deposition in the Jianchuan basin

The Jianchuan basin, filled by kilometers-thick Paleogene terrestrial sediments, has attracted much attention in order to understand the tectonic, paleoenvironmental and topographic evolution of southeast Tibet. Despite its importance, how the basin did form remains unclear. Two sets of models have been proposed to explain the basin formation and evolution. In the first set of models, the alluvial-fan and braided-stream clasts of the Baoxiangsi Fm. were interpreted as deposits coeval with the ultrapotassic magmatism from 40 to 27 Ma in a rift setting [START_REF] Wei | No sedimentary records indicating southerly flow of the paleo-Upper Yangtze River from the First Bend in southeastern Tibet[END_REF], which was induced by intraplate extension related to the delamination of a thickened lithosphere [START_REF] Chung | Intraplate extension prior to continental extrusion along the Ailao Shan-Red River shear zone[END_REF]. However, field evidences show that the deposition of the Shuanghe and Jianchuan Fms. (E2s and E2jc), rather than the Baoxiangsi Fm. (E2b), was coeval with the magmatic episode that was restricted to a very short time between 35 and 36 Ma (Table S4; [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF]this study). Therefore, the argument for the deposition of the Baoxiangsi Fm. in a rift basin is not supported by the new stratigraphy of the Jianchuan basin. Furthermore, no normal fault of that age has been described up to now, neither within nor close to the Jianchuan basin. In the second model, Paleogene sedimentation in the Jianchuan basin was proposed to be simultaneous with basement uplift and thrusting in a regional NE-SW compression based on the existence of possible syn-depositional structures (e.g., mudstone dykes in the major thrust fault plane and diapirs in the fracture of hanging wall) in the thrust (Yang et al., 2014). This hypothesis seems partly consistent with local structural observations but lends no support from our observations on the architecture of the LZTB and the syn-depositional structures of the Jianchuan basin. Our results suggest that deposition of the Baoxiangsi Fm. (E2b) in the Jianchuan basin is syn-tectonic and closely related to the development of the LZTB during crustal shortening (Fig. 8) based on several lines of evidence. Field observations show that the sediments in the Baoxiangsi Fm. (E2b) were predominately sourced from the hanging wall of the LZF. At the bottom of the Baoxiangsi Fm. (E2b1), an abrupt appearance of massive basal conglomerates and up-section sandstones bearing cross bedding marks a significant change of sedimentary facies from flood plain (i.e., the Mengyejing Fm. (E1m)) to alluvial fan and braided river (Fig. 3). This indicates prominent topographic relief generation triggered by the contractional deformation within the LZTB, which supplied large amounts of terrestrial clasts to the adjacent Jianchuan basin (Fig. 8). This inference is also corroborated by predominantly eastward and northeastward paleocurrents restored by measurements of pebble imbrications and cross beddings in the Baoxiangsi Fm. [START_REF] Wei | No sedimentary records indicating southerly flow of the paleo-Upper Yangtze River from the First Bend in southeastern Tibet[END_REF][START_REF] Wissink | Temporal and spatial patterns of sediment routing across the southeast margin of the Tibetan Plateau: Insights from detrital zircon: Tectonics[END_REF] this study; Fig. 2). Apart from these, a combination of poorly-sorted, sub-angular to sub-rounded pebbles and boulders in the basal conglomerates are composed of limestone, sandstone and volcanic rocks (Fig. 5l), which were apparently derived from proximal Permo-Triassic lithologic units in the hanging wall of the LZF. We thus propose that sedimentation of the Baoxiangsi Fm. (E2b) commenced since ~50 Ma and lasted until ~39 Ma, coevally with the duration of the crustal shortening in the LZTB. This timing is broadly in agreement with estimated Eocene age from fossil assemblages for the Baoxiangsi Fm. [START_REF] Bgmry | Bureau of Geology and Mineral Resources of Yunnan Province[END_REF], overlain by deposition of the Jiuziyan Fm. (E2jz), Shuanghe Fm. (E2s) and Jianchuan Fm. (E2jc) during the Late Eocene [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF][START_REF] Sorrel | Wet tropical climate in SE Tibet during the Late Eocene[END_REF][START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. Sedimentation during the Jiuziyan and Shuanghe Fms. (E2jz and E2s) likely took place in distal alluvial fan-deltas and sublacustrine (alluvial-lake) environments characteristics of low-lying depositional systems [START_REF] Sorrel | Wet tropical climate in SE Tibet during the Late Eocene[END_REF], which is congruent with the cessation of the fold-thrust belt and final infill of the Late Eocene intermontane Jianchuan basin.

Cretaceous-Early Cenozoic crustal deformation and uplift of the southeast Tibet and implications for the lithospheric rheology of the Tibet

Rapid Cretaceous cooling events have been revealed by thermochronometres in the east and southeast Tibet (Tian et al., 2014;[START_REF] Liu-Zeng | Multiple episodes of fast exhumation since Cretaceous in southeast Tibet, revealed by low-temperature thermochronology[END_REF]. They most likely corresponded to crustal thickening as a result of the collision between the Lhasa and Qiangtang terranes implied from the geological records of central Tibet [START_REF] Kapp | Cretaceous-Tertiary shortening, basin development, and volcanism in central Tibet[END_REF][START_REF] Kapp | Geological records of the Lhasa-Qiangtang and Indo-Asian collisions in the Nima area of central Tibet[END_REF]. We follow this hypothesis to interpret rapid Cretaceous exhumation in the Jianchuan area recorded by our thermochronological data. However, the detailed geological processes in southeast Tibet during Lhasa-Qiangtang collisional orogenesis would need much more work. We focus here on Early Cenozoic deformation as discussed below. A growing number of structural and paleomagnetic investigations suggest that southeast Tibet has been dominated by extrusion tectonics since the Late Eocene, which was predominantly accommodated by major strike slip faults along the block boundaries [START_REF] Tapponnier | Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine[END_REF][START_REF] Bgmry | Bureau of Geology and Mineral Resources of Yunnan Province[END_REF][START_REF] Cao | Initiation of leftlateral deformation along the Ailao Shan-Red River shear zone: new microstructural, textural, and geochronological constraints from the Diancang Shan metamorphic massif[END_REF][START_REF] Leloup | Structural, petrological and thermal evolution of a Tertiary ductile strike-slip shear zone, Diancang Shan[END_REF][START_REF] Leloup | New constraints on the structure, thermochronology, and timing of the Ailao Shan-Red River shear zone[END_REF][START_REF] Lin | 40 Ar/ 39 Ar dating of the Jiali and Gaoligong shear zones: Implications for crustal deformation around the Eastern Himalayan Syntaxis[END_REF][START_REF] Tong | New insights into the Cenozoic lateral extrusion of crustal blocks on the southeastern edge of Tibetan Plateau: Evidence from paleomagnetic results from Paleogene sedimentary strata of the Baoshan Terrane[END_REF][START_REF] Zhang | Structural feature and its significance of the northernmost segment of the Tertiary Biluoxueshan-Chongshan shear zone, east of the Eastern Himalayan Syntaxis[END_REF][START_REF] Zhang | The Xuelongshan high strain zone: Cenozoic structural evolution and implications for fault linkages and deformation along the Ailao Shan-Red River shear zone[END_REF], though some others argued for a geodynamic model of lower crustal flow for Late Cenozoic surface uplift [START_REF] Clark | Late Cenozoic uplift of southeastern Tibet[END_REF][START_REF] Ouimet | Regional incision of the eastern margin of the Tibetan Plateau[END_REF][START_REF] Royden | Surface deformation and lower crustal flow in eastern Tibet[END_REF]Royden et al., , 2008;;[START_REF] Schoenbohm | Propagation of surface uplift, lower crustal flow, and Cenozoic tectonics of the southeast margin of the Tibetan Plateau[END_REF][START_REF] Wang | Late Cenozoic tectonic evolution of the Ailao Shan-Red River fault (SE Tibet): Implications for kinematic change during plateau growth[END_REF]. Nevertheless, how regional crustal deformation in the Early Cenozoic was partitioned remains poorly understood. Our results indicate that the western margin of the South China block was affected by NEdirected compression since ~50 Ma nearly synchronous with the onset of the India-Asian collision, which is expressed by compressive deformation in the LZTB and simultaneous sediment deposition in the adjacent Jianchuan basin. The Permo-Triassic rocks were intensely deformed within the LZTB in a pattern of tight and recumbent fold assemblages in a short wavelength and high amplitude between major thrust faults (Fig. 2b). In contrast, the Eocene sediments in the Jianchuan basin show typical broad, long-wavelength folds in the footwall of the LZF (Fig. 2b). The discrepancy of deformation intensity between the basin and fold-thrust belt raise two questions of 1) whether southeast Tibet attained its present-day height due to crustal shortening in the Eocene, and 2) how the strain propagated to accommodate the India-Asian convergence. The Eocene paleoaltimetry of southeast Tibet, taking the Jianchuan basin in northwest Yunnan as an example, remains controversial. Previous studies argued that the Jianchuan basin has uplifted to an elevation of ~3.3±0.5 km asl. (Hoke et al., 2014) or ~2.6 km asl. [START_REF] Li | Cenozoic paleoaltimetry of the SE margin of the Tibetan Plateau: Constraints on the tectonic evolution of the region[END_REF] in the Eocene close to a modern surface height, which was interpreted as resulting from crustal shortening in response to the India-Asian collision [START_REF] Li | Cenozoic paleoaltimetry of the SE margin of the Tibetan Plateau: Constraints on the tectonic evolution of the region[END_REF]. However, recent work based on stable isotopes and fossil pollen coexistence instead argue for a lower elevation for the Eocene basin ranging from ~1.2±1.2 km asl. [START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF] to 0.9-2.9±0.6 km asl. [START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. Our structural data suggest limited uplift of the Jianchuan basin in the Eocene as follows. The long wavelength of the folds affecting the Paleogene sediments (i.e., E1m and E2b) imply a small crustal shortening (less than 5 km estimated from cross section in Fig. 2b) in the Jianchuan basin during the activity of the LZTB between ~50 Ma and 39 Ma. In addition, Late Eocene rocks (i.e., E2jz, E2s and E2jc) restricted in the southeastern corner of the Jianchuan basin, are generally flat-lying and partly involved in a broad fold with a NE-trending axis parallel to the striking of the Yulong thrust belt (Fig. 1), which was likely related to the NW-directed compression in a later stage during the basin exhumation at~28-20 Ma [START_REF] Cao | Oligocene-Early Miocene topographic relief generation of southeastern Tibet triggered by thrusting[END_REF]. Therefore, our results indicate a prominent topographic gradient in the hanging wall of the LZF that supplied clasts to the nearby lowland-Jianchuan basin, and thus support a relatively lower surface elevation for the Jianchuan basin in the Late Eocene. Independently, an altitude of 0.5-2.9±0.6 km asl. is suggested for the basin by new stable isotope results integrated with fossil pollen coexistence [START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. The topographic relief generated by intense crustal shortening within the LZTB created a local vertical vegetation variation (Fig. 8), consistent with the wide range of pollen assemblage and major flood events documented in the Late Eocene sediments of the basin [START_REF] Sorrel | Wet tropical climate in SE Tibet during the Late Eocene[END_REF][START_REF] Wu | Paleoelevations in the Jianchuan Basin of the southeastern Tibetan Plateau based on stable isotope and pollen grain analyses[END_REF]. The collision between Indian and Asian plates since ~60-50 Ma (Allègre et al., 1984;[START_REF] Ding | The India-Asia collision in north Pakistan: Insight from the U-Pb detrital zircon provenance of Cenozoic foreland basin[END_REF][START_REF] Hu | The timing of India-Asia collision onset -Facts, theories, controversies[END_REF][START_REF] Najman | Timing of India-Asia collision: Geological, biostratigraphic, and palaeomagnetic constraints[END_REF][START_REF] Rowley | Age of initiation of collision between India and Asia: A review of stratigraphic data[END_REF] has induced widespread deformation across the Tibetan Plateau, but the details of strain propagation remains debated. Apart from the Himalayan foldthrust belt bounding the collision belt [START_REF] Guillot | Reconstructing the total shortening history of the NW Himalaya[END_REF][START_REF] Decelles | Paleocene-Eocene foreland basin evolution in the Himalaya of southern Tibet and Nepal: Implications for the age of initial India-Asia collision[END_REF], a growing body of studies documented extensive upper crustal shortening and development of syn-contractional basins within the Qiangtang terrane coevally with or shortly after the onset of the India-Asian collision (Fig. 9). For example, geological mapping integrated with balanced cross section and radiometric dating revealed upper crustal shortening of 34±12 km and ~61 km in the Hoh Xil basin and Yushu-Nangqian basin since ~48-52 Ma and ~51 Ma [START_REF] Horton | Paleocene-Eocene syncontractional sedimentation in narrow, lacustrine-dominated basins of east-central Tibet[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF][START_REF] Wang | Constraints on the early uplift history of the Tibetan Plateau[END_REF][START_REF] Staisch | Eocene to late Oligocene history of crustal shortening within the Hoh Xil Basin and implications for the uplift history of the northern Tibetan Plateau[END_REF], respectively. This is also the case for the crustal shortening deformation in the Gonjo basin and LZTB in east and southeast Tibet [START_REF] Studnicki-Gizbert | Early Tertiary Gonjo basin, eastern Tibet: Sedimentary and structural record of the early history of India-Asia collision[END_REF][START_REF] Tong | Paleomagnetism of Eocene red-beds in the eastern part of the Qiangtang Terrane and its implications for uplift and southward crustal extrusion in the southeastern edge of the Tibetan Plateau[END_REF][START_REF] Yin | Geologic Evolution of the Himalayan-Tibetan Orogen[END_REF][START_REF] Gourbet | Reappraisal of the Jianchuan Cenozoic basin stratigraphy and its implications on the SE Tibetan plateau evolution[END_REF] this study; Fig. 9). In contrast, limited post-50 Ma shortening have been documented in the interiors of the Lhasa, Songpan-Garze and Kunlun terranes [START_REF] Kapp | Cretaceous-Tertiary shortening, basin development, and volcanism in central Tibet[END_REF][START_REF] Kapp | Geological records of the Lhasa-Qiangtang and Indo-Asian collisions in the Nima area of central Tibet[END_REF][START_REF] Van Hinsbergen | Restoration of Cenozoic deformation in Asia and the size of Greater India: Tectonics[END_REF]. Such an intervening deformation pattern implies that the whole Plateau has not been homogenously shortened and thickened in the early stage of the collision as often assumed [START_REF] Dewey | Tibetan, Variscan, and Precambrian basement reactivation: products of continental collision[END_REF][START_REF] England | Finite strain calculations of continental deformation 2. Comparison with the India-Asia collision zone[END_REF]. The deformation pattern approximately fit with the proposition of an Eocene Tibet corresponding to the Qiangtang terrane [START_REF] Tapponnier | Oblique stepwise rise and growth of the Tibet Plateau[END_REF]. However, other compressional structures, including the Main Pamir thrust-West Kunlun thrust belt [START_REF] Cao | Cenozoic thermo-tectonic evolution of the northeastern Pamir revealed by zircon and apatite fission-track thermochronology[END_REF][START_REF] Cao | Exhumation history of the West Kunlun Mountains, northwestern Tibet: Evidence for a long-lived, rejuvenated orogen[END_REF][START_REF] Yin | Tectonic history of the Altyn Tagh fault system in northern Tibet inferred from Cenozoic sedimentation[END_REF], the Lungmuco fault [START_REF] Leloup | Successive deformation episodes along the Lungmu Co zone west-central Tibet[END_REF], Altyn Tagh fault and Qaidam thrust [START_REF] Yin | Tectonic history of the Altyn Tagh fault system in northern Tibet inferred from Cenozoic sedimentation[END_REF], Northern Qaidam thrust belt [START_REF] Yin | Cenozoic tectonic evolution of Qaidam basin and its surrounding regions (Part 1): The southern Qilian Shan-Nan Shan thrust belt and northern Qaidam basin[END_REF] and West Qinling thrust [START_REF] Clark | Early Cenozoic faulting of the northern Tibetan Plateau margin from apatite (U-Th)/He ages[END_REF][START_REF] Duvall | Direct dating of Eocene reverse faulting in northeastern Tibet using Ar-dating of fault clays and low-temperature thermochronometry[END_REF], located far away (> 400 to 1400 km) from the plate boundary appear active soon after the collision (Fig. 9). This implies that the compressive stresses as a result of the India-Asian collision have been transmitted efficiently across the whole plateau indicating a rigid-plastic rheology, such that an early Cenozoic stage of deformation along the northern boundary of the plateau preceded the migration to the north of the main deformation events in a stepwise manner [START_REF] Tapponnier | Oblique stepwise rise and growth of the Tibet Plateau[END_REF]. We thus suggest that the deformation pattern is more complex than simple propagation from central to northern Tibet through time as proposed by [START_REF] Tapponnier | Oblique stepwise rise and growth of the Tibet Plateau[END_REF]. Accordingly, a synthesis of middle Eocene tectonic scenario throughout the India-Asian collision zone illustrates that contraction concentrated in the Qiangtang terrane, which intervened the less deformed Lhasa, Songpan-Garze and Kunlun terranes (Fig. 9). The Eocene contractional structures that localized in the Qiangtang terrane were probably inherited from preexisting structures formed during mid-Cretaceous crustal shortening related to the Lhasa-Qiangtang collision [START_REF] Kapp | Cretaceous-Tertiary shortening, basin development, and volcanism in central Tibet[END_REF][START_REF] Kapp | Geological records of the Lhasa-Qiangtang and Indo-Asian collisions in the Nima area of central Tibet[END_REF], while deformation in the Songpan-Garze and Kunlun terranes was older. The spaced deformation pattern of crustal shortening may be explained by the difference of deeper crustal strength as the deep crust of the Qiangtang terrane is composed of large volume of mélange and flysch that are relatively weaker than the Lhasa, Songpan-Garze and Kunlun terranes [START_REF] Kapp | Cretaceous-Tertiary shortening, basin development, and volcanism in central Tibet[END_REF].

Conclusions

An integration of geological mapping and geochronological and thermochronological dating illustrate Early Cenozoic configuration of tectonic deformation, rock exhumation and basin development on the western margin of the South China block (western Yunnan) during the early stage of the India-Asian collision. The Early Cenozoic deformation is expressed by the LZTB, which is a contractional structure which presently outcrop for ~120 km between the Diancang Shan and Xuelong Shan metamorphic belt in western Yunnan. This deformation belt mainly consists of two major SW-dipping brittle thrust faults, named the Ludian-Zhonghejiang fault (LZF) and the Tongdian fault from east to west. Between them, Permo-Triassic strata are involved in a set of short-wavelength, nearly vertical and southwest-vergent tight folds with axes that trend subparallel to the traces of the principal faults. The Paleocene sediments in the Jianchuan basin were deformed by a long-wavelength, vertical broad syncline. Inverse modeling with multiple low temperature thermochronological data, including ZHe, AHe and AFT, from a Triassic pluton in the hanging wall of the LZF reveals two episodes of accelerated cooling during 125-110 Ma and 50-39 Ma. The Cretaceous cooling event was probably ascribed to crustal thickening during the Lhasa and Qiangtang collision. The Eocene rapid exhumation is interpreted to date the activity of the Ludian-Zhonghejiang fold-thrust system. This timing is corroborated by the intrusive relationship between Eocene magmas of ~35-36 Ma and the fold-thrust belt. The Eocene contraction seemingly controlled deposition of alluvial-fan and braided-river sediments of the Baoxiangsi Fm. in the Jianchuan basin, which is supported by paleoflows and provenance analysis. The contractional deformation likely ended at ~39 Ma reflected by significantly decreasing cooling rates in the thermal history and the occurrence of low-lying palustrine and alluvial-lake depositional systems in the basin since then. At the plateau scale, our results along with geological records of contraction in central, northern and eastern Tibet document Eocene upper crustal shortening localized in the Himalaya, Qiangtang terrane and northern plateau margins (intervened by Lhasa, Songpan-Garze and Kunlun terranes) together with contractional basin development coevally with, or shortly after, the onset of the India-Asian collision, which is inconsistent with a homogenous crustal thickening [START_REF] Dewey | Tibetan, Variscan, and Precambrian basement reactivation: products of continental collision[END_REF][START_REF] England | Finite strain calculations of continental deformation 2. Comparison with the India-Asia collision zone[END_REF]. Moderate crustal shortening affected a large part of Tibet in a spaced way soon after the collision, prior to the main crustal thickening propagated progressively from south to north [START_REF] Tapponnier | Oblique stepwise rise and growth of the Tibet Plateau[END_REF]. This spaced deformation pattern of crustal shortening illustrates the strain of the India-Asian collision and convergence propagated from the plate boundary within the Asian continent during the Early Cenozoic in a more complex way than what were assumed in the existing geodynamic models. S1b. FFTB at ~52-48 Ma [START_REF] Wang | Constraints on the early uplift history of the Tibetan Plateau[END_REF][START_REF] Staisch | Eocene to late Oligocene history of crustal shortening within the Hoh Xil Basin and implications for the uplift history of the northern Tibetan Plateau[END_REF]; GJT at ~54 Ma (Zhang et al., 2018); Himalayan fold-thrust belt at ~50-45 Ma [START_REF] Guillot | Reconstructing the total shortening history of the NW Himalaya[END_REF][START_REF] Decelles | Paleocene-Eocene foreland basin evolution in the Himalaya of southern Tibet and Nepal: Implications for the age of initial India-Asia collision[END_REF]; LMC at 60-55 Ma (Leloup et al., 2011); LZTB at 50-39 Ma (this study); MPT-WKTB at ~50 Ma [START_REF] Cao | Cenozoic thermo-tectonic evolution of the northeastern Pamir revealed by zircon and apatite fission-track thermochronology[END_REF][START_REF] Cao | Exhumation history of the West Kunlun Mountains, northwestern Tibet: Evidence for a long-lived, rejuvenated orogen[END_REF][START_REF] Yin | Tectonic history of the Altyn Tagh fault system in northern Tibet inferred from Cenozoic sedimentation[END_REF]; QNTB at 65-50 Ma [START_REF] Yin | Cenozoic tectonic evolution of Qaidam basin and its surrounding regions (Part 1): The southern Qilian Shan-Nan Shan thrust belt and northern Qaidam basin[END_REF]; QT and ATF at ~49 Ma [START_REF] Yin | Tectonic history of the Altyn Tagh fault system in northern Tibet inferred from Cenozoic sedimentation[END_REF]; SGAT at <42.5 Ma [START_REF] Yin | Geologic Evolution of the Himalayan-Tibetan Orogen[END_REF]; WQLT at ~50 Ma [START_REF] Clark | Early Cenozoic faulting of the northern Tibetan Plateau margin from apatite (U-Th)/He ages[END_REF][START_REF] Duvall | Direct dating of Eocene reverse faulting in northeastern Tibet using Ar-dating of fault clays and low-temperature thermochronometry[END_REF], YNTB at ~51 Ma [START_REF] Horton | Paleocene-Eocene syncontractional sedimentation in narrow, lacustrine-dominated basins of east-central Tibet[END_REF][START_REF] Spurlin | Structural evolution of the Yushu-Nangqian region and its relationship to syncollisional igneous activity, east-central Tibet[END_REF]. Fig. S1 Concordia diagrams and weighted mean ages of zircon U-Pb samples. The ages that were not used for final age calculation were marked by dashed ellipses on concordia diagram. Note: Ages were accepted with up to 10% and 20% discordance for plutonic and volcanic samples, respectively. All errors are at the 1-sigma level.

Tables

1102

Table S3 Zircon U-Pb geochronologic ages for Mesozoic magmatic rocks exposed within the LZTB, SE Tibet.

Figures Fig. 1

 1 Figures

  Fig.1 (a) Simplified geological map of the southeast Tibet, showing major Cenozoic structures and basins, modified from Gourbet et al. (2017). Black arrows indicate Oligo-Miocene motion of the ASRR while red arrows indicate Plio-Quaternary motion of the Red River fault. (b) The inset shows location within Tibet. Abbreviations: ATF-Altyn Tagh fault, ASRR-Ailao Shan-Red River shear zone, BNS-Bangong-Nujiang suture, MBT-Main boundary thrust, JS-Jinsha suture, KLF-Kunlun fault, KF-Karakorum fault, RRF-Red River fault, XSF-Xianshuihe fault, IYS-Indus-Yarlung suture.

Fig. 4

 4 Fig.4 Geological map in the central segment of the LZTB, focusing on the major structures and lithological units to the west of the Jianchuan basin. Mapping based on BGMRY (1990) and this study. The structural measurements for southern section of the mapping area are partly from Tang et al. (2016). Observation sites are shown with corresponding structural observation and samples ages (Table S1). See location on Fig 2a. The lower panel is a composite cross section across the LZTB, composed of A-B, B'-C and E-F segments located on the above panel.

Fig. 5

 5 Fig.5 Photos showing the main structures of the LZTB. (a) Triassic slate thrusted above Eocene sediments at site S277. (b-f) field observations at site CD335/CD435: (b) field photo and (c) corresponding sketch interpretation, showing schistosed Triassic meta-sandstone and coal-bearing slate (T3s) resting above folded Eocene sandstones and conglomerates (E2b1/ E2b2). Black arrows indicate the direction of motion given by the striae (d-e) gently dipping fault within the Triassic metasandstone and slate (T3s) with striae indicative of thrust motion towards the northwest to northeast (see Fig. 6b). (f) a ~35 Ma lamprophyre dyke crosscutting schistosed Triassic slate (T3s) suggestive of initial thrusting prior to ~35 Ma. (g-l) field observations at sites CD237 and CD522 (cross section E-F on Fig. 4). (g) LZF placing Triassic coal-bearing slates (T3s) on top of Eocene sandstone (E2b1) at site CD237. (h) a cross section E-F between CD237 and CD522 showing the LZF placing Triassic strata (T3s) over the Baoxiangsi Fm. (E2b). (i) gently dipping striae and slickensides and (j-k) sigmoid breccia lenses and S-C fabrics in highly schistosed Triassic slate (T3s) indicating top to the NE low-angle thrusting. (l) syntectonic conglomerates in the footwall of the LZF near site CD237 with abundant cobbles and boulders of volcanic, sandstone and limestone sourced from the hanging wall of the LZF. (m) Triassic clastic sediments (T3s) thrusted above Eocene sediments (E2b2) at site S219. (n) sandstone boudins within the LZF at site CD333. (o) striae and slickensides and (p) fault gouge in the Tongdian fault suggesting thrusting at sites CD517 and CD524. (q) asymmetrical ripples in the Late Permian sandstone near site CD506 indicative of overturned bedding dipping to the SW. All sites are shown in Fig. 4 and TableS1b.

Fig. 6

 6 Fig.6 Geometry of faults and folds in the LZTB and western Jianchuan basin. Stereographic projection, lower hemisphere atop the equal area net. (a-b) fault splays within the LZF at outcrops (a) CD335/CD435 and (b) CD237, (c) ENE-striking dextral strike-slip faults at outcrops CD241, CD320, CD327, CD328 and CD347, (d) fault splays (solid curves) within the Tongdian fault (TDF) at outcrops CD516, CD517, CD518 and CD524 and cleavages (dash curves) in the Triassic volcanic rocks close to the TDF at site CD517, (e) fault splays within the Qiaohou fault (QHF) at outcrops CD500 and CD502. Arrows indicate fault kinematics (motion of the upper block). (f-i) stratification (great circles) and poles to stratification (dots). (f) and (g) Eocene sediments (E2b) in the syncline proximal to the LZF, to the NW and to the SE respectively. (h) and (i) within the fold-thrust belt west of the LZF: Triassic metasediments (T3s) and Late Permian sediments (P3s) respectively. The axis and hinge orientations of the folds are calculated based on representative strike-and-dip measurements of the limbs of the folded bedding surface. The blue lines are the planes passing by the stratification poles. The red lines are the axial planes with fold axis plotted as squares.

Table 1 .

 1 Summary of geochronological and thermochronological results within the LZTB, SE Tibet.

	Sample ID	Longitude (°E)	Latitude (°N)	Elevation (m)	Zircon U-Pb age (Ma)	Mean ZHe age (Ma)	Pooled AFT age (Ma)	Mean AHe age (Ma)
	CD144	99.5151	27.0599	2595	228 ± 5	121 ± 2	35.8 ± 2.8	-
	CD145	99.5034	27.0696	2635	-	108 ± 5	-	35.9 ± 3.2
	CD146	99.4895	27.0908	2710	-	-	45.3 ± 3.7	-
	CD147	99.4851	27.1013	2789	-	-	41.3 ± 3.4	-
	CD148	99.4927	27.1031	2939	-	119 ± 7	38.7 ± 3.2	41.7 ± 2.6
	CD149	99.4999	27.0996	2985	235 ± 5	-	44.0 ± 3.5	-
	CD316	99.6712	26.5934	3143	34.5 ± 1.3 *	-	-	-
	CD323	99.6616	26.6113	3060	34.3 ± 1.6 *	-	-	-
	CD325	99.6420	26.6105	2818	36.0 ± 0.5 *	-	-	-
	CD327	99.6304	26.6027	2806	234 ±9 *	-	-	-
	CD330	99.6248	26.6014	2842	36.3 ± 0.8 *	-	-	-
	CD331	99.6171	26.6010	2876	35.3 ± 1.7 *	-	-	-
	CD335/ CD435	99.6991	26.5534	2592	35.1 ± 0.5 *	-	-	-

Note: * denotes youngest peak ages of plutons in ≤ 10% discordance.

Table S1a

 S1a Sample location and description.

	Location	Sample ID	Lithology	Era	Longitude (°E)	Latitude (°N)	Elevation (m)
	Weixi	CD144	Granite	Triassic	99.5151	27.0599
	Weixi	CD145	Granite	Triassic	99.5034	27.0696
	Weixi	CD146	Granite	Triassic	99.4895	27.0908
	Weixi	CD147	Granite	Triassic	99.4851	27.1013
	Weixi	CD148	Granite	Triassic	99.4927	27.1031
	Weixi	CD149	Granite	Triassic	99.4999	27.0996
	Laojun Shan	CD316	Porphyry	Eocene	99.6712	26.5934
	Laojun Shan	CD323	Granitic porphyry	Eocene	99.6616	26.6113
	Laojun Shan	CD325	Granite	Eocene	99.6420	26.6105
	Laojun Shan	CD327	Dacite	Triassic	99.6304	26.6027
	Laojun Shan	CD330	Granitic porphyry	Eocene	99.6248	26.6014
	Laojun Shan	CD331	Granitic porphyry	Eocene	99.6171	26.6010
	Laojun Shan	CD335	Lamprophyre	Eocene	99.6991	26.5534
	Laojun Shan	CD435	Lamprophyre	Eocene	99.6991	26.5534
	1098
	1099

Table S1b

 S1b Sites for structural and sedimentary observations. TableS2Zircon U-Pb geochronologic data analyzed by Laser-Ablation ICP Mass Spectrometry. 1100

	CD316-1-4 CD325-1-15 CD331-2-3 CD435-1-30	2191 1614 2178 447		16.1 0.5 1.1 5.7	1.1579 0.8492 0.0726 1.2303	0.0244 0.0214 0.0044 0.0273	0.1321 0.0978 0.0060 0.1286	0.0010 0.0008 0.0001 0.0014	0.3603 0.3071 0.2186 0.4787	799.8 601.3 38.3 780.1		5.7 4.5 0.5 7.8	781.0 624.2 71.2 814.5	11.5 11.8 4.1 12.4	722.2 687.1 1402.8 905.6	43.7 53.7 118.1 44.4	799.8 601.3 38.3 780.1	5.7 4.5 0.5 7.8	2% 4% 46% 4%
	CD316-1-5 CD325-1-16 CD331-2-4 CD435-1-31	442 477 3542 385		1.9 0.5 1.1 1.5	Isotopic ratios 0.0404 0.0069 0.2829 0.0151 0.0459 0.0025 0.3062 0.0114	0.0056 0.0378 0.0058 0.0397	0.0002 0.0006 0.0001 0.0005	0.2166 0.3012 0.2329 0.3597	Apparent ages (Ma) 35.8 1.3 239.4 3.8 37.0 0.5 251.2 3.3	40.2 253.0 45.6 271.2	6.7 11.9 2.4 8.9	990.7 420.4 553.7 438.9	415.6 127.8 122.2 83.3	35.8 239.4 37.0 251.2	1.3 3.8 0.5 3.3	11% 5% 19% 7%
	CD316-1-6 CD325-1-17 CD331-2-5 CD435-1-32	858 2654 1153 332		2.6 0.9 5.3 4.6	0.9079 0.3044 1.3154 1.5409	0.0251 0.0082 0.0289 0.0383	0.1021 0.0430 0.1349 0.1506	0.0011 0.0004 0.0011 0.0017	0.4054 0.3075 0.3622 0.4562	626.8 271.2 815.9 904.1		6.7 2.2 6.1 9.6	655.9 269.9 852.5 946.9	13.4 6.3 12.7 15.3	750.0 253.8 942.6 1042.6	61.1 67.6 44.1 48.6	626.8 271.2 815.9 904.1	6.7 2.2 6.1 9.6	4% 0% 4% 5%
	Sample # CD316-1-7 CD325-1-18 CD331-2-6 CD435-1-33	U 1548 228 884 208	Th	U/Th 6.9 0.8 1.5 2.5	207Pb* 0.9978 0.3973 0.0448 8.3802	± 0.0250 0.0186 0.0065 0.1888	206Pb* 0.1105 0.0386 0.0056 0.4153	± 0.0010 0.0006 0.0001 0.0054	error 0.3567 0.3082 0.1532 0.5718	206Pb* 675.7 244.3 35.7 2239.3	± 5.7 3.5 0.8 24.4	207Pb* 702.7 339.7 44.5 2273.0	± 12.7 13.6 6.3 20.5	207Pb* 775.9 1094.4 635.2 2299.7	± 54.5 100.0 346.1 36.4	Best 675.7 244.3 35.7 2273.0	± 5.7 3.5 0.8 20.5	4% 28% 20% 1%
																	age
	Analysis CD316-1-8 CD325-1-19 CD331-2-7 CD435-1-36 CD144 CD316-1-9 CD325-1-20 CD331-2-8 CD435-1-37	(ppm) 3402 804 597 541 1903 1163 862 425	Sites (ppm)	0.5 1.2 1.5 6.6 5.7 2.7 4.1 4.8	Longitude (°E) 235U (%) 0.0384 0.0020 Latitude 238U 0.0055 1.4524 0.0367 0.1502 0.3698 0.0213 0.0375 1.3323 0.0272 0.1414 (°N) 0.9431 0.0216 0.1144 1.2839 0.0304 0.1438 0.3024 0.0143 0.0390 1.3843 0.0298 0.1462	(%) 0.0001 0.0012 0.0006 0.0017 0.0011 0.0012 0.0004 0.0017	corr. 0.2861 0.3173 0.2562 0.5974 0.4151 0.3658 0.2136 0.5363	238U 35.2 902.3 237.1 852.5 698.2 866.3 246.7 879.9	(Ma) 0.5 6.8 3.4 9.8 Target 6.3 7.0 2.5 9.5	235U 38.3 910.9 319.5 859.9 674.5 838.6 268.3 882.3	(Ma) 1.9 15.2 15.8 11.9 11.3 13.5 11.2 12.7	206Pb* 279.7 920.4 950.0 883.3 583.4 762.7 461.2 900.0	(Ma) 131.5 47.2 114.8 44.4 50.0 51.1 103.7 77.9	(Ma) 35.2 902.3 237.1 852.5 698.2 866.3 246.7 879.9	(Ma) 0.5 6.8 3.4 9.8 6.3 7.0 2.5 9.5	8% 1% 26% 1% Discordance 4% 3% 8% 0%
	CD316-1-10 CD331-2-9 CD435-1-39	CD237 472 796 396	1.6 1.7 5.8	99.7031 0.0590 0.0082 0.0738 0.0076 1.3293 0.0314	26.5370 Ludian-Zhonghejiang fault 0.0054 0.0002 0.2254 34.7 1.1 0.0059 0.0002 0.2596 38.0 1.0 0.1413 0.0017 0.5197 852.0 9.8	58.2 72.3 858.6	7.8 7.2 13.7	1418.2 1701.9 872.2	289.4 223.9 44.0	34.7 38.0 852.0	1.1 1.0 9.8	40% 47% 1%
	CD144-1-1 CD327 CD316-1-11 CD331-2-10 CD435-1-40 CD144-1-2 CD316-1-12 CD327-1-1 CD331-2-11 CD435-1-41 CD144-1-3 CD316-1-13 CD327-1-2 CD331-2-12 CD435-1-44 CD144-1-4 CD316-1-14 CD327-1-3 CD331-2-13 CD435-1-45 CD144-1-5 CD316-1-15 CD327-1-4 CD331-2-14 CD435-1-46	S219 7136 S277 535 1985 567 CD333 5259 1382 551 4955 167 CD335/CD435 3.2 1.5 1.0 6.1 4.0 0.9 1.8 1.9 1.2 4757 3.9 559 1.4 309 1.4 802 1.6 403 5.7 CD320 6075 3.7 556 1.3 2052 6.9 2532 1.6 233 2.5 CD327 6939 5.1 1369 4.0 732 1.9 5450 1.1 366 4.2	99.7030 0.2578 0.0056 99.6942 0.0344 0.0059 0.0560 0.0044 1.2748 0.0297 99.7057 0.2574 0.0069 0.0335 0.0027 0.2682 0.0133 0.0472 0.0021 2.6526 0.0732 99.6991 0.2593 0.0068 0.0653 0.0064 0.2506 0.0190 0.0599 0.0078 1.2468 0.0331 99.6851 0.2484 0.0055 0.0695 0.0061 1.1287 0.0222 0.0394 0.0032 1.2766 0.0380 99.6304 0.2412 0.0053 1.1559 0.0330 1.1503 0.0292 0.0336 0.0017 1.2720 0.0313	0.0346 26.5534 Ludian-Zhonghejiang fault 0.0003 0.4525 219.4 2.1 0.0052 0.0002 0.1872 33.6 1.1 0.0058 0.0001 0.2135 37.0 0.6 0.1369 0.0017 0.5455 827.1 9.9 26.5545 Ludian-Zhonghejiang fault 0.0368 0.0004 0.4389 232.8 2.7 0.0054 0.0001 0.2550 34.5 0.7 0.0359 0.0005 0.2898 227.4 3.2 0.0054 0.0001 0.2848 34.9 0.4 0.2297 0.0034 0.5407 1332.7 18.0 26.5532 Ludian-Zhonghejiang fault 0.0372 0.0004 0.4218 235.2 2.6 0.0058 0.0002 0.3606 37.1 1.3 0.0359 0.0006 0.2177 227.3 3.7 0.0056 0.0001 0.1987 35.9 0.9 0.1326 0.0024 0.6868 802.6 13.8 26.5534 Ludian-Zhonghejiang fault 0.0354 0.0003 0.4362 224.3 2.1 0.0053 0.0002 0.3520 34.3 1.1 0.1225 0.0011 0.4380 745.1 6.1 0.0053 0.0001 0.1862 33.9 0.5 0.1329 0.0019 0.4898 804.2 11.0 26.5668 ENE-trending dextral fault 26.6027 ENE-trending dextral fault 0.0347 0.0003 0.3948 219.7 1.9 0.1385 0.0011 0.2848 836.4 6.4 0.1228 0.0012 0.3694 746.4 6.6 0.0053 0.0001 0.2741 33.9 0.5 0.1332 0.0018 0.5550 806.1 10.4	232.9 34.4 55.3 834.5 232.6 33.4 241.2 46.8 1315.4 234.1 64.2 227.0 59.1 821.9 225.3 68.2 767.1 39.2 835.3 219.4 780.0 777.4 33.6 833.3	4.5 5.7 4.3 13.3 5.5 2.6 10.6 2.0 20.4 5.5 6.1 15.4 7.5 15.0 4.5 5.8 10.6 3.1 17.0 4.3 15.6 13.8 1.6 14.0	372.3 305.6 1044.1 847.8 227.8 100.1 376.0 750.0 1300.0 213.0 1457.4 276.0 1395.4 887.0 227.8 1820.7 816.7 387.1 920.4 213.0 633.4 861.1 42.7 905.6	50.0 322.2 162.8 152.8 57.4 179.6 114.8 102.8 53.4 55.5 201.9 177.8 265.7 53.7 43.5 197.4 38.9 185.2 65.7 50.0 61.1 54.8 118.5 56.5	219.4 33.6 37.0 827.1 232.8 34.5 227.4 34.9 1315.4 235.2 37.1 227.3 35.9 802.6 224.3 34.3 745.1 33.9 804.2 219.7 836.4 746.4 33.9 806.1	2.1 1.1 0.6 9.9 2.7 0.7 3.2 0.4 20.4 2.6 1.3 3.7 0.9 13.8 2.1 1.1 6.1 0.5 11.0 1.9 6.4 6.6 0.5 10.4	6% 2% 33% 1% 0% 3% 6% 26% 1% 0% 42% 0% 39% 2% 0% 50% 3% 14% 4% 0% 7% 4% 1% 3%
	CD144-1-6 CD316-1-16 CD327-1-5 CD331-2-15 CD435-1-47	CD328 5746 1127 559 5423 354	3.2 1.4 1.1 5.6 5.1	99.6267 0.2520 0.0057 0.0420 0.0042 0.3512 0.0156 0.0490 0.0023 1.2307 0.0342	0.0359 26.6023 ENE-trending dextral fault 0.0004 0.4433 227.4 2.2 0.0060 0.0001 0.2156 38.4 0.8 0.0403 0.0005 0.2590 254.5 2.9 0.0068 0.0001 0.2255 43.9 0.5 0.1327 0.0021 0.5758 803.2 12.1	228.2 41.8 305.6 48.6 814.7	4.6 4.1 11.7 2.2 15.6	235.3 527.8 744.5 300.1 861.1	50.0 244.4 98.9 104.6 61.1	227.4 38.4 254.5 43.9 803.2	2.2 0.8 2.9 0.5 12.1	0% 8% 17% 10% 1%
	CD144-1-7 CD144-1-8 CD316-1-17 CD327-1-6 CD331-2-16 CD435(2)-1-2 CD144-1-9 CD316-1-18 CD327-1-7 CD331-2-17 CD435(2)-1-4 CD316-1-19 CD327-1-8 CD331-2-18 CD435(2)-CD144-1-10 1-6 CD144-1-11 CD316-1-20 CD327-1-9 CD331-2-19 CD435(2)-1-7 CD144-1-12 CD144-1-13 CD144-1-14 CD327-1-10 CD331-2-20 CD435(2)-1-8 CD323 CD323-1-1 CD327-1-11 CD327-1-12 CD435(2)-1-9 CD335-1/CD435-1 CD435(2)-1-10 CD144-1-15 CD323-1-2 CD327-1-13 CD335-1-1 CD435(2)-1-12 CD323-1-3 CD327-1-14 CD335-1-3 CD435(2)-	CD347 5197 CD241 CD502 CD517 5135 1773 1634 2850 59 5066 711 324 2009 161 1609 782 1209 306 CD518 CD524 CD522 7971 5171 780 293 1417 98 5909 6337 5490 304 1339 749 484 2725 1046 531 170 5032 1026 348 1194 178 5841 447 1469 160	4.5 3.4 1.1 7.5 1.7 1.3 5.2 1.7 1.8 13.3 1.7 0.8 2.7 1.8 4.3 4.3 3.1 1.1 2.0 3.9 1.7 3.2 4.8 2.9 1.4 1.1 0.9 3.4 7.2 1.2 1.0 1.5 6.3 8.2 1.4 3.1 1.5 15.6 1.8 5.5 1.6	99.7060 0.2455 0.0060 99.6479 99.6168 99.6556 0.2508 0.0060 0.0327 0.0027 1.1003 0.0240 0.0656 0.0052 0.2816 0.0166 0.2491 0.0059 0.0346 0.0056 0.2465 0.0189 1.2834 0.0249 0.0304 0.0042 0.0420 0.0035 0.2688 0.0118 0.0409 0.0047 1.1843 0.0190 99.6136 99.6943 99.7081 0.2452 0.0047 0.2871 0.0075 0.0419 0.0051 0.3256 0.0224 0.3743 0.0169 0.0438 0.0052 0.2491 0.0056 0.2467 0.0053 0.2835 0.0053 0.2152 0.0197 0.0427 0.0047 0.0335 0.0014 0.3028 0.0150 0.9329 0.0172 0.0521 0.0056 0.0383 0.0018 0.0377 0.0037 0.2502 0.0060 1.3077 0.0306 0.2241 0.0196 1.7252 0.0310 0.0345 0.0034 0.6305 0.0113 0.3021 0.0180 1.1206 0.0228 0.0437 0.0041	0.0362 26.4792 ENE-trending dextral fault 0.0004 0.4112 229.5 2.3 26.4346 Qiaohou fault and ENE-trending dextral fault 222.9 4.9 26.5003 Qiaohou fault 0.0356 0.0003 0.3900 225.7 2.1 227.2 4.9 0.0056 0.0001 0.2247 36.1 0.7 32.7 2.7 0.1246 0.0011 0.4014 756.8 6.3 753.5 11.6 0.0056 0.0001 0.1846 36.2 0.5 64.5 5.0 0.0419 0.0006 0.0141 264.3 3.8 251.9 13.1 0.0351 0.0004 0.4766 222.3 2.5 225.9 4.8 0.0058 0.0002 0.1751 37.1 1.1 34.5 5.5 0.0353 0.0006 0.2129 223.9 3.6 223.7 15.4 0.1304 0.0009 0.3543 790.3 5.1 838.4 11.1 0.0056 0.0001 0.0021 36.3 0.9 30.4 4.1 0.0054 0.0001 0.2225 34.7 0.6 41.8 3.5 0.0390 0.0006 0.3318 246.5 3.5 241.7 9.4 0.0055 0.0001 0.1409 35.1 0.6 40.7 4.6 0.1313 0.0012 0.0413 795.0 6.9 793.3 8.9 26.5408 Tongdian fault 26.5903 Tongdian fault 26.4586 Tongdian fault 26.5396 Baoxiangsi Formation 0.0329 0.0002 0.2864 208.6 1.1 222.6 3.8 0.0380 0.0004 0.3801 240.4 2.3 256.3 5.9 0.0060 0.0002 0.2221 38.3 1.0 41.7 5.0 0.0420 0.0006 0.2175 265.4 3.9 286.2 17.1 0.0392 0.0004 0.2070 248.1 2.3 322.8 12.5 0.0055 0.0001 0.0017 35.1 0.9 43.5 5.1 0.0358 0.0003 0.4163 226.7 2.1 225.8 4.5 0.0345 0.0002 0.3264 218.8 1.5 223.9 4.3 0.0378 0.0002 0.3118 239.2 1.4 253.4 4.2 0.0361 0.0006 0.1723 228.6 3.5 197.9 16.4 0.0059 0.0001 0.1620 37.7 0.7 42.4 4.6 0.0055 0.0001 0.0018 35.1 0.4 33.4 1.3 0.0425 0.0005 0.2389 268.1 3.1 268.5 11.7 0.1058 0.0008 0.3910 648.2 4.4 669.2 9.0 0.0061 0.0001 0.1931 39.0 0.8 51.6 5.4 0.0054 0.0001 0.0017 34.5 0.6 38.2 1.8 0.0055 0.0001 0.0019 35.5 0.7 37.6 3.7 0.0371 0.0004 0.4743 234.9 2.6 226.8 4.9 0.1398 0.0013 0.4051 843.5 7.5 849.1 13.5 0.0374 0.0005 0.1673 236.7 3.4 205.3 16.3 0.1649 0.0011 0.3731 984.1 6.1 1018.0 11.6 0.0054 0.0001 0.0017 34.9 0.7 34.4 3.4 0.0745 0.0004 0.3307 463.0 2.7 496.4 7.1 0.0434 0.0006 0.2239 273.6 3.6 268.0 14.0 0.1338 0.0009 0.3385 809.6 5.3 763.3 11.0 0.0059 0.0001 0.0020 37.8 0.7 43.4 4.0	142.7 231.6 727.8 1258.9 198.2 261.2 320.4 961.1 553.7 198.2 450.0 794.4 361.2 390.8 527.8 472.3 875.9 683.3 213.0 272.3 383.4 483.4 283.4 727.8 731.5 366.7 205.6 146.4 857.4 1083.3 77.9 635.2 242.7 620.4 435.2	47.2 47.2 46.3 154.6 137.0 56.5 185.2 39.7 197.2 97.2 247.2 34.3 73.1 49.1 276.7 155.5 87.0 266.6 50.0 43.5 47.2 254.6 118.5 39.7 231.5 104.6 225.9 49.1 50.0 30.6 220.3 37.0 137.0 42.6 213.9	229.5 225.7 36.1 756.8 36.2 264.3 222.3 37.1 223.9 790.3 36.3 34.7 246.5 35.1 795.0 208.6 240.4 38.3 265.4 248.1 35.1 226.7 218.8 239.2 228.6 37.7 35.1 268.1 648.2 39.0 34.5 35.5 234.9 843.5 236.7 1018.0 34.9 463.0 273.6 809.6 37.8	2.3 2.1 0.7 6.3 0.5 3.8 2.5 1.1 3.6 5.1 0.9 0.6 3.5 0.6 6.9 1.1 2.3 1.0 3.9 2.3 0.9 2.1 1.5 1.4 3.5 0.7 0.4 3.1 4.4 0.8 0.6 0.7 2.6 7.5 3.4 11.6 0.7 2.7 3.6 5.3 0.7	3% 10% 0% 44% 5% 1% 8% 0% 6% 20% 2% 17% 2% 14% 0% 6% 8% 7% 23% 19% 6% 0% 2% 15% 11% 5% 0% 3% 10% 24% 5% 6% 1% 15% 3% 1% 4% 7% 2% 6% 13%
	CD144-1-16 CD323-1-4 CD327-1-15 CD335-1-4 1-13	5235 2615 796 897		3.5 1.2 1.3 2.8	0.2732 0.0429 0.2625 4.7725	0.0064 0.0033 0.0120 0.0849	0.0377 0.0055 0.0358 0.3283	0.0004 0.0001 0.0004 0.0026	0.4482 0.1854 0.2445 0.4379	238.3 35.6 226.5 1830.3		2.5 0.5 2.5 12.4	245.2 42.7 236.7 1780.1	5.1 3.2 9.7 15.0	305.6 524.1 353.8 1714.5	50.0 174.8 105.5 29.9	238.3 35.6 226.5 1780.1	2.5 0.5 2.5 15.0	17% 4% 3% 3%
	CD144-1-17 CD323-1-5 CD327-1-16 CD335-1-6	5291 1102 1284 2311		4.3 7.1 2.1 7.4	0.2581 1.2674 0.2667 1.0505	0.0054 0.0260 0.0097 0.0221	0.0369 0.1380 0.0387 0.1272	0.0004 0.0009 0.0004 0.0009	0.5534 0.3313 0.2759 0.3397	233.3 833.4 244.9 771.7		2.7 5.3 2.4 5.2	233.2 831.2 240.1 729.1	4.4 11.6 7.8 11.0	235.3 820.4 187.1 598.2	48.1 44.4 115.7 42.6	233.3 833.4 244.9 771.7	2.7 5.3 2.4 5.2	0% 0% 2% 6%
	CD144-1-18	7296		3.6	0.2414	0.0048	0.0349	0.0003	0.3612	221.4		1.6	219.5	3.9	194.5	46.3	221.4	1.6	1%
	CD323-1-6 CD327-1-17 CD335-1-7	845 1210 942		1.3 1.6 3.2	1.1804 1.1901 1.0315	0.0254 0.0259 0.0264	0.1281 0.1337 0.1293	0.0010 0.0011 0.0010	0.3499 0.3755 0.3135	777.0 809.0 783.6		5.5 6.2 5.9	791.5 796.0 719.7	11.9 12.0 13.2	827.8 766.7 527.8	45.5 245.4 55.5	777.0 809.0 783.6	5.5 6.2 5.9	2% 2% 9%
	CD144-1-19	5257		4.6	0.2763	0.0059	0.0389	0.0003	0.3539	246.2		1.8	247.7	4.7	253.8	46.3	246.2	1.8	1%
	CD323-1-7 CD327-1-18 CD335-1-8	128 1043 1520		1.6 5.3 4.9	0.2684 1.0494 1.0120	0.0420 0.0228 0.0237	0.0202 0.1178 0.1262	0.0006 0.0010 0.0010	0.2025 0.3734 0.3225	129.2 718.1 766.1		4.1 5.5 5.5	241.4 728.6 709.9	33.6 11.3 12.0	1620.7 753.7 538.9	294.0 44.4 48.1	129.2 718.1 766.1	4.1 5.5 5.5	46% 1% 8%
	CD144-1-20 CD323-1-8 CD327-1-19 CD335-1-9	6596 533 1223 1259		4.4 1.3 2.1 6.9	0.2655 0.9399 0.3219 0.9721	0.0061 0.0321 0.0119 0.0227	0.0350 0.0992 0.0439 0.1156	0.0003 0.0009 0.0004 0.0012	0.3964 0.2722 0.2404 0.4622	222.0 609.6 277.1 705.0		2.0 5.4 2.4 7.2	239.1 672.8 283.3 689.5	4.9 16.8 9.1 11.7	466.7 887.0 338.9 642.6	48.1 68.5 83.3 46.3	222.0 609.6 277.1 705.0	2.0 5.4 2.4 7.2	7% 9% 2% 2%
	CD149 CD323-1-9 CD327-1-20 CD335-1-10	3993 733 1624		51.6 2.0 3.4	0.7509 0.2715 1.0365	0.0153 0.0129 0.0209	0.0874 0.0375 0.1245	0.0011 0.0004 0.0009	0.5931 0.2297 0.3438	540.2 237.4 756.6		6.3 2.6 5.0	568.7 243.9 722.2	8.9 10.3 10.5	679.6 338.9 616.7	37.0 111.1 42.6	540.2 237.4 756.6	6.3 2.6 5.0	5% 3% 5%
	CD323-1-10 CD335-1-11	1612 3420		0.9 11.2	0.0315 0.4277	0.0029 0.0095	0.0052 0.0613	0.0001 0.0006	0.1998 0.4103	33.7 383.7		0.6 3.4	31.5 361.6	2.8 6.7	216.7	48.1	33.7 383.7	0.6 3.4	7% 6%
	CD149-2-1 CD330	5020		3.6	0.2551	0.0066	0.0375	0.0003	0.3126	237.2		1.9	230.7	5.4	161.2	57.4	237.2	1.9	3%
	CD323-1-11 CD335-1-12	1561 2222		1.6 6.4	1.0661 1.1468	0.0226 0.0209	0.1194 0.1332	0.0013 0.0008	0.5098 0.3412	727.1 806.0		7.4 4.7	736.8 775.7	11.1 9.9	761.1 683.3	39.7 38.1	727.1 806.0	7.4 4.7	1% 4%
	CD149-2-2 CD323-1-12 CD330-1-1 CD335-1-13	6844 2036 1776 3332		3.8 11.5 3.2 32.5	0.2470 1.2449 1.4761 0.3487	0.0054 0.0225 0.0285 0.0085	0.0346 0.1355 0.1481 0.0470	0.0003 0.0009 0.0010 0.0005	0.3682 0.3682 0.3446 0.4773	219.0 819.1 890.2 296.0		1.7 5.1 5.5 3.4	224.1 821.1 920.6 303.7	4.4 10.2 11.7 6.4	276.0 833.3 988.6 350.1	43.5 37.0 38.9 48.1	219.0 819.1 890.2 296.0	1.7 5.1 5.5 3.4	2% 0% 3% 3%
	CD149-2-3 CD323-1-13 CD330-1-2 CD335-1-14	4000 1927 905 548		3.4 3.8 2.3 0.8	0.2916 0.8840 0.1823 1.0572	0.0066 0.0189 0.0088 0.0300	0.0394 0.1003 0.0223 0.1219	0.0003 0.0008 0.0004 0.0010	0.2970 0.3520 0.4148 0.2972	249.0 615.9 142.4 741.5		1.6 4.4 2.8 5.9	259.8 643.2 170.1 732.5	5.2 10.2 7.6 14.8	366.7 738.9 694.5 698.2	51.8 44.4 128.5 63.9	249.0 615.9 142.4 741.5	1.6 4.4 2.8 5.9	4% 4% 16% 1%
	CD149-2-4 CD323-1-14 CD330-1-3 CD335-1-15	3269 2270 3233 1301		4.1 1.7 1.2 2.9	0.2671 0.0350 8.4031 1.1695	0.0064 0.0027 0.1312 0.0254	0.0398 0.0053 0.4114 0.1292	0.0003 0.0001 0.0022 0.0012	0.2932 0.1897 0.3502 0.4128	251.6 33.8 2221.5 783.1		1.7 0.5 10.3 6.6	240.4 34.9 2275.5 786.4	5.1 2.6 14.3 11.9	200.1 189.0 2315.7 790.7	57.4 177.8 20.8 46.3	251.6 33.8 2221.5 783.1	1.7 0.5 10.3 6.6	5% 3% 2% 0%
	CD149-2-5	5276		5.0	0.2542	0.0059	0.0371	0.0004	0.4614	234.5		2.5	230.0	4.7	189.0	50.0	234.5	2.5	2%
	CD323-1-15 CD330-1-4 CD335-1-16	1655 7040 495		1.6 15.5 2.4	0.1878 4.9598 0.6517	0.0077 0.0803 0.0204	0.0234 0.2995 0.0846	0.0004 0.0018 0.0008	0.4586 0.3636 0.3123	149.2 1688.7 523.8		2.8 8.8 4.9	174.7 1812.5 509.5	6.6 13.7 12.5	531.5 1950.0 455.6	76.8 28.4 75.0	149.2 1688.7 523.8	2.8 8.8 4.9	15% 7% 3%
	CD149-2-6	5795		5.4	0.2447	0.0054	0.0349	0.0004	0.4824	221.0		2.3	222.3	4.4	231.6	46.3	221.0	2.3	1%
	CD323-1-16 CD330-1-5 CD335-1-17	612 6261 1774		0.8 15.3 ####	0.6277 4.8644 0.4903	0.0237 0.0889 0.0119	0.0780 0.2941 0.0641	0.0012 0.0022 0.0005	0.3987 0.4080 0.3196	484.2 1662.0 400.2		7.0 11.0 3.0	494.6 1796.1 405.1	14.8 15.4 8.1	553.7 1946.3 420.4	76.8 29.8 53.7	484.2 1662.0 400.2	7.0 11.0 3.0	2% 7% 1%
	CD149-2-7 CD323-1-18 CD330-1-6 CD335-1-18	5110 4982 1101 1044		5.0 1.8 2.8 4.1	0.2603 0.0361 1.1849 1.2445	0.0055 0.0018 0.0289 0.0261	0.0360 0.0055 0.1262 0.1346	0.0003 0.0001 0.0010 0.0009	0.4494 0.2203 0.3238 0.3214	228.2 35.4 766.1 813.9		2.1 0.4 5.7 5.2	234.9 36.0 793.6 820.9	4.4 1.7 13.4 11.8	301.9 105.6 864.8 825.6	48.1 114.8 51.9 44.4	228.2 35.4 766.1 813.9	2.1 0.4 5.7 5.2	3% 2% 3% 1%
	CD149-2-8 CD323-1-19 CD330-1-7 CD335-1-19	4607 904 566 1014		3.9 1.3 1.1 1.5	0.2581 0.8523 0.4897 1.1755	0.0062 0.0208 0.0225 0.0270	0.0370 0.1015 0.0640 0.1294	0.0003 0.0008 0.0007 0.0010	0.3892 0.3287 0.2246 0.3284	234.5 622.9 400.2 784.7		2.1 4.8 4.0 5.6	233.1 625.9 404.7 789.2	5.0 11.4 15.4 12.6	213.0 635.2 442.6 787.0	51.8 49.1 99.1 48.9	234.5 622.9 400.2 784.7	2.1 4.8 4.0 5.6	1% 0% 1% 1%
	CD149-2-9 CD323-1-20 CD330-1-8 CD335-1-20	4747 4678 4155 1413		3.4 #### 1.4 3.3	0.2639 0.0301 8.0144 1.2181	0.0060 0.0017 0.1854 0.0279	0.0370 0.0051 0.3930 0.1268	0.0004 0.0001 0.0034 0.0009	0.4836 0.2214 0.3737 0.3131	234.1 32.7 2136.8 769.8		2.5 0.4 15.8 5.2	237.8 30.1 2232.6 808.9	4.8 1.7 20.9 12.8	333.4 2322.2 901.9	48.1 37.7 48.9	234.1 32.7 2136.8 769.8	2.5 0.4 15.8 5.2	2% 9% 4% 5%
	CD149-2-10 CD330-1-9 CD435-1-1	4069 7219 419		3.2 15.2 1.8	0.2649 4.9904 0.0423	0.0067 0.0993 0.0026	0.0376 0.2998 0.0058	0.0004 0.0019 0.0001	0.3739 0.3113 0.3774	238.1 1690.2 37.3		2.2 9.3 0.9	238.6 1817.7 42.1	5.4 16.9 2.6	239.0 1958.3 427.8	55.5 34.1 121.3	238.1 1690.2 37.3	2.2 9.3 0.9	0% 7% 11%
	CD149-2-11 CD325 CD330-1-10 CD435-1-2	4731 2696 281		3.4 1.9 2.2	0.2466 0.5 1.1364	0.0059 0.0112 0.0482	0.0348 0.0644 0.1378	0.0003 0.0005 0.0016	0.4084 0.3347 0.2739	220.5 402.3 832.2		2.1 2.9 9.1	223.8 410.4 770.8	4.8 7.6 22.9	261.2 450.0 590.8	55.5 17.6 91.7	220.5 402.3 832.2	2.1 2.9 9.1	1% 2% 8%
	CD149-2-12	6056		3.3	0.2648	0.0059	0.0380	0.0005	0.5466	240.6		2.9	238.5	4.7	213.0	44.4	240.6	2.9	1%
	CD325-1-1 CD330-1-11 CD435-1-3	2028 5867 340		0.5 1.5 4.4	0.6883 8.3841 1.0862	0.0167 0.1460 0.0529	0.0842 0.4079 0.1363	0.0006 0.0032 0.0015	0.3110 0.4461 0.2279	521.0 2205.1 823.6		3.8 14.6 8.6	531.8 2273.5 746.6	10.0 15.9 25.7	572.3 2329.3 531.5	58.3 32.6 114.8	521.0 2205.1 823.6	3.8 14.6 8.6	2% 3% 10%
	CD149-2-13 CD325-1-2 CD330-1-12 CD435-1-14	5837 1788 5935 907		4.6 2.3 12.3 12.1	0.2517 1.2091 5.2788 1.0314	0.0059 0.0335 0.0842 0.0397	0.0359 0.1219 0.3103 0.1255	0.0003 0.0012 0.0019 0.0016	0.3509 0.3631 0.3773 0.3330	227.1 741.8 1741.9 762.4		1.8 7.1 9.2 9.2	228.0 804.8 1865.4 719.6	4.8 15.4 13.7 19.9	231.6 966.4 2002.2 583.4	47.2 47.2 26.7 83.3	227.1 741.8 1741.9 762.4	1.8 7.1 9.2 9.2	0% 8% 7% 6%
	CD149-2-14 CD325-1-3 CD330-1-13 CD435-1-15	4177 5851 6758 395		3.5 17.8 0.8 5.6	0.2819 1.0207 0.2640 1.1774	0.0067 0.0188 0.0060 0.0384	0.0386 0.1145 0.0340 0.1408	0.0004 0.0009 0.0003 0.0021	0.4279 0.4171 0.3352 0.4568	244.1 698.8 215.3 849.1		2.4 5.1 1.6 11.9	252.2 714.2 237.9 790.1	5.3 9.5 4.8 17.9	324.1 750.0 477.8 635.2	50.0 38.1 50.0 69.3	244.1 698.8 215.3 849.1	2.4 5.1 1.6 11.9	3% 2% 9% 7%
	CD149-2-15 CD325-1-4 CD330-1-14 CD435-1-16	4738 1073 3305 327		5.7 0.7 2.2 7.0	0.2573 4.4102 9.1913 1.1457	0.0068 0.0835 0.1693 0.0338	0.0369 0.3031 0.4141 0.1330	0.0005 0.0021 0.0029 0.0017	0.5037 0.3601 0.3839 0.4454	233.8 1706.7 2233.5 805.0		3.0 10.3 13.4 10.0	232.5 1714.2 2357.3 775.2	5.5 15.7 16.9 16.0	216.7 1710.8 2464.8 699.7	55.5 35.2 28.5 63.0	233.8 1706.7 2233.5 805.0	3.0 10.3 13.4 10.0	1% 0% 5% 4%
	CD149-2-16 CD325-1-5 CD330-1-15 CD435-1-17	3731 307 318 443		3.8 0.8 1.6 8.3	0.2554 0.2959 0.2503 1.2145	0.0063 0.0273 0.0201 0.0322	0.0370 0.0389 0.0342 0.1356	0.0003 0.0007 0.0006 0.0022	0.3441 0.1965 0.2186 0.6102	234.2 245.9 216.8 819.5		1.9 4.4 3.8 12.4	230.9 263.2 226.8 807.3	5.1 21.4 16.4 14.8	211.2 501.9 394.5 783.3	57.4 207.4 187.0 53.7	234.2 245.9 216.8 819.5	1.9 4.4 3.8 12.4	1% 7% 4% 2%
	CD149-2-17	5222		3.1	0.2598	0.0065	0.0366	0.0004	0.4481	231.9		2.5	234.5	5.2	253.8	45.4	231.9	2.5	1%
	CD325-1-6 CD330-1-16 CD435-1-18	6189 899 318		1.2 1.1 3.8	0.1922 0.0453 1.1136	0.0087 0.0049 0.0279	0.0159 0.0056 0.1250	0.0002 0.0001 0.0014	0.2476 0.2075 0.4465	101.8 36.3 759.1		1.1 0.8 8.0	178.5 44.9 759.9	7.4 4.7 13.4	1358.3 633.0 761.1	80.3 242.6 52.9	101.8 36.3 759.1	1.1 0.8 8.0	43% 19% 0%
	CD149-2-18	6445		4.2	0.2607	0.0061	0.0368	0.0003	0.3607	232.9		1.9	235.2	4.9	253.8	47.2	232.9	1.9	1%
	CD325-1-7 CD330-1-17 CD435-1-19	817 400 300		1.2 1.7 5.7	1.4828 0.3441 1.3047	0.0416 0.0195 0.0315	0.1470 0.0414 0.1392	0.0013 0.0006 0.0018	0.3066 0.2441 0.5494	884.1 261.3 840.4		7.1 3.5 10.4	923.4 300.3 847.8	17.0 14.7 13.9	1005.6 650.0 873.8	57.4 124.1 45.4	884.1 261.3 840.4	7.1 3.5 10.4	4% 13% 1%
	CD149-2-19 CD325-1-8 CD330-1-18 CD435-1-21	4645 955 9753 345		3.3 0.7 13.9 5.7	0.2602 1.1198 4.9415 1.2496	0.0064 0.0288 0.0740 0.0306	0.0376 0.1180 0.3009 0.1326	0.0004 0.0012 0.0018 0.0021	0.4502 0.4030 0.4022 0.6321	238.1 719.3 1696.0 802.8		2.6 7.1 9.0 11.7	234.8 762.9 1809.4 823.2	5.2 13.8 12.7 13.8	211.2 900.0 1935.5 887.0	55.5 57.4 25.6 80.6	238.1 719.3 1696.0 802.8	2.6 7.1 9.0 11.7	1% 6% 6% 2%
	CD149-2-20 CD325-1-9 CD330-1-19 CD435-1-22	5398 345 2733 565		5.1 0.6 2.8 5.1	0.3621 1.4278 0.0767 0.9750	0.0115 0.0937 0.0037 0.0224	0.0400 0.0438 0.0094 0.1068	0.0003 0.0010 0.0001 0.0014	0.2637 0.3316 0.2280 0.5632	252.8 276.5 60.4 654.1		2.1 5.9 0.7 8.0	313.7 900.6 75.0 691.1	8.6 39.2 3.5 11.5	772.2 3047.8 561.1 803.4	52.8 95.2 105.5 47.2	252.8 276.5 60.4 654.1	2.1 5.9 0.7 8.0	19% 69% 20% 5%
	CD316 CD325-1-10 CD330-1-20 CD435-1-24	6070 602 862		6.5 2.4 5.7	2.1298 0.2913 1.1934	0.0467 0.0142 0.0281	0.1834 0.0369 0.1256	0.0017 0.0004 0.0015	0.4311 0.2467 0.5113	1085.4 233.8 762.8		9.5 2.8 8.7	1158.5 259.6 797.5	15.2 11.2 13.0	1264.8 524.1 900.0	35.7 111.1 47.1	1085.4 233.8 762.8	9.5 2.8 8.7	6% 10% 4%
	CD316-1-1 CD325-1-11 CD331 CD435-1-26	558 3021 515		1.4 0.5 5.0	0.0624 0.0437 1.1952	0.0059 0.0035 0.0264	0.0056 0.0056 0.1282	0.0002 0.0001 0.0015	0.3625 0.1917 0.5363	35.8 36.0 777.4		1.2 0.5 8.7	61.5 43.4 798.4	5.6 3.4 12.2	1636.7 505.6 857.4	244.4 177.6 45.5	35.8 36.0 777.4	1.2 0.5 8.7	42% 17% 3%
	CD316-1-2 CD325-1-12 CD435-1-28 CD316-1-3 CD325-1-14 CD331-2-2 CD325-1-13 CD331-2-1 CD435-1-29	871 1917 433 577 313 4329 7102 1000 204		1.0 0.7 5.5 1.5 0.6 1.4 1.6 2.9 2.8	0.0460 0.0555 1.2929 0.0366 0.2714 0.0573 0.7384 0.2735 1.2868	0.0044 0.0045 0.0287 0.0036 0.0197 0.0025 0.0203 0.0106 0.0357	0.0057 0.0058 0.1330 0.0048 0.0378 0.0057 0.0781 0.0386 0.1385	0.0001 0.0001 0.0018 0.0002 0.0006 0.0001 0.0005 0.0004 0.0021	0.2569 0.1995 0.6154 0.3339 0.2013 0.2611 0.2438 0.2741 0.5391	36.8 37.5 805.2 30.9 239.1 36.8 485.0 243.8 836.2		0.9 0.6 10.3 1.0 3.4 0.4 3.1 2.5 11.7	45.7 54.8 842.6 36.5 243.8 56.6 561.5 245.5 839.9	4.3 4.4 12.7 3.5 15.8 2.4 11.9 8.4 15.9	738.9 925.0 946.3 683.3 342.7 1020.4 855.2 276.0 870.1	222.2 166.7 43.1 245.2 169.4 91.5 56.3 88.0 59.3	36.8 37.5 805.2 30.9 239.1 36.8 485.0 243.8 836.2	0.9 0.6 10.3 1.0 3.4 0.4 3.1 2.5 11.7	32% 4% 19% 2% 35% 15% 1% 14% 0%

  Table S4 Geochronologic ages for Eocene volcanic clasts and plutonic rocks in and around the 1115 Jianchuan basin and LZTB, SE Tibet. 1116

	Location Location Weixi Sa A Within the Ludian-Zhonghejiang fold-thrust belt Sample ID Longitude (E) Sample ID Longitud e (E) CD144 99.5151 He U Th Laojun Shan CD316 99.6712 mpl li e q. Laojun Shan CD323 99.6616 Laojun Shan CD325 99.6420 Laojun Shan CD330 99.6248	Latitude (N) Latitud e (N) 27.0599 Th/ Lithology Lithology granite gr Ejec 26.5934 Porphyry U ai tion n corr. 26.6113 Granitic porphyry 26.6105 Granite 26.6014 Granitic porphyry g) (µ s m (FT2 as 38)	Ejec tion corr. (FT2 35)	Formation Age type Formatio Age type n Tgr Zircon U-Pb Ejec Zircon U-Pb weigthed mean age of the Age (Ma) 227.7 tion corr. youngest concordant zircons (10 ages) Zircon U-Pb weigthed mean age of the Zircon U-Pb age of the only youngest age Zircon U-Pb age of the only youngest age (1 age) youngest concordant zircons (5 ages) (FT2 32)	± (Ma) Age (Ma) 4.6 34.5 36.3 36.0 34.3	± (Ma) 1.3 0.8 0.5 1.6	Reference Reference This study This study This study This study This study
	Weixi Laojun Shan	CD149 5 CD335/CD43	99.4999 99.6991	27.0996 26.5534	granite Lamprophyre		Tgr	Zircon U-youngest concordant zircons (6 ages) Pb 234.5 (1 age) Zircon U-Pb weigthed mean age of the	4.7 35.1	0.5	This study This study
	Laojun Shan		CD331	99.6171	26.6010	Granitic porphyry			Zircon U-Pb weigthed mean age of the	35.3	1.7	This study
										youngest concordant zircons (6 ages)
	Laojun Shan		CD321-1	99.6713	26.6175	Granitic porphyry			Zircon U-Pb weigthed mean age of the	34.7	0.8	Gourbet et al.,
	Jianchuan CD327	99.6304	26.6027	dacite		Pantiange Fm.(T1-2p) youngest concordant zircons (12 ages) Weigthed Zircon U-Pb 234.4	8.5	This study
										mean age
										of
										youngest
										concordant
										zircons (7
										ages)
	Jianchuan CX036-8	99.6646	26.5578	granite		Tgr	Zircon U-Pb
			YU70			Monzonitic-syenitic			Zircon U-Pb	35.0	0.1	Schärer et al., 1994
	Plutonic rocks away from the Jianchuan county
	Midu Gap		Y83-803	100.2889	25.2236	Quartz	monzonite		Zircon U-Pb	34.8	0.3	Liang et al., 2007
						porphyry
	Yongping-Weishan		WS-4	100.2870	25.1545	Quartz	monzonite		Zircon U-Pb	35.4	0.6	Lu et al.,
						porphyry
	Machangqing		BXC-8	100.4258	25.5278	Biotite	amphibole		Zircon U-Pb	35.6	0.3	Lu et al.,
						monzogranite
	Machangqing		BXC-2	100.4519	25.5341	Amphibole monzogranite		Zircon U-Pb	35.0	0.2	Lu et al.,
						porphyry
	Machangqing		BXC-9	100.4258	25.5278	Granitic aplite			Zircon U-Pb	34.4	0.2	Lu et al.,
	Binchuan		BC-4	100.6568	25.7736	Biotite quartz monzonite		Zircon U-Pb	35.4	0.4	Lu et al.,
						porphyry
	Binchuan		BC-5	100.4763	25.7926	Amphibole	quartz		Zircon U-Pb	36.6	0.6	Lu et al.,
						monzonite porphyry
	Beiya		72ZK11-207			Monzogranite porphyry			Zircon U-Pb	36.9	0.3	Lu et al.,
	Beiya		BY-9	100.1804	26.1462	Alkali feldspar granite		Zircon U-Pb	36.2	0.3	Lu et al.,
						porphyry
	Beiya		56ZK14-4			Alkali feldspar syenite		Zircon U-Pb	34.6	0.5	Lu et al.,
						porphyry
	Beiya		BY-YKD	100.1845	26.1628	Biotite	monzogranite		Zircon U-Pb	36.8	0.7	Lu et al.,
						porphyry
	Beiya		TKT	100.2042	26.1640	Monzonite porphyry			Zircon U-Pb	36.9	0.7	Lu et al.,
	Beiya		LH-1	100.3294	26.4522	Biotite-amphibole-augite		Zircon U-Pb	36.9	0.3	Lu et al.,
						syenite porphyry
	Beiya		PTS	100.1864	26.2873	Quartz	monzonite		Zircon U-Pb	36.5	0.8	Lu et al.,
						porphyry
	Beiya		BL-2	100.2257	26.1478	Monzogranite porphyry			Zircon U-Pb	35.7	0.8	Lu et al.,
	Yao'an		YA-2	101.2891	25.3853	Biotite quartz monzonite		Zircon U-Pb	33.4	0.3	Lu et al.,
						porphyry
	Yongsheng-Ninglang		DHS-1	100.9860	26.8467	Biotite	quartz		Zircon U-Pb	33.1	0.4	Lu et al.,
						monzodiorite porphyry
	Yongsheng-Ninglang		DHS-4	100.9742	26.8595	Biotite granite porphyry			Zircon U-Pb	34.1	0.3	Lu et al.,
	Yongsheng-Ninglang		BNC-3	100.9307	27.3614	Granite porphyry			Zircon U-Pb	32.5	0.3	Lu et al.,
	~100 km east of Midu	Y81-974	101.2528	25.3833	Trachydacite				Zircon U-Pb	34.0	0.5	Liang et al., 2007
	~25 km east of Xiaguan	Y83-634	100.4292	25.5250	Syenite, quartz monzonite		Zircon U-Pb	35.5	0.4	Liang et al., 2007
	~25 km east of Xiaguan	Y83-620	100.4319	25.5194	Quartz	monzonite		Zircon U-Pb	34.8	0.2	Liang et al., 2007
						porphyry
	~25 km south of CD100	Y83-745	100.2028	26.1125	Quartz	monzonite		Zircon U-Pb	35.6	0.5	Liang et al., 2007
						porphyry
	~25 km south of CD101	Y83-740	100.2333	26.1631	Quartz	monzonite		Zircon U-Pb	35.7	0.6	Liang et al., 2007
						porphyry
	~25 km south of CD102	Y83-760	100.1722	26.3000	Quartz	monzonite		Zircon U-Pb	36.2	0.6	Liang et al., 2007
						porphyry
	Phan Si Pan		YS50	103.7744	22.3646	Syenite, quartz monzonite		Zircon U-Pb	35.0	0.3	Zhang and Schärrer,
											1999
	Phan Si Pan		Sh-126	103.1292	22.7500	Syenite, quartz monzonite		Zircon U-Pb	35.4	0.4	Liang et al., 2007
	Phan Si Pan		Y81-78	103.0583	22.7917	Granitic pporphyry, quartz		Zircon U-Pb	35.1	0.3	Liang et al., 2007
						monzonite porphyry
	1117

  Table S6 Apatite fission-track data. Number of grains analyzed. b Average uranium content of all crystals measured using LA-ICP-MS. c Chi-square value for υ degrees of freedom (υ=N-1). d Track length measured after 252Cf irradiation, and projected in respect to c axis (Ketchem et al., 2007). e Number of track length measured. Note: Zeta value is 8.27266 ± 0.1407.

	Sample	Ng a	Track	Density	U b	P(χ 2 ) c	Dispersion	Pooled	± 1σ	Length d	± 1σ	Nl e	Dpar	Dper
	ID		number					age
				(10 5 cm -2 )	(ppm)	(%)	(%)	(Ma)	(Ma)	(µm)	(µm)		(µm)	(µm)
	CD144	40	946	21.99	16.46	43	0.31	35.8	2.8	13.93	1.29	169	2.15	0.36
	CD146	39	872	15.87	13.35	56	0.03	45.3	3.7	13.74	1.56	171	2.15	0.36
	CD147	40	852	17.00	13.38	55	0.47	41.3	3.4	13.35	1.72	161	2.00	0.35
	CD148	40	841	17.91	12.08	66	0.00	38.7	3.2	14.01	1.41	162	2.03	0.35
	CD149	40	930	17.42	13.29	65	0.01	44.0	3.5	13.50	1.48	161	1.99	0.37
	a

Acknowledgements

We thank Peter Decelles and Jay Chapman for enlightening discussion. LA-ICP-MS apatite fissiontrack dating was accomplished by Paul O'Sullivan and Raymond Donelick at Apatite to Zircon, Inc., Viola, Idaho, USA. We are grateful to Peter Reiners and Uttam Chowdhury for help in the (U-Th)/He lab at University of Arizona. This study was funded by the China Geological Survey (No. DD20190811,

1212011121261), the NSF China (Nos. 41672195, 91755213, 41202144, 41302279), the Fundamental Research Funds for the Central Universities, China University of Geosciences (No. G1323511641) and China Scholarship Council (No. 201606415003). This project was supported by the Cai Yuanpei program (grant number 27968UC) of the China Scholarship Council/French Ministry of Education, and the SYSTER (Institut National des Sciences de l'Univers du CNRS) program. We thank one anonymous reviewer, associate editor and Syed Ali Turab for helpful comments that improved the manuscript, as well as chief editor Wenjiao Xiao for editorial handling. 244.0 5.2 Tang et al.,2016

Appendix

Supplementary material S1 Analytical procedures for geochronology and thermochronology Zircon U-Pb geochronology Zircon U-Pb geochronological analyses were conducted at China University of Geosciences, Wuhan, China. U-Pb dating was performed using an Agilent 7500a ICP-MS, which is equipped with a GeoLas 2005 excimer laser ablation system at a spot diameter of 32 µm. Zircon 91500 was used as an external standard and analyzed twice every 5 unknowns. To keep age reproducibility and instrument stability, four GJ-1 zircon standards were inserted at the beginning and end of each run. Typical operating conditions and detailed analytical procedures are described in [START_REF] Liu | In situ analysis of major and trace elements of anhydrous minerals by LA-ICP-MS without applying an internal standard[END_REF]. Selection and integration of analytic signals, time-drift correction, and quantitative calibration for U-Pb dating were performed by ICP-MS DataCal. Ages were accepted with up to 10% and 20% discordance for plutonic and volcanic samples, respectively. The results reported here are 206 Pb/ 238 U ages for zircon ages ≤1.0 Ga and 207 Pb/ 206 Pb ages for grains with ages >1.0 Ga. Age-distribution plots and age-concordia diagrams were generated using Isoplot/Ex. ver. 3.75 (Ludwig, 2012). Low-temperature thermochronology Apatite fission track analysis was performed at Apatite to Zircon, Inc., Viola, Idaho, USA. Apatite aliquots were mounted in epoxy and polished, and then etched in a 5.5 M HNO3 solution at 21°C for 20 s. Apatite fission track data were acquired using a New Wave Neodymium-YAG 213 nm laser ablation system coupled to a Finigan Element II Magnetic Sector ICP-MS at a 12 µm spot and a 5 Hz repetition rate with the laser set in constant energy mode. Analyses were corrected by 43 Ca as an internal standard for variations in ablation volume. For detailed procedures of sample analysis refer to Donelick et al. (2005) Zircon and Apatite (U-Th)/He dating was accomplished at the University of Arizona, USA. Normally, 3-5 euhedral zircon and apatite crystals without visible inclusions, fracture and stainless surface were chosen using a stereo-zoom polarized microscope. The geometry of each grain was measured and photographed. The grains larger than 60 μm but smaller than 500 μm in both length and width were accepted to processed for (U-Th)/He analysis. The zircon and apatite grains were wrapped into Nb foil tubes and degassed by laser heating, and then analyzed for He using 3 He isotope dilution, cryogenic purification and quadrupole mass spectrometry. The U, Th and Sm concentrations of each dissolved aliquots was measured on a sector inductively coupled plasma-mass spectrometer. Corrected (U-Th)/He ages were processed by applying the α-ejection correction factor (Farley, 2002)