J Y Reynaud

D Barba

M Poujol

M Rivadeneira

From accretion to forearc basin initiation: the case of SW Ecuador, Northern Andes

Keywords: forearc basin, subduction, outer forearc high, Ecuador, Andes 1. Introduction

The SW of Ecuador offers a great opportunity to study the long-term behavior of an almost entire forearc system, from the external accretionary prism to the landward limit of the forearc basin. A combination of field observations, LA-ICP-MS U-Pb dating on zircon and interpretation of different vintages of unpublished industrial seismic records are used to study the evolution of the forearc system of SW Ecuador including the accretionary prism and the forearc depocenter. The youngest dates, obtained from U-Pb dating on zircon grains believed to be derived from the arc, define the best estimate for the age of sedimentation and permits a clear description of the temporal and spatial evolution of the accretionary, post accretionary and forearc basin series between 60 Ma and 10 Ma. This reinforces the idea that forearc sediments

A C C E P T E D M A N U S C R I P T

3

During the recent years, our knowledge about how forearc areas evolve trough time has significantly increased thanks to thoughtful examinations of their tectonic and sedimentary evolution (e.g. [START_REF] Noda | Characteristics of sediments and their dispersal systems along the shelf and slope of an active forearc margin, eastern Hokkaido, northern Japan[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF][START_REF] Moore | Evolution of tectonosedimentary systems in the Kumano Basin, Nankai Trough forearc[END_REF]. However, because forearc areas show a great variability (including their accretion or erosional related subduction regime) and a complex history of subsidence very often partitioned in space and time [START_REF] Xie | Plate tectonics and basin subsidence history[END_REF][START_REF] Noda | Forearc basins: Types, geometries, and relationships to subduction zone dynamics[END_REF], it is still noticeable that the knowledge about how forearc basins evolve through time in the wake of the subduction system, especially in longlived subduction systems, remains poor. Indeed, variations in convergence kinematics (velocity, direction and slab angle), variations of the overburden resulting from erosion of the arc, slab roll-back, subduction-erosion and sediment thickness at the trench, time since initiation of subduction and tectonic escape along partitioned systems are just some of the mechanisms believed to control the forearc basin evolution [START_REF] Jarrard | Terrane motion by strike-slip faulting of forearc slivers[END_REF][START_REF] Moxon | History and controls of subsidence in the Late Cretaceous-Tertiary Great Valley forearc basin, California[END_REF][START_REF] Einsele | The Xigaze forearc basin: evolution and facies architecture (Cretaceous, Tibet)[END_REF][START_REF] Clift | Controls on tectonic accretion versus erosion in subduction zones: Implications for the origin and recycling of the continental crust[END_REF][START_REF] Melnick | Inversion of forearc basins in south-central Chile caused by rapid glacial age trench fill[END_REF][START_REF] Clift | Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru[END_REF][START_REF] Mitchell | Subduction complex uplift and exhumation and its influence on Maastrichtian forearc stratigraphy in the Great Valley Basin, northern San Joaquin Valley, California[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF][START_REF] Moore | Evolution of tectonosedimentary systems in the Kumano Basin, Nankai Trough forearc[END_REF]. The forearc basins might be a clue to hierarchize these varied tectonic controls, but their unravelling is still a challenge because most of them have uncomplete stratigraphic records. Moreover, because tectonic episodes (especially uplift) in the forearc seem to be very short in duration (see review of [START_REF] Pedoja | Coastal staircase sequences reflecting sea-level oscillations and tectonic uplift during the Quaternary and Neogene[END_REF] the record of deformation in forearc basins is often difficult to understand. As a consequence, some forearc basins have been interpreted as evolving independently from the kinematics of subduction [START_REF] Clift | Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF], whereas others may be strongly coupled to plate kinematics (e.g. [START_REF] Daly | Correlations between Nazca/Farallon Plate kinematics and forearc basin evolution in Ecuador[END_REF][START_REF] Regalla | Active forearc shortening in Tohoku, Japan: Constraints on fault geometry from erosion rates and fluvial longitudinal profiles[END_REF].

It is beyond doubt that a clear definition of basin evolution depends on how accurate the chronology of sediment deposition is defined. Obtaining depositional ages by using U-Pb age spectra of zircon grains acquired from volcanoclastic sediments depends mainly on the presence of an active arc at the moment of sedimentation [START_REF] Cawood | Detrital zircon record and tectonic setting[END_REF][START_REF] Gehrels | Detrital zircon U-Pb geochronology applied to tectonics[END_REF] The Ecuadorian forearc is an excellent candidate to unravel the complicated structuring of forearc areas in the realm of the arc-trench system. Indeed, the SW Ecuadorian margin shows long-lived forearc sedimentation that evolved conjointly with an active volcanic arc since at least the Early Paleocene [START_REF] Hall | Geochronological control for the main tectonic-magmatic events of Ecuador[END_REF][START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF][START_REF] Vallejo | Mode and timing of terrane accretion in the forearc of the Andes in Ecuador[END_REF][START_REF] Schütte | Geodynamic controls on Tertiary arc magmatism in Ecuador: Constraints from U-Pb zircon geochronology of Oligocene-Miocene intrusions and regional age distribution trends[END_REF]. Furthermore, the SW of Ecuador represents a dichotomy in the common vision of what forearc areas represent, since it shows high sediment preservation, both the accretionary prism and the forearc basin outcrop and, finally, it has been studied, for oil and gas exploration purposes, by the industry. To examine the evolution of the forearc system, we have analysed in detail the sedimentological features of the Paleocene -Late Miocene forearc infilling in SW Ecuador. Chronologic insights are obtained from in situ dating of zircon by LA-ICP-MS. The combination of sedimentological observations and U-Pb dating allow clarifying the chronostratigraphic evolution of SW Ecuador, including the temporal evolution of depositional environments and forearc basin initiation. Seismic records are used to define the regional architecture of the area, including the relationships between a newly defined outer forearc high (OFH) and the forearc basin depocenter. The evolution of the SW Ecuadorian margin resembles that of better studied forearc systems in the Nankai trough (Japan) and in the Great Valley basin (USA). Thus, the SW Ecuadorian margin offers an exceptional opportunity to study an outcropping OFH, a feature whose importance in forearc basin development has gained relevance in recent years [START_REF] Clift | Slow rates of subduction erosion and coastal underplating along the Andean margin of Chile and Peru[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF][START_REF] Moore | Evolution of tectonosedimentary systems in the Kumano Basin, Nankai Trough forearc[END_REF][START_REF] Noda | Forearc basins: Types, geometries, and relationships to subduction zone dynamics[END_REF].

A C C E P T E D M A N U S C R I P T

Forearc development during the Cenozoic

The forearc of SW Ecuador (Figs. 1 and2) is central to the debate about the evolution of the southern part of the Northern Andes as it records the oceanic subduction of the Nazca plate, the accretion of allochthonous terranes, Paleogene and Neogene arc magmatism, exhumation of the coastal area and the tectonic escape of the North Andean block. The SW Ecuadorian forearc was formed after the accretion of oceanic terranes with plume and/or island arc affinity such as the Pallatanga and Piñon terranes and their related volcanoclastic covers [START_REF] Feininger | Allochthonous terranes in the Andes of Ecuador and northwestern Peru[END_REF][START_REF] Hughes | Cretaceous and Tertiary terrane accretion in the Cordillera Occidental of the Andes of Ecuador[END_REF][START_REF] Kerr | The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints[END_REF][START_REF] Jaillard | Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?[END_REF][START_REF] Vallejo | Mode and timing of terrane accretion in the forearc of the Andes in Ecuador[END_REF]. There is a major debate about the definition of the nature, number and timing of accretions that led to crust addition and the construction of the Western Cordillera in Ecuador. For some authors, a single Caribbean type accretion may have occurred between 75-65 Ma [START_REF] Vallejo | Mode and timing of terrane accretion in the forearc of the Andes in Ecuador[END_REF], whereas other hypotheses suggest multi-episodic oceanic accretions (some of them with no

Caribbean affinities) at ~75 Ma, ~68 Ma, and ~58 Ma [START_REF] Feininger | Allochthonous terranes in the Andes of Ecuador and northwestern Peru[END_REF][START_REF] Hughes | Cretaceous and Tertiary terrane accretion in the Cordillera Occidental of the Andes of Ecuador[END_REF][START_REF] Kerr | The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints[END_REF][START_REF] Jaillard | Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?[END_REF]. The oceanic basement has been dated at ~90 Ma close to the northern border of the studied zone [START_REF] Luzieux | Origin and Cretaceous tectonic history of the coastal Ecuadorian forearc between 1 N and 3 S: Paleomagnetic, radiometric and fossil evidence[END_REF]. In this context, forearc basins most likely evolved in relation with an oceanic crust impinged to the South American margin and which may have acted, at least in part, as an undeformable backstop [START_REF] Aizprua | Tectono-stratigraphic evolution along a trench-linked sheared margin: Gulf of Guayaquil-Tumbes basin, Northern Andes, Ecuador-Peru[END_REF].

Major tectonic processes (some of them interrelated or competitive) affecting the continental margin of southern Ecuador during the Cenozoic include: 1) Breakup of the Farallon plate at ~25 Ma [START_REF] Handschumacher | Post-Eocene Plate Tectonics of the Eastern Pacific[END_REF][START_REF] Hey | Tectonic evolution of the Cocos-Nazca spreading center[END_REF]; 2) Subduction of ocean plate asperities, such as the Carnegie Ridge and the Grijalva Fracture System [START_REF] Collot | Exploring the Ecuador-Colombia active margin and interplate seismogenic zone[END_REF] A C C E P T E D M A N U S C R I P T 6 [START_REF] Sage | Interplate patchiness and subduction-erosion mechanisms: Evidence from depth-migrated seismic images at the central Ecuador convergent margin[END_REF][START_REF] Michaud | Influence of the subduction of the Carnegie volcanic ridge on Ecuadorian geology: Reality and fiction[END_REF]; 3) Tectonic escape of the North Andean block and related formation of the Gulf of Guayaquil-Tumbes basin [START_REF] Witt | Development of the Gulf of Guayaquil (Ecuador) during the Quaternary as an effect of the North Andean block tectonic escape[END_REF][START_REF] Witt | Forearc basin formation in the tectonic wake of a collision-driven, coastwise migrating crustal block: The example of the North Andean block and the extensional Gulf of Guayaquil-Tumbes Basin (Ecuador-Peru border area)[END_REF] and 4) A subduction-erosion regime working at the plates interface [START_REF] Bourgois | Tectonic record of strain buildup and abrupt coseismic stress release across the northwestern Peru coastal plain, shelf, and continental slope during the past 200 kyr[END_REF]. All of these processes resulted in basin formation or disruption. Thus, the variable localisation and timing of these processes lead to the superimposition of basin depocenters, a process currently poorly understood for the Andean forearc.

The sedimentary record of SW Ecuador starts during the Late Cretaceous with the deepwater volcaniclastic deposits of the Cayo, Santa Elena and Guayaquil Formations (Fig. 3) in an island arc setting. It is believed that afterwards, SW Ecuador was accreted at ~58 Ma, a process resulting in the quartz-rich turbiditic deposits of the Azúcar Formation, which constitutes the infilling of an early trench slope basin [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF]. After accretion, the forearc of SW Ecuador may have been under extension during the sedimentation of the Ancón Group. It is suggested that compression was then renewed during the Eocene [START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF][START_REF] Jaillard | Les déformations paléogènes de la zone d'avant-arc sudéquatorienne en relation avec l'évolution géodynamique[END_REF], although this deformation period remains unconstrained. The Paleocene and Eocene series crop out along the Santa Elena Peninsula and along its offshore extension (the Playas High; Fig. 2A). The modern forearc started during the Oligocene with the onset of the Progreso basin, a fault-bordered triangular shaped depocenter located between the Chongón-Colonche hills and the Estancia hills (Fig. 2) and mainly exposing in ascending order the Zapotal, Villingota, Dos Bocas, Subibaja and Progreso Formations (Fig. 3). The forearc sediments show a shoaling trend trough time which has been attributed to several geodynamic factors, such as the kinematics of the subduction system (including accretions) and the subduction of the Carnegie ridge [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF]. One of the most accepted models suggests that the extensional deformation leading to the formation of the Progreso basin (mainly controlled by the Carrizal Fault; Fig. 2) resulted from the northwards

A C C E P T E D M A N U S C R I P T 7
displacement of a forearc sliver [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF]. The entire evolution of the forearc is believed to be strongly correlated with plate kinematics [START_REF] Daly | Correlations between Nazca/Farallon Plate kinematics and forearc basin evolution in Ecuador[END_REF]. Furthermore, uplift is active in several zones of the Peninsula and marked by the presence of Pleistocene marine terraces [START_REF] Pedoja | Plio-Quaternary uplift of the Manta Peninsula and La Plata Island and the subduction of the Carnegie Ridge, central coast of Ecuador[END_REF].

U-Pb ages younger than 100 Ma obtained from detrital zircon grains show that the forearc sediments of SW Ecuador were mainly sourced from the Western (Occidental)

Cordillera (Ecuador and Peru), which acted as a topographic barrier from ~60 Ma to ~10 Ma and prevented sourcing from inner (eastwards) sections of the Andean Cordillera [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF]. The input of older zircon grains (i.e. older than 100 Ma) is related to the Amotapes Massif or similar terranes. The onset of exhumation of such a topographic barrier is most likely coeval with the early accretion of oceanic terranes, which took place between 75-65 Ma [START_REF] Jaillard | Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?[END_REF][START_REF] Vallejo | Mode and timing of terrane accretion in the forearc of the Andes in Ecuador[END_REF] although evidence for the accretion in the forearc is, at least in part, younger and dated at ~60-55 Ma [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF][START_REF] Jaillard | Les déformations paléogènes de la zone d'avant-arc sudéquatorienne en relation avec l'évolution géodynamique[END_REF]this work).

Sampling and methods

The chronologic data set used in this work consists of ten new sets of U-Pb detrital zircon analyses and ten sets of previously published analyses [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF] for which the younger age spectra (e.g. <100Ma) were not previously examined. The twenty samples were collected from the Paleocene to the Upper Miocene sedimentary outcrops in the Peninsula de Santa Elena and Progreso basin (Fig. 2). Sampled localities are shown in Figure 2 and listed in U-Pb geochronology of zircon grains was conducted by in-situ laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) at Géosciences Rennes using an ESI NWR193UC Excimer laser coupled to a quadrupole Agilent 7700x ICP-MS equipped with a dual pumping system to enhance sensitivity [START_REF] Paquette | Sensitivity Enhancement in LA-ICP-MS by N2 Addition to Carrier Gas: Application to Radiometric Dating of U-Th-Bearing Minerals[END_REF]. Concordia ages and diagrams were generated using Isoplot/Ex [START_REF] Ludwig | Isoplot 3.75: A Geochronological Toolkit for Microsoft Excel[END_REF]. Following the recommendations of 1 are provided at 1 sigma. In all the diagrams (concordia and weighted average) the data are reported at 2 sigma as well as when ages are calculated. When a concordia age (as of Ludwig, 1998) is calculated, the MSWD value is reported as "concordance+equivalence". Further information on the protocol used in this work can be found in [START_REF] Manzotti | Detrital zircon geochronology in blueschist-facies metaconglomerates from the Western Alps: implications for the late Carboniferous to early Permian palaeogeography[END_REF]; [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF] and in the Complementary Table 1.

Stratigraphic evolution and U-Pb constraints

A C C E P T E D M A N U S C R I P T 9

Youngest U-Pb zircon dates point to depositional age

Detrital zircon age spectra are controlled mainly by the presence of: 1) igneous activity coeval with deposition (primary zircon); 2) the potential of zircon grains preservation and 3) the degree of incorporation of older zircon grains into the sedimentary record [START_REF] Cawood | Detrital zircon record and tectonic setting[END_REF][START_REF] Gehrels | Detrital zircon U-Pb geochronology applied to tectonics[END_REF][START_REF] Schoene | U-Th-Pb geochronology[END_REF]. Detrital zircon ages in forearc sedimentary rocks generally show a unimodal distribution with a main population provided by zircon derived from magma emplaced during sediment deposition [START_REF] Cawood | Detrital zircon record and tectonic setting[END_REF]. Gehlers (2014) suggested that if the youngest age decreases progressively up-section, a reasonable interpretation is that measured ages record volcanism during sedimentation. Data presented here come from reworked tuffs and volcanic-rich sandstones with high potential to show a synsedimentary volcanic input. Furthermore, the obtained youngest ages, apart from three exceptions, are systematically younger up-section (Fig. 3) and show a good correlation with paleontological records, mainly those of Ordoñez et al. (2005; see Comp.Fig. 1). We consider that the analyses presented here define the ages of deposition, or ages very close to the deposition age.

To further constraint the relationship between youngest ages and depositional ages we double dated three outcrops (samples CP010-CP011, CP207-CP402 and CP022-CP023). These samples gave comparable ages within error (or very similar ages), thus giving further support for primary zircon input being coeval with sedimentation. Data presented here reinforces the idea that U-Pb detrital zircon dating is an excellent tool to date sedimentary series in forearc basins that developed synchronously with and in proximity to an active magmatic arc.

Additionally, several grain size fractions (60-100µm, 100-160µm and 160-200 µm) were dated

A C C E P T E D M A N U S C

The accretion series: the Paleocene Azúcar Formation

The Azúcar Formation contains the first products of erosion resulting from the accretion of SW Ecuador against the continental South American margin [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Jaillard | Basin development in an accretionary, oceanic-floored fore-arc setting: southern coastal Ecuador during late Cretaceous-late Eocene time[END_REF]. The accretion event is marked by the first appearance of metamorphic clasts in the

A C C E P T E D M A N U S C R I P T 11
forearc sediments (Fig. 3D; [START_REF] Luzieux | Origin and late Cretaceous-Tertiary evolution of the Ecuadorian forearc[END_REF], as well as the presence of Paleozoic and Triassic detrital zircon U-Pb ages [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF]. The last two aspects are believed to constrain sourcing resulting from the erosion of the Amotapes Massif (or other terranes sharing the same age affinities; e.g. Olmos Terrane or Western Cordillera of Peru) located south of the studied area [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF]. Because of different degrees of deformation between the Azúcar Formation and its underlying and overriding series, it has been proposed that both the base and the top of the Azúcar Formation are erosional boundaries [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF]. The Azúcar Formation yielded the assemblage of benthic foraminifera such as Rzehakina epionga and Bathysiphon gerochi, the calcareous nannoplankton Heliolithus kleimpellii, Fasciculithus involutus, Cruciplacolithus tenui and Chiasmolithus bidens and palynomorph Foveotriktes margaritae, which are diagnostic of a Paleocene age (Comp.Fig. 1; [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF].

Fossil associations suggest a deep sedimentation environment up to 2000-3000 m deep [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF].

The best outcrops of the Azúcar Formation are located in the SE part of the Peninsula at site 1 (Fig. 2). They display steep NW-SE directed (strike) strata of siliciclastic facies, ranging from shale to conglomerate. The lowermost sections of the Azúcar Formation at site 1A exhibit a typical flysch-like facies (Fig. 4A). The monotonous interbedding, the aggradational pattern and the distribution of strata suggest a low confinement environment, probably related to the depositional fringe of a deep, turbiditic system. The common occurrence of Bathysiphon foraminifera species in these deposits argue in favor of a deep marine setting. A more proximal setting of this system crops out at site 1B, where the facies is composed of unsorted conglomeratic and thicker sandstone beds (Fig. 4B). The degree of confinement is stronger than at site 1A. Sandstone beds are pervasively laminated (flat at the base, grading upward to arcuate to crossbeds) with locally fluidization at the top (Comp.Fig. 2A) and bioturbated

A C C E P T E D M A N U S C R I P T

interval observed at the sand-to-sand contacts. These conglomerate-sandstone successions can be interpreted as Lowe sequences of coarse-grained gravity flows emplaced on a westward dipping submarine slope. The feeders of the turbiditic system, found at site 1C (Fig. 4C), correspond to >10 m deep channels infilled by conglomerates and coarse-grained sandstones with numerous evidences of by-pass (traction carpets). Conglomerate clasts are mainly composed of well-rounded quartz and dark quartzite or chert. In some places imbrications and crossbeds show a SW directed current. Summarising, the Azúcar Formation at site 1 corresponds to a classical submarine fan sequence of [START_REF] Walker | Facies Models 2. Turbidites and Associated Coarse Clastic Deposits[END_REF], ranging from outer fan sequences at site 1A to to suprafan lobes at site 1B and inner fan channel fill at site 1C. In site 2, the Azúcar Fm exhibits syn-sedimentary mass wasting structures in conglomeratic facies similar to that at site 1C (Fig. 4D). North of site 6 very fine-grained series affected by intense penetrative deformation may be ascribed to the Azúcar Formation (Comp. Four samples of the Azúcar Formation provided zircon dates of various quality, especially with regard to the concordance of youngest grains. This is true for sample CP007 (a massive sandstone; Fig. 4B) as only three of the 10 youngest analyses are concordant within error (Fig. 4E). These three concordant analyses yield a concordia age of 61.2 ± 2 Ma (MSWD=2.6). The ten youngest analyses return a weighted average 206 Pb/ 238 U date of 60.7 ± 0.6 Ma (MSWD=1.2). Sample CP006 (Fig. 4C) yielded 42 apparent ages between 61.8 ± 0.8 Ma and 56.0 ± 0.8 Ma with a weighted average 206 Pb/ 238 U date of 59.9 ± 0.3 Ma (MSWD=1.5;

Comp.Fig. 3). Sample CP103 (a thick sandstone deposit near the Estancia hills; Comp.Fig. 1C)

A C C E P T E D M A N U S C R I P T
13 yields a Concordia age of 57.1 ± 1.2 Ma (MSWD=2.8, N=5) which is confirmed by the weighted average 206 Pb/ 238 U date of 57.0 ± 1.3 Ma (MSWD=3.7; Comp.Fig. 3) obtained from the seven youngest grains (Comp.Fig. 2D). In site 2 (Fig. 2), mass transport deposits includes centimetric boulders (Fig. 4D) with characteristics very similar to the sediments of the Azúcar Formation found at site 1B. One boulder (sample CP107) was sampled from this debris flow.

The three youngest concordant data yield a Concordia age of 55.2 ± 1.6 Ma (MSWD=0.2, Fig. 4G). In the light of these data, the Azúcar Formation was deposited between ~61 Ma and ~55

Ma in good agreement with the Late Danian -Late Lutetian age proposed from paleontological records (see Comp.Fig.1;Ordóñez et al., 2006).

The Upper Paleocene -Lower Eocene accretionary series close to the Chongón-

Colonche hills

Deformed sediments located at site 3 (Fig. 2) have been classically correlated with the Ancón Group by [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF], although as shown in this work, its sedimentary and compositional characteristics differ from those observed in that group. The outcrop is arranged in a long wavelength antiform with a reference reworked white (tuffaceous) layer observed in the eastward and westward borders (Fig. 5A). The deposit is mostly composed of monotonous whitish volcanosedimentary material with some meter-thick tuff layers in the antiform core.

Due to the mineral composition, the fine grain size and conformable parallel bedding, these deposits were likely formed by fallout of volcanic ash in a quiet submarine setting. The western flank of the antiform is slightly overturned (Fig. 5B), whereas the eastern flank dips gently (Fig. 5C). Several normal faults were rotated during the main compressional step, and as for the

A C C E P T E D M A N U S C R I P T 14
Azúcar Formation deformation in this sedimentary series is most likely younger than the sedimentation.

A thick ~4 m laminated tuffaceous layer was sampled (sample CP 212; Fig. 5C). The four youngest zircon analyses return a concordia age of 52.8 ± 1.3 Ma (MSWD=2.4). This age is slightly younger than the ages obtained for the Azúcar Formation. The sample also yielded a significant population between 75 and 70 Ma. Because of significant sedimentary differences, the fine-grained sediments of the Pacoa area found in site 3 should probably be considered as a different formation, not related with neither the Azúcar Formation nor the Ancón Group

The post-accretionary Eocene Ancón Group

The Ancón Group outcrops along kilometer-scale cliffs in sites 4, 5 and 6 in the west of the Peninsula (Fig. 2A); whereas its lowermost part has hitherto only been observed in seismic records. Outcrops of the Ancón Group have been related to the Seca, Socorro and Punta Ancón formations (see [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF][START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]Fig. 6), all of them being defined in the past as lithological rather than chronostratigraphic units. Because of the absence of a clear stratigraphic criteria, we made no difference between the Socorro and Seca Formations which [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF].

In site 4, outcrops of the Seca-Socorro sequence exhibit a mud breccia unit, starting by an intraformational conglomerate and passing upward to an olistostrome (Figs. 6A and Comp.Fig. 2F). The intraformational conglomerate is matrix-supported, with angular to subrounded pebbles/cobbles of greyish, laminated sandstones. The matrix is a massive grey silty mud rich in bitumen but some dm-thick, lense-shaped layers have a sandy matrix and a higher abundance of small pebbles. The absence of lamination in the matrix suggests a high density, rapid flow (mudflow). This deposit, ascribed in the literature to the so called Clay-pebble beds unit (see [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF], is interpreted as a large debris flow forming a submarine masstransport complex (MTC). The MTC is truncated at the top by a >10m deep channel system infilled by flat-bedded sandstones passing upward to heterolithic strata (Fig. 6A). The massive sandstone beds would correspond to high density bottom flows confined with the channel, whereas the heterolithic beds indicate low density turbiditic spillout deposits. The perfect parallel bedding and very large lateral extent of even the thinnest beds suggest that they are distal, low density turbidites. Many bedsets of the finest-grained facies show convolute bedding with shear structures (that does not affect their thickness regularity), which is consistent with a high sedimentation rate on a submarine slope with the mud breccia beds and slumps being associated with slope failure. Although some meter scale reverse faults are observed (Fig. 6B), deformation at site 4 is mostly extensional and related to meter scale normal faults (Fig. 6C).

As no clear extensional regime is observed and deformed series are rapidly sealed, deformation is most likely related to instability pulses of the depositional profile. Further sedimentary observations in site 4 are detailed in CompFigs. 1G and 1H.

A C C E P T E D M A N U S C R I P T

16

Site 5 shows a 50 m thick succession of massive sandstones overlying, with an erosional disconformable surface, a succession of fine-grained, ripple-laminated sandstone and locally organic-rich (peat-like) claystone facies. Olistoliths of the claystone facies, >1m in size, are present at the bottom of the massive sandstone unit (Fig. 6D), which grades upward to the ripple-laminated sandstone and claystone facies. The idealized succession of the facies at this place is a large-scale channel-fill with the massive sandstone, passing upward to the laminated sandstone and claystone forming levee and overbank deposits. A strong energy and discharge are indicated by the supercritical regime in the massive sandstone (namely hummocky cross stratification, HCS) and by the climbing ripples in the overlying laminated deposit (Comp.Fig. 2I). The organic-rich clay, together with the abundance of trace fossils of the Skolithos assemblage, suggest a deltaic setting. Paleocurrents, indicated by the ripples, were toward the south and may be consistent with the paleoslope of the basin. The deformation is related to cmscale normal faults most likely younger than sedimentation (Comp.Fig. 2J).

In site 6, a more than 200 m thick section has been correlated with the uppermost series of the Ancón Group (e.g. Punta Ancón Formation; [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF]. At the base, the series are mostly dominated by an alternation of cross-bedded sandstones and flaky, lignite rich layers, delivering a various collection of large burrows with passive fills (Comp.Fig. 2K). Several beds show Thalassinoid sp. assemblages, whereas others show lignite beds and wood fragments (Fig. 6E). This succession is overlain by a massive sandstone bed (15-20 m) with metric olistolits and floating coal clasts, where sample CP010 (sandstone) was collected. The massive sandstone grades upward to a poorly stratified, lithic-rich coarse sandstone with stringers of gravels and finally to a massive gravelly conglomerate with lignite clasts and an iron-rich matrix. A metric channeled deposit is observed in this deposit, the base of which being coincident with sample CP011 (tuff, Comp.Fig. 2L). The section terminates by an alternation of

A C C E P T E D M A N U S C R I P T 17
sand-mud layers with abundant volcaniclasts, mud pebbles and Ophiomorpha. These heterolithic deposits are organized in 2m-thick sigmoidal bedsets, laterally stacked and truncating each other (Fig. 6F), with superimposed smaller-scale oblique trough crossbedding.

The entire section can be interpreted as a forced regressive succession across a fluvialdominated deltaic margin, in concordance with previous observations [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF]. The proximity of a terrestrial source is testified by the abundant lignite-rich beds and wood fragments. The heterolithic deposits at the top are interpreted as sinuous channel bars of the deltaic plain, whereas the underlying conglomerate would correspond to the delta front or mouth bar. The overall coarse grain size for this deposit may indicate a still active uplift of the sourcing region.

Sample CP014 was obtained from the base of the sandy series at site 4. The three youngest zircon analyses yield a concordia age of 54.5 ± 1.9 Ma (MSWD=3.2) confirmed by the weighted average 206 Pb/ 238 U date of 53.4 ± 1.1 Ma (MSWD=3.3) given by the four youngest grains (Fig. 6G and Comp.Fig. 3). Paleontological assemblages suggest a younger age (~46-44 Ma) for the sandy sedimentation at this site [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF], although the major debris flow shown in Figures 6A may be older and deposited between ~50 and ~46 Ma.

Although the low number of young zircon grains dated for sample CP014 prevents to clearly define a true depositional age, the dated grains here are in relatively good correlation (within errors) with the paleontological ages proposed for the debris flow at the base of the unit. The sequence of site 5 is overlain by a volcanic rich tuffaceous deposit, most probably reworked.

We collected a similar reworked tuffaceous deposit 10 km to the north of this area (sample CP017). The six youngest grains are all concordant and define a concordia age of 48.6 ± 0.6 Ma (MSWD=1.2). (Comp.Fig. 2M). Because of the facies similarities and similar structural position of the two tuffaceous outcrops we suggest that deposition of the sedimentary series and6I). Based on these results, the Ancón Group records the transition from the deep-water slope to the deltaic shelf edge of the basin that occurred between ~55 Ma to ~41 Ma, although further constraints are necessary to better date the base of the group.

A C C E P T E D M A N U S C

The Progreso forearc basin and coeval sediments in the North Peninsula

The Zapotal Formation marks the transition from the accretionary and post-accretionary system to the forearc basin depocenter. Outcrops of the Zapotal Formation are located on the western edge of the Progreso Basin (including its southernmost extension through Puná Island)

and are bounded to the west by the Estancia Hills. Indeed, the Estancia hills separates the Paleocene -Eocene series of the Peninsula (west) from the Oligocene-Miocene series of the forearc depocenter (east). In the basin border, eastwards from the Estancia Hills the sedimentary infilling is highly deformed (including sub-vertical strata) and composed of a Cretaceous Santa Elena Formation (Comp.Fig. 2N). The Zapotal Formation holds marine fossils and plants, but there is a lack of diagnostic fossil for biozone. However, some benthic foraminifera were determined at the species level, such as Gyriodina sp., Cibicides sp., Bathysiphon sp. and Rhabdamina sp. The relative age is determined with the position of the sediments and estimated as Oligocene (Comp.Fig. 1; [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF].

Sediment thickness of the Zapotal Formation decreases from approximately 1000 m in the center of the basin to ~220 m at the basin border (Estancia Hills; [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF]. At the type-locality, the Zapotal Formation is composed of tuffaceous sandstone and polygenic, massive, clast-supported conglomerates with rounded elements (Site 7, Fig. 7A). Chert fragments observed in the conglomerate facies are most probably derived from the deeper rocks exposed at the Estancia Hills. The bottom of the conglomerate beds above the sandstones is commonly marked by burrows infilled by gravels, suggesting a kind of firm or hard ground and the sandstones are commonly cross-bedded (Fig. 7B). These facies have been interpreted as deposits related to fluvial and marine shallow water environments [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF].

Sample CP018 (reworked tuff; Fig. 7B), yielded a concordia age of 32.5 ± 0.9 Ma (MSWD=2.8, N=4; Fig. 7C) and a weighted average date of 32.5 ± 0.3 Ma (MSWD=0.4;

Comp.Fig. 3) calculated with the 10 youngest grains (Fig. 7C). The sandstone sample CP218 obtained from NW Puná Island (Comp.Fig. 2O) yielded a concordia age of 29.6 ± 0.4 Ma (MSWD=0.2; N=5; Fig. 7D) and a weighted average date of 29.5 ± 0.4 Ma (MSWD=2.5) obtained with the 15 youngest grains. The ages obtained here suggest that the Zapotal Formation was deposited during the earliest Oligocene; thus redefining the Oligocene The forearc basin deposit continued in the early Miocene with the sedimentation of the Dos Bocas and Villingota Formations. Outcrops of the Dos Bocas and Villingota Formations are very sparse in the Progreso basin depocenter and confined to a strip parallel to the Estancia hills (Fig. 2). In the northernmost areas of the Santa Elena Peninsula, a shallow-water series ascribed to the Dos Bocas Formation outcrop in Site 8 in the Montañita area (Fig. 2A). The outcrop consists of a succession of units of yellowish litharenites and sandstones bounded by low angle unconformities (Fig. 8A). The deposits are parallel bedded or structureless, with locally large diagenetic nodules. The beds are bounded and traversed by boxworks of large arthropod burrows (Comp.Fig. 2Q). They also exhibit marine mammal bones (Comp.Fig. 2R)

and some patch reefs of bivalves and worms are locally found. These beds were deposited in a protected shallow-water setting, likely under a period of strong tectonic deformation (as indicated by the progressive unconformities). Near the axis of the Progreso basin, outcrops ascribed to the Dos Bocas Formation (Fig. 2B) are observed in site 9 (Fig. 8B); it consists of a flat bedded tuff arenite with superimposed symmetrical ripples, passing upward to hummocky crossbeds. It is incised at the top by a channel, several meters deep, floored by a tuff conglomerate. These facies are typical of the succession expected in shoreface bars and rip channels.

Sample CP705 (sandstones attributed to the Dos Bocas Formation) yielded a concordia age of 23.5 ± 0.4 Ma (MSWD=0.7; N=3; Fig. 8C and Comp.Fig. 3). The eight youngest grains return a weighted average date of 22.9 ± 0.6 Ma (MSWD=4; Comp.Fig. 3). This depositional age is in high concordance with paleontological records. Indeed, the Dos Bocas Formation where oyster patch reefs overlie the shoreface deposits by way of a regressive surface of marine erosion. These features are the hint of a reduced subsidence in these formations. Sample CP405, taken from a tuffaceous interval in this outcrop, yielded a concordia age of 15.6 ± 0.2 Ma (MSWD=1.5; N=7; Fig. 9E) identical within error with the weighted average date of 15.9 ± 0.3 Ma (MSWD=1.7; Comp.Fig. 3) calculated with the 11 youngest grains. Similar downward shifts of facies are observed near the Zacachun locality (Fig. 2A), where oyster patch reefs overlie the shoreface deposits by way of a regressive surface of marine erosion.

Three outcrops of the upper part of the Subibaja Formation are exposed at site 11, near Las Juntas (Fig. 2A). Although it was not possible to structurally correlate these outcrops, they show similar successions of facies and might represent lateral equivalents. The lower part of the section exhibits loose, gravelly sand and litharenite with a gastropod fauna indicative of freshwater to brackish water. It is therefore interpreted as a fluvial to estuarine proximal

A C C E P T E D M A N U S C R I P T

23 channel deposit (Fig. 9B). This facies is erosionally overlain by a finer-grained facies, either sandy and structureless, with long vertical burrows (Rosselia ?), crossbedded with mud drapes (Fig. 9C), or locally flat bedded with rhythmic mud drapes interstatified. A Glossifungites facies lies in between, infilling large arthropod burrows (Comp.Fig. 2T). The mud drapes (Fig. 9C) is interpreted as the effect of tidal dynamics, and the Glossifungites surface as a transgressive surface. The dominant tidal paleocurrent measured in this level is toward the east, which indicate a flood dominance. The upper part of the outcrops is composed of cross-bedded gravelly sandstone with mud pebbles at the bottom, and locally containing silicified wood logs.

The crossbeds indicate paleocurrents toward the west. It is interpreted as the return to a fluvial or deltaic setting. We collected two sandstone samples from site 11A (CP207 and CP402), from which eleven concordant grains from sample CP207 yield a concordia age of 14.2 ± 0.3 Ma (MSWD=1.6, Comp.Fig. 2W) and in sample CP402, 36 grains yield a concordia age of 14.3 ± 0.1 Ma (MSWD=1.5). The 50 youngest grains return a similar weighted average date of 14.2 ± 0.1 Ma (MSWD=2). Thus, at site 10 and 11, spanning about 2 Ma, the Subibaja Formation records relative sea-level falls in a siliciclastic setting ranging from the outer shelf to the shoreline, with incised valleys and embayments influenced by tidal dynamics.

The Progreso Formation is exposed at Sites 12 and 13. According to the literature [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF] it corresponds to the last marine transgression over the area, after a fluvialdominated sedimentation at the top of the Subibaja Fm (Zacachun Mb.). The base of the Progreso Formation holds Globigerina nepenthes and Globorotalia siakensis, an assemblage corresponding to the Middle Miocene, whereas the upper part of the formation has a Late Miocene age (Comp.Fig. 1; [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]. The two studied outcrops exhibit agradational units of large lateral extent. In site 12, each unit (about 2-5 m thick) has a sharp bottom, underlined by a dense network of Thalassinoides (Comp.Fig. 2U). This surface is

A C C E P T E D M A N U S C R I P T

24 overlain by oyster patches, grading upward to a muddy calcarenite with numerous Skolithos and Cylindrichnus burrows (Fig. 9D). The upper part of the unit is a fine-grained calcarenite with mud drapes. These units are interpreted as high frequency, transgressive systems tracts. In site 13 (Comp.Fig. 2V) the deposits are more siliciclastic and tuff-rich. They are dominantly composed of poorly bedded muds, with a sharp bounded, 8m-thick interstratified sandy unit composed at the bottom by convolute beds, grading upward to large-scale trough crossbeds, the bottom of which is underlined by thick mud drapes. The muddy background is interpreted as a shelf highstand deposit, and the interstratified sandy unit as a forced regressive delta-front, the top of which being reworked into dunes in a tide-influenced setting (mud drapes). Two samples, CP022 and CP023, were collected in the deltaic facies from a reworked tuff and a sandy layer, respectively. Dating on sample CP022 shows three subconcordant grains with ages comprised between 11.5 Ma and 10.5 Ma (Comp.Fig. 2X). In sample CP023, three concordant grains yield a concordia age of 10.3 ± 0.2 Ma (MSWD=0.9; Fig. 9G) whereas the five youngest grains return a weighted average date of 10.2 ± 0.4 Ma (MSWD=4.5; Comp.Fig. 3). These data confirm the Tortonian depositional age obtained for the CP022 sandy sample.

Seismic interpretation

Five key lines (Figs. Furthermore, the chronology of superficial reflections was constrained by the U-Pb ages presented here.

The seismic line W8 (Fig. 10A) is located in the south of the Peninsula and parallels the coastline coincident with site 1. Although the quality of reflections is relatively poor, the seismic line is mainly divided into three main units. The lowermost unit may correspond to the Upper Cretaceous volcaniclastics deposits, the top of which is tentatively related to the angular unconformity roughly observed in the line and that may correspond to a décollement-surface.

Above the unconformity, the Azúcar Formation consists of very chaotic high amplitude reflections with illegible geometries. The deformed series are bounded upwards by an angular unconformity interpreted to dip towards the south, as the Azúcar Formation reaches the surface 2 km towards the north of Line 1 at site 1. The upper unit consist of less deformed sedimentary units located above the unconformity and attributed to the post accretionary series of the Ancón Group, the difference in deformation between the lower and upper series being similar to that observed in the field. The horizontal uppermost series are most probably of Quaternary age.

The NE-SW directed Line GS05 (Fig. 10B) is located in the westernmost part of the study area. It clearly displays two major thrust systems with a northeastward vergence formed by mostly parallel reflections. Deformation seems more pronounced towards the southern limit of the line, where closely-spaced highly dipping reflections may be related to thrust faults. The The NE limit of the forearc basin is related to the Carrizal fault system. Inlines 1780 and 1380 show that the Carrizal fault system has followed an inversion period, which disrupted the basin floor. Inversion is related to uplifted growth sediments at the basin border and onlaping terminations basinwards. Onset of inversion is coeval with the onlaping reflections above the black dashed thin marker (Figs. 11A and11B) and seems to be older than ~16 Ma.

DISCUSSION

The accretionary prism and the post-accretion series

The compressional deformation observed at the Santa Elena Peninsula and the Playas high, beneath the depocenters of the Miocene Progreso basin and most likely beneath the

A C C E P T E D M A N U S C R I P T 28
Miocene-Quaternary Gulf of Guayaquil-Tumbes basins, define an accretionary prism (Fig. 12B). This definition is mostly related to the deformation style and the position of the fold-andthrust series between the active arc in the Western Cordillera and the trench. Besides the eventual loss of some parts of the prism via subduction-erosion processes, the current extension of this accretionary prism is considered as relatively local. Indeed, no coeval deformed series have been observed north of the Chongón-Colonche hills and further south in North Peru,

where the older sediments of the modern forearc (i.e. the Salinas Formation) are younger than the Azúcar Formation (i.e. Early Eocene) and are significantly less deformed [START_REF] Witt | An U-Pb zircon chronology based correlation for forearc sediments trough the Ecuadorian -Peruvian border[END_REF].

The Guayaquil Formation may contain the oldest sediments having a sialic composition in the entire Ecuadorian forearc (whole-rock geochemistry analysis; [START_REF] Witt | An U-Pb zircon chronology based correlation for forearc sediments trough the Ecuadorian -Peruvian border[END_REF]; an aspect also evidenced by the presence of heavy minerals with continental affinity [START_REF] Luzieux | Origin and late Cretaceous-Tertiary evolution of the Ecuadorian forearc[END_REF]; Fig. 3). Nevertheless, although this could be tentatively defined as an early proximity of SW Ecuador to a continental magmatic arc, other aspects such as the presence of acid intrusions in the Pascuales area (e.g. north Guayaquil) may have resulted in the acid geochemistry of the Guayaquil Formation Regardless of the origin of the continental-like affinity of the Guayaquil Formation, the detrital character and deformation of the Paleocene Azúcar Formation recorded the main event related to the accretion of SW Ecuador against continental South America. Furthermore, the Azúcar Formation recorded the first metamorphic input as shown in their heavy mineral record (Fig. 3D; [START_REF] Luzieux | Origin and late Cretaceous-Tertiary evolution of the Ecuadorian forearc[END_REF]. The U-Pb ages presented here, in combination with former paleontological data, suggest that the accretion of SW Ecuador took place between 61 and 56 Ma. Thus, confirming (at least partially) former hypotheses that account for a multi-episodic construction of the Ecuadorian forearc basement

A C C E P T E D M A N U S C R I P T 29
through several accretion events [START_REF] Hughes | Cretaceous and Tertiary terrane accretion in the Cordillera Occidental of the Andes of Ecuador[END_REF][START_REF] Jaillard | Accreted oceanic terranes in Ecuador: southern edge of the Caribbean Plate?[END_REF][START_REF] Kerr | The nature and provenance of accreted oceanic terranes in western Ecuador: geochemical and tectonic constraints[END_REF].

Both the Azúcar Formation and sediments in the Pacoa area are devoid of evidence of syn-sedimentary deformation, which suggests that construction of the accretionary prism occurred after ~55 Ma (Fig. 12B). This aspect is corroborated by the parallelism of deformed reflectors in seismic lines and by the presence of boulders of the Azúcar Formation in highly deformed series related to the accretionary prism (Fig. 4D), which confirms the post ~55 Ma age for the deformation (Figs. 4D and4G). The high degree of deformation, the relative scarcity of outcrops and the poor quality of seismic reflections prevent a clear characterization of the internal geometry of the prism including its main vergence. Thus, strain directions seem to have rotated through time as evidenced by structural analysis of the Santa Elena Formation [START_REF] Jaillard | Les déformations paléogènes de la zone d'avant-arc sudéquatorienne en relation avec l'évolution géodynamique[END_REF]. Although a clear NE vergence may be defined in the westernmost parts of the Peninsula, to the SE, near site 1 the thrust vergence is not clear in the field or in seismic records. Formation of the accretionary prism may have raised deep sediments in concordance with the >2000 m water depth depositional paleoenvironment proposed for some parts of the Azúcar Formation [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]. Although more evidence is required the highly penetrative deformed sediments observed near Ancón (Comp.Fig. 2B) may represent parts of an outer prism in which deformation was more assisted by fluids. Accretionary prisms are common features of the upper part of subduction zones. Based on the reviews of [START_REF] Clift | Controls on tectonic accretion versus erosion in subduction zones: Implications for the origin and recycling of the continental crust[END_REF] and [START_REF] Noda | Forearc basins: Types, geometries, and relationships to subduction zone dynamics[END_REF] the presence of an accretionary prism may result from a significant amount of sediments at the trench (excess of ~1 km) and a great convergence velocity (greater than ~60 mm/yr). Nevertheless, the development of more local prisms is believed to result from other factors such as oblique convergence and terrane accretion. A new model for the formation of an accretionary wedge related to the Azúcar Formation has been recently proposed in new paleogeographic models for the evolution of SW Ecuador and NW Peru [START_REF] Aizprua | Tectono-stratigraphic evolution along a trench-linked sheared margin: Gulf of Guayaquil-Tumbes basin, Northern Andes, Ecuador-Peru[END_REF]. Also, an accretionary-type model has been recently proposed for the evolution of the forearc of NW Peru [START_REF] Espurt | Deciphering the Late Cretaceous-Cenozoic Structural Evolution of the North Peruvian Forearc System: Tectonics[END_REF].

Up-section, deformation in the Ancón Group is mainly related to extensional tectonics (Fig. 12C), although small-scale compressional deformation has been observed in several locations (Fig. 6B). The syn-tectonic style characterized by mass-transport deposits, cliff-scale slump features and extensional faulting most likely defines gravity-driven structures (Fig. 6C).

The presence of instability features and the absence of major compressional deformation suggest that the sedimentation of the Ancón Group occurred after the main period of formation of the accretionary prism. In this context and taking into account that U-Pb ages for the Ancón Group are between ~54 and ~40 Ma it is suggested that the accretionary prism was active mainly between ~55 and ~54 Ma and that probably ongoing, but significantly weaker deformation characterized the prism from ~54 to ~40 Ma. Nevertheless, more efforts are needed to properly constraint the age of the base of the Ancón Group.

The accretion to post-accretion stages form a first depositional stage during which the basin was a turbiditic slope with currents mostly directed in a north south axis (Sites 1 to 3).

The overall fining-upward deposits in this system, from the Azúcar Formation to the Ancón Group, marks a progressive decay of the southward tilting linked to the decrease of the activity of the accretionary prism. The final progradation of the slope fan leads to the build-up of a shelf margin where shallower deltaic systems develop as those observed in Sites 4 and 5.

Furthermore, the slope may have been directed westwards by the end of deposition of the Ancón Group [START_REF] Jaillard | Les déformations paléogènes de la zone d'avant-arc sudéquatorienne en relation avec l'évolution géodynamique[END_REF]. The provenance of these sediments is in strike relationship with the magmatic arc developed in the Western Cordillera [START_REF] Witt | Tracking ancient magmatism and Cenozoic topographic growth within the Northern Andes forearc: Constraints from detrital U-Pb zircon ages[END_REF]. A comparison of

A C C E P T E D M A N U S C R I P T

31 the zircon record found in the Paleocene -Eocene sediments of the forearc and the age of intrusive arc-related bodies in the Cordillera may shed some light on detailed provenance aspects and should be considered in further studies.

The outer forearc high

The seaward part of accretionary active margins (accretionary forearcs) is often divided into two parts; the first one, an inner forearc basin usually showing flat-topped or low slope surfaces and related to depocenters evolving between the arc and the outer forearc high (OFH;

a structural high usually coincident with the slope break) and the second one, the outer forearc system which is often coincident with the continental slope. From the earliest works dealing with forearc evolution the OFH was regarded as a major factor controlling the evolution of forearc areas [START_REF] Dickinson | Structure and stratigraphy of forearc regions[END_REF]. The strong control being simple in nature and related first to the rate at which the OFH rises and second to how the sedimentation rate can pace with it [START_REF] Dickinson | Structure and stratigraphy of forearc regions[END_REF][START_REF] Mitchell | Subduction complex uplift and exhumation and its influence on Maastrichtian forearc stratigraphy in the Great Valley Basin, northern San Joaquin Valley, California[END_REF]. Thus, the trapping of sediments at the inner forearc or the by-pass of sediments through the outer forearc and trench is a major aspect controlling the subduction regime and therefore the architecture of the outer margin.

Nevertheless, with some remarkable exceptions as the Nankai accretionary margin in Japan [START_REF] Moore | Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF][START_REF] Buchs | Sediment flow routing during formation of forearc basins: constraints from integrated analysis of detrital pyroxenes and stratigraphy in the Kumano Basin, Japan[END_REF] or the Great Valley basin in USA [START_REF] Mitchell | Subduction complex uplift and exhumation and its influence on Maastrichtian forearc stratigraphy in the Great Valley Basin, northern San Joaquin Valley, California[END_REF] the relationships between the OFH and the forearc basin remain relatively unexplored. Shoaling sedimentation from bathyal or slope to shallow water environments has been observed in many forearc basins with most hypothesis suggesting driving factors ascribed to the uplift of the outer forearc high or to basal sediment accretion [START_REF] Encinas | Major forearc subsidence and deepmarine Miocene sedimentation in the present Coastal Cordillera and Longitudinal Depression of south-central Chile (38°30′S-41°45′S)[END_REF][START_REF] Buchs | Sediment flow routing during formation of forearc basins: constraints from integrated analysis of detrital pyroxenes and stratigraphy in the Kumano Basin, Japan[END_REF].

A C C E P T E D M A N U S C R I P T 32
The river and shallow water deposits of the Zapotal Formation are bounded to the west by the Estancia Hills (Fig. 12D). Evidence shown here constrain a compressional regime for the formation of the topographic high; they include: 1) the pervasive thinning of stratigraphic series towards the structural high; 2) the absence of normal faults near the structural high; 3) important erosion related to the presence of debris flows downlapping ancient reflections; 4) onlapping of the Zapotal Fm above the upper part of the debris flow and 5) the high degree of zircon recycling, as evidenced in Miocene series of the Villingota and Subibaja Formations. All of this evidence suggests the activity of a thrust fault, which may be related to the accretionary prism described in the previous sections, although not directly observed in seismic data. It is proposed in this work that the Estancia Hills acts as an outer forearc high (OFH) separating the forearc basin to the west from the accretionary and post-accretionary series to the east (Fig. 12D). Uplift along this OFH may be important as deep rocks of the Upper Cretaceous volcaniclastics series (cherts of the Santa Elena Formation) crop out near the surface to the southwest of site 7 (Comp.Fig. 2N). The activity of the OFH seems pervasive during the Neogene as seismic records shows constant thinning of series younger than 32-30 Ma and no Oligocene or younger sediments are observed west of the OFH.

OFHs are crucial features in the evolution of trench-forearc systems. It is believed that formation of an OFH results in a landward increase of accommodation space [START_REF] Moore | Three-Dimensional Splay Fault Geometry and Implications for Tsunami Generation[END_REF][START_REF] Buchs | Sediment flow routing during formation of forearc basins: constraints from integrated analysis of detrital pyroxenes and stratigraphy in the Kumano Basin, Japan[END_REF][START_REF] Noda | Forearc basins: Types, geometries, and relationships to subduction zone dynamics[END_REF]. The evolution of accretionary prims, as other types of fold-and-thrust belts, is controlled by the interaction between internal factors such as the slope of the basal décollement and the topographic surface (the addition of both being the taper), the strength of the materials forming the prism and the décollement and by external factors such as sedimentation and erosion. Thus, fold-and-thrust belts will grow by frontal accretion only when Ecuador to be formed during Oligocene times, but a decrease of the taper angle, inferred here from 54 to 41 Ma and probably subsequently related with a yet-to-be defined non-depositional step during 41-32 Ma may be an option, as no sedimentation has been observed for this period.

The difficulty in defining the origin of the OFH in the wake of the accretionary prism comes first from the impossibility to clearly define the geometry of the prism and its vergence near the OFH, the vergence of structures shown in Figure 12 being related to the clearest vergence observed between sites 3 and 5. Nevertheless, a relationship between the Estancia Hills and the activity of a deep thrust fault was already proposed in the early work of [START_REF] Benitez | Evolution géodynamique de la province côtière sud-équatorienne au Crétacé supérieur-Tertiaire[END_REF].

Uplift along the OFH, caused the depositional locus to move eastwards (Figure 12E)

with syn-tectonic growth strata on-laping former slope deposits. This is a mechanism very similar to that observed in other forearc -OFH assemblages, such as the Great Valley Basin (USA; [START_REF] Mitchell | Subduction complex uplift and exhumation and its influence on Maastrichtian forearc stratigraphy in the Great Valley Basin, northern San Joaquin Valley, California[END_REF] and the Kumano basin (Japan; [START_REF] Moore | Evolution of tectonosedimentary systems in the Kumano Basin, Nankai Trough forearc[END_REF][START_REF] Takano | Variation in forearc basin configuration and basin-filling depositional systems as a function of trench slope break development and strike-slip movement: examples from the Cenozoic Ishikari-Sanriku-Oki and Tokai-Oki-Kumano-Nada forearc basins, Japan[END_REF]. The direction of the OFH probably changed trough time, as extensional and strike slip systems affected the zone during the opening of the GGTB during Miocene to Quaternary times [START_REF] Witt | Development of the Gulf of Guayaquil (Ecuador) during the Quaternary as an effect of the North Andean block tectonic escape[END_REF][START_REF] Witt | Forearc basin formation in the tectonic wake of a collision-driven, coastwise migrating crustal block: The example of the North Andean block and the extensional Gulf of Guayaquil-Tumbes Basin (Ecuador-Peru border area)[END_REF]. In any case, based in our knowledge, the Estancia

Hill may correspond to one of the best preserved exposures of an ancient outer forearc high worldwide.

A C C E P T E D M A N U S C R I P T 34

The shallow-water forearc basin infilling

As in other forearc basins related to the formation of an OFH, the Progreso basin depocenter consists of shallow water sediments lying unconformably on deep slope sediments.

The onset of the basin resulted from the definite rise of the OFH, isolating the semi-enclosed triangular Progreso basin (protected bay) which fills up mainly with shallow marine sediments (Fig. 12E), whereas the Peninsula area may have been emerged ever since. The OFH remains stable during the entire basin evolution from ~32 to ~10 Ma, as there is no evidence of basin dissection and outcrops of Oligocene -Miocene deposits in the Peninsula area.

The protected geographic configuration produced by the OFH favours the development of tidal dynamics, which is recorded for the first time in the Subibaja Formation (site 10) at ~16

Ma. The tidal currents running through the Progreso Basin would then have been trending The Progreso basin records at least one episode of tectonic inversion as evidenced by the shallowing of reflectors at the Carrizal fault system (structural limit between the Chongón-Colonche Hills and the Progreso basin). Seismic evidence suggest that the main tectonic inversion step took place before ~16 Ma (Fig. 11B), the basin floor was probably flatter before the inversion. Although, more work is needed to constrain the timing of uplift of the Chongón-Colonche Hills and its eventual relationships with the sedimentary input in the Peninsula and Progreso basin, it seems reasonable that topographic growth in the hills is probably linked with the recycled zircon component from 30 to 16 Ma in the basin; the hills acting as a semiregional topographic barrier preventing direct sourcing from Andean derived primary zircons.

Moreover, this process was of lesser importance or inexistent in the westernmost sections of the hills (Montañita area; site 8) where primary 23 Ma zircons are present. [START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]. Abbreviations are explained on the legend. D)

Heavy mineral associations obtained from [START_REF] Luzieux | Origin and late Cretaceous-Tertiary evolution of the Ecuadorian forearc[END_REF]. Note the difference between the scale of local observations performed in the field compared with the regional distribution of tectonic structures and sedimentary units observed in seismic lines.

  . Detailed sedimentary constraints come from field observations whereas tectonic constraints were obtained from field observations and from unpublished industrial seismic records. 2D lines in the Peninsula area were obtained during the eighties whereas seismic lines along the Progreso basin were derived from a 3D seismic cube obtained in 2010. More details are provided in the seismic interpretation section.

  of SW Ecuador is defined by three main stratigraphic successions that define the accretion, post-accretion, and forearc basin series. Thirteen different sites are described. Site and sample locations are shown in Figure 2. Complementary field pictures and age constraints are shown in Complementary Figure 2 (Com.Fig.2) and weighted average 206 Pb/ 238 U ages, where possible, are shown in Complementary Figure 3 (Com.Fig.3).

  Fig. 2B). Alteration patterns suggest the presence of a great amount of fluids. The sedimentary rocks are intensively sheared; although some folded structures are still noticeable. Sedimentary facies and deformation are very different from those observed in other nearby outcrops of the Azúcar Formation (or the Ancón Group, see below).

  are treated as the same unit in the present work. The Ancón Group yielded the calcareous nannoplankton Tribrachiatus orthostylus and Discoaster lodoensis from the eponymous biozones indicating a late Early Eocene (Comp.Fig. 1; Ordoñez et al., 2006). In detail, the Socorro Formation corresponds to the Discoaster binodosus and the lower Tribrachiatus orthostylus calcareous nannoplankton biozones, the Seca Formation to the Tribrachiatus A C C E P T E D M A N U S C R I P T 15 orthostylus calcareous nannoplankton Biozone and the Punta Ancón Formation to the Discoaster lodoensis calcareous nannoplankton Biozone (Comp.Fig. 1;

  Azúcar and Ancón facies including some cherts most presumably of the Late

  from paleontological assemblages and constraining the forearc basin initiation at around 32-29 Ma.

  abundance and diversity of fossils; there are planktic foraminifera, radiolarians and numerous calcareous nannoplankton. The base of the formation yielded diagnostic fauna indicating the early Early Miocene Cyrtocapsela tetrapera radiolarian Biozone (Comp.Fig.1;[START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]. The U-Pb age is also coincident with the age proposed for a dolphin skeleton recently found in the same unit in the Montañita area and dated as Chatian(upper Oligocene, 26-24 Ma;[START_REF] Tanaka | A new tropical Oligocene dolphin from Montañita/Olón, Santa Elena, Ecuador[END_REF]; and 2) previous macro and micro fauna observations from[START_REF] Bristow | On the age of the Zapotal Sands of Southwest Ecuador[END_REF]. Sandstones samples, CP702 (Dos Bocas Formation) and CP019 (Villingota Formation), near the basin border, did not yield a depositional age component (Figs.8D and 8E) and the extensive record of ~30 Ma and ~43 Ma zircons is believed to be derived from erosion of the Zapotal Formation and the Ancón Group, respectively. Similarly, an outcrop attributed to the Subibaja Formation (sample CP021;Comp.Fig.2P) showed a representative family at ~60 Ma and 3 zircon grains at ~ 30 Ma, which are ascribed to the Azúcar and Zapotal Formations, respectively. From all our dated samples, CP702, CP019 and CP021 are the only ones in which the youngest dates are not related to the depositional age. Not coincidentally, these samples are: 1) close to the main structural high of the Progreso basin, which suggests that reworking processes are stronger within sedimentary rocks located near to the structural high and 2) coeval with basin-inversion processes taking place at the NE basin limit (see seismic interpretation section). Furthermore, three other analyzed samples of the same formations near the Estancia Hills did not contain any zircon grain.Site 10 corresponds to the type-locality of the Subibaja Formation The Subibaja Formation show diagnostic foraminifera from the Globigerinatella insueta, Globorotalia foshi peripherodonda and Globorotalia foshi foraminifera biozones, indicating a Middle Miocene age for that formation (Comp.Fig.1;[START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF]. The lower part of the section isA C C E P T E D M A N U S C R I P T22 composed of a silty, volcaniclast-rich mudstone (Fig.9A) with numerous nodules and pipes that are likely related to early diagenesis. Due to the absence of tractive bedforms, and the occurrence of many floating bivalve shells in connection, this facies is interpreted as a lower offshore setting. The overlying deposits are coarsening upward and show a progressive return of current action at the sea-bed, by way of offshooting ripples, interpreted as wave ripples, which indicate an upper offshore setting (Comp.Fig.2S). The offshore deposits are overlain by a regressive facies tract, composed of a volcaniclastic litharenite comprising hummocky crossstratification (HCS), Ophiomorpha and cross strata infilling channels at the top. The HCS would correspond to shoreface deposits and the cross strata, which comprise upper-plane bedding, is interpreted as foreshore runnel infill. The sharp erosion at the bottom of the coastal facies and the lesser preservation of the shoreface argue in favor of a forced regression at this point. Similar downward shifts of facies are observed near the Zacachun locality (Fig.2A),

  10 and 11) have been chosen from a set of hundreds (including different 3D seismic cubes) to show the accretionary, post accretionary and forearc basin series (line location is shown in Fig. 2). The seismic lines of Figure 10 were obtained during the 1980's whereas the 2D seismic lines shown on Figure 11 were derived from a 3D seismic cube (30 m trace separation) coincident with the Progreso basin; obtained in 2010 by Petroamazonas. Although there is poor stratigraphic control on exploratory wells, a relatively good correlation A C C E P T E D M A N U S C R I P T 25 of chronological markers (i.e. formation tops) were derived from well data (Petroamazonas confidential data and internal reports) and from facies analysis performed in the present work.

  Fig. 11) as constrained by the age of sample CP405. Several angular unconformities are of

  is reached. When sedimentation modifies the taper angle deformation often migrates away from the deformation front in order to reconstitute a critical taper. This is the critical taper theory[START_REF] Dahlen | Critical Taper Model of Fold-And-Thrust Belts and Accretionary Wedges[END_REF] extensively used during the last 50 years to analyse the evolution of fold-and-thrust belts. OFHs have been generally ascribed to out-of-sequence deformation (e.g. that resulting from a sub-critical taper in order to gain taper and return to growth by frontal accretion). It is difficult to clearly define what caused the OFH in SW

  WNW-ESE. Owing to the likelihood that the north-western boundary of this basin (i.e.Chongón-Colonche Hills) was already uplifted, the tides might have entered in the basin from the east (Guayas area). Depending on the local configuration and systems tracts, either flood currents (to the WNW, ex. within channels) or ebb currents (to the ESE, ex. within sand bars) would have dominate. Open coast shoreline deposits might still have existed at this time (e.g. site 10). During the Progreso Formation, the tectonic quiescence of the basin brings about a decrease of the coarse clastic supply, favouring the onset of a carbonate system where oyster patch reefs develop close to the shoreline (site 12). Although the sedimentary evidence points to forced regression periods a thorough examination of forearc sedimentation in the wake of the eustatic variations during the last 30 Ma is difficult to achieve as field evidence is sparse and the early period of the forearc basin evolution comprised between 30 and 16 Ma has not beenA C C E P T E D M A N U S C R I P T35 yet dated accurately, because of absence of primary zircons. The necessary accommodation for the deposition of the 2-3 km forearc sediments may have resulted from the formation of the OFH (a process suggested for other forearc basins) although the south-eastwards deepening of reflectors may also attest for an increase of subsidence towards the Gulf of Guayaquil-Tumbes basin, which opening period may have started and clear tidal dynamics reached at least in Quaternary times[START_REF] Reynaud | Tide-dominated deltas in active margin basins: Insights from the Guayas estuary, Gulf of Guayaquil, Ecuador[END_REF]. The sedimentary succession in the upper part of the Progreso basin looks similar to that of other forearc Andean embayments, as those observed in the Valdivia complex in Chile (le[START_REF] Le Roux | Sedimentologic development of a Late Oligocene-Miocene forearc embayment, Valdivia Basin Complex, southern Chile[END_REF].

Figure 1 .

 1 Figure captions

Figure 2 .

 2 Figure 2. The SW Ecuadorian forearc. A) SRTM-derived topography showing geologic

Figure 3 .

 3 Figure 3. Stratigraphy, age constraints and sediment depositional environment in SW Ecuador.

Figure 4 .

 4 Figure 4. The Azúcar Formation A) Flysh-like deep series. B) Slope deposits showing flat-base

Figure 5 .

 5 Figure 5. Outcrop near the Pacoa locality at site 3. A) General view of the folded outcrop

Figure 6 .

 6 Figure 6. Outcrops of the Ancón Group in the cliffs of Ancón (site 4), Ballenita (site 5) and

Figure 7 .

 7 Figure 7. A) Conglomeratic facies of the Zapotal Formation at the locality type near the

Figure 8 .

 8 Figure 8. A) Yellowish litharenites and sandstones (Dos Bocas Formation) bounded by low

Figure 9 .

 9 Figure 9. The Neogene infilling of the Progreso forearc basin. A) White tuffaceous sandstones

Figure 10 .

 10 Figure 10. Time migrated seismic lines of key sections of the accretionary prism. Location of

Figure 11 .

 11 Figure 11. Time migrated seismic lines and line drawing of key sections of the Progreso basin

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

 1234567891011 Figure 1

Figure 12

 12 Figure12

Table

  R I P T 18 observed in the site 4 may have occurred at ~48 Ma, an age slightly older than the ~46 Ma, which was proposed by[START_REF] Ordoñez | Micropaleontología Ecuatoriana[END_REF] as the older age for these units, based on

	paleontology. Samples CP010 and CP011 yielded a very significant young component of
	zircons ranging between 45 and 40 Ma, with most likely two different clusters in this range
	(Figs. 6H and 6I). For sample CP010 (Fig. 6H), the 4 youngest concordant data yield a
	concordia age of 40.9 ± 0.6 Ma (MSWD=1.8). In sample CP011 (Fig. 6I), the four youngest
	concordant analyses return a concordia age of 40.5 ± 0.6 Ma (MSWD=1.8). These ages are in
	very high concordance with paleontological analysis (Ordoñez et al., 2006), which indicate a
	41-40 Ma age (zone P13 of planktic foraminifera; Bolli et al., 1989; Comp.Fig. 1) for the Punta
	Ancón succession. Samples CP010 and CP011 yielded very important clusters of ages
	weighted at 43.1 ± 0.2 Ma and 43.1 ± 0.4 Ma, respectively (Figs. 6H

Acknowledgements

We would like to thank Petroamazonas, and especially Manuel Rivera for letting us to publish the seismic material. Patrice Baby, Galo Montenegro and Nelson Jimenez are kindly thanked for helpful discussions in the field. Reviews of A. Noda and G. Moore were very appreciated and improved the quality of this paper. This work was found by Petroamazonas (Ecuadorian Petroleum Company) and INSU (Institut National de Sciences de l'Univers, France).

ACCEPTED MANUSCRIPT

A C C E P T E D M A N U S C R I P T

48


Benjamin Moreau
email: benjamin.moreau@ls2n.fr

Patricia Serrano-Alvarado

Emmanuel Desmontils
email: emmanuel.desmontils@ls2n.fr

Cali

Patricia Serrano-Alv

CaLi: A Lattice-Based Model for License Classifications

come   L'archive ouverte pluridisciplinaire

INTRODUCTION AND MOTIVATION

Web applications facilitate combining resources (linked data, web services, source code, documents, etc.) to create new ones. For a resource producer, choosing the appropriate license for a combined resource involves choosing a license compliant with all the licenses of combined resources and controlling the reusability of the resulting resource through the compatibility of its license. The risk is either, to choose a license too restrictive making the resource difficult to reuse, or to choose a not enough restrictive license that will not sufficiently protect the resource.

We consider that a license l j is compliant with a license l i if a resource licensed under l i can be licensed under l j without violating l i . If a license l j is compliant with l i then we consider that l i is compatible with l j

Finding the right trade-off between compliance and compatibility is a difficult process. An automatic classification over licenses protecting resources would facilitate this task.

Our research question is: given a license l i , how to automatically position l i over a set of licenses in terms of compatibility and compliance?

We propose CaLi, a lattice-based model to classify licenses. CaLi is able to answer questions like, "what are the licenses with which l i is compliant?" and "what are the licenses with which l i is compatible?". We show the usability of a CaLi classification through a prototype of a license-based search engine for the Web of Data.

The remainder of this abstract is as follows. Section 2 discuses related works, Section 3 introduces the CaLi model, Section 4 shows the implementation of a license-based search engine for linked data and Section 5 concludes.

RELATED WORK

There exist some tools to facilitate the creation of license compliant resources such as TLDRLegal1 , CC Choose2 , ChooseALicense3 , CC search4 , Web2rights5 and Licentia 6 . Unfortunately, one of them is able to order licenses in terms of compatibility or compliance.

The problem of license compatibility and license combination are addressed in Web services [START_REF] Gr Gangadharan | Service License Composition and Compatibility Analysis[END_REF], in collaborative environments [START_REF] Mesiti | On the Composition of Digital Licenses in Collaborative Environments[END_REF] and in the Web of Data [START_REF] Governatori | [END_REF][START_REF] Soto-Mendoza | Policies Composition Based on Data Usage Context[END_REF][START_REF] Villata | Licenses Compatibility and Composition in the Web of Data[END_REF]. These works focus on combining operators for automatic license combination but do not propose to position a license over a set of licenses.

Concerning the problem of license classification to facilitate the selection of a license, [1,[START_REF] Kapitsaki | Automating the License Compatibility Process in Open Source Software With SPDX[END_REF] propose a compatibility graph to classify licenses. However, such graph is build from a manual interpretation of each license, so its generalization and automation is not possible.

In the domain of access control, [START_REF] Denning | A Lattice Model of Secure Information Flow[END_REF] proposes a lattice model of secure information flow to automatically classify security classes with associated resources. [START_REF] Sandhu | Lattice-Based Access Control Models[END_REF] describes several models based on this approach but none focuses on classifying licenses.

None of these works answers our research question. In our work we propose a lattice-based model inspired by [START_REF] Denning | A Lattice Model of Secure Information Flow[END_REF]. Existing combining operators like [START_REF] Gr Gangadharan | Service License Composition and Compatibility Analysis[END_REF][START_REF] Governatori | [END_REF][START_REF] Soto-Mendoza | Policies Composition Based on Data Usage Context[END_REF][START_REF] Villata | Licenses Compatibility and Composition in the Web of Data[END_REF] make feasible the automatic generation of a lattice. This model is independent on any license combination approach, license description language and licensed resources so that it can be used in a wide variety of domains.

CALI: A LATTICE-BASED LICENSE MODEL

CaLi is a model that allows to express license classifications with a lattice structure. The model considers a finite set of licenses, a combining operator, a compatibility relation over licenses, resources and their association with licenses, and a set of constraints. The combining operator applied to the set of licenses produces a lattice that expresses the compliance and compatibility among licenses. This model is introduced next. A license is considered as a set of actions. Actions used in L are taken from A = {a 1 , ..., a n }, a set of actions that can be applied on resources.

is an associative and commutative binary operator that specifies for any pair of licenses, the combined license that is compliant with both licenses. For licenses l i and l k , if l i l k = l j then l j is compliant with l i and l k .

For licenses l i and l j , we write l i → l j iff l i is compatible with l j (or l j is compliant with l i ). l i → l j implies l i l j = l j , i.e., l j overcomes l i .

We write r i → l i when the resource r i is protected by l i . For r i → l i , if l i is compatible with l j then r i can be protected by l j .

In addition we introduce the concepts of viability of a license and viability of a → relation.

• A viable license is a license that allows the licensed resource to be used. A license l i is viable iff it respects all C L constraints.

BDA, October, 2018

Benjamin Moreau, Patricia Serrano-Alv arado, and Emmanuel Desmontils

• A viable compatible with relation, l i → l j , is a relation that allows a resource licensed under l i to be licensed under l j . A → relation between two licenses is viable iff it respects all C → constraints. l i is compatible with l j if there exists a path from l i to l j where all compatible with relations and all licenses are viable.

We demonstrate that the set of licenses L, the compatible with relation → and the combining operator form a lattice where: (1) ⟨L, →⟩ is a partially ordered set.

(2) L is finite.

(3) L has an infimum (or greatest lower bound) I such that

I → l i ∀l i ∈ L. (4)
is a totally defined least upper bound operator on L.

A LICENSE-BASED LINKED DATA SEARCH ENGINE

We experiment the usefulness of our work with a license-based search engine for the Web of Data. This search engine is based on the following CaLi classification: L = {⟨P, O, Pr ⟩}; P, O, Pr are sets of permissions, obligations and prohibitions containing actions ∈ A. A is the set containing the 72 actions considered by ODRL 7 . is the license combining operator, l i l j ≡ ⟨P l i ∩ P l j , O l i ∪O l j , Pr l i ∪ Pr l j ⟩ where P l i is the permission set of l i , O l i is the obligation set of l i , and Pr l i is the prohibition set of l i . → is the compatible relation stating that l i → l j iff P l i ⊇ P l j and

O l i ⊆ O l j and Pr l i ⊆ Pr l j . C = ⟨C L , C → ⟩ where C L = {ω L 1 , ω L 2 } and C → = {ω → 1 , ω → 2 }.

Concerning the set of constraints that characterizes viable licenses and viable → relations:

ω L 1 specifies that viable licences have sets of permissions, obligations and prohibitions that have to be mutually disjoint.

ω L 2 specifies that if an action a i is prohibited, all the actions included in a i must not be permitted nor obligated to be a viable license. For example, a license that prohibits Use is not viable if it permits or obligates Commercial Use.

ω → 1 specifies that cc:ShareAlike term obligates the distribution of derivative works only under the same license.

ω → 2 specifies that if cc:DerivativeWorks is prohibited in a license l i then resources protected by l i should not be protected by l j .

The generation of a lattice has a complexity of O (2 n ). In our case, n = 2|A| and the number of nodes in the lattice is 2 144 . The number of nodes grows exponentially with the number of terms resulting in a combinatorial explosion. Generating the complete lattice is not suitable for a real scenario with a large number of terms. Thus we propose algorithms to generate part of the lattice on the fly. Our approach is in O (n) where n is the number of existing nodes.

Answering our questions with the CaLi classification is straightforward. Finding all licensed datasets whose licenses are compliant with a particular license l i means to retrieve datasets protected by l i and all datasets protected by licenses that are above l i in the graph. Similarly, finding all licensed datasets whose licenses are compatible with a specific license l i means to retrieve datasets protected by l i and all datasets protected by licenses that are below l i in the graph. 7 https://www.w3.org/TR/odrl-vocab/#actionConcepts The prototype of this search engine is available at http://cali. priloo.univ-nantes.fr8 .

CONCLUSIONS

In this paper we proposed CaLi, a model to express license classifications. The goal of our work is to encourage the publication and reuse of resources in a license compliant web.

CaLi can be used to classify licenses in different contexts where resources need to be reused. It considers a set of licenses, a combining operator, a compatibility relation over the set of licenses and a set of constraints. The combining operator applied automatically to the set of licenses produces a lattice that expresses both compliance and compatibility among licenses. This lattice garantees a partial order over licenses.

Definition 3 . 1 .

 31 CaLi = ⟨L, , →, R, →, C⟩. L = {l 1 , ..., l n } is a set of licenses.is a license combining operator. → is the compatible with relation defined on pairs of licenses. R = {r 1 , ..., r m } is a set of resources. → is the protected by relation between R and L. C = ⟨C L , C → ⟩ is a finite set of constraints to express viability. C L is a set of constraints over L and C → is a set of constraints over → in L × L.

https://tldrlegal.com/

https://creativecommons.org/choose/

https://choosealicense.com/

https://ccsearch.creativecommons.org/

http://www.web2rights.com/creativecommons/

http://licentia.inria.fr/

A video demonstration is available at https://youtu.be/YkSWHSiD-Ps.

ACKNOWLEDGMENTS

Authors thank Matthieu Perrin for his helpful comments on this work.


Stéphanie Rey

Anke Brock

Célia Picard

Mustapha Christophe Bortolaso

Mustapha Derras

Nadine Couture

Individualized Visits to Foster the Engagement and the re-visit in Museums

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Design of authoring tools to:

Individualized Visits to Foster Engagement and Revisit in Museums To understand the needs of museum staff, we adopted a Human-Computer Interaction (HCI) participative and iterative design process.

We conducted, with museum professionals:

 meetings,  semi-directive interviews studies,  experimental observations
 Diversify the visits depending on the visitor, multiply the points of view on the collection, adapt the content to the public  Collect and analyse data on the visitors  Be autonomous to create, evolve and maintain the solution Visitors service professionals are almost never involved before the end of exhibition design process. Thus, they have no mean to shape the scenography in order to adapt it to visitors.

But they have the skills for selecting the most appropriate information, using storytelling to improve the learning of the visitors and adapting dynamically to their audience in guided visits.

Method: end-user observation and analysis

Main results of the analysis

Tangible interfaces for the personalisation of the visits Thus, they are in competition with the entertainment industry to attract and expand their audience.

But museums lack adequate budget, skills and IT infrastructure to support this approach and solutions over time.

4 2

Museums have a strong need for encouraging local visitors' engagement and revisit in their permanent collections.

Diversifying the visits is a solution considered by museums, but relying on temporary exhibits is too costly for small museums and creating thematic visits is not participatory enough.

Museums, have long been part of Berger-Levrault's clients. Today, Berger-Levrault is willing to reconquer the museum market and the e-tourism market by providing innovative software and services dedicated to tourists, visitors and public services. This PhD Thesis is a first step in this direction, in addition to the marketing team working on the subject.

1

  Definition extracted from ICOM, International Council of Museums at http://icom.museum/la-vision/definition-du-musee/L/2/ accessed the 13/02/2018 2 Stéphanie Rey. 2017. Museomix: Lessons learned from an open creative hackathon in museums. In CEUR Workshop Proceedings -Proceedings of the 3rd European Tangible Interaction Studio (ETIS 2017), 1861, pp.5. Stéphanie REY 1,2,3 , Anke Brock 4 , Celia Picard 4 , Christophe Bortolaso 1 , Mustapha Derras 1 , Nadine Couture 2,3 1 Berger-Levrault, Toulouse, France 2 LaBRI, Univ. Bordeaux, Bordeaux, France 3 ESTIA, Bidart, France 4 ENAC, Toulouse, France Context « A museum is a non-profit, permanent institution [...] which acquires, conserves, researches [...] and exhibits the tangible and intangible heritage of humanity [...] for the purposes of education, study and enjoyment. » 1 Museums want to foster the participation of their visitors. The Museomix cultural hackathon is part of this new ambition. During this three days event, the « visitor-actors » create new museum exhibits and invent new ways of sharing knowledge 2 . Cité du Vin (Bordeaux), Musée Saint-Raymond (Toulouse), Musée de minéralogie des Mines Paris Tech (Paris), Cité de l'Océan (Biarritz), Musée des Beaux Arts, Cap Science (Bordeaux).