Nicolas Olivier
email: n.olivier@opgc.fr

Arnaud Brayard

Emmanuelle Vennin

Gilles Escarguel

Emmanuel Fara

Kevin G Bylund

James F Jenks

Gwénaël Caravaca

Daniel A Stephen

Evolution of depositional settings in the Torrey area during the Smithian (Early Triassic

Keywords: Early Triassic, Smithian, Utah, microbialites, depositional environments, biotic recovery, bioconstructions

INTRODUCTION

Deleterious oceanic conditions are generally associated with the aftermath of the Permian-Triassic mass extinction, the most devastating biotic crisis in the Phanerozoic [START_REF] Raup | Size of the Permo-Triassic bottleneck and its evolutionary implications[END_REF][START_REF] Erwin | Extinction. How Life on Earth nearly ended 250 million years ago[END_REF]. Indeed, large environmental perturbations, combining ocean acidification, anoxia, euxinia, and fluctuating productivity [START_REF] Payne | Large perturbations of the carbon cycle during recovery from the end-Permian extinction[END_REF][START_REF] Galfetti | Timing of the Early Triassic carbon cycle perturbations inferred from new U-Pb ages and ammonoid biochronozones[END_REF][START_REF] Grasby | Recurrent Early Triassic ocean anoxia[END_REF], likely constrained the biotic recovery during the Early Triassic. Until recently, post-crisis environments appeared to be particularly suitable for widespread development of abiotic and microbial deposits [START_REF] Schubert | Early Triassic stromatolites as post-mass extinction disaster forms[END_REF][START_REF] Baud | Biotic response to mass extinction: the lowermost Triassic microbialites[END_REF][START_REF] Baud | The Lower Triassic anachronistic carbonate facies in space and time[END_REF][START_REF] Mata | Microbes and mass extinctions: paleoenvironmental distri bution of microbialites during times of biotic crisis[END_REF][START_REF] Woods | Microbial ooids and cortoids from the Lower Triassic (Spathian) Virgin Limestone, Nevada, USA: evidence for an Early Triassic microbial bloom in shallow depositional environments[END_REF], whereas the metazoan recovery was assumed to be delayed. However, for some marine groups such as ammonoids (Brayard et al., 2009b) and conodonts [START_REF] Orchard | Conodont diversity and evolution through the latest Permian and Early Triassic upheavals[END_REF], or where permitted by favorable environmental conditions (Krystyn et al.,(38°10'21.58"N,111°11'54.89"W), situated within Capitol Reef National Park, 13 km south of Fruita.

In the Torrey area, the Lower Triassic sedimentary succession is represented by interfingered siliciclastic and carbonate deposits [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF]. These sediments belong to the Moenkopi and Thaynes groups (sensu Lucas et al., 2007), which unconformably overly the Permian carbonate Kaibab Formation [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. Directly above the Permian rocks, the Black Dragon Formation corresponds to the first occurrence of red beds (Fig. 1b). These siliciclastic deposits correspond to reddish to brownish siltstones, sandstones and even conglomerates [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. The transition to the carbonate deposits of the Smithian Sinbad Formation can be gradual. Although, [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF] placed the boundary between the Black Dragon and the Sinbad formations below the first carbonate bed, other workers considered transitional carbonate beds observed within the red beds as part of the Black Dragon Formation [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF]. This work follows the lithostratigraphical definition of [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. The Sinbad Formation can be readily subdivided into two main units (Fig. 1b): a massive microbial limestone unit (lower Sinbad Formation) and a bioclastic limestone unit (upper Sinbad Formation). Contact with the overlying deposits of the Spathian Torrey Formation is classically described as a conformable surface between the bioclastic limestones of the Sinbad Formation and a second occurrence of red beds [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF].

During the Early Triassic, the western USA basin was located at a near-equatorial position on the western margin of the Pangea. A large epicontinental sea about 500 to 600 km-wide and extending from southern Utah to British Columbia, exhibited a deepening trend from the south-east to the north-west [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Paull | Interpretation of Early Triassic nonmarine-marine relations, Utah[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF]. Thus, most of the terrigenous sediments belonging to the Moenkopi Group can be found in southern and southeastern Utah and they represent the most proximal settings and paleoshoreline positions [START_REF] Olivier | Smithian Shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)[END_REF]. Carbonate deposits of the Thaynes Group represent more open-marine conditions and can be found mainly in central and northwestern Utah, southeastern Idaho and northeastern Nevada [START_REF] Kummel | Triassic stratigraphy of southeastern Idaho and adjacent areas[END_REF]Hose and Repenning, 1959;[START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Collinson | Early Triassic paleogeography and biostratigraphy of the Cordilleran miogeosyncline[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF][START_REF] Guex | Spathian (Lower Triassic) ammonoids from western USA (Idaho, California, Utah and Nevada)[END_REF][START_REF] Brayard | Transient metazoan reefs in the aftermath of the end-Permian mass extinction[END_REF][START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF].

Preliminary information regarding regional ammonoid and conodont biostratigraphy, from previous studies indicate that the Sinbad Formation in the Torrey area is late Smithian (sensu [START_REF] Brühwiler | High-resolution biochronology and diversity dynamics of the Early Triassic ammonoid recovery: The Smithian faunas of the Northern Indian Margin[END_REF] in age due to the occurrence of the Anasibirites kingianus zone (Stewart et al., 1972;[START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF], Lucas et al., 2007;[START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF]. Several new ammonoid specimens,collected bed-by-bed from the Torrey area, have been integrated with the new regional biostratigraphic framework proposed by [START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. Juvenites aff. spathi, Parussuria compressa, Meekoceras gracilitatis and Lanceolites compactus occur in the uppermost part of the lower Sinbad Formation (interval A1; Fig. 1b), suggesting a likely middle Smithian age (basal Owenites beds by comparison with neighbouring localities; see [START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. Interval A2, situated in the middle of the upper Sinbad Formation, yields ammonoids identified as Lanceolites compactus, Hedenstroemia kossmati, Churkites noblei, Guodunites hooveri and Dienoceras dieneri. Such an assemblage is diagnostic of the Owenites beds, which are typically middle Smithian in age (Brayard et al., 2009a[START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. Interval A3 includes Wasatchites perrini and Anasibirites kingianus, indicating a late Smithian age [START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. Rare conodonts occurring near the base of the upper Sinbad Formation are represented by Furnishius triserratus, Parachirognathus ethingtoni and some ellisonids, also indicating a Smithian age (N. Goudemand, pers. com. 2012).

SECTIONS AND FACIES DESCRIPTION

French Fork section

The Permian Kaibab limestones are not exposed at the base of the French Fork section (Fig. 2a). The entire section can be subdivided into three main lithological units (Figs 3,4). The first unit includes the uppermost 12 m of red beds of the Black Dragon Formation (Fig. 1b).

Facies (F1) consists of mm-to cm-thick red, dolosiltstone beds with small asymmetrical ripples (Table 1). Some muddy sheets display mud cracks locally. Other observed sedimentary structures include megaripples and climbing ripples. Quartz grains are abundant and subangular to subrounded. Also present are few cm-to dm-thick beds particularly rich in secondary gypsum.

The second unit occupying the interval between 12 and 23 m consists of two main limestone facies, which constitute the lower Sinbad Formation. Facies F2, which occurs only as a thin cm-thick interval at the base of this second lithological unit, corresponds to an intraclastic floatstone, with frequent basal erosive surfaces. Flat pebbles made of peloidal wackestone (locally mudstone or packstone) and exhibiting desiccation cracks are also present. Smaller intraclasts are poorly sorted and subangular to subrounded. A few domal stromatolites are visible locally.

Facies F3 corresponds to a massive peritidal limestone interval (Fig. 2a). Several undulating surfaces can be followed laterally along the cliff, permitting the identification of six meter-scale subunits (Fig. 4). These subunits consist of cm-to dm-thick beds that show important lateral variations in thickness. These variations tend to form local meter-scale patches (Figs 2a,5a and b). In greater detail, two main subfacies can be identified at French Fork (Fig. 5c andd). The first fenestral limestone subfacies (F3b) is made of fenestrae, oncoids, peloids, aggregate grains, and some ooids and cortoids. Locally, some undulating laminated crusts binding the different grains are present (Fig. 5e andf). The sizes of the fenestrae are classically mm-scale, but some can be coalescent and form dm-scale aligned structures (Fig. 6a andd). Within these large fenestrae, microbialitic crusts are observed on the walls and roofs of the cavities with upward and downward growth direction (Fig. 6b andc, e). The relatively poor fauna is composed only of gastropods, bivalves, ostracods and siliceous sponges (Fig. 6f). Some fenestrae exhibit vadose silts (Fig. 7c). The second subfacies (F3c) consists of laminated micrites with domal and horizontal sheet cracks, and tepee structures (Figs 5g and h,7d). Some stromatolites are also observed locally. The biota is sparse, consisting mainly of ostracods, gastropods, and siliceous sponges (Fig. 6g). Subfacies F3b an F3c can either be observed juxtaposed or superimposed (Fig. 7).

The third lithological unit, observed from 23 to 45 m, represents the upper Sinbad Formation. At French Fork, seven facies are identified in this uppermost lithological unit Fig. 4; Table 1). Facies F5 corresponds to dm-to m-thick intervals of dolostones with common cm-thick intercalations of siltstones and rare sandstones. Peloids and common-to-abundant subrounded quartz grains mainly represent non-biotic grains. This facies generally appears barren of organisms, but some ostracods and bivalve moldic voids can be observed. Evidence of infaunal activity is uncommon; only rare and localized trace fossils can be observed. Sedimentary structures are common and correspond to low-angle cross laminations. Facies F8 consists of ooid-bioclastic grainstone, which is only observed in a thin interval between 27 and 27.5 m. Facies F9 corresponds to peloid-bioclastic grainstone, which is also only observed within a thin interval at the top of the section (close to 45 m).

Facies F10 is more frequent within the section, consisting of a grainstone (locally packstone) made of abundant gastropods and bivalves. Dense, deep bioturbation can also be present, and trough cross-stratifications are common. Facies F11 consists of grainstone to packstone with bivalves, serpulids, rare echinoderm plates and peloids. This facies is only observed in the interval between 25 and 27 m in the section. Facies F12 is composed of a peloid-bioclastic packstone with abundant bivalves, gastropods, and echinoderm plates associated with some ammonoids and serpulids. This facies is observed at two intervals within the section (~35 m and 43.5 m). Facies F13 consists of a peloid-bioclastic wackestone to packstone. This intensely and deeply bioturbated facies is observed in two thin intervals within the section (~32 m and 37.5 m). Ammonoids are observed in three intervals within the third lithological unit (Fig. 4). Meekoceras is documented between 34.5 and 35 m in facies F12. The second main occurrence consists of Guodunites and Churkites, observed in facies F10 and F13, between 36.5 and 37.5 m. The uppermost occurrence of common Anasibirites and Wasatchites is observed in facies F10 between 41 and 42 m.

Beas Lewis Flats section

This section can be subdivided into four lithological units (Figs 2b,8). The first unit, which is beyond the scope of this work, corresponds to the Permian bioclastic and bioturbated limestones of the Kaibab Formation. The base of the section displays a 20 m-thick interval composed mainly of dolomitized and silicified limestones. Only the uppermost 7 m of this lithological unit are illustrated in figure 8. An intense bioturbation emphasized by silicification is recorded in these Permian limestones. Two bioclastic-rich intervals with cross bedding are observed at about 15 m above the base of the section. These Permian limestones are also locally affected by intense karstification (Fig. 8).

The second lithological unit is 34 m thick and corresponds to the red beds of the Black Dragon Formation. These red beds (Facies F1) are similar to those observed at the base of the French Fork section. The Beas Lewis Flats section exhibits a progressive transition between the second and the third lithological units.

The ~ 6 m-thick third lithological unit corresponds to the massive peritidal limestones (F2 and F3) of the lower Sinbad Formation. This unit is only half as thick as corresponding beds in the French Fork section; it does not exhibit conspicuous m-scale patchy microbial structures. It can be subdivided into three subunits (Fig. 8). The basal subunit (between 53.5 m and 56 m) includes the first limestone beds that interfinger with the dolosiltstones (F1) of the red bed unit. These uppermost red bed intercalations are notably richer in micritic intraclasts. This first subunit is comprised of floatstone with some localized small cm-to dmlarge domal stromatolites (F2; Figs 9a, 10). Rare gastropods and siliceous sponges also occur.

Additionally, even though burrows could not be clearly identified, the distribution of sedimentary grains tends to record an apparent infaunal activity. The second subunit (between 56 m and 58.5 m) corresponds to relatively well-bedded limestone (F3), including 3 main subfacies (F3a-c; Fig. 10). Each bed exhibits a basal part with abundant gastropods (F3a;Figs 9b,11). This subfacies can also be rich in intraclasts and it also includes some rare siliceous sponges (Fig. 10k-m). The middle part of these beds corresponds to fenestral limestone subfacies (F3b; Figs 10h-j, 12), and the upper part displays laminated mudstones with sheet cracks (F3c; Figs 10e-g , 11). The third subunit (between 58.5 m and 60 m) consists of oncoid-fenestral limestones (F3e) with abundant peloids and some ooids, aggregate grains, gastropods, serpulids and ostracods (Fig. 10b-d). This subfacies is characterized by large fenestrae that display internal stromatolites with upward and downward growth directions.

The fourth lithological unit of the Beas Lewis Flats section is characterized by a succession of dolostone intervals (F5) with various bioclastic, oolitic or peloidal limestones (F6-F10, F12 and F13). This bioclastic limestone unit comprises the upper 30 m of the section. From 61.5 to 65 m, two m-thick beds correspond to a peloid-intraclastic grainstone (F6). From 65 to 69.5 m, ooid-bioclastic grainstone (F8) and peloid-bioclastic grainstone (F9) are particularly well represented, interfingering with thin intervals of dolostones (F5). At about 70 m, a thin dm-thick interval of intraclastic grainstone (F7) is observed, in which subangular to angular limestone intraclasts are associated with well-rounded lithoclasts. The first occurrence of peloidal and bioclastic wackestone (F13) is documented above this intraclastic interval. From 74 m, dolostone intervals interfinger with bioclastic limestone beds of facies F10, F12 and F13. At about 78 m, specimens of the ammonoid Anasibirites kingianus are observed in a thin dm-thick interval within facies F13.

Pleasant Creek section

The Pleasant Creek section is subdivided into three lithological units (Fig. 12). Permian limestones of the Kaibab Formation are visible within a 15 m interval at the base of the section (Fig. 2c). These limestones are strongly dolomitized and no fossil grains could be identified. Nonetheless, some sedimentary structures are still recognizable, such as abundant planar laminations, small asymmetrical ripples, and some trough cross-bedding.

Above a stratigraphic gap of 5 m, a 15 m-thick red bed unit of the Black Dragon Formation is documented. The uppermost part of this unit corresponds to F1 that displays frequent conglomeratic intervals. Some tepee structures and desiccation cracks are also observed.

The third lithological unit corresponds to the bioclastic limestone unit of the upper Sinbad Formation. The thick microbial limestone unit of the lower Sinbad Formation observed at French Fork and Beas Lewis Flats is therefore not recorded at Pleasant Creek. In the basal 5 m, several intervals of intraclastic limestone (F2) are interfingered with dolostones (F5). At 38.5 m, a dm-thick bed exhibits domal stromatolites (F4; Fig. 13a). Microscopically, these stromatolites consist of dense micritic laminae, which sometimes reveal desiccation cracks, alternating with fenestral laminae (Fig. 13b). From 40 to 45 m, dolostones (F5) are interfingered with dm-to m-thick peloidal-intraclastic limestones (F6). These beds display internal cross bedding, frequent mudclasts, and important changes in lateral thickness. A second occurrence of intraclastic limestones (F2) and stromatolites (F4) is recorded between 45 m and 46 m. In this case, the stromatolitic interval can be subdivided into a lower bed characterized by dm-scale wavelength domal stromatolites and an upper stratiform bed displaying a wavy laminated structure (Fig. 13c). Microscopically, these wavy microbial carbonates are comprised of an alternation of dense micritic laminae with clotted laminae (Fig. 13d).

The rest of the section is characterized by a succession of dolostones (F5) with various bioclastic, ooidal, and peloidal limestones. From 46 m to 48 m, a thick ooid-peloidal grainstone (Facies F8) displays herringbone cross-stratification in its uppermost part (Fig. 13e). It is characterized by well-sorted ooids associated with some gastropods (Fig. 13f).

From 49.5 m to 52.5 m, the section displays an interval characterized by an alternation of dolostones (F5) with bioclastic facies (F10, F12, and F13). This interval is notably characterized by its intense bioturbation and the presence of echinoderm fragments (Fig. 12; Table 1). At about 55 m, an oolite-rich bed (F8) contains abundant Anasibirites kingianus. In the uppermost part of the section (at 57 m), some cm-scale beds with basal erosive parts are particularly rich in bivalves (F11 and F12; Fig. 13g) that exhibit siliceous sponges under their disarticulated valves (Fig. 13h).

FACIES MODELS AND DEPOSITIONAL ENVIRONMENTS

For the studied stratigraphic interval, the 13 identified facies can be placed into two facies models (Fig. 14; Table 1). The first model is characterized by the red beds (F1) of the Black Dragon Formation and the microbial limestones (F2 and F3) of the lower Sinbad Formation (Fig. 14a). Progressive gradation between the red bed deposits and the microbial limestones observed in the Beas Lewis Flats section supports a common facies model for these deposits.

Previous workers mentioned the vertical interfingering between the Black Dragon red beds and the Sinbad carbonates [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Blakey | Petroliferous lithosomes in the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF].

Red beds can have originated in various depositional environments such as marginal marine, deltaic, and coastal plain settings [START_REF] Voigt | Coastal-plain origin of trace-fossil bearing red beds in the Early Permian of Southern New Mexico, U.S.A. Palaeogeography[END_REF]Thomson and Lovelace, 2014). In this first depositional model, the red beds display both cm-scale planar-or ripple-bedding structures and climbing ripples that are consistent with a tide-dominated setting. Rippled siltstones and fine sandstones are interpreted as deposits of the lower intertidal (low tidal flats) to shallow subtidal zone, where bedload transport occurs during moderate tidal activity [START_REF] Alam | Tide-dominated sedimentation in the Upper Tertiary succession of the Sitapahar anticline, Bangladesh[END_REF]. The paucity of tidal channels in the red beds can be considered as an evidence of a low palaeotidal range [START_REF] Walker | Shorelines of weak tidal activity: Upper Devonian Catskill Formation; Central Pennsylvania[END_REF]. It may also indicate a gentle palaeoslope, such as a low gradient inner shelf or embayment, in which the tidal currents were not strong enough to develop tidal channels [START_REF] Alam | Tide-dominated sedimentation in the Upper Tertiary succession of the Sitapahar anticline, Bangladesh[END_REF]. Limestones (F2 and F3) of the lower Sinbad Formation represent a facies association interpreted as peritidal, which formed in environments around the tidal zone [START_REF] Wright | Peritidal carbonate facies models: A review[END_REF][START_REF] Flügel | Microfacies of carbonate rocks[END_REF]. The rarity of siliciclastic grains suggests a position still under terrigenous influence, but sufficiently removed from the terrigenous sources. In situ and reworked desiccation cracks observed in F2 provide evidence of at least temporarily emerged small islands. Small cm-scale stromatolitic domes observed locally in this facies highlight some zones of higher accommodation, also allowing for an infaunal activity. The peritidal limestones (F3) are subdivided into five subfacies (F3a-e; Table 1). These subfacies vary both laterally and vertically in the same bed, suggesting a patchy facies distribution (facies mosaic; [START_REF] Wright | The carbonate factory continuum, facies mosaics and microfacies: an appraisal of some of the key concepts underpinning carbonate sedimentology[END_REF]Strasser and Védrine, 2009). Gastropod-rich packstone (F3a), which show important lateral thickness changes, may represent winnowed subtidal skeletal deposits in zones of gently sloping gully surfaces (Fig. 14a). These gastropods can also be found in the margin of small ponds that merged with surrounding intertidal flats [START_REF] Shinn | Anatomy of modern carbonate tidal-flat, Andros Island, Bahamas[END_REF]. The fenestral limestones (F3b) are the most common deposits of the peritidal facies association and represent supratidal or intertidal sediments [START_REF] Shinn | Practical significance of birdseye structures in carbonate rocks[END_REF]. With biofilms that coated numerous fenestrae and diverse grains, this subfacies commonly developed a small synoptic relief above the sea floor. Vadose silts observed in some fenestrae are consistent with areas intermittently exposed at the time of deposition. Mudstone deposits (F3c) with sheet-cracks, a restricted fauna (ostracods and gastropods), and some stromatolites reflect supratidal to intertidal low-energy settings. Ooidoncoid-peloidal grainstone (F3d) deposited in subtidal high-energy gullies. The latter may have enhanced the patchy geometry of these peritidal deposits. Large sheet-like fenestrae limestones with oncoids and sparse ooids (F3e) are interpreted to reflect more distal shallow subtidal settings. The presence of siliceous sponges and gastropods in these peritidal limestones (F3) is also indicative of marine conditions and thus, of a seaward position of the lower Sinbad limestones as compared to the red beds of the Black Dragon Formation.

The second facies model is characterized by deposits of the bioclastic limestone unit (i.e., the upper Sinbad Formation; Fig. 14b). The 11 facies included in this model can be grouped into three facies associations typical of the following three different depositional settings: (i) tide-dominated interior platform; (ii) tide-dominated shoal complex; and (iii) open wave-dominated marine platform. Dolostones (F5) represent internal muddy and low-energy depositional settings, recording variable amount of terrigenous inputs. It differs from the red beds (F1) by recording obvious marine influences shown by the presence of bivalves, gastropods and echinoderm plates. These dolostones are consistent with deposition on a vast interior platform or a large embayment system. Stromatolites made of small domes and wavy laminated structures (F4) may have formed in upper intertidal and supratidal zones within this interior platform. Ooid-bioclastic grainstone with some bivalves (F8) is probably indicative of stronger tidal currents, and possibly wave action that impacted the shoal complex area. As observed on both the ocean-ward and platform-ward sides of the oolitic shoal, the peloidbioclastic grainstone with bivalves and sparse ooids (F9) logically points to less vigorous tidal currents. Well-marked herringbone cross-stratifications observed in these shoal deposits (F8 and F9) indicate a tide-dominated process. Intraclastic rudstone (F7) and peloid-intraclastic limestones (F6) were deposited in channels that cut across the shoal. Seaward of the tidaldominated shoal complex, sediments may have evolved from peloidal and ooidal sands into a mixture of skeletal (gastropods, bivalves, serpulids and echinoderms) and peloidal sands (Halley et al., 1983, p. 472). More abundant bioclasts recorded in grain-supported sediments (F10 and F11) may have been deposited on the seaward side of the tide-dominated shoal complex. An inner-to mid-shelf transition zone is marked by the deposition of bioclastic packstone (F12). Mud-supported texture and intense bioturbation that characterize peloidalbivalve wackestone (F13) indicate deposition below the fair-weather wave base in an offshore position. The record of vertically oriented bivalves in F12 and F13 suggests local turbulent and rotary flows during storms [START_REF] Pérez-López | Tempestite facies model for the epicontinental Triassic carbonates of the Betic Cordillera (southern Spain)[END_REF]. The frequent record of ammonoids in these facies also confirms an open-ocean influence. Thus, in a large embayment system, the shoal complex can be considered as tide dominated, even if its seaward margin was impacted by open-sea waves.

SECTION CORRELATION AND DEPOSITIONAL SEQUENCES

The only previous attempt to correlate sections in the Torrey area was largely based on a lithostratigraphic approach [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. For the herein studied sections, age assignments are nevertheless possible owing to conodont and ammonoid occurrences. Conodonts from the base of the upper Sinbad Limestone at French Fork yield a Smithian age. However, no definite conodont zonation and correlation are possible between the French Fork, Beas Lewis Flats and Pleasant Creek sections. Therefore, the record of the Anasibirites fauna within dmscale levels in the upper part of these three sections is the only correlation timeline available within the Torrey area (Fig. 15). Based on these Anasibirites beds, it is possible to recognize distinct hierarchical stacking patterns and facies evolution in the sedimentary succession, thus allowing for the identification of large-, medium-, and small-scale depositional sequences. At each hierarchical level, the facies evolution of depositional sequences generally indicates deepening and shallowing trends defined by transgressive surfaces (Strasser et al., 1999).

The Black Dragon and Sinbad formations reflect a large-scale depositional sequence, which is similar to the facies evolution previously described in the San Rafael Swell area [START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF]. The Black Dragon red beds, which represent clastic tidal-flat deposition [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF], mark the beginning of the transgressive trend. Maximum accommodation corresponds to the Anasibirites beds observed in the uppermost Sinbad Formation. The sequence boundary may either be at the top of the Sinbad Formation or in the lower part of the Spathian Torrey Formation, in agreement with the interpretation of [START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF].

Five medium-scale sequences are identified (S.I-V; Fig. 15). The first sequence is initiated at the top of the Permian limestones, but no clear facies evolution can be observed in the dolosiltstones of the red beds. The second medium-scale depositional sequence is well visible at French Fork and Beas Lewis Flats. Intraclastic limestones (F2) observed at the base of the microbial unit of the lower Sinbad Formation mark the transgressive interval of this second medium-scale depositional sequence. The sparse ammonoid record at French Fork and the presence of large fenestrae and oncoids (F3e) in the uppermost part of the microbial limestone unit at Beas Lewis Flats underline the maximum flooding interval (Figs 4,8). This second depositional sequence is more difficult to observe at Pleasant Creek, where the microbial limestone unit is absent (Fig. 15). The progressive decrease in thickness of the microbial limestone unit between French Fork and Beas Lewis Flats and its absence in Pleasant Creek is consistent with a general retrogradational pattern of this facies toward the southeast [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. The erosional surface at the top of the microbial limestone unit at Beas Lewis Flats marks the sequence boundary of this second medium-scale sequence. The remaining three medium-scale depositional sequences are characterized by a facies evolution with deepening-shallowing trends marked by a complex interplay between lower shoreface, shoal, and tidal flat deposits. Thus, the third medium-scale sequence displays a basal transgressive interval, well recorded at Pleasant Creek with stromatolitic (F4) and intraclastic (F2) deposits. The progressive incursion of seaward bioclastic shoal deposits at French Fork and of shoal complexes at Beas Lewis flats is consistent with a deepening trend. The maximum flooding interval is marked by the presence of subtidal bars made of bivalve-rich limestones (F11) at French Fork, allowing the accumulation of thick ooidic shoal deposits at Beas Lewis Flats. A thick interval of interior platform dolostones (F5) underlines the progradational trend at the end of this third medium-scale sequence. During the initiation of the deepening trend of the fourth medium-scale depositional sequence, lower shoreface deposits with ammonoids are recorded at French Fork, whereas at Beas Lewis Flats, only a thin oolitic interval is observed. In a more proximal setting, stromatolitic (F4) and intraclastic (F2) deposits mark this transgressive interval at Pleasant Creek. The record of Anasibirites ammonoid fauna in the three sections indicates the maximum flooding interval. The shallowing trend is characterized by the presence of ooidic shoal deposits in Pleasant Creek and then dolostones (F5), which are relatively thick at Beas Lewis Flats. The fifth mediumscale depositional sequence is well visible only at Beas Lewis Flats. Seaward bioclastic shoal deposits (F9-F12) mark the deepening trend. Offshore deposits (F13) underline the maximum flooding interval. The shallowing trend is evidenced by deposition of a thick interval of dolostones (F5), and the sequence boundary corresponds to the limit between the deposits of the Sinbad and Torrey formations.

Within such large-and medium-scale hierarchical stacking patterns, more than fifteen small-scale depositional sequences can be identified. In the middle Smithian microbial limestones of the French Fork section, five small-scale sequences can be recognized. Dmthick intervals of thin laminated beds (F3c) or erosive surfaces delimit these sequences in which m-scale patch reefs developed (Fig. 2a). Such a stacking pattern is not observed at Beas Lewis Flats, where facies evolution reflects a medium-scale increase in accommodation (Figs 8,10). With the change of depositional settings during the late middle to late Smithian (Fig. 14), small-scale sequences are marked by rapid facies shifts between offshore, shoal and interior platform deposits. In some intervals, correlation between these small-scale sequences is apparently possible, but for other intervals, their numbers and thicknesses differ greatly between the three studied sections, making their correlation difficult (Fig. 15).

Depositional sequences characterized by a facies evolution corresponding to the shortest recognizable cycle of environmental change are called elementary sequences (Strasser et al., 1999). These elementary sequences, which generally correspond to one bed, are observed within 13 successive beds of the microbial limestone unit at Beas Lewis Flats (Fig. 11). Facies evolution of these elementary sequences involves a succession of gastropodrich accumulations (F3a), fenestral limestones (F3b), and laminated mudstones (F3c; Fig. 11).

ORIGINS OF DEPOSITIONAL SEQUENCES

Global sea-level curves indicate a general rise during the Permian-Triassic transition [START_REF] Haq | Phanerozoic cycles of sea-level change on the Arabian Platform[END_REF][START_REF] Haq | A chronology of Paleozoic sea-level changes[END_REF]. During this global trend, several world-wide localities record third order sea-level cycles in Lower Triassic rocks [START_REF] Embry | Global sequence boundaries of the Triassic and their identification in the western Canada sedimentary basin[END_REF]Vigran et al., 1998;[START_REF] Lehrmann | Lower Triassic peritidal cyclic limestone: an example of anachronistic carbonate facies from the Great Bank of Guizhou, Nanpanjiang Basin, Guizhou province, South China[END_REF]Lehrmann et al., , 2007a, b), b). In the western USA basin, the Lower Triassic sedimentary succession records three third-order transgressive-regressive sequences, namely in the Griesbachian, Smithian and earliest-middle Spathian (Paull andPaull, 1993, 1997). In southern Utah, the Early Triassic transgression began in the early middle Smithian [START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF][START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. The large-scale depositional sequence recognized in the Torrey area is consistent with this Smithian third-order sea-level cycle.

The medium-scale sequences can be correlated across the three studied sections. Indeed, they display relatively close bed-stacking patterns and facies evolution (e.g. the progressive retrogradation of offshore deposits in the bioclastic limestone unit; Fig. 15) that are congruent with a sea-level control. Based on published U/Pb ages and the comparison of average Smithian ammonoid zone durations inclusive of separation intervals (see Brühwiler et al., 2010 for details), the Sinbad Formation likely represents a duration less than 490 kyr in the Torrey area. Thus, observed medium-scale depositional sequences may reflect the orbital cycle of eccentricity. The lack of a regressive trend in the second medium-scale depositional sequence coupled with the presence of a truncated surface at the top of the microbial limestone unit of the lower Sinbad Formation is consistent with a sudden drop in sea level, which may have a tectonic origin. A regional tectonic uplift probably related to the Sonoma Orogeny [START_REF] Collinson | Permian-Triassic boundary in eastern Nevada and west-central Utah[END_REF] has also been identified at the top of fenestral-microbial limestones of the Sinbad Formation in southwest Utah [START_REF] Olivier | Smithian Shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)[END_REF]. Additionally, a local inherited topography at the top of the microbial limestone unit may also explain the formation of a thick ooidic shoal system in the Beas Lewis Flats area.

The origin of small-scale sequences is often more difficult to assess because autocyclic processes inherent in the depositional system also played a role in their formation (Strasser et al., 2012). These autocyclic processes, including progradation or lateral migration of sedimentary bodies (tidal flats, shoals or delta lobes), can lead to the formation of shallowing-up depositional sequences [START_REF] Ginsburg | Landward movement of carbonate mud: new model for regressive cycles in carbonates (abstract)[END_REF][START_REF] Pratt | The St George Group (Lower Ordovician) of western Newfoundland: tidal flat island model for carbonate sedimentation in shallow epeiric seas[END_REF][START_REF] Satterley | The interpretation of cyclic successions of the Middle and Upper Triassic of the Northern and Southern Alps[END_REF][START_REF] Drummond | Carbonate cycle stacking patterns and hierarchies of orbitally forced eustatic sea level change[END_REF][START_REF] Burgess | The signal and the noise: forward modeling of allocyclic and autocyclic processes influencing peritidal carbonate stacking patterns[END_REF]. At Beas Lewis Flats, the upper Sinbad Formation consists of tide-dominated ooidic shoal deposits that actually reflect important lateral facies migration. Along the three studied sections, small-scale sequences show a disordered pattern and a limited lateral consistency. All these observations argue for a preponderant role by autocyclic processes rather than putative orbitally-forced sea-level changes in the formation of small-scale depositional sequences.

Observed elementary sequences reflect a facies evolution corresponding to the succession of gastropod-rich accumulations (F3a), fenestral limestones (F3b), and laminated mudstones (F3c; Fig. 11). This shortest recognizable cycle of environmental change is relatively similar to the Alpine Late Triassic Lofer (Dachstein) cycles originally described in the Austrian northern calcareous Alps [START_REF] Fischer | The Lofer cyclothems of the Alpine Triassic[END_REF]. Interpretation of these peritidal cyclic carbonate sequences is controversial. They can be interpreted as reflecting a deepeningupward cycle (Fisher, 1964), a shallowing-upward cycle [START_REF] Goldhammer | Depositional cycles, composite sealevel changes, cycle stacking patterns, and the hierarchy of stratigraphic forcing: examples from Alpine Triassic platform carbonates[END_REF][START_REF] Satterley | The interpretation of cyclic successions of the Middle and Upper Triassic of the Northern and Southern Alps[END_REF][START_REF] Cozzi | Orbitally forced Lofer cycles in the Dachstein Limestone of the Julian Alps (northeastern Italy)[END_REF], or as a structure formed in tune with autocyclic processes [START_REF] Enos | Lofer cyclothems revisited (Late Triassic, Northern Alps, Austria)[END_REF]. Even though such sequences are now largely documented in Middle and Late Triassic deposits, they are generally considered as unknown in Lower Triassic sedimentary successions [START_REF] Weidlich | Differential severity of Permian-Triassic environmental changes on Tethyan shallow-water carbon-ate platforms[END_REF]. However, one site in the Smithian-Spathian strata of the Great Bank of Guizhou (South China) records thrombolitic reef mounds within peritidal cyclic limestones [START_REF] Lehrmann | Controls on facies architecture of a large Triassic carbonate platform: the Great Bank of Guizhou, Nanpanjiang Basin, South China[END_REF][START_REF] Lehrmann | Lower Triassic peritidal cyclic limestone: an example of anachronistic carbonate facies from the Great Bank of Guizhou, Nanpanjiang Basin, Guizhou province, South China[END_REF]. These deposits display a typical thrombolite-bearing parasequence -i.e., another term illustrating the fundamental building block of sequences [START_REF] Mitchum | High-frequency sequences and their stacking patterns: sequence-stratigraphic evidence of high-frequency eustatic cycles[END_REF] -that consists in the upward succession of a basal oolitic grainstone overlain by skeletal packstone, thrombolite reef mounds, and capped by flaser-bedded limestones. Such a parasequence (0.2 to 7.4 m-thick) has been interpreted as reflecting low-amplitude, high frequency (5 th order, 0.01-0.1 my) sealevel fluctuations resulting from greenhouse conditions [START_REF] Lehrmann | Lower Triassic peritidal cyclic limestone: an example of anachronistic carbonate facies from the Great Bank of Guizhou, Nanpanjiang Basin, Guizhou province, South China[END_REF]. At Beas Lewis Flats, gastropod accumulations are laterally discontinuous, suggesting a concentration in subtidal local topographic low points. It may also represent lag deposits during phases of lateral migration of gullies (Fig. 14a). Subfacies F3b, with abundant fenestrae, some microbial deposits and sparser gastropods, represents intertidal deposits that progressively filled available space in local ponds or abandoned gullies. Subfacies F3c, with abundant sheet cracks, some stromatolites and a restricted fauna (some ostracods and gastropods), reflects an intertidal to supratidal area prone to record intermittent exposure and desiccation. At French Fork, fenestral (F3b) and muddy laminated (F3c) subfacies are laterally observed in the same bed (Fig. 7). Such an observation, coupled with the limited lateral consistency of these subfacies between French Fork and Beas Lewis Flats, supports an autocyclic origin of the observed elementary sequences.

SIGNIFICANCE OF MICROBIAL DEPOSITS: ARE THEY LINKED TO DELETERIOUS ENVIRONMENTS?

It is classically assumed that a return to pre-extinction levels in taxonomic and functional diversity after the end-Permian mass extinction did not occur until the end of the Early Triassic [START_REF] Schubert | Aftermath of the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western USA[END_REF][START_REF] Lehrmann | Timing of recovery from the end-Permian extinction: Geochronologic and bio-stratigraphic constraints from south China[END_REF][START_REF] Chen | The timing and pattern of biotic recovery following the end-Permian mass extinction[END_REF]Pietsch and Bottjer, 2014). Lower Triassic rocks are thus often considered to record low-diversity benthic faunas [START_REF] Lehrmann | Lower Triassic peritidal cyclic limestone: an example of anachronistic carbonate facies from the Great Bank of Guizhou, Nanpanjiang Basin, Guizhou province, South China[END_REF][START_REF] Fraiser | The non-actualistic Early Triassic gastropod fauna: A case study of the Lower Triassic Sinbad Limestone Member[END_REF][START_REF] Pruss | A global marine sedimentary response to the End-Permian mass extinction: examples from southern Turkey and the western United States[END_REF]. In this context, microbialites are thought to have flourished as a consequence of continuous or recurrent environmental stresses such as anoxia or high water temperature (Song et al., 2014, Pietsch et al., 2014) and in the absence of developed benthic faunas (Schubert andBottjer, 1992, 1995). Indeed, several microbialite pulses have been identified in Early Triassic rocks [START_REF] Baud | The Lower Triassic anachronistic carbonate facies in space and time[END_REF][START_REF] Algeo | Spatial variation in sediment fluxes, redox conditions, and productivity in the Permian-Triassic Panthalassic Ocean[END_REF][START_REF] Mata | Microbes and mass extinctions: paleoenvironmental distri bution of microbialites during times of biotic crisis[END_REF]. It has therefore been suggested that these microbialite episodes may reflect the unusual chemistry of Early Triassic oceans (Pruss and Bottjer, 2004;[START_REF] Woods | Assessing Early Triassic paleoceanographic conditions via unusual sedimentary fabrics and features[END_REF]. However, recent studies have demonstrated that the rediversification of some nekto-pelagic organisms such as ammonoids (Brayard et al., 2009b) and conodonts [START_REF] Orchard | Conodont diversity and evolution through the latest Permian and Early Triassic upheavals[END_REF] was explosive after the mass extinction. The consensual view of widespread depauperate benthic faunas throughout the entire Early Triassic is now obsolete, as shown by the diversified assemblages recently described from various time intervals and latitudes (Twitchett et al., 2004;Wheeley and Twitchett, 2005;[START_REF] Beatty | Anomalously diverse Early Triassic ichnofossil assemblages in northwest Pangea: a case for a shallow-marine habitable zone[END_REF]McGowan et al., 2009;Shigeta et al., 2009[START_REF] Kaim | Early Triassic (Late Griesbachian) gastropods from South China (Shanggan, Guangxi)[END_REF][START_REF] Hautmann | An unusually diverse mollusc fauna from the earliest Triassic of south China and its implications for benthic recovery after the end-Permian biotic crisis[END_REF][START_REF] Hautmann | Bivalves from the Olenekian (Early Triassic) of south-western Utah: systematics and evolutionary significance[END_REF][START_REF] Hofmann | New trace fossil evidence for an early recovery signal in the aftermath of the end-Permian mass extinction[END_REF]Hofmann et al., , 2013Hofmann et al., a, b, 2014)).

In the Torrey area, the observed lithological succession is consistent with two depositional models (middle and late middle to late Smithian, respectively; Fig. 14). The first model implies an extension of peritidal microbial limestones (F3) over tens of kilometres (see also [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF], which laterally pass to more internal tidal-flat red beds (F1; Fig. 14a).

Within these microbial limestones, the associated fauna, although common, is of relatively low diversity and is mainly represented by ostracods, gastropods, some bivalves and rare foraminifers. Such a biotic assemblage could be interpreted as representing an impoverished and low-complexity marine ecosystem, typified by primary producers and opportunistic consumers [START_REF] Lehrmann | Lower Triassic peritidal cyclic limestone: an example of anachronistic carbonate facies from the Great Bank of Guizhou, Nanpanjiang Basin, Guizhou province, South China[END_REF][START_REF] Chen | The timing and pattern of biotic recovery following the end-Permian mass extinction[END_REF]Crasquin and Forel, 2013). In this context, microbialites are expected to be widespread and capable of forming patch reefs (Schubert andBottjer, 1992, 1995;Lehrmann, 1999;Pruss and Bottjer, 2004). Nevertheless, at French Fork, the occurrence of frequent siliceous sponges in the reef framework confirms the existence of an advanced ecological step above microbe-only constructions early in the Early Triassic [START_REF] Pruss | Placunopsis bioherms: the first metazoan buildups following the End-Permian mass extinction[END_REF][START_REF] Brayard | Transient metazoan reefs in the aftermath of the end-Permian mass extinction[END_REF][START_REF] Marenco | Paleoecology and geochemistry of Early Triassic (Spathian) microbial mounds and implications for anoxia following the end-Permian mass extinction[END_REF][START_REF] Pandolfi | Gaining insights from past reefs to inform understanding of coral reef response to global climate change[END_REF]Vennin et al., in press). Similar sponge-microbe reefs have already been reported from the early Smithian of central Utah [START_REF] Brayard | Transient metazoan reefs in the aftermath of the end-Permian mass extinction[END_REF], thus demonstrating that the Smithian occurrence is not anecdotal in the western USA basin. Their diachronous formation during the Smithian transgression also suggests that they are probably linked to water depth/energy/nutrient conditions.

The record of the Early Triassic biotic recovery appears to be strongly dependent on the type of depositional setting [START_REF] Pruss | A global marine sedimentary response to the End-Permian mass extinction: examples from southern Turkey and the western United States[END_REF][START_REF] Beatty | Anomalously diverse Early Triassic ichnofossil assemblages in northwest Pangea: a case for a shallow-marine habitable zone[END_REF][START_REF] Mata | Origin of Lower Triassic microbialites in mixed carbonatesiliciclastic successions: ichnology, applied stratigraphy, and the end-Permian mass extinction[END_REF][START_REF] Olivier | Smithian Shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)[END_REF]. In the Torrey area, previous studies interpreted the sediments of the Black Dragon and Sinbad formations as part of the same depositional model [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF]. However, high-resolution correlation between the three studied sections does not support such a lateral facies distribution between microbial limestones (F3) of the lower Sinbad Formation and the more diversified bioclastic limestones (F10-F13) of the upper Sinbad Formation (Fig. 14a andb). Such a lateral facies variation was nevertheless assumed in southwestern Utah in time-equivalent Sinbad limestones [START_REF] Olivier | Smithian Shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)[END_REF]. The lack of a fauna in the Black Dragon Formation red beds (F1) must be considered from the perspective that these deposits formed in a tidal-system reflecting important terrigenous inputs (Fig. 14a).

In such depositional settings, significant sediment mobility (caused by tidal currents) and abundant suspended sediment particles (that prevent the colonization by filter-feeding organisms) may cause intertidal settings to be prohibitive environments for common benthic organisms (Davies and FitzGerald, 2004). Indeed, the western USA basin corresponds to a narrow epicontinental shallow sea that progressively transgressed southward during the Smithian [START_REF] Paull | Interpretation of Early Triassic nonmarine-marine relations, Utah[END_REF][START_REF] Goodspeed | Stratigraphy, sedimentology, and sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, Utah[END_REF][START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]. Abundant lower-middle Smithian terrigenous red-bed deposits in central and southern Utah indicate the existence of complex topographic highs as well as significant continental erosion along the margins of an epicontinental sea tongue or embayment system [START_REF] Blakey | Stratigraphic and depositional analysis of the Moenkopi Formation[END_REF][START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF][START_REF] Nielson | Petrology, sedimentology and stratigraphic implications of the Rock Canyon conglomerate, southwestern Utah[END_REF][START_REF] Olivier | Smithian Shoreline migrations and depositional settings in Timpoweap Canyon (Early Triassic, Utah, USA)[END_REF]. Thus, the intense microbial development in the lower Sinbad Formation coupled with the lack of a fauna in the contemporaneous red beds of the Black Dragon Formation may be explained by specific local environmental conditions.

Microbialites are not consistent with high rates of sedimentation [START_REF] Kershaw | A ?microbialite carbonate crust at the Permian-Triassic boundary in South China, and its paleoenvironmental significance[END_REF], and therefore microbial limestones (F3) could not have formed very close to the terrigenous sources where the red beds were deposited. On the other hand, associated with the terrigenous flux in marine systems, nutrient-rich conditions may have appeared, thus favouring the formation of microbial deposits [START_REF] Dupraz | Nutritional modes in coral-microbialite reefs (Jurassic, Oxfordian, Switzerland): evolution of trophic structure as a response to environmental change[END_REF][START_REF] Olivier | Coral-microbialite reefs in pure carbonate versus mixed carbonate-siliciclastic depositional environments: the example of the Pagny-sur-Meuse section (Upper Jurassic, northeastern France)[END_REF]. Red beds were favoured by an intense weathering of silicate rocks, which could have increased the amount of carbonate minerals delivered to the oceans [START_REF] Ferris | Precipitation of carbonate minerals by microorganisms: implications for silicate weathering and the global carbon dioxide budget[END_REF][START_REF] Locklair | A model of Phanerozoic cycles of carbon and calcium in the global ocean: Evaluation and constraints on ocean chemistry and input fluxes[END_REF]. Carbonate precipitation depends on carbonate alkalinity and the availability of free calcium [START_REF] Dupraz | Microbial lithification in marine stromatolites and hypersaline mats[END_REF][START_REF] Aloisi | The calcium carbonate saturation state in cyanobacterial mats throughout Earth's history[END_REF]. The intense erosion of calcareous Permian deposits of the Kaibab Formation also supports the existence of seawaters enriched in Ca 2+ [START_REF] Arp | Microbialite formation in seawater of increased alkalinity, Satonda Crater Lake, Indonesia[END_REF]. Coupled with the rare skeletal carbonate sinks during the middle Smithian, a shift in the carbonate saturation of seawater can help to explain the intense development of microbialites [START_REF] Pruss | The unusual sedimentary rock record of the Early Triassic: A case study from the southwestern United States[END_REF][START_REF] Payne | Erosional truncation of uppermost Permian shallow-marine carbonates and implications for Permian-Triassic boundary events[END_REF]. Thus, the formation of middle Smithian microbial deposits in the lower Sinbad Formation may have occurred in a specific depositional window corresponding to a peritidal setting sufficiently distant from terrigenous sources but still under the influence of alkaline and/or nutrient-rich waters.

During the late-middle to late Smithian, the depositional environment changed drastically. Faunas, which are notably more abundant and diversified, include bivalves, gastropods, echinoderms, ammonoids and serpulids. An intense infaunal activity is also recorded (Fig. 14b). This environmental change may be explained by an acceleration of the transgression following a significant sea-level drop of probable tectonic origin at the top of the microbial limestone unit. The inherited topography probably allowed the formation of an oolitic shoal complex in the Beas Lewis Flats area (Fig. 15). It also permitted recurrent incursions of seaward shoal complex deposits characterized by a more diversified fauna.

These ooid-bioclastic limestones comprise the upper Sinbad Limestone Formation. This unit exhibits a relatively high diversity and abundant fauna up to the Anasibirites kingianus beds [START_REF] Brayard | Smithian ammonoid faunas from Utah: implications for Early Triassic biostratigraphy, correlation and basinal paleogeography[END_REF]Pietsch et al., 2014[START_REF] Hofmann | Recovery of benthic marine communities from the end-Permian mass extinction at the low latitudes of eastern Panthalassa[END_REF]. These bioclastic limestones (F10-13) interfinger with intertidal interior platform dolostones (F5) that contain a sparse and poorly preserved fauna. In the upper Sinbad facies model (Fig. 14b), microbial deposits are still documented, but their nature and depositional setting strongly differ from their lower Sinbad counterparts. In the youngest case, dm-thick beds of domal stromatolites or wavy carbonate structures (F4) display a laminated micritic fabric. Such microbial carbonates may have played a stabilizing role on the internal part of the shoal complex such as do modern seagrass communities [START_REF] Rankey | Contrasts between wave-and tide-dominated oolitic systems: Holocene of Crooked-Acklins Platform, southern Bahamas[END_REF]. However, modern and ancient microbialites observed near high-energy shoals incorporate sand-size detrital particles [START_REF] Riding | Oolite stromatolites and thrombolites, Miocene, Spain: analogues of Recent giant Bahamian examples[END_REF][START_REF] Feldmann | Stromatolite-thrombolite associations in a modern environment, Lee Stocking Island, Bahamas[END_REF][START_REF] Planavsky | Taphonomy of modern marine Bahamian microbialites[END_REF]. Fine-grained microbial deposits closely associated with high-energy shoals are known in the Middle Jurassic and they are interpreted as being deposited in tune with sea-level fluctuations (Tomás et al., 2013). This is not the case in the Torrey area where depositional sequences, including microbial, oolitic and dolostone deposits, are better explained by autocyclic processes. Early Triassic wrinkle structures have also been described associated with cross-laminated siltstones interbedded with shales on supratidal flat environments [START_REF] Hips | Lower Triassic storm-dominated ramp sequence in northern Hungary: an example of evolution from homoclinal through distally steepened ramp to Middle Triassic flat-topped platform[END_REF], Pruss et al., 2004;[START_REF] Mata | Microbes and mass extinctions: paleoenvironmental distri bution of microbialites during times of biotic crisis[END_REF]. Late middle to late Smithian dolostones (F5) in the Torrey area reflect a tide-dominated interior platform with minor terrigenous influences. Thus, observed wavy microbial carbonates can display structures similar to their wrinkle siliciclastic analogues. However, since they formed in a mud-dominated setting, they could not have integrated siliciclastic grains [START_REF] Luo | Carbonate reticulated ridge structures from the lower Middle Triassic of the Luoping area, Yunnan, southwestern China: Geobiologic features and implications for exceptional preservation of the Luoping Biota[END_REF]. Observed wavy microbial carbonates may therefore reflect local low-energy topographic highs in the interior platform, whereas dm-scale domal stromatolites probably formed in an area characterized by a slightly higher accommodation (Fig. 14b). All of these microbial limestones (F4) are clearly contemporaneous with the more distal and more diversified bioclastic limestones (F10-13) of the upper Sinbad Formation. They can be considered as reflecting marine and oxic waters, as previously suggested for younger Spathian microbialites in the Virgin Limestone Formation in western USA (Schubert andBottjer, 1992, 1995). Thus, both lower and upper Sinbad microbialites (F3 and F4) observed in the Torrey area indicate that Early Triassic microbialites were able to form in various depositional settings that did not necessarily reflect deleterious environments.

CONCLUSIONS

The lithological succession in the Torrey area represents a general transgression after the Permian-Triassic mass extinction. This transgression corresponds to the middle Smithian 3 rd order sea-level cycle. The stacking pattern of the studied stratigraphical interval allows the identification of large, medium, small-scale and elementary depositional sequences. While one particular medium-scale depositional sequence observed in the lower Sinbad Formation (middle Smithian) may reflect a regional tectonic uplift, others possibly formed in tune with orbitally (eccentricity) controlled sea-level fluctuations within the upper Sinbad Limestone Formation (late middle to late Smithian). Autocyclic processes better explain small-scale and elementary depositional sequences. Microbialites occur in both lower and upper Sinbad depositional models. During deposition of the lower Sinbad, the initiation of the transgression allowed the development of a large microbial-dominated peritidal area seaward of a siliciclastic tidal flat in which red beds devoid of any fauna were being deposited. The formation of these microbialites seems to have occurred in a specific depositional window sufficiently far from terrigenous sources, but still under the influence of alkaline and/or nutrient-rich waters. During the upper Sinbad deposition, the sea-level rise permitted the formation of a mixed wave-tide dominated sedimentary system and the microbialitic growth was limited to a small area in the dolostone interior platform. A rather low-diversity fauna characterizes the lower Sinbad microbial deposits, whereas upper Sinbad stromatolites are contemporaneous with a much more diversified and abundant fauna. The nature of microbialites and their formation apparently depend strongly on the type of depositional setting. These Smithian microbialites do not reflect the peculiar deleterious environmental conditions that are classically assumed for the Early Triassic time interval.

TABLE AND FIGURE CAPTIONS

Table 1. Facies descriptions and depositional settings. See Table 1 for facies descriptions and Figure 3 for legend. Abundant quartz grains (subrounded to subangular), rare micas and some intraclasts (cm-scale subangular to sub-rounded mud chips and mud pebbles). Locally rare primary gypsum needles Rare gastropods and siliceous sponge spicules Frequent cm-scale flat pebbles and subangular to subrounded intraclasts, common peloids, rare ooids and oncoids, aggregate grains. Presence of quartz grains and rare micas Abundant gastropods, common ostracods and some siliceous sponges Abundant intraclasts and peloids Rare gastropods, ostracods, siliceous sponges and bivalves Abundant oncoids, peloids, aggregate grains. Some ooids and cortoids Rare ostracods, small gastropods and siliceous sponges Some intraclasts and mud flakes No biota Abundant peloids, oncoids and ooids Common gastropods, some serpulids and ostracods Abundant peloids and oncoids. Some ooids, aggregate grains and mud clasts No biota Common peloids, some intraclasts Rare bivalves, gastropods and ostracods, often as modic voids. Rare echinoderms Rare to common, locally abundant, quartz grains (sub-rounded to sub-angular). Some intraclasts, mud flakes and peloids. Rare micas Common bivalves and presence of gastropods Abundant peloids and intraclasts, common cortoids, ooids and aggregate grains. Some oncoids. Rare quartz grains Rare echinoderms (fragments) Common intraclasts (sub-rounded to sub-angular). Some lithoclasts, peloids and ooids Common bivalves and gastropods fragments Abundant ooids, some peloids and intraclasts, aggregate grains, oncoids, cortoids and mud flakes. Rare quartz grains Abundant bivalve fragments, some gastropods and rare echinoderms Abundant peloids. Some ooids, oncoids, cortoids and intraclasts Abundant bivalves and gastropods. Common echinoderms (fragments) and some serpulids and ammonoids Common peloids and micritic intraclasts. Rare ooids and phosphate grains. Presence of quartz grains Abundant bivalves. Some serpulids, rare gastropods and echinoderms Abundant peloids. Rare intraclasts and phosphate grains. Common sub-rounded quartz grains Abundant bivalves, gastropods and echinoderms. Some ammonoids, serpulids and siliceous sponges Common peloids. Some phosphate grains. Quartz grains are common Common bivalves. Some serpulids, echinoderms, ammonoids, gastropods and siliceous sponges (cf. [START_REF] Dean | Carbonate petrology and depositional environments of the Sinbad Limestone Member of the Moenkopi Formation in the Teasdale Dome Area, Wayne and Garfield Counties, Utah[END_REF] Common peloids, some intraclasts.

  During the Smithian, the sedimentary systems documented in the Torrey area show depositional settings characteristic of an embayment or a sea tongue. The sedimentation reflects a tide-dominated regime that displays wave influences only during major phases of transgression. The first depositional model highlights the juxtaposition between the Black Dragon (red beds) and Lower Sinbad formations, corresponding to a siliciclastic tidal flat and peritidal microbial limestones, respectively. Microbial limestones developed m-scale patch reefs and display a rather low-diversity benthic fauna with gastropods, ostracods, rare foraminifers, and common siliceous sponges. The contribution of siliceous sponges to the reef framework indicates an advanced ecological step above microbial-only reefs. Similar spongemicrobe associations were also documented from older beds of the early Smithian of central Utah, indicating that these bioconstructions were probably common within the western USA basin. The second upper Sinbad depositional model is characterized by three main facies associations: (i) tidal flat dolostones of the interior platform; (ii) ooid-bioclastic deposits of a tide-dominated shoal complex; and (iii) bioclastic limestones of open wave dominated marine settings.

Figure 1 .

 1 Figure 1. (a) Geographic location of the French Fork, Beas Lewis Flats and Pleasant Creek sections in the Torrey area (southern Utah). (b) Synthetic lithological succession of the Torrey area and its depositional sequence interpretation.

Figure 2 .

 2 Figure 2. Field views of the three studied sections and their main lithological units. (a) Lower part of the French Fork section. Note the patchy morphology visible locally in the microbial unit. (b) Beas Lewis Flats section. Note the truncation surface at the top of the microbial limestone unit (white arrows: stratal terminations). (c) Pleasant Creek section. The microbial limestone unit documented both at French Fork and Beas Lewis Flats is absent here.

Figure 3 .

 3 Figure 3. Legends for French Fork, Beas Lewis Flats and Pleasant Creek log sections.

Figure 4 .

 4 Figure 4. Log of the French Fork section including lithology, texture and relative abundance of quartz grains. Facies distribution and depositional sequence interpretation is also indicated.

Figure 5 .

 5 Figure 5. (a) and (b) Field views of the bedding stacking pattern of the microbial limestone unit in the French Fork section. In (a) the black window represents photograph in (c). Some beds show important lateral thickness variations (dashed lines in b) generating dm-patch reef morphologies. (c) and (d) Field view and sketch of a bed that displays a lateral thickness variation in the microbial limestone unit at French Fork. Note that this bed can be subdivided into two subunits: a lower part made of a fenestral limestone subfacies (F3b) and an upper part made of a laminated mudstone subfacies (F3c). (e) Oncoid-ooid-peloidal-intraclast grainstone with fenestrae (F3b). Note the laterally discontinuous stromatolitic crusts that coated some grains (white arrows). (f) Microbial laminae or crusts (F3b; white arrow). (g) Large domal spar-filled sheet cracks (F3c). (h) Mudstone with sparse and laterally discontinuous horizontal cracks, small gastropods and ostracods (F3c).

Figure 6 .

 6 Figure 6. (a) Field view of a fenestral-rich bed in microbial limestone unit at French Fork. (b) and (c) Thin section and sketch of microbial crusts (both planar and columnar) in a large fenestrae illustrated in (a) (white window). Note that planar stromatolites bind an oolitic grainstone or an oncolitic floatstone and are overlain by columnar stromatolites, which exhibit an upward growth direction inside the fenestrae. (d) Field view of large fenestrae (black arrow) in a bed of the microbial limestone unit at French Fork. (e) Thin section of large fenestrae with downward and upward microbial growth directions (white arrows). (f) and (g) Siliceous sponges in the microbial limestone unit at French Fork section. (f) Sponge in the fenestral limestone subfacies (F3b). The sponge is partially dissolved and replaced by a cavity infilled by microbes and cements. (g) Sponge in the laminated mudstone subfacies (F3c).

Figure 7 .

 7 Figure 7. (a) and (b) Lateral facies variations observed in a bed of the microbial limestone unit at French Fork. (c) Fenestral limestone subfacies (F3b). Note the internal vadose silts preserved in some fenestrae (white arrow). (d) Laminated facies (F3c) with local small fenestrae and tepee structures (white arrow).

Figure 8 .

 8 Figure8. Log of the Beas Lewis Flats section including lithology, texture and relative abundance of quartz grains. Facies distribution and depositional sequence interpretation is also indicated along the section. See Table1for facies descriptions and figure 3 for legends.

Figure 9 .

 9 Figure 9. Field views of (a) a cm-scale domal stromatolite (55.6 m, F2, subunit 1) and (b)subfacies F3a with dense accumulation of gastropods (56.1 m). Beas Lewis Flats section.

Figure 10 .

 10 Figure 10. Schematic evolution of the main facies types in the microbial limestone unit at Beas Lewis Flats. (a) Synthetic log of the microbial limestone unit (F3) subdivided into 3 subunits. Each bed of the second subunit (see Figs 8, 11) includes a succession of the three subfacies (F3a-c). (b-d) Subfacies F3e, subunit 3. (b) Peloidal, oncoidal, fenestral fabric. (c) Stromatolitic crust showing the alternation of thin dark microbial lamina with ooid-peloidal grainstone. (d) Downward growth of stromatolitic columns with horizontal cracked lamina at the roof of large fenestrae. (e-g) Subfacies F3c, subunit 2. (e) Small columnar to domal stromatolite. (f) Domal muddy sheet cracks. (g) Micrite with gastropods and ostracods. (h-j) Subfacies F3b, subunit 2. (h) Peloid-oncoid-ooid-fenestral grainstone intervals coated with thin microbial lamina. (i) Irregular fenestrae with downward and lateral microbial growth. (j) Subfacies F3c with micrite, ostracods and siliceous sponge (lower-half thin section) and

Figure 11 .

 11 Figure 11. Bed stacking pattern of the microbial limestone unit (subunit 2) at Beas Lewis Flats. (a) Field view of several dm-thick beds displaying similar internal organization. (b) and (c) Field view and schematic sketch of a bed-scale depositional sequence. a.: gastropod-rich basal interval (F3a); b.: fenestral-rich intermediate interval (F3b); c.: Mud sheet crack or stromatolite upper interval (F3c).

Figure 12 .

 12 Figure12. Log of the Pleasant Creek section including lithology, texture and relative abundance of quartz grains. Facies distribution and depositional sequence interpretation is also indicated along the section. See Table1for facies descriptions and figure 3 for legends.

Figure 13 .

 13 Figure 13. Field views and thin section illustrations of microbialites observed in the upper Sinbad Formation at Pleasant Creek. (a) Dm-scale domal stromatolites (F4 at around 38.5 m in Fig. 12). (b) Laminated microfabric of stromatolites illustrated in (a). (c) Laminated wavy structures in a dm-thick microbialitic bed (F4 at 45 m in Fig. 14). (d) Laminated microfabric of stromatolites illustrated in (c). (e) Field view of bidirectional cross bedding in oolitic grainstone (F9) in the upper Sinbad Formation. (f) Thin section of oolitic grainstone (F9) with gastropods. (g) Field view and (h) thin section of a peloidal and bioclastic packstone (F13) with bivalves that display umbrella structures with underlying siliceous sponges. Pleasant Creek section.

Figure 14 .

 14 Figure 14. Depositional models (a) for the red beds of the Black Dragon Formation and microbial limestone unit of lower Sinbad Formation (middle Smithian) and (b) for the bioclastic limestone unit of the upper Sinbad Formation (late middle to late Smithian). SeeTable 1 for facies description and figure 3 for legends.

Figure 15 .

 15 Figure 15. Correlation of the French Fork, Beas Lewis Flats and Pleasant Creek sections illustrating the general facies architecture of the Torrey area during the Smithian. S.I to S.V: medium-scale depositional sequences.

A

  Fig.1

  Fig.2

  Fig.3

Fig. 5

 5 Fig. 5

Fig. 6

 6 Fig. 6

  Fig. 7

  Fig. 9

  Fig.12

Fig. 13

 13 Fig. 13

  Fig. 14

Table 1 .

 1 Common quartz grains, rare micas and very rare detrital dolorhombs Facies description and depositional settings. thick beds with frequent basal erosive surfaces. Presence of tepees, desiccation cracks, fenestrae and few cm-scale stromatolitic domes. Bioturbation. Some crossed lamination and asymmetrical ripplesSubtidal to intertidalCm-to dm-thick beds. Cm-to dm-longs fenestrae with internal stromatolitic crusts (with upward and downward growth) and stromatactis. Locally, microbial laminated biofilms Thin cm-thick (rarely dm-thick) beds. Asymmetrical ripples, climbing ripples, planar et crossed lamination.Tepees, convolutes and very rare and localized bioturbation in the transition beds to F3Basal bed (cm-thick) intervals, lateraly discontinuous. Basal erosive surfaces. Some fenestrae, micritic geopetal filling of gastropod cavities Peloidal micrite, sparitic cement Cm-to dm-thick beds (strong lateral thickness variations). Abundant fenestrae and undulated laminated biofilms

	Subtidal to
	intertidal
	Intertidal
	Intertidal
	(supratidal)
	Subtidal to
	intertidal
	Subtidal to
	intertidal
	channels

ACKNOWLEDGEMENTS

This work is a contribution to the ANR project AFTER (ANR-13-JS06-0001-01). The Région Bourgogne and the CNRS INSU Interrvie also supported this study. N. Goudemand (Zurich) is thanked for his help with conodont determinations. D.A. Stephen is grateful for the ongoing financial support of the College of Science & Health at Utah Valley University. Beas Lewis Flats and French Fork sections are located on US public land under the stewardship of the Bureau of Land Management (BLM) of the US Department of the Interior, their management and access to these lands is much appreciated. The Pleasant Creek section is located in Capitol Reef National Park, and was studied and collected under Permit # CARE-2013-SCI-0005, thanks to Sandy Borthwick for her help with the permitting process. Pedro Marenco and Spencer G. Lucas are thanked for their helpful comments on the manuscript.