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1 Data Repository (B25407): Localities and descriptions of measured sections of study areas Table 1. Localities of the measured sedimentary sections in the NW Sichuan Basin Section Number Stratigraphy Locality Section 1 Qixia and Dalong Fms (Upper Permian), Feixianguan and Jialinjiang Fms (L. Triassic), and Leikoupo Fm (M. Triassic) Shangsi, ~ 6 km northwest of Railway Station called Dongba, Guangyuan city, Sichuan province (Roughly N32 18, E ) Section 2 Xujiahe Fm (Upper Triassic), and Baitianba Fm (Lower Along the road on eastern side of the Jialinjiang River, near Xujiahe ~6 km Jurassic) north of Guangyuan city, Sichuan province (Roughly N32 29, E ) Section 3 Baitianba Fm (Lower Jurassic) Xiasi, ~34 km southwest of Guangyuan City (Roughly N32 17, E ) Section 4 Baitianba Fm (Lower Jurassic) Along the road on eastern side of Donghe River, ~5 km north of Wangcang county, Sichuan province (Roughly N32 16, E ) Section 5 Baitianba Fm (Lower Jurassic) ~ 5 km south of Wanyuan county, Sichuan province (Roughly N31 59, E Section 6 Baitianba Fm (Lower Jurassic) Shiziba, Tongjiang county, northern Sichuan province (Roughly N32 22, E ) Section 7 Ziliujing Fm (Lower Jurassic), equivalent to the Baitianba Fm Penglaizhen, Sichuan province (Roughly N30 33, E ) Section 8 Qianfoyan to Shaximiao Fms (Middle Jurassic), and Suining Fm (Upper Jurassic) Along road from Qianfoyan to Wujia, Guangyuan city, Sichuan province (Roughly from N32 28, E to N32 24, E ) Section 9 Lianhuakou Fm (Upper Jurassic) and Jianmenguan, Hanyangpu and Jiange Fms (Lower Cretaceous) Along the road from Jianmenguan to Lianhuakou, Jiange county, Sichuan province (Roughly N32 13, E )

2 Table 2. Brief descriptions of sedimentary facies associations of Upper Permian to Lower Middle Triassic strata (Section 1) Stratigraphy Facies descriptions Interpretation Leikoupo Fm 183 m thick Thick- to medium-bedded grayish limestones Carbonate platform (M Triassic) 179 m Thick- to medium-bedded grayish dolomites and some shales 1312 m Thick- to medium-bedded grayish dolomites and some limestones 508 m Thick- to medium-bedded grayish limestone and dolomites interlayered with shales Jialinjiang Fm 48 m Brecia limestones and thick- to medium-bedded limestone. Carbonate platform (L Triassic) 207 m Thick- to medium-bedded light-gray limestone with intercalations of shales, containing marine fossils, such as bivalves Eumorphotis, Claraia, and Myophoria. 74 m Thick- to medium-bedded light-gray limestone and brecia limestones Feixianguan Fm 53 m Rippled siltstones and thin-bedded fine-grained partially cross-stratified sandstones Offshore (L Triassic) 46 m Thin-bedded muddy limestones, interbedded with shales 82 m Dominated by mudstones, siltstones, and fine sandstones 41 m Thin-bedded muddy limestones, with laterally extensive dark-colored mudstones 68 m Predominated by siltstones and fine sandstones, with intervals of medium- to thickbedded sharp-based medium-grained, partially graded, sandstones 73 m Parallel laminated shales and siltstones are dominant, interlayered with fine sandstone 42 m Dominated by siltstones and fine sandstones, interlayered with shales 43 m Thin- to medium-bedded fine-grained sharp-based sandstone with plane and cross stratifications. Bioturbations are common. 55 m Medium- to thick-bedded light-gray muddy limestones Carbonate platform Dalong Fm ~6 m Black to dark gray calcareous shales, thin-bedded black chert and cherty shales Offshore (U Permian) Maokou Fm (U Permian) > 50 m Medium- to thick-bedded light-gray limestones, containing intercalations of shales and abundant marine fossils, such as fusulinids Neoschwagerina, and corals Ipciphyllum Carbonate platform

3 Table 3. Summary of sedimentary facies associations of U. Triassic Xujiahe Fm & L. Jurassic Baitianba Fm (Section 2) Baitianba Fm (Lower Jurassic) Dominated by clast-supported well-rounded oligomictic conglomerate with interlayers of pebbly and coarse sandstone in lower portion. Gravels are mainly quartzite, and partially imbricated. Middle and upper portions are cross and parallel stratified sandstones, with lenticular conglomeratic interlayers and rippled siltstones. Gravelly fluvial fan and low-sinuosity fluvial deposits Xujiahe Fm Member 4 Planar and trough cross-bedded coarse-grained sandstones, and conglomerate Channel fills of braided river (Upper Triassic) layers of varying thickness, with gravels predominated by carbonate rocks, contrasting with quartzitic gravels in Baitianba Formation conglomerates. Fine-grained sediments occur occasionally in the middle. Member 3 Characterized by medium- and fine-grained cross-bedded sandstones, couplets Channel fills of meandering river of siltstone and mudstone, and coals. Lateral-accretion cross bedding, and massive sandstone and slump intervals exists. Various-scale fining-upwards units make up most of the succession. Member 2 Dominated by coarse-grained planar and trough cross-stratified sandstone with sharp erosive bases. Structureless sandstones also occur, and contain floating mudstone clasts. Siltstone/ mudstone intervals develop in the uppermost part. Channel fills of braided river Member 1 Composed mostly of mudstone and siltstone with ripple and horizontal Floodplain deposits stratifications. Intervals of massive fine sandstones and siltstones occur within the fine facies, characterized by soft-sediment deformations and dewatering structures. A regional parallel unconformity exists, separating it from the underlying strata. Leikoupo Fm (Middle Triassic) Grayish thick- and medium-bedded limestones, containing thin dark shales and siltstones. Marine carbonate platform

4 Table 4. Brief descriptions of sedimentary facies associations of Lower Jurassic Baitianba Fm (Section 3) Qianfoyan Fm Medium- and thick-bedded coarse- and medium-grained sandstone. Channel sandstone bodies (M. Jurassic) 53 m thick Medium- and thick-bedded, trough and planar cross-stratified, medium- and coarse-grained sandstone, interbedded with fine-grained sandstone and siltstone/mudstone. They make up a number of fining-upward units. Point-bar of meandering river Lower Jurassic Baitianba Fm 46 m Interlayered fine-grained sandstone, siltstone, and mudstone, abundant in ripple cross Levee and crevasse splay stratifications. Medium to thick-bedded cross-stratified sandstone develop on occasion. 24 m ~8-m-thick conglomeratic beds with pronounced erosive base, passing up into medium- and thickbedded sandstones. Mid-channel or transverse bars of gravelly braided river 16 m Pebbly conglomerate at base, passing upward to cross-bedded medium- and coarse-grained Point-bar deposits sandstone, and then to interlayered rippled siltstone and mudstone, and some coals. 52 m Dominated by siltstone/mudstone facies, with intervals of cross-stratified and massive fine-grained sandstone of varying thickness. Coals exist as well. Floodplain and crevasse splays 25 m Clast-supported erosive-based pebbly and cobbly conglomerates with crude stratifications and. Mid-channel or transverse bars well-rounded quartzitic gravels, interlayered with cross and parallel stratified, medium- and thick-bedded coarse- and medium-grained lenticular sandstone beds. Little fine-grained sediments present. Xujiahe Fm Siltstone and mudstone, with interlayers of cross-bedded and massive sandstones Floodplain (U. Triassic)

5 Table 5. Brief descriptions of sedimentary facies associations of Lower Jurassic Baitianba Fm (Section 4) Qianfoyan Fm At base are clast-supported pebbly conglomerates, overlain by medium- and thick-bedded coarse- Channel deposits (M. Jurassic) and medium-grained cross-stratified sandstones that pass up to fine-grained facies. 87 m thick Siltstone-mudstone couplets abundant in climbing ripple cross laminations, occasionally containing fine- to medium-grained sharp-based cross- and parallel-stratified sandstones up to 0.6 m thick. Floodplain deposits Lower Jurassic Baitianba Fm 44 m Medium- and thick-bedded trough and planar cross-stratified, and parallel-laminated medium- and Channel deposits coarse-grained sandstone, occasionally containing massive and slump intervals. 37 m Rippled and horizontally laminated siltstones, silty mudstones, and coals, containing intervals of Floodplain and splay deposits medium- and thick-bedded structureless sandstones with apparent erosive bases. 5 m Thick tabular and trough cross-bedded medium- and coarse-grained sandstones, containing Channel deposits lenticular well rounded pebbly conglomerates at base. 24 m Starting with fine-grained sandstones with crude cross-beddings, and the rest is dominated by rippled siltstones, horizontally laminated silty mudstone and mudstone as well as coals. Floodplain and levee-crevasse splays 8 m Sharp-based clast-supported well-rounded fairly sorted pebbly conglomerates, containing Mid-channel bar of gravelly river lenticular medium- and thick-bedded, coarse- to medium-grained sandstones. Gravel imbrications are common, and quartzites are the dominant components of gravels. Xujiahe Fm Siltstone and mudstone, with some interlayers of cross-bedded sandstone Floodplain (U. Triassic)

6 Table 6. Brief descriptions of sedimentary facies associations of Lower Jurassic Baitianba Fm (Section 5) Qianfoyan Fm Medium-bedded coarse- and medium-grained cross-bedded sandstones Channel sandy bar (M. Jurassic) 61 m thick Interbedded siltstone and mudstone fine-grained facies, with intervals of structureless fine- and medium-grained erosive-based sandstones. Floodplain Lower Jurassic Baitianba Fm 42 m Clast-supported pebbly sharp-based conglomerates, and medium- and thick-bedded medium- and Channel gravelly bar coarse-grained sandstone with trough, planar, parallel, and complex cross stratifications. Siltstones and mudstones exist occasionally. 5 m Interlayered cross- and horizontally-stratified fine-grained sandstones and rippled siltstones Inter-channel deposits 26 m Alternations of clast-supported pebbly sharp-based conglomerates, and thin- to medium-bedded Channel gravelly bar cross-stratified lenticular sandstone beds. Gravels are well-rounded quartzite and on occasion show imbrication structures. 8 m Thick to medium-bedded cross and parallel-stratified medium- and coarse-grained erosive-based sandstones, containing intraformational clasts at bases. Channel sandy bar 7 m Clast-supported, partly matrix-supported pebbly & cobbly erosive-based conglomerates with thin- Channel gravelly bar to medium-bedded, laterally continuous and discontinuous sandstone layers. Gravels are mostly well-rounded well-sorted quartzites and quartz vines, and occasionally show imbrications and crude low-angle cross stratifications. Xujiahe Fm Siltstones and mudstones, containing interlayers of cross-bedded sharp-based sandstones Floodplain (U. Triassic)

7 Table 7. Brief descriptions of sedimentary facies associations of Lower Jurassic Baitianba Fm (Section 6) Qianfoyan Fm Medium-bedded coarse- and medium-grained sandstones that pass up to fine-grained facies. Channel bar (M. Jurassic) 41 m thick Interbedded siltstones and mudstones, containing fine-grained cross-stratified and structureless Floodplain and crevasse splay sandstone intervals. 15 m Medium to thick-bedded coarse-grained sandstone, interbedded with sharp-based lenticular thick to massive clast-supported channelized conglomeratic beds. Channel bar of gravelly river Lower Jurassic Baitianba Fm 18 m Medium- to thick-bedded, cross- and plane-stratified sandstones, displaying lateral accretion Point-bar deposits bedding, then passing up to fine-grained cross-stratified sandstones, rippled siltstones as well as mudstone. The facies associations in general exhibit a fining-up trend. 71 m Thick to medium-bedded cross and parallel stratified medium- and coarse-grained sandstones and Channel bar of gravelly river thick-bedded to massive clast-supported erosively based conglomerates. 28 m Interlayered cross- and horizontally-stratified fine-grained sandstone and rippled siltstones Inter-channel deposits 27 m Thick-bedded and massive clast-supported sharp-based conglomerates, alternating with Channel bar of gravelly river erosive-based coarse to medium sandstones of varying thickness, occasionally draped by mudstone and siltstone. 8 m Cross- and horizontally-stratified fine-grained sandstones, interlayered with rippled siltstones Inter-channel deposits 26 m Clast-supported pebbly & cobbly conglomerates with interlayers of thin- to medium-bedded, sandstone. Gravels are mainly well-rounded well-sorted quartzites, and show pebble imbrications as well as crude cross-beddings. Channel bar of gravelly river 58 m Dominated by cross- and parallel-stratified, medium- and coarse-grained erosively based Point-bar deposits sandstones, interlayered with fine-grained cross-laminated sandstones. Siltstone and mudstone facies occur in the middle part, and contain coals. The facies are in fault contact with underlying Middle Triassic carbonate strata. Leikoupo Fm (M. Tr) Thick- to medium-bedded light-gray carbonate rocks Shallow-marine carbonate platform

8 Table 8 Brief descriptions of sedimentary facies associations of Lower Jurassic Ziliujing Fm (Stratigraphically equivalent to Baitianba Fm) (Section 7) 34 m thick Thin- to thick-bedded, cross- and horizontally-stratified fine- and medium-grained sandstone, and siltstone and mudstone facies, making up various-scale fining-up units. Shallow margins of lake Lower Jurassic Ziliujing Fm 46 m Mudstone and rippled, horizontally laminated siltstone, with occasional intervals of thin- to Offshore of lake medium-bedded cross- and horizontally-stratified fine-grained sandstone. 82 m Dominated by dark-colored mudstone and rippled and horizontally laminated siltstones, with Lacustrine chemical deposits interlayers of grayish thin- to medium-bedded freshwater limestones. 103 m Interlayered mudstone and rippled and horizontally laminated siltstone, containing intervals of Offshore of lake thin- to medium-bedded cross- and horizontally-stratified fine-grained sandstone. 7 m Thick to medium-bedded limestone with intercalations of mudstone and muddy siltstone, containing abundant freshwater fossils Lacustrine chemical and biogenetic deposits 68 m Rhythmite couplets of gray ripple-laminated siltstones and mudstones, occasionally interlayered Offshore of lake with laterally extensive thin- to thick-bedded horizontal and cross- stratified fine-grained sandstones. Xujiahe Fm Interlayered siltstone and mudstone facies Floodplain (U. Triassic)

9 Table 9. Summary of sedimentary facies associations of M. Jurassic Qianfoyan and Shaximiao Fms & U. Jurassic Suining Fm (Section 8) Lianhuakou Fm (Upper Jurassic) Thick-bedded and massive conglomerate, unconformably over underlying strata. Channel gravelly bar deposits Suining Fm (Upper Jurassic) Shaximiao Fm (Middle Jurassic) Qianfoyan Fm Upper (Middle Jurassic) Middle Lower Baitianba Fm (Lower Jurassic) Composed of planar and trough cross-bedded sandstones, conglomerates, and rippled and Mixed-loaded fluvial deposits parallel laminated siltstones. These facies build up varying-scale fining upwards units, starting with pebbly conglomerate or gravelly coarse- and medium-grained sandstones. Fine-grained facies are dominant. ~320 m thick. Consisting mainly of laterally extensive fine-grained planar and trough cross-laminated Lacustrine deposits and parallel laminated sandstones, and couplets of thin-bedded siltstones and mudstones. Coarse- and medium-grained thin- to medium-bedded sharp-based sandstones are present within the fine-grained facies, and some display internal graded beddings. ~1670 m thick. Composed dominantly of medium- and thick-bedded, trough and planar cross-stratified Bedload fluvial deposits and parallel-stratified coarse- and medium-grained sandstones. ~65 m thick. Consisting mostly of fine-grained facies, such as cross-bedded or parallel-laminated Lacustrine deposits fine-grained sandstone, and couplets of rippled or horizontal-laminated siltstones and silty mudstones. ~250 m thick. Thick-bedded erosively based conglomerate at base, unconformably over the Baitianba Mixed-loaded fluvial deposits Fm. Medium- and coarse-grained cross-bedded sandstones are dominant, containing siltstone and discontinuous mudstone intercalations. ~60 m thick. Fine-grained sandstones. Floodplain deposits

10 Table 10. Summary of sedimentary facies associations of U. Jurassic Lianhuakou Fm & L. Cretaceous Jianmenguan, Hanyangpu and Jiange Fms (Section 9) Jiange Fm (Lower Cretaceous) Dominated by cross-bedded erosively based sandstones and ripple- and parallel-laminated siltstones. Clast-supported conglomerates develop at basal part, displaying erosive bases, Bedload and mixed-loaded river deposits internal crude cross-beddings, and pebble imbrications. ~140 m thick. Hanyangpu Fm Pebbly or cobbly clast-supported conglomerates and gravelly sandstones at basal part, and Bedload river deposits (Lower Cretaceous) the rests dominated by medium to thick bedded, medium- and coarse-grained, planar crossand parallel-stratified sandstones, interlayered with rippled siltstone. Sandstone bodies are erosively based and obviously lens-shaped to varying lateral extent. ~230 m thick. Jianmenguan Fm (Lower Cretaceous) Lower part is dominated by massive or very thick-bedded matrix-supported pebbly and cobbly conglomerate, and gravelly coarse-grained sandstone that usually develops atop the conglomerate and displays cross beddings; Upper part is made up mostly of fine-grained sandstone and siltstone/mudstone, and some medium-grained cross-bedded sandstones. They together comprise a number of ~3 10-m-thick fining-upwards sequences. ~530 m thick. Alluvial fan and bedload river deposits (lower part); Mixed-loaded river deposits (upper part) Lianhuakou Fm (Upper Jurassic) Upper Dominantly cross-bedded and parallel laminated sandstones, alternating with rippled and horizontally laminated siltstone and mudstone facies. Stratified clast-supported lenticular Bedload and mixed-loaded river deposits conglomeratic beds are also present, with pebble imbrications and marked erosive bases. Intervals of massive sandstones with soft-sediment deformation also exist. Coarse and fine facies together often make up fining-up units 3-15 m in thickness. ~1360 m thick. Lower Consisting of massive and thick-bedded matrix- and clast-supported oligomictic cobbly and pebbly conglomerates, interlayered with gravelly coarse-grained plane-bedded sandstones. Gravity-flow dominated alluvial fan deposits Cross-bedded erosively based sandstones are also common and often display lens-shaped. Gravels are mostly well-rounded quartzites, and partially imbricated. ~480 m thick. Suining Fm (Upper Jurassic) Planar and trough cross-bedded sandstones, and rippled and parallel laminated siltstones. Channel bar deposits

11 Table 11. Comparison of Middle and Upper Triassic depositional sequences in NW Songpan-Ganzi terrane and NW Sichuan basin NORTHEASTERN SONGPAN-GANZI TERRANE NORTHWESTERN SICHUAN BASIN Age Stratigraphy Facies association Interpretation Stratigraphy Facies association Interpretation Late Triassic Zhuwo Fm (Carnian) Structureless and normally graded fine- to medium-grained Deep-marine turbidite system Xujiahe Fm (Norian Parallel- and cross-stratified medium- and thick-bedded red- Alluvial fan and fluvial systems sandstones, massive and rippled siltstones, and horizontally laminated silty mudstone. Slump intervals, and dewatering and convolute structures are common. Deep-marine trace fossils and flutes well develop. Rhaetian) colored sandstones, containing plant fragments, mudcracks, and coals. Clast-supported erosively based conglomerates are associated with cross-bedded sandstones. Massive sandstones with intraformational mud-clasts and dewatering are common. Zhagashan Fm (Ladinian) Fine- and medium-grained, thinto thick-bedded, on occasion normally graded sandstones with sharp bases and transitional tops. Channelized matrix-supported conglomerates also occur. Flutes develop at bottoms of sandstones Xiaotangzi Fm (Norian) Massive and cross-bedded sandstones, interlayered with ripple and parallel laminated siltstones and mudstones. Rapid transition from shallow to deep marine facies, indicating platform drowning during Ladinian episode A stratigraphic gap exists from Ladinian to Carnian, with the fluvial facies directly overlying Middle Triassic marine carbonate facies Middle Triassic Guojiashan Fm (Anisian) Thick- and medium-bedded limestones with intercalations of mudstones Shallow-marine carbonate platform Leikoupo Fm (Anisian) Thick- and medium-bedded limestones and dolostones Shallow-marine carbonate platform

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