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四川盆地及邻区广元-旺苍、城口-鄂西、开江-梁平海槽是上二叠统—下三叠统飞仙关组(P_3—T_(?))的深水碳酸盐沉积区。该区上二叠统上部大隆组是硅质岩、硅质泥岩、硅质灰岩组合,含放射虫、有孔虫等化石,厚12．5～29．0 m,为海槽裂陷期凝缩沉积。三叠系飞仙关组下部为远洋沉积的暗色泥岩、微晶碎屑灰岩和重力流沉积的浊积岩、角砾灰岩组成的深水碳酸盐沉积,厚50．0～300．0 m,是裂陷期后的海槽充填沉积。海槽相区沉积在晚二叠统世末达到最大海泛面沉积了大隆组。海平面缓慢下降期沉积了补偿充填性质的飞仙关组深水碳酸盐岩。海槽相区上二叠统一下三叠统飞仙关组构成了一个完整的三级层序。深水沉积物的有机碳平均值高达6．21%,是良好的烃源岩。但在海槽相区上二叠统不发育生物礁,飞仙关组缺乏鲕粒岩。
The Guangyuan-Wangcang, Chengkou-Western Hubei and Kaijiang-Liangping troughs in the Sichuan Basin and its adjacent areas are characterized by deep-water carbonate deposition of the Upper Triassic Feixianguan formation (P_3-T_ (?)) Area. The Upper Permian Upper Dalong Formation is composed of siliceous rocks, siliceous mudstones, siliceous limestone assemblages, and fossils including radiolarians and foraminifera with thickness of 12.5-29.0 m, Period of condensation deposition. The Lower Triassic Feixianguan Formation is composed of dark mudstone, microcrystalline crustal limestone and gravity flow sedimentary turbidite and breccia limestone with the thickness of 50.0 ~ 300.0 m, is the trough filling and deposition after the rifting period. Tidal sediments deposited in the trough area reached the maximum sea level at the end of the Late Permian. Feixianguan Formation deep water carbonate rock with compensatory filling properties was deposited during the slow decline of sea level. The TGP formation in Feixianguan Formation of the Upper Permian in the Trough Zone constitutes a complete third-order sequence. The average organic carbon in deep-water sediments is as high as 6.21%, which is a good source rock. However, there are no reefs in the Permian in the Tachai area and no oolitic rocks in Feixianguan formation.