福建晚三叠世－中侏罗世地层划分

On Classification of Late Triassic-Middle Jurassic Strata in Fujian Province

福建晚三叠世－中侏罗世地层以陆相盆地沉积为主，仅闽西南局部有海陆交互相沉积。地层分区大致以政和－大埔断裂为界，分为闽西地层小区和闽东地层小区。根据各盆地地层序列及岩石组合特征，岩石地层单位可划分为陆相沉积的大坑村组、文宾山组、焦坑组、梨山组及漳平组和以海陆交互相沉积的象牙群，包括下村组和藩坑组。其中大坑村组相当于年代地层单位的上三叠统卡尼－诺利阶，文宾山组、焦坑组相当于诺利阶上部－瑞替克阶，梨山组相当于下侏罗统赫塘－托尔阶，漳平组相当于中侏罗统巴柔－卡洛阶中下部，下村组相当于下侏罗统赫塘－辛涅缪尔阶，藩坑组相当于辛涅缪尔－托尔阶。此外，文中还论述了各门类生物群的组合特征及其分布范围。

The late Triassic-middle Jurassic Strata in Fujian Province are mainly distributed on the western part of the Zhenghe-Dapu Fault, and only a little on the Eastern part. According to the lithological characteristics and sequence of the late Triassic -middle Jurassic strata, the implication of previous lithostratigraphic units has been revised in the paper and the strata have been grouped into 1 Group and 7 Formations. They are in ascending order: Dakengcun Formation, which is mainly made up of the greyish black siltstone and mudstone and sandstone interbedded with coal beds; Wenbinshan Formation, which is composed of the grey and greyish black siltstone and sandstone interbedded with carbonaceous mudstone and coal beds and some volcanic rocks: Jiaokeng Formation, which is mainly comprised of the greyish black siltstone and carbonaceous siltstone and sandstone interbedded with coal beds and volcanic rock and polygenetic conglomerate in the lower; Lishan Formation, which, is mainly composed of the greyish and grey siltstone and sandstone interbedded with greyish black carbonaceous siltstone and feldspathic quartz conglomerate in the lower; Xiangya Group, including Xiacun Formation and Fankeng Formation; Xiacun Formation, which is mainly made up of the grey quartzose sandstone and graywacke interbedded with greyish black siltstone; Fankeng Formation, which is mainly comprised of the grey andesite and trachybasalt interbedded with tuffaceous siltstone and siltstone; Zhangping Formation, which is mainly composed of the greyish and greyish purple and purplish red siltstone, mudstone, sandstone interbedded with conglomerate.The late Triassic -middle Jurassic biota in Fujian Province, according to their distribution and abundance in the strata, can be respectively divided into the following assemblages: Glossophyllum -Todites assemblage (in Dakengcan Formation), Lepidopteris -Ptilozamites assemblage (in Wenbinshan Formation and Jiaokeng Formation ), Coniopteris- Phoenicopsis assemblage (in Lishan Formation ); BakevelloidesJiangxiella fauna (in Wenbinshan Formation), Parainoceramus - Camptonectes faun a (in Xiacun Formation and Fankeng Formation), qiyangia fauna (in Fankeng Formation), Ferganoconcha - Sibireconcha fauna (in Lishan formation), Pseudocardinia -Tutuella fauna (in Zhangping Formation), Cuneopsis- PsilunioEolamprotula fauna (in Zhangping Formation): Euestheria indiana -Eulimnadia fauna (in Wenbinshan Formation ), Palaeolimnadia houjiensis- Euestheria shandanensis fauna (in the lower part of Lishan Formation),Eosolimnadiopsis- Asiolimnadiopsis fauna (in the upper part of Lishan Formation ), Euestheria yan jiawanensis -Euestheria complanata assemblage (in the lower part of Zhangping Formation ); Gomphocythere (?)rhomboidalis -G. (? ) yubacunensisassemblage (in the lower part of Lishan Formation ), Darwinula sarytirmenensis- Darwinula magna fauna (in the lower part and the middle part of Zhangping Formation); Coroniceras- Arietites assemblage (in the lower part of Fankeng Formation).The correlation of chronostratigraphic units and lithostratigraphic units shows that the Dakengcun Formation is equivalent to the upper Carnian- Norian stage, the Wenbinshan Formation and Jiaokeng Formation are equivalent to the upper Norian- Rhaetian stage, the Lishan Formation equivalent to the Hettangian -Toarcian stage, the Xiacun Formation equivalent to the Hettangian- Sinemurian stage, the Fankeng Formation equivalent to the Sinemnrian- Toarcian stage and the Zhangping Formation equivalent to the Bajocian -lower Callovian stage.