四川广安谢家槽剖面早―中三叠世有孔虫

EARLY AND MIDDLE TRIASSIC FORAMINIFERA FROM THE XIEJIACAO SECTION,GUANG'AN,SICHUAN PROVINCE,CHINA

四川海相三叠系地层分布广泛,发育富含有孔虫化石的碳酸盐岩,是我国研究三叠纪有孔虫生物地层的理想地区之一。四川广安谢家槽剖面早—中三叠世地层中产丰富的有孔虫化石,共识别出12属34种(包括未定种)。根据有孔虫化石群在地层中的分布特点,自下而上划分出4个组合带,即Rectocornuspira kalhori-Cornuspira mahajeri,Glomospirella vulgaris-Arenovidalina chialingchiangensis,Meandrospira pusilla-Glomospirella irregulariformis和Glomospira sinensis-Arenovidalina amylovoluta组合带。有孔虫化石带的建立为该地区海相三叠系地层的时代确定和划分对比提供了重要的化石依据。

Abundant Early--Middle Triassic foraminiferal fossils were collected from the limestones of the Xiejiacao section, Guan＇an, Sichuan, China of which 34 species in 12 genera have been identified and described systematically. According to the distribution characteristics of the foraminiferal assemblages on this section, 4 foraminiferal assemblage zones are recognized from the bottom up as follows： （1） Rectocornuspira kalhori-Cornuspira mahajeri Zone; （2） Glomospirella vulgaris-Arenovidalina chialingchiangensis Zone; （3） Meandrospira pusilla-Glomospirella ir- regulariformis Zone; （4） Glomospira sinensis-Arenovidalina amylovoluta Zone. These foraminiferal zones provide very important fossil evidence for the precise biostratigraphical sub-division and correlation of the marine Triassic strata in this region.