上扬子地台西北部志留系研究新进展  

Recent Progress in the Research of the Silurian System on the Northwestern Margin of the Upper Yangtze Platform

作　　者：金淳泰[1] 万正权[1] 陈继荣[1] 

机构地区：[1]地矿部成都地质矿产研究所

出　　处：《沉积与特提斯地质》1997年第21期144-183,共16页Sedimentary Geology and Tethyan Geology

基　　金：地质矿产部地质行业基金科技项目"上扬子地台西北部志留系统界划分及文洛克统研究"

摘　　要：上扬子地台西北部志留系研究新进展１金淳泰万正权陈继荣２（地矿部成都地质矿产研究所）上扬子地台西北部龙门山地区（包括广元一带）是否存在志留纪文洛克世的沉积及志留系统界的划分，是古生物学者长期关注的问题之一。笔者自１９９３年９月始至１９９５年１２月，先后...The northwestern margin of the Upper Yangtze platform includes,in the present paper,a strip of territory from Guangyuan through Beichuan to Erlang mountain area in Sichuan.Having been studied for several decades,the Llandoverian strata are proved to be developed in the study area.The research results in recent years indicate the Ludlovian and Pridolian(late subsilurian)sediments also crop out there.But whether or not there are the Wenlockian strata in this region is an open question.The authors in the present paper are strongly inclined to the view that the Wenlock series is absent in the study area,and there is a parallel unconformity between the Llandovery and Ludlow series. The Ningqiang Formation in the Guangyuan district was originally referred to the lower part of the Wenlock series.The discovery of Spathognathodus cellont Walliser in the upper aprt of the Ningqiang Formation excludes the possibility that the middle part of the formation may be the overlap lineage zone of celloni and amorphognathoides zones.The upper part of the Ningqiang Formation and its underlying strata(including Yangpowan,Wangjiawan,Cuijiangao and Longmaxi Formations in descending order)should all be assigned to the Llandovery series.Recently Eospirifer paraminutus Jiang resembling Eospirifer minutus Rong et Yang which occur in significant quantities in the Xiangshuyuan Formation in northeastern Guizhou has been recognized in the upper part of the Baohuoyan Formation in the Erlang mountain area which was previously ascribed to the upper part of the Wenlock series.In addition,the well preserved Demirastrites triangulatus (Harkness) was also discovered in the upper part of the Luoquanwan Formation which was previously attributed to the uppermost of the Llandovery series.All these facts demonstrate that the upper part of the Luoquanwan Formation should be ascribed to the middle Llandovery series rather than the uppermost of the Llandovery series.The Longdanxi,Changyanzi and Baohuoyan Formations overl

关 键 词：宁强组 腕足动物化石 牙形石 文洛克世 兰多弗里世 床板珊瑚 拉德洛统 上扬子地台 二郎山 广元地区 

分 类 号：P534.43[天文地球—古生物学与地层学]