赣西北志留纪晚期地层的发现和西坑组的厘定  

THE DISCOVERY OF LATE SILURIAN XIAOXI FORMATION AND EMENDATION OF LOWER SILURIAN XIKENG FORMATION IN NORTH-WESTERN JIANGXI, SOUTH CHINA

作　　者：王怿 蒋青 唐鹏 张小乐[1,2] 黄冰[1] 詹仁斌 孙存礼 戎嘉余 WANG Wi;JIANG Qing;TANG Peng;ZHANG Xiao-lez;HUANG Bing;ZHAN Ren-bin;SUN Cun-li;RONG Jia-yu(State Key Laboratory of Palaeobiology and Stratigraphy,Center for Excellence in Life and Paleoenvironment,Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing 210008;School of Earth and Space Sciences of Peking University,Beijing 100871;The Survey Team of the Regional Geology,Jiangxi 330002)

机构地区：[1]现代古生物学和地层学国家重点实验室中国科学院生物演化与环境卓越创新中心中国科学院南京地质古生物研究所,江苏南京210008 [2]北京大学地球与空间科学学院,北京100871 [3]江西省区域地质调查大队,江西南昌330002

出　　处：《地层学杂志》2018年第3期257-266,共10页Journal of Stratigraphy

基　　金：国家自然科学基金委员会(Nos.41530103;41521061;41290260);中国科学院B类先导专项培育项目(XDPB05)共同资助

摘　　要：依据对赣西北地区线形植物、大型虫管遗迹和微体植物化石的研究,在原西坑组上部划出了志留纪晚期的小溪组。对原西坑组进行了厘定,将其"一分为二",上部为小溪组,下部为厘定后的西坑组。厘定后的西坑组以黄绿色、紫红色薄—中厚层粉砂岩和泥岩为主,夹细砂岩,属于"上红层",与下伏夏家桥组呈整合接触,与上覆小溪组呈假整合接触,其地质时代为兰多维列世特列奇中晚期。基于皖赣鄂边区志留纪晚期小溪组的研究,表明在扬子上升后,皖赣鄂边区发育志留纪晚期沉积,证明该区遭受过海侵,在一定区域内沉积了一定厚度的地层;陆生线形植物和早期维管植物在该区的产出,表明其沉积区距物源区不远,该区河流发育,海域的海水发生淡化现象。Based on the study of nematophyte plant, stout tubuluar trace and micro- plant fossils from north-western Jiangxi, South China, the upper part of the former Xikeng Formation is recognized as the Xiaoxi Formation. The original Xikeng Formation is emended, and divided into two parts： the upper part is now the Xiaoxi Formation, and the lower part is the emended Xikeng Formation. The emended Xikeng Formation is mainly composed of yellowish-green, purple thin- and medium-bedded siltstones and mudstones intercalated with the fine sandstones; is conformably underlain by the Xiajiaqiao Formation and overlain by the Xiaoxi Formation; and belongs to the Upper Red Beds （URBs）. The geological age of this formation is middle-late Telychian, Llandovery. After an analysis of the distribution of the Xiaoxi Formation in the Wan-Gan-E border area, it is concluded that, after the Yangtze Uplift, the Wan-Gan-E border area experienced transgression and accumulation of marine sediments of late Silurian age. The presence of nematophyte and early vascular land plants indicates that the provenance was not far, sedimentation was influenced by riverine input, and incursion of brackish water occurred occasionally.

关 键 词：生物地层 线形植物化石 小溪组 西坑组 特列奇中期 志留纪晚期 赣西北 

分 类 号：P534.43[天文地球—古生物学与地层学]