滇西潞西(芒市)的奥陶系和志留系  

ORDOVICIAN-SILURIAN SEQUENCES IN LUXI(Mangshi),WESTERN YUNNAN,SW CHINA

作　　者：吕勇[1] 山克强[1] 谢运球[1] 尹福光[2] 胡志鹏[3] 肖玲 廖家飞[1] 

机构地区：[1]中国地质科学院岩溶地质研究所、国土资源部岩溶动力学重点实验室,广西桂林541004 [2]成都地质矿产研究所,四川成都610081 [3]华北水利水电大学,河南郑州450045 [4]云南省地质调查院,云南昆明650051

出　　处：《地层学杂志》2014年第2期161-169,共9页Journal of Stratigraphy

基　　金：中国地质调查局地质调查项目(1212010784008,1212011220390)联合资助

摘　　要：滇西奥陶系潞西组顶部发现丰富的以Hirnantia magna为代表的"赫南特贝动物群",可作为奥陶系-志留系界线的划分标志。Hirnantia-Kinnella组合标志着冰川作用处于高潮期,海退显著,而仁和桥组笔石页岩相则是冰川消融、海平面快速上升后海侵作用所致,这一转换面上下岩性野外易识别,可近似代表滇西奥陶系-志留系界线野外填图划分界面。仁和桥组底部含Parakidograptus acuminatus,Neodiplograptus shanchongensis等化石,其时代为志留系兰多维列统。潞西地层小区与施甸地层小区的志留系研究对比表明,它们的沉积相特征差异明显,前者以碎屑岩为主,而后者碎屑岩与碳酸盐岩各占约1/2且岩石地层较连续,化石丰富。综上所述,滇西地区志留系的地层划分对比还有许多工作可做。The Hirnantiafauna has been found in the Ordovician Luxi Formation for the first time in western Yunnan,with abundant specimens of Hirnantia magna that indicates a Hirnantian Stage（Upper Ordovician）.The Silurian Renheqiao Formation contains Parakidograptus acuminatus and Neodiplograptus shanchongensis,suggesting a Rhuddanian age（Early Siliurian）.The demise of the shallow and cool/cold water Hirnantiafauna coincides with the start of the continental glaciation in the Upper Ordovician,and the Renheqiao Fomation black graptolite shale facies indicates a deep-water,anoxic,and restricted sedimentary environment,caused by glacial retreat and sea level rise.The transition between these two facies represents the Ordovician-Silurian boundary.Comparison of strata in the Luxi and Shidian stratigraphic areas shows that there are significant differences in sedimentary-facies,with the former dominated by clastic facies and the latter by clastic and carbonate facies.

关 键 词：生物地层 赫南特贝动物群 奥陶系 志留系 保山 潞西(芒市)地区 滇西 

分 类 号：P534.42[天文地球—古生物学与地层学] P534.43[天文地球—地质学]