多巴区幅地质调查新成果及主要进展  

New results and major progress in regional geological survey of the Toiba District Sheet

作　　者：曲永贵[1] 王永胜[1] 张树岐[1] 王忠恒[1] 吕鹏[1] 段建祥[1] 

机构地区：[1]吉林省地质调查院,吉林长春130061

出　　处：《地质通报》2004年第5期492-497,共6页Geological Bulletin of China

基　　金：中国地质调查局青藏高原1:25万多巴区幅(H45C001004)地调项目(编号:20001300009251)成果。

摘　　要：在地层古生物、蛇绿岩、生态环境、矿产资源等方面取得了丰硕成果。主要有:中奥陶世北方大陆珠角石动物群的发现为研究这一地区早古生代的构造属性提供了重要资料;准确地确定了区内奥陶系与志留系的界线;发现了目前国内发育最完整的志留系生物地层剖面之一,并将区内的志留系划分为4个统;新建多布日组、日拉组、康曲组、余穷组、索尔碎屑岩等岩石地层单位;晚三叠世多布日组底部沉积不整合的发现,证明存在印支运动;永珠蛇绿岩带上大规模席状岩墙群的发现,证明有海底扩张存在,另据同位素测年和生物资料,确定永珠蛇绿岩带的形成时代为中侏罗世—早白垩世。During regional geological survey, outstanding results have been achieved in aspects of stratigraphy and paleontology, ophiolites, ecological environment and mineral resources. They are mainly as follows: the discovery of the Middle Ordovician boreal Antinoceras fauna provides important information for the study of the attributes of the Early Paleozoic structure in the area; the Ordovician-Silurian boundary in the area is accurately defined; one of the most complete Silurian biostratigraphic section in China are found and on that basis the Silurian in the area is divided into four series; such lithostratigraphic units as the Duoburi Formation, Rila Formation, Kangqu Formation, Yuqiong Formation and Suoer clastic rocks are newly established; the discovery of the sedimentary unconformity at the base of the Late Triassic Duoburi Formation supports the existence of the Indosinian movement; the discovery of large-scale sheeted dike swarms in the Yonzhug ophiolite belt proves the existence of sea-floor spreading, and according to the isotope dating and fossil data, the age of the Yonzhug ophiolite belt is determined to be Middle Jurassic-Early Cretaceous.

关 键 词：中侏罗世-早白垩世 席状岩墙群 角度不整合 印支运动 奥陶纪 志留纪 冈底斯 

分 类 号：P623.12[天文地球—地质矿产勘探]