赤布张错幅地质调查新成果及主要进展  

New results and major progress in regional geological survey of the Chibuzhang Co Sheet

作　　者：姚华舟[1] 段其发[1] 牛志军[1] 王建雄[1] 白云山[1] 甘金木[1] 魏君奇[1] 曾波夫[1] 

机构地区：[1]中国地质调查局宜昌地质矿产研究所,湖北宜昌443003

出　　处：《地质通报》2004年第5期530-537,共8页Geological Bulletin of China

基　　金：中国地质调查局青藏高原1:25万赤布张错幅(H46C003001)地调项目成果;湖北省地球表层系统对外开放实验室课题资助(编号LESS-0102)。

摘　　要：于二叠纪—古近纪地层中发现动物化石、植物化石和孢粉多属多种。其中所有孢粉和植物化石在测区均为首次发现。发现软体动物并建立1新属2新种(QuemocuomegalodonorientusYaoShaetZhang,Q.longitatusYaoShaetZhang)。在藏北地区首次发现典型的古近纪双壳类化石(PisidiumamnicumMüller)。在上三叠统中发现厚度超过800m的钙碱性岛弧型中酸性火山岩。岩浆侵入岩获得一批岩石化学资料和21个喜马拉雅期的同位素年龄数据(23～48Ma),显示南部同碰撞、北部造山后拉张的特点。新近纪火山岩分布于测区北部,划分为2个喷发旋回,为板内裂谷活动的产物。发现中—晚侏罗世地层与晚三叠世地层的明显角度不整合接触面。查明了测区北部的二叠纪地层与上覆晚三叠世至侏罗纪地层为角度不整合接触。Various genera and species of fossil animals and plants and sporopollen have been found in Permian to Paleogene strata, of which all the sporopollen and fossil plants are for the first time found in the mapping area. One new genus and two new species (Quemocuomegalodon orientus Yao Sha et Zhang and Q. longitatus Yao Sha et Zhang) of mollusks have been discovered and established; and very characteristic Eogene bivalve fossils (Pisidium amnicum Müller) have been found in northern Tibet. Calc-alkaline island-arc intermediate-acid volcanic rocks more than 800 m thick have been found in the Upper Triassic. A number of rock chemical data and 21 isotopic age data (Himalayan, 23-48 Ma) of intrusive rocks have been obtained, indicating syncollision in the south and post-orogenic extension in the north during the Himalayan stage. Neogene volcanic rocks are widely distributed in the north part and may comprise two eruptive cycles. They are the product of within-plate rifting. Distinct angular unconformities between the Mid-Upper Jurassic and the Upper Triassic and between the Permian and the Upper Triassic to Jurassic have been discovered.

关 键 词：二叠纪-古近纪 动植物化石 三叠系岛弧火山岩 角度不整合 印支运动 同位素年代数据 

分 类 号：P623.12[天文地球—地质矿产勘探]