塔里木板块西南缘晚侏罗世古地磁研究  

Paleomagnetic Study of the Late Jurassic at the Southwestern Margin of Tarim

作　　者：李永安[1] 陈岩[2] Cogne Jean PASCAL Gilder STUART 孙东江[1] 

机构地区：[1]新疆地质矿产勘查开发局地质矿产研究所,乌鲁木齐830000 [2]奥尔良大学 [3]巴黎第七大学 [4]巴黎地球物理所

出　　处：《地质学报》2003年第2期151-157,共7页Acta Geologica Sinica

摘　　要：塔里木板块西南缘托云、奥依塔格晚侏罗世古地磁研究,获得了托云地区特征磁化方向:Ds=1.5°,Is=50.8°;古地磁极:λ=81.0°,ψ=247.0°,古纬度31.5°N。奥依塔格地区特征磁化方向:Ds=118.4°,Is=55.9°;古地磁极:λ=4.9°,ψ=120.6°,古纬度=36.4°N。从古地磁结果认为:①托云和奥依塔格相对托云地区产生顺时针旋转;②这两个地区古纬度为31°～36°左右,与塔里木平均古纬度30°N是基本一致的,但与现在纬度差达8°～10°左右,造成纬度差主要原因是构造运动造成的;③塔里木晚侏罗世古地磁亦与华北、华南基本一致,说明晚侏罗世塔里木、华北、华南三板块已联合成一个整体,拼合成统一的中国大陆,其位于热带—亚热带古气候环境。The paleomagnetic study has been completed in the Tuoyun and Uytag areas at the southwestern margin of the Tarim plate. The paleomagnetic results in the Tuoyun area show that the characteristic magnetic orientations are Ds = 1. 5° and Is=50. 8°; paleomagnetic poles are A=81. 0° and 95=247. 0°; and paleolattitude is 31. 5°. Those results in the Uytag area show that the characteristic magnetic orientations are Ds = 118. 4°, and Is=55. 9°; paleomagnetic poles are λ=4. 9°, (?)=120. 6°; and paleolattitude is 36. 4°. The paleomagnetic results reveal that the compression since the Jurassic in the Tuoyun and Uytag areas causes a shortening of up to 400 km, and Uytag was rotated clockwise relative to Tuoyun. The paleolattitude of 31°~36° N in the two areas accord primarily with that of 30°N in Tarim. But a difference of 8 ~ 10° exists between the present latitude and paleolatitude in the two areas, which is mainly caused by tectonic movements. The approximately same paleomagnetic poles during the Late Jurassic in Tarim and North China as well as South China indicate that they have been amalgamated to form a unified continent with a tropical-subtropical paleoclimate.

关 键 词：塔里木板块 晚侏罗世 古地磁 古气候环境 古纬度 古地磁极 新疆 

分 类 号：P318[天文地球—固体地球物理学]