中中新世以来阿尔金断裂走滑未造成柴达木盆地整体旋转  

Strike-Slip of Altyn Tagh Didn't Result in Qaidam Basin Rotation Since Middle-Miocene

作　　者：裴军令[1] 周在征 李海兵[2] 孙知明[1] 

机构地区：[1]中国地质科学院地质力学研究所/国土资源部古地磁与古构造重建重点实验室,北京100081 [2]中国地质科学院地质研究所/大陆动力学国家重点实验室,北京100037

出　　处：《吉林大学学报（地球科学版）》2016年第1期163-174,共12页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局基础研究项目(1212011121267;1212011120964);国家自然科学基金项目(41172177)~~

摘　　要：通过柴达木盆地南八仙剖面磁性地层学研究，建立了部分上油砂山组磁极性序列，认为该剖面时代为7．5～9．0Ma。从320块样品的古地磁数据分析，揭示了一组高温特征剩磁分量，在95％置信度下通过倒转检验（B级），说明这组高温分量很可能代表岩石形成时的原生剩磁，其特征剩磁方向为：地理坐标下为Dg=358．5°，Ig=40．5°，k=28．5,α95=4．2，层面坐标下为Ds=1．0°，Is=41．5°，k=34．0，α95—3．8；相应的极位置为λp=75．9°N，φp=270．5°E，dp=2．8°，dm=4．6°。通过与同时代柴达木盆地及邻区的古地磁极对比，说明中中新世以来柴达木地块整体上没有经历明显旋转运动，阿尔金断裂活动致使肃北等毗邻断裂带地区发生了构造旋转。Based on the magnetostratigraphic study at Nanbaxian section, Qaidam basin, a magnetie polarity sequence of Shangyoushashan Formation has been established. The magnetostratigraphic result suggests the age of 7. 5- 9. 0 Ma. A stable high temperature characteristic remanence component is isolated by stepwise thermal demagnetization from 320 samples through a positive reversal test at the 95% confidence level, which may possibly represent the rock＇s primary remanence. The mean direction is Dg=358.5°, Ig=40.5°, k=28.5,α95=4.2, Ds=1. 0°, Is=41.5°, k=34.0,α95 =3.8,corresponding to a paleopole at λp=75.9°N, φp=270.5°E,dp=2.8°, dm =4.6°. In comparison of this paleomagnetic poles from the Qaidam basin with those from adjacent region, no tectonic rotation in Oaidam basin has been identified; however the tectonic rotation of Subei basin has been occurred and resulted from the left-slip of Altyn Tagh fault since Middle-Miocene.

关 键 词：柴达木盆地 古地磁 阿尔金断裂 磁性地层 构造旋转 中新世 

分 类 号：P539.3[天文地球—古生物学与地层学] P542[天文地球—地质学]