Characteristics of magnetic fabrics and paleocurrent directions of Cenozoic sediments in the Kelasu River,Kuqa Depression
Characteristics of magnetic fabrics and paleocurrent directions of Cenozoic sediments in the Kelasu River,Kuqa Depression
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发表时间：
2013
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通讯作者：
Zhang Zhi
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作者：
Zhang Zhi
库车坳陷克拉苏河沿岸沿着新生代地层发育，系统采集了塔里木盆地新生代两个剖面（A、B）的重定向岩心样品1700个。岩石磁学分析表明，新生代沉积物中以赤铁矿和次要磁铁矿为主，AMS结果表明，两个剖面的磁性面理较明显最大磁轴（к1）指示A剖面古水流方向，库木格列木组古水流为NEE-SWW向，当苏维依（SWY）南天山组沉积期间古水流方向的急剧转向表明南天山可能经历了一次快速隆升，特别是在其西北部。к3的叠瓦状构造也是古水流方向的指示。从JDK Fm.to库车组下部，古水流方向为NNW-SSE，并有转向东的趋势，表明南天山在这一时期缓慢隆升，或东、西同时隆升，西快东慢。
Cenozoic strata developed well along the Kelasu River,Kuqa Depression,Tarim Basin.A total of 1700 reoriented core samples were collected systematically from the two Cenozoic sections(A and B) at the two banks of the Kelasu River.Rock magnetism analysis shows that hematite and subordinate magnetite are dominant magnetic carriers in the Cenozoic sediments.The results of AMS indicate that the magnetic foliation of the two sections is more obvious than the magnetic lineation,and the minimum magnetic axes(к3) is nearly perpendicular to bedding planes,which illustrates a primary sedimentary fabric.The maximum magnetic axis(к1) was used to indicate the paleocurrent directions in section A.The paleocurrent of Kumugeliemu(KMGLM) Fm.was in NEE—SWW,while it turned to NNE—SSW when Suweiyi(SWY) Fm.was deposited.The sharp turning of the paleocurrent direction during the deposition of SWY Fm.suggests that southern Tianshan might have experienced a rapid uplift,especially in its northwestern part.The imbrication of к3 is also an indicator of the paleocurrent direction.From JDK Fm.to the lower part of Kuqa Fm.,the paleocurrent was in NNW—SSE,with a tendency to turn to the east.It implies that the southern Tianshan was uplifting slowly or the east and west of the Tianshan were rising simultaneously,with a larger rate in the west than in the east during this time.