摘要:
作者用磁性地层方法研究了塔里木盆地周缘库车组西域组地层。结果表明：库车组记录了吉尔伯特（Gilbert）负极性带，年龄为3.40～5.30Ma，其中显示了柯奇蒂（Cochiti）正极性亚带（3.80～3.90），努尼瓦克（Nunivak）正极性亚带（4.05～4.20Ma）、西杜夫加尔（Sidufjal）正极性亚带（4.32～4.47Ma）及思维拉（Thvera）正极性亚带（4.85～5.00Ma）。下西域组记录了高斯（Gauss）正极性带，所龄为2.48～3.40Ma。其中包括凯纳（Kaena）负极性亚带（2.92～3.01Ma）与马莫斯（Mammoth）负极性亚带（3.05～3.15Ｍａ）。上西域组记录了松山（Matuyama）负极性带下段，年龄为1.50～2.48Ma。其中包括留尼昂（Reunion）正极性亚带（2.12～2.15Ma）与奥尔都维（Olduvai）正极性亚带（1.67～1.87）Ma）。根据上述古地磁资料，作者将库车组划为下上新统（N1 2ｋ），年龄为3.40～5.30Ｍａ。下西域组划为上上新统（N2 2ｘ），年龄为2.48～3.40Ma。上西域组划为下下更新统（Q1 1），年龄为1.50～2.48 Ma 。作者认为由于印度板块向欧亚板块的俯冲造成塔里木盆地周缘山系的迅速抬升 ,形成高大山系的时代为上新世初期 ,大约 5.30 Ma 。
Abstract:
The paper studied the ages of Kuche and Xiyu Formations on the edge of Tarim Basin by The means of magnetostratigraphy , and discussed the epoch when the mountains around and Qinghai- Tibet rapidly lifted. The results showed that Gilbert reversal polarity zone was recorded in the Kuche Formation (about 3.40～5.30 Ma), including Cochiti (3.80～3.90 Ma), Nunivak (4.05～4.20 Ma) , Sidufjall(4.32～4.47 Ma) and Thvera (4.85～5.00 Ma) normal polarity subzones. Gauss polarity zone(2.48～3.40 Ma), occurred within the lower Xiyu Formation, including Kaena(2.92～3.01 Ma) and Mammo the(3.05～3.15 Ma) reversal polarity subzones. While the upper Xiyu formation, which recorded the Reunion normal polarity subzone (2.12～2.14 Ma) and Olduvai normal polarity subzone (1.67～1.87 Ma), was deposited during the early Matuyama reversal polarity time about (1.50～2.48 Ma). The Kuche Formation, as a result, was formed during Early Pliocene(N1 2 k), 3.40～5.30 MaBP) The lower Xiyu formation was taken shape during Late Pliocene (N2 2 x , 2.48～3.40MaBP and the upper Xiyu Formation during Early Plioctocene(Q1 1), (1.50～2.48 MaBP). Interms of data above, it was deduced that the epoch, when the speedily lifting of Qinghai-Tibet and the Ginantic mountains on the edge of the Tarim basin occured, was at the early stage of Ea rlyPliocene, about 5.30 Ma.
点击查看大图
下载:
