Late Mesozoic tectonics of Central Asia based on paleomagnetic evidence
Late Mesozoic tectonics of Central Asia based on paleomagnetic evidence
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DOI：
10.1016/j.gr.2009.12.008
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发表时间：
2010-09
影响因子：
6.1
通讯作者：
D. Metelkin;V. Vernikovsky;A. Kazansky;M. Wingate
中科院分区：
文献类型：
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作者：
D. Metelkin;V. Vernikovsky;A. Kazansky;M. Wingate
本文介绍了西伯利亚地台（维尔霍扬斯克海槽）及其西南边缘（外贝加尔盆地和米努萨海槽）晚中生代（中侏罗世至白垩纪末期）岩石的古地磁数据。我们确定了 165、155、135、120 和 75Ma 的一系列关键古地磁极，它们定义了西伯利亚的中生代视极漂移路径 (APWP)。这种定量方法为中亚中生代构造的总体修正提供了机会。许多研究人员认为欧亚大陆在中生代时期已经完全稳定。然而，我们证明了相应的中生代极点与西伯利亚和欧洲的系统偏差，并将这些差异解释为由于西伯利亚板块相对于欧洲板块顺时针旋转而导致大规模左旋走滑运动的证据。我们的结论是，在晚古生代组装之后，欧亚板块内部并不稳定，即不是刚性的。西伯利亚中生代地质演化以走滑构造为主。与裂谷相关的地堑形成于西西伯利亚沉积盆地的基底内，造山事件发生在中亚构造省内的西伯利亚克拉通西南缘。我们的古地磁重建还表明，在侏罗纪末期之前，蒙古-鄂霍茨克洋仍未完全闭合。我们认为最终的碰撞发生在早白垩世，在中侏罗世到晚侏罗世期间，大洋岩石圈向北俯冲导致了从西向东倾斜的海洋闭合（“剪刀状”模型）。该闭合是由西伯利亚克拉通显着的左旋走滑运动控制的。这一过程在外贝加尔地区体现为广泛的双峰式火山活动和裂谷相关结构（包括拉裂盆地）的发育。
This paper presents paleomagnetic data for Late Mesozoic (Middle Jurassic to end-Cretaceous) rocks of the Siberian platform (Verkhoyansk Trough) and its southwestern margin (Transbaikalian basins and Minusa Trough). We determine a series of key paleomagnetic poles for 165, 155, 135, 120, and 75Ma, which define the Mesozoic apparent polar wander path (APWP) for Siberia. This quantitative approach provides the opportunity for a general revision of Mesozoic tectonics of Central Asia. Many researchers have considered the Eurasian continent to have been completely stable during the Mesozoic era. However, we demonstrate systematic deviations of corresponding Mesozoic poles from Siberia and Europe, and interpret the discrepancies as evidence for large-scale sinistral strike-slip motion due to clockwise rotation of the Siberian plate relative to the European plate. We conclude that, following its Late Paleozoic assembly, the Eurasian plate was not internally stable, i.e. not rigid. The Mesozoic geological evolution of Siberia was dominated by strike-slip tectonics. Rift-related grabens formed within the basement of the West Siberia sedimentary basin and orogenic events occurred along the southwestern margin of the Siberian craton, within the Central Asia tectonic province. Our paleomagnetic reconstruction indicates also that the Mongol-Okhotsk Ocean was still not closed completely before the end of the Jurassic. We propose that final collision occurred in the Early Cretaceous, and during the Middle to Late Jurassic interval, northward subduction of oceanic lithosphere resulted in oblique, west-to-east ocean closure (a “scissors-like” model). The closure was controlled by significant sinistral strike-slip motion of the Siberian craton. This process is reflected in Transbaikalia by extensive bimodal volcanic activity and development of rift-related structures, including pull-apart basins.