Paleomagnetic constraints on the paleogeography of the East Asian blocks during Late Paleozoic and Early Mesozoic times
Paleomagnetic constraints on the paleogeography of the East Asian blocks during Late Paleozoic and Early Mesozoic times
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DOI：
10.1016/j.earscirev.2018.02.004
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发表时间：
2018-11-01
影响因子：
12.1
通讯作者：
Zhou, Tinghong
中科院分区：
文献类型：
--
作者：
Huang, Baochun;Yan, Yonggang;Zhou, Tinghong
虽然地球磁场的轴向和主导地心特征意味着古经度是不确定的，但古地磁学是地球科学家用来限制古地理学和重建大陆块运动学演化的唯一真正定量方法。在过去的半个世纪里，大量的古地磁结果提供了大量的定量约束的起源和构造演化的主要构造分区，现在包括东亚。在本文中，我们首先评估了现有的早古生代早白垩世古地磁结果从中国南方，华北和塔里木地块使用国际公认的可靠性标准。然后，我们构建了一个运行平均通过20 Ma窗口加权极点根据他们的Q-因子，并拟合一个球面样条与平滑因子为300，以获得这三个主要区块的视极移（APW）路径在这早古生代晚中生代的时间间隔。结合柴达木、羌塘、拉萨、锡布马苏、印支等地区晚古生代-早中生代古地磁极资料，对中奥陶世-晚侏罗世东亚主要地块和小地块进行了一系列古地理重建（类似于460-160 Ma），虽然主要基于古地磁证据，但旨在包含地质约束。最后，我们讨论了目前的证据，古亚洲，勉略，和东古特提斯海洋的封闭时间，其中包括有关东亚大陆拼贴和碰撞的基本问题与盘古超大陆的北方主体。我们使用的集体证据认为，这些主要的古海洋已经关闭的晚三叠世，东亚部分的超大陆已经团结起来，成为一个不可分割的一部分盘古大陆的时候（类似于220马）。
Although the axial and dominant geocentric character of the Earth's magnetic field means that paleolongitude is indeterminate, paleomagnetism is otherwise the only truly quantitative method available to the Earth scientist for constraining paleogeography and reconstructing the kinematic evolution of continental blocks. During the past half-century numerous paleomagnetic results have provided substantial quantitative constraints on the origin and tectonic evolution of the major tectonic divisions now comprising Eastern Asian. In this paper we first assess the available Early Paleozoic to Early Cretaceous paleomagnetic results from the South China, North China, and Tarim blocks using internationally-recognized reliability criteria. We then construct a running mean through a 20 Ma window by weighting the poles according to their Q-factors and fit a spherical spline with smoothing factor of 300 to derive apparent polar wander (APW) paths for these three major blocks during this Early Paleozoic to Late Mesozoic time interval. Together with Late Paleozoic to Early Mesozoic paleomagnetic poles from the Qaidam, Qiangtang, Lhasa, Sibumasu, Indochina, and some other smaller blocks/terranes of East Asia, we produce a series of paleogeographic reconstructions for these major blocks and lesser terranes of East Asia between mid-Ordovician and late Jurassic times (similar to 460-160 Ma) which, although based primarily upon paleomagnetic evidence, aim to embrace the geological constraints. Finally, we discuss the current evidence for closure times of the Paleo-Asian, Mianlue, and East Paleo-Tethyan oceans which incorporate fundamental issues concerning the formation of the East Asian continental collage and collision with the northern main body of the Pangean supercontinent. We use the collective evidence to argue that these major paleo-oceans had closed by the Late Triassic, and that the East Asian sector of the supercontinent had united to become an integral part of Pangea by that time (similar to 220 Ma).