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首页> 外文期刊>Brazilian Journal of Geology >Paleomagnetism of the Amazonian Craton and its role in paleocontinents
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Paleomagnetism of the Amazonian Craton and its role in paleocontinents

机译：亚马逊克拉通的古磁性及其在古大陆中的作用

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In the last decade, the participation of the Amazonian Craton on Precambrian supercontinents has been clarified thanks to a wealth of new paleomagnetic data. Paleo to Mesoproterozoic paleomagnetic data favored that the Amazonian Craton joined the Columbia supercontinent at 1780 Ma ago, in a scenario that resembled the South AMerica and BAltica (SAMBA) configuration. Then, the mismatch of paleomagnetic poles within the Craton implied that either dextral transcurrent movements occurred between Guiana and Brazil-Central Shield after 1400 Ma or internal rotation movements of the Amazonia-West African block took place between 1780 and 1400 Ma. The presently available late-Mesoproterozoic paleomagnetic data are compatible with two different scenarios for the Amazonian Craton in the Rodinia supercontinent. The first one involves an oblique collision of the Amazonian Craton with Laurentia at 1200 Ma ago, starting at the present-day Texas location, followed by transcurrent movements, until the final collision of the Amazonian Craton with Baltica at ca. 1000 Ma. The second one requires drifting of the Amazonian Craton and Baltica away from the other components of Columbia after 1260 Ma, followed by clockwise rotation and collision of these blocks with Laurentia along Grenvillian Belt at 1000 Ma. Finally, although the time Amazonian Craton collided with the Central African block is yet very disputed, the few late Neoproterozoic/Cambrian paleomagnetic poles available for the Amazonian Craton, Laurentia and other West Gondwana blocks suggest that the Clymene Ocean separating these blocks has only closed at late Ediacaran to Cambrian times, after the Amazonian Craton rifted apart from Laurentia at ca. 570 Ma.
机译：在过去的十年中，得益于大量新的古磁数据，亚马逊克拉通对前寒武纪超大陆的参与得以澄清。古到中元古代的地磁数据支持亚马逊克拉通在1780 Ma以前加入哥伦比亚超大陆，这种情况类似于南美洲和南美洲的构造（SAMBA）。然后，克拉通内部的古磁极不匹配意味着，在1400 Ma之后，圭亚那和巴西-中盾之间发生了右旋过流运动，或者在1780至1400 Ma之间发生了亚马逊-西非块体的内部旋转运动。目前可用的晚中古生代古磁数据与罗迪尼亚超大陆的亚马逊克拉通的两种不同情况兼容。第一个涉及亚马逊克雷顿与劳伦蒂亚在1200 Ma之前的倾斜碰撞，从今天的得克萨斯州位置开始，随后进行横贯运动，直到亚马逊克雷顿与波罗的海最后一次碰撞发生在大约1200 Ma。 1000毫安第二个步骤要求在1260 Ma之后使亚马逊克拉通和波罗的海远离哥伦比亚的其他地区，然后顺时针旋转并使这些区块与Laurentia在1000 Ma沿格伦维连带碰撞。最后，尽管亚马孙克拉通与中非块碰撞的时间尚有争议，但可用于亚马孙克拉通，劳伦西亚和西贡多瓦纳的几个新元古代/寒武纪古磁极表明，分隔这些块的Clymene海洋仅在埃迪亚卡兰（Ediacaran）晚期至寒武纪，亚马逊流域的克雷顿（Craton）于大约在Laurentia裂开。 570毫安。

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