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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >The Neoproterozoic Supercontinent: Rodinia or Palaeopangaea?
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The Neoproterozoic Supercontinent: Rodinia or Palaeopangaea?

机译：新元古代超大陆：罗迪尼亚还是古潘盖亚？

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The Rodinia reconstruction of the Neoproterozoic Supercontinent has dominated discussion of the late Precambrian Earth for the past decade and originated from correlation of sedimentary successions between western North America and eastern Australia. Subsequent developments have sited other blocks according to a distribution of approx 1100 Ma orogenic belts with break-up involving a putative breakout of Laurentia and rapid reassembly of continent crust to produce Gondwana by early Phanerozoic times. The Rodinia reconstruction poses several serious difficulties, including: (a) absence of palaeomagnetic correlation after approx 730 Ma which requires early fragmentation of continental crust although geological evidence for this event is concentrated more than 150 Ma later near the Cambrian boundary, and (b) the familiar reconstruction of Gondwana is only achieved by exceptional continental motions largely unsupported by evidence for ocean consumption. Since the geological evidence used to derive Rodinia is non-unique, palaeomagnetic data must be used to evaluate its geometrical predictions. Data for the interval approx 1150-500 Ma are used here to test the Rodinia model and compare it with an alternative model yielding a symmetrical crescent-shaped analogue of Pangaea (Palaeopangaea). Rodinia critically fails the test by requiring Antarctica to occupy the location of a quasi-integral Africa, whilst Australia and South America were much closer to heir Gondwana configurations around Africa than implied by Rodinia. Palaeopangaea appears to satisfy palaeomagnetic constraints whilst surmounting geological difficulties posed by Rodinia. The relative motions needed to produce Gondwana are then relatively small, achieved largely by sinistral transpression, and consistent with features of Pan-African orogenesis; continental dispersal did not occur until the Neoproterozoic-Cambrian boundary. Analogies between Palaeopangaea and (Neo)pangaea imply that supercontinents are not chaotic agglomerations of continental crust but form by episodic coupling of upper and lower mantle convection leading to conformity with the geoid.
机译：在过去的十年中，新元古代超大陆的Rodinia重建主导了前寒武纪地球的讨论，其起源于北美西部和澳大利亚东部之间的沉积演替关系。随后的发展根据约1100 Ma的造山带分布确定了其他区块，并破裂，其中包括推定的Laurentia破裂和大陆壳的快速重组，以在古生代早期就生产了冈瓦纳。 Rodinia重建带来了若干严重的困难，其中包括：（a）大约730 Ma之后没有古地磁相关性，这需要大陆地壳的早期破碎，尽管此事件的地质证据集中在寒武纪边界附近超过150 Ma之后，和（b）冈瓦纳人熟悉的重建工作只能通过特殊的大陆运动来实现，而这些运动在很大程度上没有海洋消耗的证据支持。由于用于得出罗迪尼亚的地质证据是不唯一的，因此必须使用古磁数据来评估其几何预测。此处使用大约1150-500 Ma区间的数据来测试Rodinia模型，并将其与产生Pangea（Palaeopangaea）对称月牙形类似物的替代模型进行比较。罗丹尼亚严格要求南极洲占据准整体非洲的位置，从而使这项测试严重失败，而澳大利亚和南美比非洲罗丹尼亚所暗示的更接近非洲的继承人冈瓦纳人。古盘古类似乎可以满足古地磁约束，同时克服了罗迪尼亚所造成的地质困难。这样，产生冈瓦纳人所需的相对运动就相对较小，主要通过鼻窦压迫来实现，并且与泛非造山运动的特征相一致。直到新元古代-寒武纪边界才出现大陆扩散。古pangaea和（neo）pangaea之间的类比表明，超大陆不是大陆壳的混沌团聚，而是由上，下地幔对流的偶发耦合形成的，从而与大地水准面保持一致。

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