The Columbia supercontinent: Retrospective, status, and a statistical assessment of paleomagnetic poles used in reconstructions
The Columbia supercontinent: Retrospective, status, and a statistical assessment of paleomagnetic poles used in reconstructions
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DOI：
10.1016/j.gr.2022.06.014
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发表时间：
2022-06
影响因子：
6.1
通讯作者：
J. Meert;M. Santosh
中科院分区：
文献类型：
--
作者：
J. Meert;M. Santosh
早在2002年，就有人提出在Rodinia之前就存在一个古-中元古代超大陆--哥伦比亚。同年，一个类似的提议详细讨论了分布在整个地球仪的2.1-1.8 Ga造山带，这些造山带被认为代表了哥伦比亚的集合。在接下来的20年里，支持哥伦比亚的证据越来越多，但它的确切配置和各种彗星之间的几何关系仍然难以捉摸。重建哥伦比亚的几个挑战之一是缺乏高质量的古地磁数据。在这个领域，进展缓慢，但稳定，因为它需要艰苦的实地和实验室工作来产生一个新的极点。尽管数据库中存在很大的差距，但我们已经生成了哥伦比亚的可测试模型。不幸的是，很少有来自许多大陆的同时代极点，重建代表了哥伦比亚生命周期中的小时间片段。在这方面的贡献，我们回顾了历史的哥伦比亚假说，证据安装在支持的想法和地位的模型。我们提出了一种统计方法来评估拟合优度在古地磁为基础的重建数据在时间和空间上分离。波罗的海和亚马逊河流域经常与东劳伦提斯连在一起，形成一个长期存在的哥伦比亚增生造山边缘。这个所谓的桑巴舞模型最初被假设为哥伦比亚和Rodinia的10亿年（1.8-0.8 Ga）固定装置。古地磁数据支持这种连接从1.75-1.5 Ga，但不是在年轻的时候。我们还测试了最近的哥伦比亚模型的基础上，最高质量的古磁极在那个时候。我们的分析揭示了数据和模型之间的许多差异，随着重建哥伦比亚号的工作持续进行，需要解决这些差异。
The proposal that a Paleo-Mesoproterozoic supercontinent, Columbia, preceded the existence of Rodinia was forwarded in 2002. A similar proposal that same year provided a detailed discussion of 2.1–1.8 Ga orogenic belts distributed throughout the globe thought to represent the assembly of Columbia. In the 20 years that followed, evidence in favor of Columbia has grown but its exact configuration and geometrical relationships between various cratons remains elusive. One of several challenges in reconstructing Columbia is the paucity of high-quality paleomagnetic data. Progress is slow, but steady, in this realm as it requires painstaking field and laboratory work to generate a new pole. Despite large gaps in the database, we have generated testable models of Columbia. Unfortunately, there are seldom coeval poles from many continents and reconstructions represent small time-slices in Columbia’s lifespan. In this contribution, we review the history of the Columbia hypothesis, evidence mounted in support of the idea and status of the model. We present a statistical method to evaluate goodness of fit in paleomagnetically based reconstructions where data are separated in both time and space. Baltica and Amazonia are often linked together with eastern Laurentia to form a long-lived accretionary orogenic margin of Columbia. This so-called SAMBA model was originally posited as a one billion year long (1.8–0.8 Ga) fixture in both Columbia and Rodinia. Paleomagnetic data are supportive of this connection from ∼ 1.75–1.5 Ga, but not during younger times. We also test a recent model of Columbia based on the highest quality paleomagnetic poles available at that time. Our analysis reveals numerous discrepancies between data and models that will need to be addressed as work towards reconstructing Columbia continues unabated.