Testing Pangea Reconstructions with New Late Permian - Early Triassic Paleomagnetic Studies

盘古大陆存在于古生代晚期和中生代早期，由北方大陆群（劳亚大陆，包括北美，格陵兰岛，欧洲和亚洲）和冈瓦纳大陆南部组成，包括南美洲，非洲，澳大利亚，马达加斯加，印度和南极洲。一般认为，在盘古大陆，冈瓦纳的西北非洲边缘与北美的阿巴拉契亚边缘相邻;这种重建被称为盘古大陆-A。然而，在晚三叠世之前，来自冈瓦纳和劳亚大陆的古地磁数据与盘古大陆-A的拟合并不一致，这导致科学家们要么质疑这些数据的有效性，要么提出一个不同的拟合，称为盘古大陆-B。盘古大陆-B重建的主要问题是，每个人都同意，到晚三叠世的时候，适合的是盘古大陆-A，这意味着盘古大陆-B在二叠纪或三叠纪转变为盘古大陆-A。完成这一变化的相对运动包括冈瓦纳和劳亚之间令人惊讶的3500公里或更大的右旋巨型剪切。对于这样一个巨大的剪切，几乎没有地质证据存在，地质学家因此忽略了盘古-B的建议。相关的晚二叠世和早三叠世的古地磁数据迄今为止仍然明显质量较差，因此，我们打算收集这段时间的新的古地磁数据来测试盘古大陆的拟合，并确定从盘古大陆B到盘古大陆A的变化是否发生在晚二叠世之前或之后，如果确实发生的话。大多数新的收集将来自阿根廷，那里存在分层火山岩，可能会产生可靠的结果。超大陆盘古大陆是地球古代地理学中一个非常基本和突出的方面，它的构造的准确性对任何研究地球科学的人都很感兴趣。本研究的目的是确定是否有任何证据的盘古大陆重建晚二叠世-早三叠世古地磁数据，其中南美洲西北部位于毗邻北美阿巴拉契亚边缘。这种盘古大陆-B的重建与经典的和广泛接受的盘古大陆-A的拟合有很大的不同，在盘古大陆-A的拟合中，南美洲西北部与北美洲的德克萨斯边缘相邻。令人惊讶的是，二叠纪和早三叠世的古地磁记录似乎更倾向于盘古大陆B，这让地质学家困惑了几十年。如果盘古大陆B存在，那么它一定在二叠纪或三叠纪期间经历了一次大的扭动运动。这项研究旨在确定先前的，而不是初步的结果，有利于盘古-B的支持，仔细确定新的古地磁数据。如果发现盘古大陆B存在，这项研究将通过推论获得巨大的横向断层运动的证据，长度为3500公里或更长，在后盘古大陆的地球历史中，也就是说，在过去的2亿年中，没有任何记录。

Pangea, as it existed in late Paleozoic and early Mesozoic time, consisted of a northern group of continents (Laurasia, comprised of North America, Greenland, Europe and Asia) and the southern Gondwana assembly, which includes South America, Africa, Australia, Madagascar, India, and Antarctica. It is generally assumed that in Pangea, Gondwana's Northwest-African margin was adjacent to North America's Appalachian margin; this reconstruction is called Pangea-A. However, for times before the Late Triassic the available data from paleomagnetism derived from Gondwana and Laurasia do not agree well with the Pangea-A fit, which have led scientists to either question the validity of these data or to propose a different fit, called Pangea-B. The main problem with the Pangea-B reconstruction is that everyone agrees that by Late Triassic time, the fit was that of Pangea-A, which implies that Pangea-B transformed into Pangea-A in Permian or Triassic time. The relative movements to accomplish this change consist of a surprisingly large 3500-km or greater dextral mega-shear between Gondwana and Laurasia. For such a mega-shear, little geological evidence exists, and geologists have therefore ignored the Pangea-B proposal. Relevant Late Permian and Early Triassic paleomagnetic data have thus far remained of demonstrably inferior quality, and we intend, therefore, to collect new paleomagnetic data for this time interval to test Pangea fits, and to determine whether a change from Pangea-B to Pangea-A occurred before or after the Late Permian, if it did occur at all. The majority of the new collections will be from Argentina, where stratified volcanic rocks exist that will likely yield reliable results. The supercontinent Pangea is a very fundamental and prominent aspect of the ancient geography of the Earth, and the accuracy of its configuration is of interest to anyone studying Earth Science. The aim of this study is to determine whether there is any evidence for a Pangea reconstruction in Late Permian-Early Triassic paleomagnetic data, in which northwestern South America was located adjacent to the Appalachian margin of North America. Such a Pangea-B reconstruction is rather different from the classically and widely accepted Pangea-A fit in which northwestern South America is, instead, adjacent to the Texas margin of North America. The available paleomagnetic records for Permian and Early Triassic time surprisingly seem to favor Pangea-B, which has puzzled geologists for decades. If Pangea B existed, then it must have undergone a large wrenching movement during either the Permian or the Triassic. This study intends to establish whether the previous, rather preliminary results that favor Pangea-B are supported by carefully determined new paleomagnetic data. If Pangea-B is found to have existed, the study will by inference have obtained evidence for enormous lateral fault movements, of the order of 3500 km in length or more, the likes of which are not documented for any time in the post-Pangea history of the Earth, that is, in the last 200 million years.