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

盘古大陆存在于晚古生代和中生代早期，由北部大陆群(劳拉西亚，由北美、格陵兰、欧洲和亚洲组成)和南部冈瓦纳群岛(包括南美洲、非洲、澳大利亚、马达加斯加、印度和南极洲)组成。人们普遍认为，在盘古大陆，冈瓦那的西北-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-A。然而，在晚三叠世以前，从冈瓦那和劳拉西亚获得的古地磁数据与盘古A拟合不太吻合，这导致科学家们要么质疑这些数据的有效性，要么提出一种不同的拟合，称为盘古B。盘古B期重建的主要问题是，所有人都认为，到晚三叠世，盘古A期为盘古A期，这意味着盘古B期在二叠纪或三叠纪转变为盘古A期。完成这一变化的相对运动包括冈瓦那和劳拉西亚之间令人惊讶地大到3500公里或更大的右行巨切变。对于这样的巨型剪切，几乎没有地质证据，因此地质学家忽略了盘古-B的提议。到目前为止，相关的晚二叠世和早三叠世的古地磁数据仍然质量明显较差，因此，我们打算收集这一时间段的新的古地磁数据，以检验盘古适合度，并确定从盘古A到盘古A的变化是在晚二叠世之前还是之后发生的，如果确实发生了变化的话。大多数新的收藏品将来自阿根廷，那里存在层状火山岩，可能会产生可靠的结果。超大陆盘古大陆是地球古代地理的一个非常基本和突出的方面，其形状的准确性对任何研究地球科学的人都是感兴趣的。这项研究的目的是确定是否有证据表明南美洲西北部毗邻北美阿巴拉契亚边缘的晚二叠世-早三叠世古地磁数据中存在盘古重构。这样的盘古-B重建与经典的和广泛接受的盘古-A匹配相当不同，相反，南美洲西北部毗邻北美的德克萨斯边缘。令人惊讶的是，现有的二叠纪和三叠纪早期的古地磁记录似乎有利于盘古B，这让地质学家们困惑了几十年。如果盘古B存在，那么它一定在二叠纪或三叠纪经历了一次巨大的扭动运动。这项研究旨在确定之前相当初步的有利于盘古B的结果是否得到了仔细确定的新的古地磁数据的支持。如果发现盘古B的存在，通过推断，这项研究将获得长度约为3500公里或更长的巨大侧向断裂运动的证据，这类运动在后盘古地球历史中，即过去2亿年中，从未被记录在案。

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.