Collaborative Research: Integrated Geochronology and Paleomagnetism of Neoarchean-Paleoproterozoic Dikes in Wyoming, A Keystone of North American Cratons

当大陆聚集在一起时，地球上就会出现超级大陆，通常是在地球的一侧，作为多次构造碰撞的结果。超大陆过去的存在引起了构造学科学界和整个社会的极大兴趣，例如对矿藏的追踪。今天的大陆是盘古超级大陆的碎片，存在于恐龙的中生代。有几条证据表明，这项研究的主题是更早的超级大陆的存在。这些研究人员的目标是重建27亿至21亿年前大陆板块的排列，以确定古代超大陆旋回是否在当时发生。这项研究将在怀俄明州的所有主要山脉进行，由两名主要研究人员及其研究生和本科生在两个夏季野外季节采集岩石样本。此外，这些方法和数据将被纳入针对市中心九年级学生的科学推广计划。最后，结果将以电脑动画的形式向公众提供，作为教育资源。这项研究的重点是怀俄明州，这是北美的克拉通之一，目前最不为人所知的是它在新太古代-古元古代之间的位置变化。研究人员将检查漂移历史、共轭边缘和克拉通年代学，以用于超大陆重建。在许多方面，怀俄明州是新太古代-古元古代北美克拉通排列的中心基石。这项研究将需要两种互补的方法：使用几种成熟和精确的同位素方法的地质年代学，以及含有特别抵抗重置的磁区的岩石和矿物样品的古地磁。这些分析的结合为分析超大陆旋回提供了一种强有力的跟踪方法。这些对时间和空间的测量将应用于怀俄明州现在被侵蚀的熔岩平原的古老根部的岩脉岩石。初步数据表明，堤防是这两种研究方法紧密结合的理想靶区。这些数据令人振奋，这项研究的精炼视极移路径可能会导致对新太古代-古元古代超级大陆组合的重新评估。

Supercontinents arise on the Earth when the continents cluster together, typically on one side of the Earth, as a result of multiple tectonic collisions. The past existence of supercontinents is of great interest to the tectonics scientific community, and society in general, for example for the tracing of mineral deposits. The continents today are fragments of the Pangean supercontinent, which existed during the Mesozoic age of the dinosaurs. Several lines of evidence suggest the existence of even earlier supercontinents, the subject of this study. These researchers aim to reconstruct the arrangement of continental pieces between 2.7 and 2.1 billion years ago, to determine whether ancient supercontinent cycles occurred at that time. The research will be carried out in all the major mountain ranges of Wyoming, over two summer field seasons of rock sample collection by the two principal investigators and their graduate and undergraduate students. In addition, the methods and data will be incorporated into scientific outreach programs aimed at ninth-grade inner-city students. Finally, the results will be illustrated in a computer animation made available to the general public as an educational resource. The study focuses on Wyoming, one of the cratons of North America that currently is least well known in terms of its changing positions through the Neoarchean-Paleoproterozoic interval. The researchers will be examining drift histories, conjugate margins, and cratonic chronologies for purposes of supercontinental reconstruction. In many regards, Wyoming is a central keystone in the arrangement of North American cratons during the Neoarchean-Paleoproterozoic eras. The research will entail two complementary methods: geochronology using several well established and precise isotopic methods, and paleomagnetism of rock and mineral samples that contain magnetic domains that are particularly resistant to resetting. The combination of these analyses provides a powerful tracking method for the analysis of supercontinent cycles. These measurements of time and space will be applied to dike rocks from the ancient roots of now-eroded lava plains in Wyoming. The dikes are ideal targets for the close integration of the two research methods, as indicated by preliminary data. Such data have generated much excitement that refined apparent polar wander paths from this study may result in a re-evaluation of Neoarchean-Paleoproterozoic supercontinental assembly.