Ediacaran Paleomagnetism and Geochronology of Eastern Baltica: A Key to Paleogeography and Climatic History of the Continent

地质时代的所有时间段都充满了奥秘和谜团，但有些时间段提供的谜团比其他时间段更复杂。从新元古代晚期到寒武纪中期(约8亿至5.01亿年前)的地质时间跨度预示着复杂动物的进化；地球历史上一些最严重的冰川事件；大陆形状的快速变化；大气和海洋中氧气水平的增加以及许多其他神秘的地质、地球物理和天文事件。特别是，这段时间包括了-5.13亿年前的寒武纪‘大爆发’。地球历史上这一独特生物时期的确切原因尚不清楚，但对动物崛起的猜测从纯粹的内在生物原因到外部触发因素，或者两者的某种组合。在同一时间间隔内发生的构造事件创造了“指导”当今地球显生界发展的框架。耐人寻味的是，许多表面上互不关联的现象似乎在深层次上是相互关联的。人们曾多次尝试提供这段时间的古地理地图，而实现这一目标的一个重要工具就是古地磁。古地磁研究提供了唯一的定量方法，可以用来确定主要陆块的古代空间分布。然而，正是这段时间，古地磁数据最具争议。北美和波罗的海的问题尤其严重，这些地区的古地磁数据被认为支持高纬度或低纬度位置、快速大陆漂移、快速真极移、惯性交换真极移和不寻常的磁场配置。这项工作正在研究波罗的海边缘(乌拉尔山脉)沉积序列中记录的古地磁特征，以努力揭开寒武纪爆发期间和之前的古地理复杂性。这项研究是佛罗里达大学科学家和俄罗斯研究人员之间的国际合作的一部分。除了该项目的科学目标外，该提案还通过为研究生和本科生提供支持，帮助培训下一代地质学家(包括该领域通常代表性不足的群体)。该项目还通过佛罗里达大学的地质科学大使小组和佛罗里达州公民科学组织向公众传播研究成果。

All intervals of geologic time are filled with mysteries and enigmas but some offer more intrigue than others. The span of geologic time that stretches from the late Neoproterozoic through the Middle Cambrian (~800-501 million years ago) heralded the evolution of complex animals; some of the most severe glacial episodes in Earth history; rapid changes in continental configurations; increased oxygen levels in the atmosphere and oceans and a host of other enigmatic geological, geophysical and astronomical events. In particular, this interval of time includes the Cambrian 'explosion' from 535-513 million years ago. Precise causes for this unique biological period in Earth history are unknown, but speculation about the rise of animals has run the gamut from purely intrinsic biological causes to extrinsic triggers or some combination of both. Tectonic events during this same time interval created the framework that 'guided' the Phanerozoic development of the present-day globe. It is intriguing that numerous and superficially disconnected phenomena seem to be interrelated at a profound level. There have been many attempts to provide paleogeographic maps for this interval of time and one important tool for accomplishing this goal is paleomagnetism. Paleomagnetic studies provide the only quantitative method from which the ancient spatial distribution of major landmasses can be established. Yet, it is precisely this time period where paleomagnetic data are the most controversial. The problems are particularly acute for North America and Baltica where the paleomagnetic data are argued to support high or low latitude positions, rapid continental drift, rapid true polar wander, inertial interchange true polar wander and unusual magnetic field configurations. This work is examining the paleomagnetic signature recorded in sedimentary sequences along the margins of Baltica (in the Ural Mountains) in an effort to unravel the complexities of paleogeography during and preceding the Cambrian explosion. The research is part of an international collaboration between scientists of the University of Florida and Russian researchers. In addition to the scientific goals of the project, the proposal is helping to train the next generation of geologists (including groups typically under-represented in the field) by providing support for graduate and undergraduate students. The project is also communicating research results to the general public via outreach efforts through the Geological Science Ambassador group at the University of Florida and Florida Citizen's for Science.