Resolving Mesoproterozoic supercontinent configuration with an integrated multi-tool approach to sedimentary provenance analysis

超大陆旋回包括地球各大洲的周期性组合成一个单一的超大陆，然后解体和分散。哥伦比亚（也被称为努纳）是最古老的超级大陆之一，存在着重大的地质限制，它被认为是在大约15亿年前形成的。大约15亿到14亿年前在北美西部沉积的沉积物中包含了北美缺乏已知来源的矿物质，因此表明在哥伦比亚境内与北美西部相邻的是另一个大陆。然而，在大约15亿年前到大约10亿年前形成下一个超大陆（称为罗迪尼亚）之间，这个大陆的身份和任何重排发生的程度仍然存在争议。已经提出的模式将澳大利亚北部、澳大利亚南部和/或南极洲东部与北美西部相邻。这项研究将通过详细分析蒙大拿州、爱达荷州和亚利桑那州古代沉积岩中矿物的年龄和成分，并与澳大利亚和南极洲的潜在来源进行比较，来测试这些不同的模型。对从南极洲收集的古代沉积岩中矿物的可比分析将提供进一步的限制。这个项目将支持马萨诸塞大学洛厄尔分校（UML）的研究生和本科生的研究，为在冰川国家公园及其周围举办的UML学生开发一个新的夏季野外地质学和生态学课程（这是该项目中感兴趣的岩石的关键地点），将支持的研究纳入UML的其他本科生课程，并与爱达荷州、亚利桑那州、华盛顿州、德克萨斯州和明尼苏达州的科学家合作。该项目的目标是测试与中元古代超大陆哥伦比亚连接的北美西部大陆块体的身份和位置模型。该研究将重点关注北美西部中元古代沉积岩的来源，特别是蒙大拿/爱达荷州的Belt超群和亚利桑那州类似年龄的岩石。这些沉积层序以前通过常规碎屑锆石年代测定被认为是非北美输入的。这项工作将采用一种创新的综合方法，通过同时对碎屑锆石、独居石和金红石进行U-Pb定年和微量元素指纹鉴定，以及分别对碎屑锆石和长石进行Hf和常见Pb同位素表征，来确定物源。结果将与北澳大利亚克拉通、南澳大利亚克拉通和东南极克拉通的潜在烃源岩进行比较。先前从东南极洲收集的沉积样本也将包括在这项研究中，以扩大对这片冰雪覆盖的大陆的前寒武纪基底地质学的了解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The supercontinent cycle involves the periodic assembly of the Earth’s continents into a single supercontinent followed by breakup and dispersal. One of the oldest supercontinents for which significant geologic constraints exist is Columbia (also referred to as Nuna), which is thought to have been assembled by about 1.5 billion years ago. Sediments deposited between ~1.5 and 1.4 billion years ago in western North America include minerals that lack known North American sources and thus suggest that another continent was adjacent to western North America within Columbia. However, the identity of this continent and the extent to which any rearrangement occurred between ~1.5 billion years ago and the formation of the next supercontinent (called Rodinia) at ~1.0 billion years ago remains debated. Models have been proposed that place either northern Australia, southern Australia, and/or eastern Antarctica adjacent to western North America. This research will test these different models through detailed analyses of the ages and compositions of minerals within ancient sedimentary rocks in Montana, Idaho, and Arizona and comparison with potential sources in Australia and Antarctica. Further constraints will be provided from comparable analyses of minerals in ancient sedimentary rocks collected from Antarctica. This project will support graduate and undergraduate student research at the University of Massachusetts Lowell (UML), the development of a new summer field geology and ecology course for UML students held in and around Glacier National Park (which is a key locality for the rocks of interest in this project), incorporation of supported research into other undergraduate courses at UML, and collaborations with scientists in Idaho, Arizona, Washington, Texas, and Minnesota.The goal of this project is to test models for the identity and positions of continental blocks that were connected to western North America in the Mesoproterozoic supercontinent Columbia. The study will focus on the provenance of Mesoproterozoic sedimentary rocks in western North America, particularly the Belt Supergroup in Montana/Idaho and similarly aged rocks in Arizona. These sedimentary sequences have previously been recognized as having non-North American input via conventional detrital zircon dating. This work will use an innovative and integrative approach to determining provenance by way of simultaneous U-Pb dating and trace element fingerprinting of detrital zircon, monazite, and rutile, along with Hf and common Pb isotope characterization of detrital zircon and feldspar, respectively. Results will be compared to potential source rocks in the North Australian craton, South Australia craton, and East Antarctic craton. Previously collected sedimentary samples from East Antarctica will also be included in this study in order to expand knowledge of the Precambrian basement geology of that ice-covered continent.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.