SWEAT, AUSWUS, AUSMEX, or Other? Testing Proterozoic Supercontinent Reconstructions by Refining 1.8-1.6 Ga Apparent Polar Wander Paths from Laurentia and Australia

世界各地元古界岩石的构造地层合成使新元古代早期超级大陆Rodinia及其前身努纳(由1.8Ga组装)的合理重建成为可能。然而，许多不同的重建假设尚未得到高质量的古地磁数据的检验。劳伦西亚(北美克拉通)和澳大利亚太古代-元古界地体之间的构造地层学相似性构成了大多数现代罗迪尼亚概念的基础；如果有效，这些比较也将适用于努纳构造。最近的一项高质量的古地磁研究让人们对最流行的元古界劳伦蒂亚和澳大利亚早期的并列产生了怀疑，这种并置被称为汗水和澳大利亚；那项研究确定了第三种可能的重建，称为AUSMEX。PI试图通过从加拿大中部和澳大利亚北部保存完好的1.8-1.6Ga火山-沉积序列中收集新的古地磁和地质年代学数据，进一步检验这些假设的并置。这些结果将为这段时间内的两个克拉通生成精确的视极游走路径，从而可以对努纳和罗迪尼亚的重建进行定量测试。在这项拟议研究产生更广泛的科学影响之前，人们认识到，准确的大陆重建构成了地球表面过程所有方面的古地理基础，并为地幔地球动力学模型提供了边界条件。更广泛的影响还包括为研究生和本科生提供研究培训，包括一名立志在学术界谋职的女研究生。

Tectonostratigraphic syntheses of Proterozoic rocks worldwide have allowed plausible reconstructions for Rodinia, the early Neoproterozoic supercontinent, and its predecessor Nuna, assembled by 1.8 Ga. Many different reconstructions have been postulated, however, that have yet to be tested with high-quality paleomagnetic data. Tectonostratigraphic similarities between Archean-Proterozoic terrains in Laurentia (cratonic North America) and Australia form the bases for most modern conceptions of Rodinia; if valid, these comparisons would also pertain to Nuna configurations. One recent high-quality paleomagnetic study has cast doubt upon the most popular earlier juxtapositions of Proterozoic Laurentia and Australia, known as SWEAT and AUSWUS; that study identified a third possible reconstruction, dubbed AUSMEX. The PI seeks to test these hypothesized juxtapositions further, by collecting new paleomagnetic and geochronological data from well preserved 1.8-1.6 Ga volcanic- sedimentary successions in central Canada and northern Australia. These results will generate refined apparent-polar-wander paths for the two cratons during that interval and thus permit quantitative tests for Nuna and Rodinia reconstructions. Broader scientific impacts of the proposed research follow the recognition that accurate continental reconstructions form paleogeographic foundations for all aspects of Earth surface processes, and they provide boundary conditions for models of mantle geodynamics. Broader impacts also include research training for graduate and undergraduate students, including a female graduate student aspiring toward a career in academia.