Collaborative Research: Testing Precambrian Siberia-Laurentia Geologic Connections with U-Pb Geochronology

根据古地磁资料、基底穿洞点和裂谷边缘的最佳拟合，重建了西伯利亚-西劳伦西亚克拉通，对元古代岩脉群进行了排列，并对元古代盆地进行了并置。在这个俄美合作项目中，PI通过检查火成岩的结晶年龄和沉积岩的地层学和碎屑锆石系统来测试修复，这些沉积岩被截断在西劳伦森和东西伯利亚克拉通边缘。具体来说，他们计划进行以下测试。1)连接北西伯利亚Anabar地块与Belt-Purcell盆地及其邻近的蒙大拿西南部和怀俄明州基底的脉岩-基岩群的U-Pb定年；2)西伯利亚北部碎屑岩碎屑锆石的U-Pb定年，可能与年代确定的Belt-Purcell超群相联系；3)西伯利亚东南部Uy群中部和死亡谷Kingston峰组的基岩群和基岩流的U-Pb定年，可能形成了一个大型火成岩省。4)西伯利亚东南部Uy组和Yudoma组碎屑岩中碎屑锆石的U-Pb定年，以及可能构成一个盆地的Kingston峰组和死亡谷Noonday白云岩的潜在关联。所申请的资金将用于对死亡谷和西伯利亚东南部的相互地质考察，随后进行U-Pb地质年代学实验室工作。PI还将对俄罗斯地质学家先前收集的样本进行测年。如果能最终证明西伯利亚-劳伦西亚恢复的有效性，该项目将产生重大的地质影响，因为这是更广泛的罗迪尼亚超大陆假说的关键组成部分，并对几个地质和地球动力学问题产生影响，包括全球冰河时代、真极漂移、冈瓦纳的形成和寒武纪后生动物革命。如果结果证明是否定的，该研究将消除对Rodinia的一种潜在解释，并将为西伯利亚和Laurentian元古代地质演化提供有价值的新约束。更广泛的影响包括资助对地球科学学生的高级培训，通过国际科学合作促进和平与科学进步，以及支持俄罗斯的科学基础设施。

Abstract Reconstruction of a Siberia-west Laurentia craton, in accordance with paleomagnetic data, basement piercing points, and the best fit of the rift margins, aligns Proterozoic dike/sill swarms and juxtaposes Proterozoic basins. In this collaborative Russian-American project, the PI's test the restoration by examining the crystallization ages of igneous rocks and the stratigraphy and detrital zircon systematics of sedimentary rocks that are truncated at the west Laurentian and east Siberian cratonic margins. Specifically, they plan the following tests. 1) U-Pb dating of a dike-sill swarm that may link the Anabar massif of north Siberia with the Belt-Purcell basin and adjacent basement of southwest Montana and Wyoming.2) U-Pb dating of detrital zircons from clastic rocks of northern Siberia that may link to the well-dated Belt-Purcell Supergroup.3) U-Pb dating of sill swarms and flows in the middle Uy Group of southeast Siberian and Kingston Peak Formation of Death Valley that may have formed one large igneous province.4) U-Pb dating of detrital zircons from clastic rocks in the Uy and Yudoma groups of southeast Siberian and potentially correlative Kingston Peak Formation and Noonday Dolomite of Death Valley that may have comprised parts of one basin. Requested funds will cover reciprocal geological excursions to Death Valley and southeast Siberia, to be followed by U-Pb geochronological lab work. The PI's will also date samples previously collected by Russian geologists. The project will have significant geological impact should it conclusively demonstrate the validity of the Siberia-Laurentia restoration because this is a critical component of the broader Rodinia supercontinent hypothesis, and has implications for several geologic and geodynamic problems, including global ice ages, true-polar wander, formation of Gondwana, and the Cambrian metazoan revolution. Should the results prove negative, the study will remove one potential interpretation for Rodinia, and will also provide valuable new constraints for Siberian and Laurentian Proterozoic geological evolution. Broader impacts include the advanced training of geoscience students supported by the grant, the promotion of peace and advancement of science through international scientific collaboration, and support of the Russian scientific infrastructure.