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

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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.