GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 112-3
Presentation Time: 8:35 AM


SEARS, James W., Geosciences, University of Montana, Missoula, MT 59812 and MACLEAN, John S., Geology, Southern Utah University, SC 309, 351 West University Boulevard, Cedar City, UT 84720,

The Siberia-west Laurentia paleocontinental reconstruction connects numerous distinct Proterozoic tectonic elements between the two cratons, including Paleoproterozoic basement terranes and shear zones, Mesoproterozoic cratonic basins and dike swarms, and Neoproterozoic rifts zones and conjugate margins. The early Mesoproterozoic Mukun and Billyakh groups (N Siberia) and the lithologically similar Neihart, Fort Steele, and Altyn formations (W Laurentia) form platformal cover sequences upon correlative basement provinces. In the reconstruction, the Udzha-Khastakh (NE Siberia) and Belt-Purcell (W Laurentia) basins inset the platform in a triple-rift system laced with 1470 Ma and 1370 Ma mafic sills and dikes. The late Mesoproterozoic-Neoproterozoic Sette-Daban basin (SE Siberia) restores bed-for-bed against the Amargosa basin (SW Laurentia), and the basins contain similar detrital zircon signatures. The reconstruction juxtaposes parallel Grenville foreland basement uplifts of SE Siberia and SW Laurentia. Detailed matches of lithologic and faunal assemblages support Neoproterozoic to Paleozoic separation of the cratons and establishment of closely matching conjugate passive margins with correlative subsidence histories. Paleozoic paleomagnetic data is permissively consistent with translation of the Siberian craton along coast-parallel transform faults from an early Paleozoic position against SW Laurentia to its late Paleozoic position in Eurasia.