Paleogeographic reconstruction of a late Paleozoic arc collision zone, southern Mongolia

June 21 (GSA Bulletin) Matthew J. Heumann and colleagues present the first published collection of detrital zircon geochronology results from southeastern Mongolia as well as a detailed field investigation for two areas within the region, Bulgan Uul and Nomgon. Results show the first radiometric age constraints on Permian strata for Bulgan Uul and Nomgon and provide strong evidence for these deposits having once been part of the same ocean basin, which is now bisected and offset in a left-lateral sense across the East Gobi Fault zone. This paper contributes to the growing volume of published research for southeastern Mongolia, which until the late 1990s had largely gone unnoticed in the geologic community. It also adds to the understanding of the tectonic and depositional history for the region, while highlighting many of the inconsistencies in previous tectonic models for central Asia.