Preservation of a Paleoproterozoic rifted margin in the Himalaya: Insight from the Ulleri-Phaplu-Melung orthogneiss

Abstract

Orthogneiss within the Paleoproterozoic strata of Lesser Himalayan sequence across the Himalaya has been variably linked to development in a continental arc setting, Indian basement, or a continental rift. New whole rock and trace element geochemical data and U/Pb zircon geochronology indicate that the granitoid protoliths to these rocks were derived from upper crustal sources in the Paleoproterozoic and have within-plate, A-type affinities. This is consistent with their generation in a rifted margin and is compatible with paleogeographic reconstructions that indicate an open boundary for present-day northern India in the Paleoproterozoic. Keywords: Himalaya, Geochemistry, Paleogeography, Rifting, Geochronology