Age of the Holenarsipur Greenstone Belt, relationships with the surrounding gneisses (Karnataka, south India)

Abstract

A rhyolitic volcanic flow included in the Holenarsipur greenstone belt, has a simple igneous population of zircons which has a SHRIMP 207Pb/206Pb age of 3298 ± 7 Ma, interpreted as the crystallization age of this flow and considered synchroneous with deposition of the coeval sedimentary pile. The Holenarsipur greenstone belt is now documented as the oldest supracrustal accumulation in the Dharwar craton. From field and other published geochronological results it is concluded that a large part of the surrounding gneisses are very close in age to this rhyolite. -from Authors