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Paleomagnetic and Geochemical studies of Paleoproterozoic mafic dykes of WDC: constraints on magma plumbing systems.

Lingadevaru Muddaramaiah1,  Bidisha Bayan1

Abstract

The Dharwar craton in southern India represents one of the oldest and well-preserved Archean crustal blocks and is characterized by a complex tectonic history, with the presence of late-Archean greenstone belts that are intruded by granitic plutons. One of the key features of the Dharwar craton is the presence of widespread mafic dyke swarms giving us a glimpse of the magmatic and tectonic evolution of the region. Old and discontinuous dyke swarms cut through the older western Dharwar craton and hence is lesser studied than the Eastern Dharwar craton. The WDC, with its complex history of magmatic intrusions and dyke swarms, offers a unique opportunity to investigate these connections. Here we present new paleomagnetic and geochemical data along with in-depth study of magmatic origin of these mafic dykes and account of the LIP's that occurred concurrently, the role of precious metal emplacement through these conduits and large fracture systems. The orientation and distribution of dykes found in the WDC reveal the prevailing stress field during magma emplacement. Dykes often propagate perpendicular to the minimum compressive stress, providing a record of past tectonic stress regimes, Our current document highlights the presence of older, discontinuous dyke swarms in the WDC, suggesting a complex tectonic history and the magma chamber geometry through the shape and depth of magma chambers. These chambers can be influenced by tectonic forces. e.g.-extensional settings may favor the formation of shallow, elongated magma chambers, while compressional settings may lead to deeper, more vertically oriented chambers. WDC- Western Dharwar Craton