[T11-P-8] Meso-NeoArchean Basin Formation and associated deformation in the Dharwar Craton : new insights from structural relation and Zircon U–Pb geochronology.
Keywords:Archean, Dharwar Craton, Tectonics, Failed rift, Geochronology
Dharwar Craton (DC, 3500–2500 Ma) is one of the well-studied Archean terrane in the world. The DC divided into three Western Dharwar Craton (WDC), Central Dharwar Craton (CDC), and, Eastern Dharwar Craton (EDC) based on various geological and geophysical parameters. Volcanosedimentary sequences in the DC is divided into the Sargur Group and Dharwar SuperGroup. The Dharwar SuperGroup further divided into the Bababudan, Chitradurga and Hiriyur Groups. In this presentation we will discuss about the evolutionary history and tectonic significance of each Group within the WDC. We will discuss the detailed geochronological results and structural relations from each stratigraphic unit and highlight their tectonic significance.
Our study propose that the Sargur and Bababudan Groups were formed through distinct rifting events associated with mantle plumes. The Chitradurga and Hiriyur Groups, on the other hand, represent back-arc rifts associated with the convergence process in the far east. However, it is evident that none of these rifting processes resulted in the formation of a complete oceanic sequence, indicating multiple failed rift events. In this presentation we will present the detailed geochronological data about the initiation and termination of each rifting events within the WDC.Regarding deformation, our study identified five episodes, with D2 and D3 representing regional-scale events. D2 corresponds to a fold-and-thrust belt characterized by NNW–SSE trending axial planes and parallel reverse faults dipping to the east. The D3 event indicates strike-slip deformation with a transpression component, signifying the later reactivation of D2 faults and other geological contacts. The fold-and-thrust belt observed in the area likely evolved from a back-arc fold-and-thrust belt, with the D3 event representing late-stage orogenic strike-slip escape or transpression associated with oblique convergence. The present structural architecture of the WDC thus probably represent hinterland fold-and-thrust belt after the NeoArchean collisional event.
Our study propose that the Sargur and Bababudan Groups were formed through distinct rifting events associated with mantle plumes. The Chitradurga and Hiriyur Groups, on the other hand, represent back-arc rifts associated with the convergence process in the far east. However, it is evident that none of these rifting processes resulted in the formation of a complete oceanic sequence, indicating multiple failed rift events. In this presentation we will present the detailed geochronological data about the initiation and termination of each rifting events within the WDC.Regarding deformation, our study identified five episodes, with D2 and D3 representing regional-scale events. D2 corresponds to a fold-and-thrust belt characterized by NNW–SSE trending axial planes and parallel reverse faults dipping to the east. The D3 event indicates strike-slip deformation with a transpression component, signifying the later reactivation of D2 faults and other geological contacts. The fold-and-thrust belt observed in the area likely evolved from a back-arc fold-and-thrust belt, with the D3 event representing late-stage orogenic strike-slip escape or transpression associated with oblique convergence. The present structural architecture of the WDC thus probably represent hinterland fold-and-thrust belt after the NeoArchean collisional event.