Reassembly of the Dharwar and Bastar cratons at ca. 1 Ga: Evidence from multiple tectonothermal events along the Karimnagar granulite belt and Khammam schist belt, southern India

Abstract

The northern part of the Nellore-Khammam schist belt and the Karimnagar granulite belt, which are juxtaposed at high angle to each other have unique U-Pb zircon age records suggesting distinctive tectonothermal histories. Plate accretion and rifting in the eastern part of the Dharwar craton and between the Dharwar and Bastar craton indicate multiple and complex events from 2600 to 500 Ma. The Khammam schist belt, the Dharwar and the Bastar craton were joined together by the end of the Archaean. The Khammam schist belt had experienced additional tectonic events at ∼1900 and ∼1600 Ma. The Dharwar and Bastar cratons separated during development of the Pranhita-Godavari (P-G) valley basin at ∼1600 Ma, potentially linked to the breakup of the Columbia supercontinent and were reassembled during the Mesoproterozoic at about 1000 Ma. This amalgamation process in southern India could be associated with the formation of the Rodinia supercontinent. The Khammam schist belt and the Eastern Ghats mobile belt also show evidence for accretionary processes at around 500 Ma, which is interpreted as a record of Pan-African collisions during the Gondwana assembly. From then on, southern India, as is known today, formed an integral part of the Indian continent.

Depositional history and provenance of cratonic “Purana” basins in southern India: A multipronged geochronology approach to the Proterozoic Kaladgi and Bhima basins

“…The basin formation and sedimentation in the PG Valley and Chhattisgarh basins developed later in the Mesoproterozoic (~1,600 Ma) and continued intermittently to Neoproterozoic times (Saha et al, ). Amalgamation of Peninsular India with the formation of the Rodinia supercontinent towards the end of the Mesoproterozoic is evidenced in the PG Valley and Chhattisgarh Basin areas (Joy, van der Linde, Choudhury, Deb, & Tappe, ; Merdith et al, ).…”

“…Data shown are for acid leachates (low Rb/Sr) and complementary residues (high Rb/Sr) for six separates (four from EHV956, two from EHV957). The data define pooled isochrons in the range of 797-812 Ma [Colour figure can be viewed at wileyonlinelibrary.com] areas (Joy, van der Linde, Choudhury, Deb, & Tappe, 2018;Merdith et al, 2017).…”