Imprints of a Proterozoic tectonothermal anomaly below the 1.1 Ga kimberlitic province of Southwest Cuddapah basin, Dharwar craton (Southern India)

Abstract

S U M M A R YA detailed 2-D modelling of the seismic structure and other geological and geophysical signatures across the Cuddapah basin of the southern Indian shield suggests upwarping of highvelocity and high-density layers, which are observed close to the surface below the southwestern part of the basin. This anomalous feature is constrained by (i) a strong gravity high anomaly of about 55 mGal, (ii) a 100 km wide high conductivity anomaly (resistivity < 100 -m) extending from surface to a minimum depth of 50 km in the mantle lithosphere and (iii) large scale massive intrusive activity. These features are interpreted to be an expression of a thermal anomaly, which may have acted like a plume during the Proterozoic and could well correspond to a 1.1 Ga kimberlitic activity. Below this region, the thin granitic-gneissic crust is underlain by well-differentiated, high-velocity layers, possibly due to underplating and densification of much of the crust by extruded magma.

Upwarped high velocity mafic crust, subsurface tectonics and causes of intraplate Latur-Killari (M 6.2) and Koyna (M 6.3) earthquakes, India – A comparative study

“…Besides Killari, there are several other localities in peninsular India, where the granulitic crust has come up quite close to the surface for example, Mumbai offshore, Hyderabad granitic region, flanks of the Godavari graben, southwestern part of the Cuddapah basin, etc. (Rathore et al, 2000;Pandey et al, 2002;Pandey and Rao, 2006;Ram Babu and Lakshmi, 2005;Reddy et al, 2004;Mall et al, 2008).…”

Petrogenesis of Mesoproterozoic lamproite dykes from the Garledinne (Banganapalle) cluster, south-western Cuddapah Basin, southern India

“…Despite these studies, the origin and evolution of the Cuddapah Basin still remains unclear with diverse models in vogue viz. : (i) Mesoproterozoic rifting (Chaudhuri et al 2002); (ii) astrobleme impact (Krishna Brahmam and Dutt 1992); (iii) thermal subsidence (Bhattacharji and Singh 1984;Drury 1984;Mall et al 2008); (iv) separation of the Napier Complex (presently in Antarctica) from the southern Indian block (Mohanty 2011); and (v) a peripheral foreland basin that evolved through continent-continent collision (Singh and Mishra 2002).…”

Delineation of intra crustal horizon in Eastern Dharwar Craton – An aeromagnetic evidence

“…4 of Reddy et al, 2004). Mall et al (2008) have derived a velocity model for the crust of EDC between Challakere (SP 360)-Badvel (SP120) along the Kavali-Udipi DSS profile. Their analysis indicated a velocity interface with P-wave velocity of 6 km/s up to a depth of 10 km in the Eastern part of the EDC.…”