Super-mobility of hot indian lithosphere

Lithospheric structure beneath Laxmi Ridge and late Cretaceous geodynamic events

“…Deccan magmas are indeed highly differentiated and have low Mg ratios (Pandey and Negi 1987a;Sen 1988). Our estimated depth to the thermal lithosphere beneath the Laxmi Ridge (,-~ 35 km) suggests a considerable degeneration of its base (about 40 km), as proposed under the entire Indian continental region after its breakup from the Gondwanaland (Negi et al 1986b;Pandey and Negi 1987b). The thinning of the lithosphere beneath the ridge may have been caused as a result of super mobility of the Indian plate between 80 and 53 Ma when its velocity is known to have jumped from 3 5 cm yr -1 to more than 20 cm yr -1 (Negi et al 1986b;McA Powell, 1979).…”

“…1). These features appear to have developed between 80 and 53 Ma, when the Indian subcontinent was super mobile (18-20cm yr -1) (Negi et al 1986b;Pandey and Negi 1987a,b). During this period, many plate tectonic changes and reorganizations, including the ridge jump of greater than 500 km in the northern Mascarene Basin, Deccan Flood volcanism, and initiation of the northern Carlsberg ridge took place (Hartnady 1986).…”

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

“…In fact, owing to the presence of thermal anomalies underneath, many Indian cratonic segments have become much warmer and contain extremely thin lithosphere (Negi et al, 1986;Rogers and Callahan, 1987;Pandey and Agrawal, 1999;Kumar et al, 2007a).…”

Shallowing of mafic crust and seismic instability in the high velocity Indian Shield

“…Despite being one of the oldest terrain, its cratonic segments could not resist internal deformation and shearing at lithospheric mantle level due to ongoing geodynamic and other underlying geoprocesses (Pandey and Agrawal, 1999), which modified the seismic and compositional structure of the crust and upper mantle. Consequently, Indian cratonic lithosphere became highly evolved, inhomogeneous and non-rigid besides being warmer and thinner (~ 110 km on an average) with a high dose of heat flow from the mantle (Negi et al 1986;Polet and Anderson, 1995;Pandey and Agrawal, 1999;Priestley et al 2006;Kumar et al 2007;Pandey et al 2009a, b). GPS and seismological studies suggest very high strain rates (Ramalingeswara Rao, 2000;Talwani and earthquake occurrences could be related to plate tectonic forces only, as present study would indicate.…”

“…They have often been attributed to the NNE compressive forces, generated due to collision/subduction of northward moving Indian plate with Eurasia. This may be an important factor in seismogenesis, but not all the INTRODUCTION Indian subcontinent with dynamic past and active history of rifting, multiple plume interaction and continental breakups, is considered unique among stable areas of the Earth (Negi et al 1986;Radhakrishna and Naqvi, 1986;Rogers and Callahan, 1987;Naqvi and Rogers, 1987;Pandey and Agrawal, 1999). Besides five ArchaeanProterozoic cratons, it contains several rift valleys, sutures and mega lineaments which have been repeatedly rejuvenated since at least 1.5 Ga.…”