Structure of the deep crust beneath the Central Indian Tectonic Zone: An integration of geophysical and xenolith data

Dessai, A. G.; Peinado, Mercedes; Gokarn, S. G.; Downes, Hilary

doi:10.1016/j.gr.2009.04.013

Cited by 25 publications

(17 citation statements)

References 37 publications

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“…6a, b) (Rai and Thiagarajan, 2006). Ambient temperature derived from mantle xenoliths for the same depths is about 1200 C (Dessai et al, 2010) (Fig. 6c).…”

Section: Previous Geophysical Studiesmentioning

confidence: 85%

“…1b), has not been studied in detail. The major part of this region is covered by continental flood basalts and associated magmatic provinces of the Deccan Traps (Dessai et al, 2010).…”

Section: The Central India Tectonic Zonementioning

confidence: 99%

“…8). Even though we have not used velocity information in this Figure 6 Modeled temperatureedepth profile (a) near Ujjain; (b) near Rahatgaon in CITZ (modified after Rai and Thiagarajan, 2006); and (c) for CITZ (modified after Dessai et al, 2010).…”

Section: Figurementioning

confidence: 99%

“…Graphite is stable at low oxygen fugacity and could occur as interconnected films (Gough, 1986;Frost et al, 1989;Jones, 1992). The presence of titanomagnetite and magnetite as recorded from xenolith samples from the CITZ (Dessai et al, 2010) can also account for the anomalous conductivity (Mareschal et al, 1992;Duba et al, 1994). However, accumulation of ore minerals like magnetite, titanomagnetite, pyrrhotite or other accessory minerals over few hundreds of km (from west coast to eastern part of CITZ) is difficult to envisage as there are no known major oxide or sulphide mineralization in the area, nor a feasible crustal or mantle rock composition and fractionation mechanism to explain such anomalous conductors (see Schilling et al, 1997).…”

Section: Precambrian Suture Zone As a Deep Crustal Fluid Reservoirmentioning

confidence: 99%

“…It is known that large volumes of basaltic magma were extracted into the crust from upper mantle during the Deccan flood basalt regime in the Mesozoic (Dessai et al, 2010, and references therein). One of the significant features reflected in the MT models is that the faults in this region are associated with highly conductive bodies, representing fault-controlled emplacement of basic/ultrabasic intrusions from a deeper reservoir of underplated basaltic magma.…”

Section: Precambrian Suture Zone As a Deep Crustal Fluid Reservoirmentioning

confidence: 99%

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Geophysical signatures of fluids in a reactivated Precambrian collisional suture in central India

Naganjaneyulu

Santosh

2011

Geoscience Frontiers

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The Central India Tectonic Zone (CITZ) marks the trace of a major suture zone along which the south Indian and the north Indian continental blocks were assembled through subduction-accretioncollision tectonics in the Mesoproterozoic. The CITZ also witnessed the major, plume-related, late Cretaceous Deccan volcanic activity, covering substantial parts of the region with continental flood basalts and associated magmatic provinces. A number of major fault zones dissect the region, some of which are seismically active. Here we present results from gravity modeling along five regional profiles in the CITZ, and combine these results with magnetotelluric (MT) modeling results to explain the crustal architecture. The models show a resistive (more than 2000 U$m) and a normal density (2.70 g/cm 3 ) upper crust suggesting dominant tonaliteetrondhjemiteegranodiorite (TTG) composition. There is a marked correlation between both high-density (2.95 g/cm 3 ) and low-density (2.65 g/cm 3 ) regions with high conductive zones (<80 U$m) in the deep crust. We infer the presence of an interconnected grain boundary network of fluids or fluid-hosted structures, where the conductors are associated with gravity lows. Based on the conductive nature, we propose that the lower crustal rocks are fluid reservoirs, where the fluids occur as trapped phase within minerals, fluid-filled porosity, or as fluid-rich structural conduits. We envisage that substantial volume of fluids were transferred from mantle into the lower crust through the younger plume-related Deccan volcanism, as well as the reactivation, fracturing and expulsion of fluids transported to depth

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“…6a, b) (Rai and Thiagarajan, 2006). Ambient temperature derived from mantle xenoliths for the same depths is about 1200 C (Dessai et al, 2010) (Fig. 6c).…”

Section: Previous Geophysical Studiesmentioning

confidence: 85%

“…1b), has not been studied in detail. The major part of this region is covered by continental flood basalts and associated magmatic provinces of the Deccan Traps (Dessai et al, 2010).…”

Section: The Central India Tectonic Zonementioning

confidence: 99%