Crustal configuration of the Narmada-Tapti region (India) from gravity studies

Singh, Aneesha; Meißner, R.

doi:10.1016/0264-3707(95)00003-r

Cited by 75 publications

(31 citation statements)

References 22 publications

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“…The ages of large igneous provinces (Rajmahal, Madagascar-South India and Deccan traps) by Ar-Ar methods (Basu et al, 1993;Baksi, 1994Baksi, , 1995Storey et al, 1995;Radhakrishna et al, 1999;Anil Kumar et al, 2001) also lie between Cretaceous to early Tertiary times. Further, these alkaline complexes are associated with relatively long wavelength gravity highs (Tewari et al, 1991;Raval and Veeraswamy, 1997;Suryaprakasa Rao, 2003) and are strongly suggestive of deep-seated magmatic underplating which is also corroborated by the cospatial high velocity layer inferred by deep seismic studies (Tewari et al, 1991;Singh and Meissner, 1995). In addition, these corridors, which were affected by the crust-mantle interaction, also exhibit tectonic uplift which, according to McKenzie (1984), is caused by magmatic underplating.…”

Section: Geophysical and Tectonic Evidence Of Channelingmentioning

confidence: 84%

“…1(a)). A number of geophysical anomalies and geotectonic features have been attributed to the interaction of the Indian lithosphere with these plumes since the Cretaceous (Raval, 1989;Kent, 1991;Basu et al, 1993;Singh and Meissner, 1995;Storey et al, 1995;Atchuta Rao et al, 1996;Mall et al, 1999;Mishra et al, 1999;Courtillot et al, 2000;Veeraswamy, 2000, 2003;Anil Kumar et al, 2001;Tewari et al, 2001;Mukhopadhyay, 2002;Roy, 2004;Mahoney et al, 2002). These plumes (P) appear to have affected the MB network of India.…”

Section: Three-phase Breakupmentioning

confidence: 99%

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Chipping of cratons and breakup along mobile belts of a supercontinent

Veeraswamy

Raval

2014

Earth Planet Sp

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Probably one of the most significant heterogeneities of a continental lithosphere is the noticeable difference in the thickness and properties of its cratonic and mobile parts. The trans-continental mobile belts (Paleoorogens/paleo-sutures) represent a relatively thinner, warm, wet and weak lithosphere, which makes it more vulnerable to episodic mantle (or plume) upwellings and compressional forces. Here evidence is presented from the Indian continental lithosphere to show that these properties of mobile belts (MB) facilitate channeling of thermomagmatic fluxes (TMF) in both lateral as well as vertical directions. This, to a major extent, can account for the observed concentration (or focusing) of geophysical anomalies, tectonomagmatic features and strain along these MBs. In addition, a closer examination of the three continental breakups of Greater India since the Cretaceous reveals that the combination of a sufficiently weakened MB and mantle plume could become 'fatal' for the supercontinental stability. On the other hand, the thick (>200 km) or deep-rooted continental lithosphere beneath cratons is characterized by a relatively cold and dry lithosphere, which resists remobilization. From this relative impenetrability, TMFs are channeled mostly through the MBs following the long-term stability of the cratonic lithosphere. This difference in cratonic and MB regimes results in strongly heterogeneous thermal blanketing. However, in certain situations, the edge of a cratonic region may also get chipped-off following a number of thermotectonic rejuvenations of adjoining MBs-as exemplified by the breakup of the Antongil and Masora cratonic blocks (now lying on the Madagascar) from the Western Dharwar craton (India) during the IndiaMadagascar separation. From the study of supercontinental dispersals, it seems that the processes of breakup along pre-existing mobile belts may be globally applicable. This is, at times, also accompanied by chipping of cratons.

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Section: Geophysical and Tectonic Evidence Of Channelingmentioning

confidence: 84%

Section: Three-phase Breakupmentioning

confidence: 99%

Chipping of cratons and breakup along mobile belts of a supercontinent

Veeraswamy

Raval

2014

Earth Planet Sp

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“…1). Gravity studies over the NSL suggest lateral movement of intruding magma at the crust/mantle boundary (SINGH and MEISSNER, 1995). The NSL region has experienced several cycles of vertical mass transfer on either side of the Narmada zone through the deep Narmada fractures, and the Moho configuration is highly disturbed due to intense crustal movements SHIVAJI and AGARWAL, 1995).…”

Section: Discussionmentioning

confidence: 99%

Subcrustal Low Velocity Layers in Central India and their Implications

Murty

Tewari

Kumar

et al. 2005

Pure appl. geophys.

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A 2-D subcrustal velocity model for the central Indian continental lithosphere has been derived by travel time and relative amplitude modeling of a digitally normalized analog seismic record section of the Hirapur-Mandla DSS profile, using a ray-tracing technique. Some prominent wave groups with apparent velocities slightly higher than the Moho reflection phase (P M P) are identified on the normalized record sections assembled with a reduction velocity of 6 km s )1 . We interpret these phases as the wide-angle reflections from subcrustal lithospheric boundaries. Comparison of synthetic seismograms with the observed record section shows that the observed phases cannot be explained either by multiples or by the P-to-S converted phase (P M S) from the Moho. Subcrustal velocity models either with a velocity increase or with a single low velocity layer (LVL) also do not provide a satisfactory fit. We infer that a subcrustal velocity model with two alternate LVLs (velocity 7.2 km s )1 ), separated by a 6-km thick high velocity layer (velocity 8.1 km s )1 ), can satisfy both the observed travel times and amplitudes. The prominent reflection phases are modeled at depths of 49, 51, 57 and 60 km. It is inferred that the subcrustal lithosphere in the central Indian region has a lamellar structure with varying structural and mechanical properties. The alternating LVLs, occurring at relatively shallow depths below Moho, may be associated with the zones of weakness and lower viscosity suggesting continued mobility, with a possible thermal source in the upper mantle. This explains the source of observed high heat flow values in the central Indian region.

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“…1(b)) and inferred block structures (Verma and Banerjee, 1992). These were followed by gravity studies (e.g., Singh and Meissner, 1995) that identified underplated material with a thickness varying from 5 to 20 km. More recently, seismic and gravity studies have estimated the crustal thickness is about 40 km (Tewari and Kumar, 2003) (Fig.…”

Section: Introductionmentioning

confidence: 99%

Granitic and magmatic bodies in the deep crust of the Son Narmada Region, Central India: constraints from seismic, gravity and magnetotelluric methods

Naganjaneyulu

2010

Earth Planet Sp

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Magnetotelluric (MT) data at 24 locations in the Son Narmada region, Central India, were collected across the Tapti North Fault and Son Narmada Fault along the Chinchpada-Godhra profile (220 km). MT impedance tensors were then estimated in the period range 0.001-1,000 s using robust processing codes. The N70• E geo-electric strike direction was obtained by multi-site, multi-frequency analysis. The data were modeled using non-linear conjugate gradient scheme taking both apparent resistivity and phase into account. The two-dimensional MT model obtained (after static shift correction) represents resistive bodies (1,000-3,000 ohm-m) and conductive bodies (<20 ohm-m) in the deep crust. The resistive bodies in the lower crust are interpreted to be granitic intrusive complexes. The conductor on the south of Son Narmada Fault is attributed to the presence of magmatic bodies due to underplating, and the conductor on the north as due to the presence of fluids. The highly resistive (>2,000 ohm-m) upper crust is interpreted to comprise felsic rocks of granitic composition, and the low-resistive (<100 ohm-m) deep crust as being composed of dense mafic granulites. The Domal upwarp structure near Son Narmada Fault, with a thick felsic crust sandwiched between the mafic and intermediate crust, can be explained by underplated sediments/felsic crust which jacked-up the lithounits above.

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Crustal configuration of the Narmada-Tapti region (India) from gravity studies

Cited by 75 publications

References 22 publications

Chipping of cratons and breakup along mobile belts of a supercontinent

Chipping of cratons and breakup along mobile belts of a supercontinent

Subcrustal Low Velocity Layers in Central India and their Implications

Granitic and magmatic bodies in the deep crust of the Son Narmada Region, Central India: constraints from seismic, gravity and magnetotelluric methods

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