Lithospheric and upper mantle structure of the Indian Shield, from teleseismic receiver functions

Saul, Joachim; Kumar, M. Ravi; Sarkar, Dipankar

doi:10.1029/1999gl011128

Cited by 107 publications

(104 citation statements)

References 18 publications

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“…This study however, does not mention about values that are specific to regions like the DVP. Receiver function analysis of data from the GEOSCOPE station at Hyderabad (HYB) on the Eastern Dharwar Craton, image the 410 and 660 km discontinuities at depths of 409 and 659 km, respectively [40]. These values compare well with those from the DVP.…”

Section: And 660 Km Discontinuitiessupporting

confidence: 62%

Mantle discontinuities beneath the Deccan volcanic province

Kumar

Gurusamy

2005

Earth and Planetary Science Letters

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Section: And 660 Km Discontinuitiessupporting

confidence: 62%

Mantle discontinuities beneath the Deccan volcanic province

Kumar

Gurusamy

2005

Earth and Planetary Science Letters

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“…3-8). Interestingly enough, average S-velocity and Poisson's ratio are also almost similar (3.7-3.8 km/s and 0.24-0.27 respectively) beneath EDC and SGT (Saul et al, 2000;Ravi Kumar et al, 2001;Gupta et al, 2003).…”

Section: Discussion Of Results and Conclusionmentioning

confidence: 99%

“…Such an inference is supported by seismic evidence that suggest even shallower cratonic root depths (∼100 km only) beneath the Indian shield compared to about 250-450 km found elsewhere (Polet and Anderson, 1995). The cratonic mantle lithosphere appears to contain a highly conductive, hydrous and seismically anisotropic metasomatic zone between the depth of 90 and 105 km (Saul et al, 2000;Sastry et al, 1990) where the estimated temperature could be 850-975…”

Section: Heat Flow Distribution Temperature Regime and Geoelectric Smentioning

confidence: 99%

Unusual lithospheric structure and evolutionary pattern of the cratonic segments of the South Indian shield

Agrawal

Pandey

2014

Earth Planet Sp

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The southern Indian shield, characterised by several prominent geological and geophysical features, can be divided into three distinct tectonic segments: Western Dharwar craton (WDC), Eastern Dharwar craton (EDC) and Southern Granulite terrain (SGT). With the exception of WDC, the entire crust beneath EDC and SGT has been remobilized several times since their formation during the mid-to late Archeans (3.0-2.5 Ga). In order to understand the evolutionary history of these segments, a multiparametric geological and geophysical study has been made which indicates that the south Indian shield, characterized by a reduced heat flow of 23-38 mW/m 2 has a much thinner (88-163 km) lithosphere compared to ∼200-450 km found in other global shields. In the EDC-SGT terrain, high velocity upper crust is underlain by considerably low mantle velocity with a thick high conductive/low velocity zone sandwiched at mid crustal level. Our study reveals that the entire EDC region is underlain by granulite facies rocks with a density of about 2.85 to 3.16 g/cm 3 at a shallow depth of about 8 km in the southern part and at even shallower depth of about 1 to 2 km below the Hyderabad granitic region in the north. Cratonic mantle lithosphere beneath EDC may contain a highly conductive, anisotropic and hydrous metasomatic zone between the depth of 90 and 105 km where estimated temperatures are in the range of 850-975• C. It is likely that before the early Proterozoic, the entire south Indian shield was a coherent crustal block which subsequently got segmented due to persistent plume-induced episodic thermal reactivations during the last 2.7 Ga. These reactivations led to self destruction of cratonic roots giving rise to negative buoyancy at deeper levels which may have been responsible for crustal remobilisations, followed by regional uplifting and erosion of once substantially thick greenstone belts. Consequently, the crustal column beneath the EDC has become highly evolved and now corresponds closely to SGT at depth.

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“…On the Indian shield, Saul et al [2000] observe a direct P-to-S conversion from the top of a similar layered structure at 90 km depth below the Dharwar craton (station Hyderabad) on both radial and transverse components. Although, the back-azimuthal distribution of events for stations in central India is limited, the strength of the signal and its moveout argue strongly for an origin in near horizontal, depth localized anisotropy.…”

Section: Discussionmentioning

confidence: 99%

The teleseismic signature of fossil subduction: Northwestern Canada

Mercier¹,

Bostock²,

Audet³

et al. 2008

J. Geophys. Res.

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broadband, three-component seismometers were deployed along the MacKenzie-Liard Highway in Canada's Northwest Territories as part of the joint Lithoprobe-IRIS Canada Northwest Experiment (CANOE). These stations traverse a paleo-Proterozoic suture and subduction zone that has been previously documented to mantle depths using seismic reflection profiling. Teleseismic receiver functions computed from $250 earthquakes clearly reveal the response of the ancient subduction zone. On the radial component, the suture is evident as a direct conversion from the Moho, the depth of which increases from $30 km to $50 km over a horizontal distance of $70 km before its signature disappears. The structure is still better defined on the transverse component where the Moho appears as the upper boundary of a 10 km thick layer of anisotropy that can be traced from 30 km to at least 90 km depth. The seismic response of this layer is characterized by a frequency dependence that can be modeled by upper and lower boundaries that are discontinuous in material properties and their gradients, respectively. Anisotropy can be characterized by a ±5% variation in shear velocity and hexagonal symmetry with a fast axis that plunges at an oblique angle to the subduction plane. The identification of this structure provides an unambiguous connection between fossil subduction and fine-scale, anisotropic mantle layering. Previous documentation of similar layering below the adjacent Slave province and from a range of Precambrian terranes across the globe provides strong support for the thesis that early cratonic blocks were stabilized through processes of shallow subduction.

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Lithospheric and upper mantle structure of the Indian Shield, from teleseismic receiver functions

Abstract: Abstract.Receiver

Cited by 107 publications

References 18 publications

Mantle discontinuities beneath the Deccan volcanic province

Mantle discontinuities beneath the Deccan volcanic province

Unusual lithospheric structure and evolutionary pattern of the cratonic segments of the South Indian shield

The teleseismic signature of fossil subduction: Northwestern Canada

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