Abstract
The deep crustal structure of eastern Dharwar craton has been investigated through τ-p extremal inversion of P-wave travel times from a network of seismographs recording quarry blasts. Travel times have been observed in the distance range 30–250 km in a laterally homogeneous lithospheric segment Main features of the inferred velocity-depth relationship include: (a) 29 km thick combined upper and middle crust velocity varying from 6 km/s to 7 km/s, with no observable velocity discontinuity in this depth range; (b) a lower crust (∼ 29–41 km) with velocity increasing from 7.0 to 7.3 km/s; (c) an average upper mantle velocity of 8.1 km/s; and (d) presence of a 12 km thick high velocity crustal layer (7.4 – 7.8 km/s) in the depth range 41–53 km, with a distinct velocity gradient marking a velocity increase of 0.4 km/s. The anomalous 53 km thick crust is viewed as a consequence of magmatic underplating at the base of the crust in the process of cratonization of the eastern Dharwar craton during late Archaean. The underplated material reflects here with the velocity of 7–3 to 7–8 km/s below the depth of 40 km. Our proposition of magmatic underplating is also supported by the presence of large scale I-granitoid, a product of partial melting of the upper mantle material.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Bessonova E N, Fishman V M, Ryaboyi V Z and Sitmikova G A 1974 The tau method for the inversion of travel time-I Deep seismic sounding data;Geophys. J. R. Astron. Soc. 36 377–398
Durrheim R J and Mooney W D 1991 Archaean and proterozoic crustal evolution: Evidence from crustal seismology;Geology 19 606–609
Durrheim R J and Mooney W D 1994 Evolution of the Precambrian Iithosphere: Seismological and geochemical constraints;J. Geophys. Res. 99 15359–15374
Durrheim R J and Green R W E 1992 A seismic refraction investigation of the Archaean Kaapval craton, South Africa, using mine tremors as the energy source;Geophys. J. Int. 108 812–832
Drummond B J and Collins C D N 1986 Seismic evidence for underplating of the lower continental crust of Australia;Earth Planet Sci. Lett. 79 361–372
Dziewonski A M and Anderson D L 1983, Travel times and station corrections for P-wave at teleseismic distances;J. Geophys. Res.,88 3195–3214
Furlong K P and Fountain D M 1986 Continental crust underplating: Thermal considerations and seismiopetrologic consequences;J. Geophys. Res. 91 8285–8294
Herzberg C T, Fyfe W S and Carr M J 1983 Density contrasts on the formation of the continental Moho and the crust;Contrib. Miner. Petrol. 84 1–5
Jayananda M, Martin H, Parcat J and Mahabaleswar B 1995 Late Archaean crust-mantle interaction: Geochemistry of LREE enriched mantle derived magma,Contrib. Miner. Petrol. 19 314–329
Kaila K L, Roy Chowdhury K, Reddy P R, Krishna V G, Hari Narain, Subbotin S1, Sollogub V B, Chekunov A V, Kharetchko G E, Lazerenko M A and Ilchenko T V 1979 Crustal structure along Kavali-Udipi profile in the Indian Peninsular Shield from deep seismic sounding;J. Geol. Soc. India 20, 307–333
Rennet B L N 1976 A comparison of travel time inversions;Geophys. J. R. Astron. Soc. 44 517–536
Meissner R 1986 The continental crust: A geophysical approach,International Geophysical Series, (New York: Academic Press)
Naqvi S M and Rogers J J W 1987Precambrian geology of India (New York: Oxford Univ. Press) pp 223
Nelson K D 1991 A unified view of craton evolution motivated by recent deep seismic reflection and refraction results;Geophys. J. Int. 105 25–35
Prakasam K S and Rai S S 1996 Teleseismic delay time tomography of upper mantle beneath south eastern India,Geophys. J. Int. (in press)
Rogers J J W and Maulain 1994 A review of the terrains of southern India, inVolcanism (ed) K V Subba Rao (Wiley Eastern Ltd) 157–172
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rai, S.S., Sarma, P.V.S.S.R., Prakasam, K.S. et al. Seismic evidence for thick and underplated late Archaean crust of eastern Dharwar craton. Proc. Indian Acad. Sci. (Earth Planet Sci.) 105, 431–439 (1996). https://doi.org/10.1007/BF02842314
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02842314