Abstract
Analysis of teleseismic waves usingS-P converted phases, travel time-terms and residual travel times point to the presence of an anomalous thick (4—5 km thicker) low velocity (−3%) crust beneath Kodaikanal (KOD) on granulites characterized by an oriented inhomogeneity inferred as possibly due to Mylonites in contrast to the nature of crust beneath the adjoining precambrian granite-gneiss terrain. The observed seismic signatures in the South India granulites (represented by KOD) offer an opportunity to discriminate between the competing hypotheses of tectonic thickening and magmatic underplating to explain the origin of the granulites of South India. This analysis lends support to the hypothesis of a continent-continent collision origin for the granulites in the study region.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Bath M and Stefansson R 1966 S-P conversion at the base of the crust;Ann. Geophys. 19 119–130
Brown A, Kamineni D C and Martin C D 1990In situ stress compared to structures in the Lac du Bonnet batholith, Manitoba, Canada;Tectonophysics 186 151–162
Burdick L J and Langston C A 1977 Modelling crustal structure through the use of converted phases in teleseismic body waveforms;Bull. Seismol. Soc. Am.67 677–691
Drury S A, Harris N B W, Holt R W, Reeves-Smith G J and Wightman R T 1984 Precambrian tectonics and crustal evolution in south India;J. Geol. 92 3–20
Dziewonski A M and Anderson D L 1983 Travel times and station corrections of P-waves at teleseismic distances;J. Geophys. Res. 88 3296–3314
Fountain D M and Salisbury M H 1981 Exposed cross-sections through the continental crust: Implications for crustal structure, Petrology, and evolution;Earth Planet. Sci. Lett. 56 263–277
Furlong K P and Fountain D M 1986 Continental crustal underplating: Thermal considerations and Seismic — petrologic consequences;J. Geophys. Res. 91 8285–8294
Gopalakrishnan K, Venkata Rao V and Viswanathan T V 1990 Role of Paleosutures in the evolution of southern granulite terrain; (extended abstract), Discussion on “Suture zone – Young and Old”, Wadia Institute of Himalayan Geology, Dehradun, April 1990, 55–60
Gowd T N, Srirama Rao S V and Gaur V K 1992 Tectonic stress field in the Indian subcontinent;J. Geophys. Res. (in press)
Hsu K J 1979 Thin skinned plate tectonics during neo-Alpine orogenesis;Am. J. Sci. 279 353–366
Hyndman R D and Shearer P M 1989 Water in the lower continental crust: Modelling magnetotelluric and seismic reflection results;Geophys. J. Int. 98 343–365
Iyer H M and Healy J H 1972 Teleseismic residuals at LASA-USGS extended array and their interpretation in terms of crust and upper mantle structure;J. Geophys. Res. 77 1503–1527
Jones T D and Nur A 1982 Seismic velocity and anisotropy in mylonites and the reflectivity of deep crustal faults;Geology 10 260–263
Jordan T H and Frazer L N 1975 Crustal and upper mantle structure from Sp phases;J. Geophys. Res. 80 1504–1518
Kind R, Kosarev G L, Makeyeva L I and Vinnik L P 1985 Observation of laterally inhomogeneous anisotropy in the continental lithosphere;Nature (London) 318 358–361
Mezger K, Bohlen S R and Hanson G N 1990 Metamorphic history of Archaean Pikwitonei Granulite Domain and cross lake subprovince, superior province, Manitoba Canada;J. Petrol. 31 483–517
Mishra D C 1990 Precambrian rifts and associated tectonics of Peninsular India, in Precambrian continental crust and its economic resources, (ed) S M Naqvi (Holland: Elsevier), Developments in Precambrian Geology8 487–502
Naha K, Srinivasan R and Jayaram S 1991 Sedimentological, structural and migmatic history of the Archaean Dharwar Province, south India;Proc. Indian Acad. Sci. (Earth Planet. Sci.) 100 413–433
Newton R C and Perkins D 1982 Thermodynamic calibration of geobarometers based on the assemblages garnet-plagioclase-orthopyroxene-(clinopyroxene)-quartz,Am. Mineral. 67 203–222
Newton R C and Hansen E C 1986 The South India — Sri Lanka high grade terrain as a possible deep crust section; In: The nature of the Lower Continental Crust,Geol. Soc. (London) Supl. Pub. 24 297–307
Nicolas A and Christensen N I 1987 Formation of anisotropy in upper mantle peridotites — a review; In: Composition, structure and dynamics of the lithosphere — asthenosphere system, (eds) K Fuchs and C Froidevaux, Washington D. C, American Geophysical Union.Geodynamics Series 16 111–123
Owens T J 1987 Crustal structure of the Adirondacks determined from Broadband teleseismic waveform modelling;J. Geophys. Res. 92 6391–6401
Peseckis L L and Burdick L J 1982 Station site characteristics of WWSSN stations in India and southern Asia;Bull. Seism. Soc. Am. 72 1207–1218
Pichamuthu C S 1953 The charnockite problem;Mys. Geol. Assoc, Bangalore
Ramesh D S, Prakasam K S, MakeyevaL I, Vinnik L P and Gaur V K 1990 First report on continental anisotropy in the south Indian shield;Geophys. J. Int. (under revision)
Rao P S 1978 Some aspects of structure and tectonics of Kerala region, India and related mineralisation; In part IIIGeol. Surv. India. Misc. Publ. No. 34 51–64
Rai S S, Srinagesh D and Gaur V K 1992 Granulite evolution in South India – A seismic tomographic perspective; J. Geol. Soc. India (in press)
Siegesmund S and Kern H 1990 Velocity anisotropy and shear wave splitting in rocks from the mylonite belt along the Insubric Line (Ivrea zone, Italy);Earth Planet. Sci. Lett. 99 29–47
Silver P G and Chan W W 1988 Implications for continental structure and evolution of seismic anisotropy;Nature (London) 335 34–39
Singh D D and Rastogi B K 1978 Crustal structure of the peninsular shield beneath Hyderabad (India) from the spectral characteristics of long period P-waves; Tectonophysics51 127–137
Smith W D 1970 S to P conversion as an aid to crustal studies;Geophys. J. R. Astron. Soc. 19 513–519
Subba Rao D V 1987 Regional gravity and crustal structure; NGRI annual report 1986—87 16—17
Taylor S R and Toksoz M N 1979 Three-Dimensional crust and upper mantle structure of the northeastern United States;J. Geophys. Res. 84 7627–7644
Trumpy R 1980 Geology in Switzerland; (Basel: Wepf Co.)
Vinnik L P, Kosarev G L and Makeyeva L I 1984 Anisotropy of the lithosphere from the observations of SKS and SKKS;Proc. Acad. Sci. USSR (in Russian),78 1335–1339
Vinnik L P, Kind R, Kosarev G L and Makeyeva L I 1989 Azimuthal anisotropy in the lithosphere from observations of long period S waves;Geophys. J. Int. 99 549–559
Wong Y K, Smithson S B, Zawislak R L 1982 The role of seismic modeling in deep crustal reflection interpretation; In part I: University of Wyoming contributions to Geology.20 91–109
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ramesh, D.S., Srinagesh, D., RAI, S.S. et al. Anomalous granulite crust of South India — signatures from converted teleseismic waves. Proc. Indian Acad. Sci. (Earth Planet Sci.) 101, 283–298 (1992). https://doi.org/10.1007/BF02878138
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02878138