Secular evolution of continental crust: recorded from massif-type charnockites of Eastern Ghats belt, India

Samarendra Bhattacharya, Ashwini Kumar Chaudhary

.

DOI: 10.4236/ns.2010.210134                

Abstract

It is reasonably well established that the Earth has substantially cooled from the Archean to the pre-sent and hence the sites, rates and pro- cesses of crust formation must have changed through geo-logic time. Archean and Proterozoic granitic rocks are the principal record of such changes. Massif-type charnockites in the Eastern Ghats granulite belt, India, of Archean and Proterozoic ages mirror the changing conditions and/or processes of continental crust for- mation. Though both can be explained by dehydration melting of mafic rocks, the conditions differ. Potasium and rubidium rich Proterozoic charnockites have significant negative Eu ano- maly indicating melting at shallow depths in the stability field of plagioclase. In contrast, sodium and strontium rich Archean charnockites with less LREE enrichment and less depletion in Eu indicate melting at greater depths in the stability field of garnet or amphibole.

Keywords

Secular changes; Continental crust; Massif-charnockites; Eastern Ghats

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Soesoo, A. (2000) Fractional crystallization of mantle- derived melts as a mechanism for some I-type granite petrogenesis: An example from the Lachlan Fold Belt, Australia. Journal of Geological Society, 157, 135-149.
[2]	Kemp, A.I.S. and Hawkesworth, C.J. (2004) Granitic perspectives on the Generation and secular evolution of the continental crust. Treatise on Geochemistry, 3, 349- 411.
[3]	Taylor, S.R. and McLennan, S.M. (1985) The continental crust: Its composition and evolution. Blackwell Publishing, Oxford.
[4]	Taylor, S.R. and McLennan, S.M. (1995) The geochemi-cal evolution of the continental crust. Reviews of Geo-physics, 33, 241-265.
[5]	Rudnick, R.L. and Gao, S. (2004) Composition of the continental crust. Treatise on Geochemistry, 3, 1-65.
[6]	Condie, K.C. (1998) Episodic continental growth and supercontinents: A mantle avalanche connection? Earth and Planetary Science Letters, 163, 97-108.
[7]	Martin, H. (1995) Archean grey gneisses and genesis of continental crust. In: Condie, K.C. Ed., Archean crustal evolution, Elsevier, Netherlands, 205-260.
[8]	Whalen, J.B., Percival, J.A., McNiccol, V.J. and Longstaffe, F.J. (2002) A mainly crustal origin for tonalitic granitoid rocks, superior province, Canada: Implications for late archean tectonomagmatic processes. Journal of Petrology, 43, 1551-1570.
[9]	Bhattacharya, S., Kar, R., Misra, S. and Teixeira, W. (2001) Early Archaean continental crust in the Eastern Ghats granulite belt, India: Isotopic evidence from a charnockite suite. Geological Magazine, 138, 609-618.
[10]	Rickers, K., Mezger, K. and Raith, M. (2001) Evolution of the continental crust in the Proterozoic Eastern Ghats belt, India and new constraints for Rodinia reconstruction: Implications from Sm-Nd, Rb-Sr and Pb-Pb isotopes. Precambrian Research, 112, 183-210.
[11]	Kovach, V.P., Simmat, R., Rickers, K., Berezhnaya, N.G., Salnikova, E.B., Dobmeier, C., Raith, M.M., Yakovleva, S.Z. and Kotov, A.B. (2001) The western charnockite zone of the Eastern Ghats belt, India: An independent crustal province of late Archean (2.8 Ga) and Paleopro-terozoic (1.7-1.6 Ga) terrains. Gond Research, 4, 666-667.
[12]	Mezger, K. and Cosca, M.A. (1999) The thermal history of the Eastern Ghats belt (India) as revealed by U-Pb and 40Ar / 39Ar dating of metamorphic and magmatic minerals: Implications for the SWEAT correlation. Precambrian Research, 94, 251-271.
[13]	Simmat, R. and Raith, M.M. (2008) U-Th-Pb monazite geochronometry of the Eastern Ghats Belt, India: Timing and spatial disposition of poly-metamorphism. Precam-brian Research, 162, 16-39.
[14]	Subba Rao, M.V. and Divakara Rao, V. (1988) Chemical constraints on the origin of the charnockites in the Eastern Ghat Mobile belt, India. Chemical Geology, 69, 37-48.
[15]	Bhui, U.K., Sengupta, P. and Sengupta, P. (2007) Phase relations in mafic dykes and their host rocks from Kon-dapalle, Andhra Pradesh, India: Implications for the time- depth trajectory of the Paleoproterozoic (late Archean?) granulites from southern Eastern Ghats belt. Precambrian Research, 156, 153-174.
[16]	Wolf, M.B. and Wyllie, P.J. (1994) Dehydration melting of amphibolite at 10 Kbar: Effects of temperature and time. Contributions to Mineralogy and Petrology, 115, 369-383.
[17]	Patino Douce, A.E. and Beard, J.S. (1995) Dehydration melting of biotite gneiss and quartz amphibolite from 3 to 15 Kbar. Journal of Petrology, 36, 707-738.
[18]	V`ielzeuf, D. and Schmidt, M.W. (2001) Melting relations in hydrous systems revisited: Application to meta- pelites, metagreywackes and metabasalts. Contributions to Mineralogy and Petrology, 141, 251-267.
[19]	Bhattacharya, S. (2003) Dehydration melting in mafic rocks in the Eastern Ghats Belt, India: Implications for variable composition of charnockitic melt and hetero-geneity of source rocks. Geological Society of India, 52, 131-144.
[20]	Kar, R., Bhattacharya, S. and Sheraton, J.W. (2003) Hornblende dehydration melting in mafic rocks and the link between massif-type charnockite and associated granulites, Eastern Ghats Granulite Belt, India. Contribu-tions to Mineralogy and Petrology, 145, 707-729.
[21]	Foley, S., Tiepolo, M. and Vannucci, R. (2002) Growth of early continental crust in subduction zones controlled by melting of amphibolite. Nature, 417, 837-840.
[22]	Bhattacharya, S. (2010) Review: The charnockite problem: A twenty-first century perspective. Natural Science, 2, 402-408.
[23]	Halden, N.M., Bowes, D.R. and Dash, B. (1982) Struc-tural evolution of migmatites in a granulite facies terrane: Precambrian crystalline complex of Angul, Orissa, India. Transactions of the Royal Society, 73, 109-118.
[24]	Bhattacharya, S. (1997) Evolution of Eastern Ghats gra- nulite belt of India in a compressional tectonic regime and juxtaposition against Iron Ore craton of singhbhum by oblique collision-transpression. Proceedings of Indian Academy of Sciences, 106, 65-75.
[25]	Sen, S.K., Bhattacharya, S. and Acharyya, A. (1995) A multi-stage pressure-temperature record in the Chilka Lake granulites: The epitome of the metamorphic evolution of Eastern Ghats, journal of metamorphic geology, 13, 287-298.
[26]	Dasgupta, S. and Sengupta, P. (2003) Indo-Antarctic cor- relation: A perspective from the Eastern Ghats Granulite belt, India. Geological Society, 206, 131-144.
[27]	Bhattacharya, S., Das, P., Chaudhary, A.K. and Saw, A.K. (2010) Mafic granulite xenoliths in the Eastern Ghats Granulite belt: Implications for lower crustal processes in the southeastern Indian Peninsula. Indian Journal of Ge-ology, 80, 55-69.
[28]	McCulloch, M.T. and Chappel, B.W. (1982) Nd isotopic characteristics of S- and I-type granites. Earth and Plane- tary Science Letters, 58, 51-64.
[29]	Bhattacharya, S., Kar, R., Teixeira, W. and Basei, M. (2003) High-temperature crustal anatexis in a clockwise P-T path: Isotopic evidence from a granulite-granitoid suite in the Eastern Ghats belt, India. Journal of the Geological Society, 160, 39-46.