Petrology and Geochemistry of Hornblendic Rocks from Kanigiri-Gogulapalle Area, Andhra Pradesh
Authors
-
National Geophysical Research Institute, Hyderabad
P. Rama Rao -
Andhra University, Waltair
A. Narasinga Rao
Abstract
Hornblendic rocks (hornblende schists, amphibolites, and hornblendites) occur in intimate association with metasedimentary schists and granitic rocks in the Kanigiri Gogulapalle area of Andhra Pradesh, India. Field studies indicate that a majority of these rocks are possibly concordant intrusives, some of them being metasedimentary. Petrographic study shows that most of them consist of hornblende and plagioclase as essential minerals, whereas some are characterized by tremolite and plagioclase with accessory calcic minerals. Absence of detrital minerals and pyroxenic cores in the amphiboles characterize all the rocks.
Geochemical studies reveal that the rocks are most probably magmatic intrusives judged from the low Niggli k and high TiO2 values and the presence of high Sr, Cr, V, and Ni amongst the trace elements.
Downloads
Issue
Section
Downloads
Published
How to Cite
References
BLYTH F. G. H. and LAMBERT, R., ST, J., (1970) Chemical Data from the Malvernian of the Malvern Hills, Herefordshire, Quart. Jour. Geol. Soc. Lond., v. 125, pp. 543-555.
BUTLER, J. R., (1953) The Geochemistry and Mineralogy of Rock Weathering (I), The Lizard Area, Cornwall, Geochim. et Cosmochim. Acta, v. 4, pp, 157-178.
ENGEL, A. E. J., ENGEL, C. G. and HAVENS, R. G., (1964) Mineralogy of Amphibolite Interlayers in the Gneiss Complex. Northwest Adirondack Mountains, New York, Jour. Geol. v. 72, pp. 131-156.
EVANS, B. W. and LEAKE, B. E., (1960) The Composition and Origin of the Striped Amphibolites of Connemara, Ireland. Jour. Petrol., v. I, pp. 337-363.
GOMES, C. D. B., SANTINI, P. and DUTRA, C. V., (1964) Petrochemistry of a Pre-Cambrian Amphibolite from the Jaragua Area, Sao Paulo, Brazil, Jour. Geol., v. 72, pp. 664-680.
GREEN, J. and POLDERVAART, A.. (1958) Petrochemical Fields and Trends, Geochim, et Cosmochim, Acta, v. 13, pp. 87-122.
HIETANEN, A., (1967) On the facies series in various types of metamorphism, Jour. Geol., v. 75, pp, 187-214.
JENKINS, L., (1954) The Determination of Potassium and Sodium in Siliceous, Argillaceous and Phosphatic Rocks by the Flame Photometer, U.S. Geol. Surv., TEI-453.
LEAKE, B. E., (1963) Origin of amphibolites from northwest Adirondacks, New York, Bull. Geol. Soc. Amer., v. 74, pp. 1193-1202.
LEAKE, B. E., (1964) The Chemical distinction between Ortho- and Para-amphibolites, Jour. Petrol., v. 5, pp. 238-254.
LEAKE, B. E., (1969) The Discrimination of Ortho- and Para-Charnockitic Rocks, anorthosites and amphibolites, The Ind. Mineralogist, v. 10, pp. 89-104.
MITCHELL, R. L., (1948) 'The Spectrographic Analysis of Soils, Plants and Related Materials', Commonwealth Bureau of Soil Science, Technical Communication, no. 48.
NOCKOLDS, S. R., (1954) Average Chemical Compositions of some Igneous Rocks, Bull. Geol. Soc. Amer., v. 65, pp. 1007-1032.
RAMA RAO, P., (1972) Petrology and Geochemistry of Granites and Associated Rocks of Kanigiri-Gogulapalle area, Andhra Pradesh, India, Ph.D. Thesis, submitted to Andhra University (Unpublished).
RAMBERG, H., (1952) The Origin of Metamorphic and Metasomatic Rocks, The University of Chicago Press, Chicago.
SHAW, D. M., (1954) Trace Elements in Pelitic Rocks, Part I, Variation during Metamorphism, Bull. Geol. Soc. Amer., v. 65, pp. 1151-1166.
TUREKIAN, K. K. and KULP, J. L., (1956) The Geochemistry of Strontium. Goochim, et Cosmochim. Acta, v. 10, pp. 245-296.
TURNER, F. J. and VERHOOGEN, J., (1962) Igneous and Metamorphic Petrology, Ind. Ed., Allied Pacific Private Limited, Bombay.
WINKLER, H. G. K., (1965) Petrogenesis of Metamorphic Rocks, Springer-Verlag, Berlin, First Edition.
