Abstract Views :238 |
PDF Views:151
Authors
Affiliations
1 Geological Survey of India, 40th Cross, Jayanagar, Bangalore 560041, IN
2 Geochronology Division, Geological Survey of India, Calcutta 700 016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 22, No 6 (1981), Pagination: 299-301
Abstract
Four 40K/40Ar mica ages of the granitoid suite around Kadavur range from 475 to 527 Ma with a mean around 500 Ma. Since (i) there is a close agreement in mica ages between variants of the granitoid suite and between size fractions and (ii) the dated minerals are from post-tectonic, undeformed and unmetamorphosed rocks, this mean age appears to closely approximate the age of intrusion of the granitoids. One hornblende separate from the older invaded hornblende leuco-gabbro of the Kadavur gabbro-anorthosite complex with a 40K/40Ar age of 492 Ma is most probably a thermally reset age.
Full Text