A PRECISE ZIRCON U-PB AGE FOR THE BASE OF THE BIF OF THE MULAINGIRI FORMATION, (BABABUDAN GROUP, DHARWAR SUPERGROUP) OF THE KARNATAKA CRATON

Authors
TRENDALL AF DELAETER JR NELSON DR MUKHOPADHYAY D
Citation
Af. Trendall et al., A PRECISE ZIRCON U-PB AGE FOR THE BASE OF THE BIF OF THE MULAINGIRI FORMATION, (BABABUDAN GROUP, DHARWAR SUPERGROUP) OF THE KARNATAKA CRATON, Journal of the Geological Society of India, 50(2), 1997, pp. 161-170
Citations number
33
Categorie Soggetti
Geosciences, Interdisciplinary
Journal title
Journal of the Geological Society of India → ACNP
ISSN journal
00167622
Volume
50
Issue
2
Year of publication
1997
Pages
161 - 170
Database
ISI
SICI code
0016-7622(1997)50:2<161:APZUAF>2.0.ZU;2-L
Abstract
SHRIMP U-Pb analyses of zircon grains from two thin dark shales believ ed to be syndepositional ashfall tuffs close to the base of the banded iron-formation (BIF) within the Mulaingiri Formation of the Bababudan Group (Dharwar Supergroup) of the western Karnataka Craton provide a precise age for the onset of BIF deposition in the basin. Sample 12001 9C, from the exact base of the BIF, gave an age of 2720 +/- 7 Ma, whil e sample 120018C, 14.5m above the base, gave an age of 2718 +/- 6 Ma. The second sample contained younger grains which may have been affecte d by a late thermal event.