Record Details

A review of the inferred geodynamic evolution of the Dharwar craton over the ca. 3.5-2.5 Ga period, and possible implications for global tectonics

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title A review of the inferred geodynamic evolution of the Dharwar craton over the ca. 3.5-2.5 Ga period, and possible implications for global tectonics
 
Creator RAJU, PVS
ERIKSSON, PG
CATUNEANU, O
SARKAR, S
BANERJEE, S
 
Subject CHITRADURGA SCHIST BELT
LATE ARCHEAN EVOLUTION
SOUTHERN INDIA
CRUSTAL EVOLUTION
KAAPVAAL CRATON
PENINSULAR GNEISS
KARNATAKA CRATON
MESOPROTEROZOIC SUPERCONTINENT
KALDURGA CONGLOMERATE
SEQUENCE STRATIGRAPHY
 
Description The geological history and evolution of the Dharwar craton from ca. 3.5-2.5 Ga is reviewed and briefly compared with a second craton, Kaapvaal, to allow some speculation on the nature of global tectonic regimes in this period. The Dharwar craton is divided into western (WDC) and eastern (EDC) parts (separated possibly by the Closepet Granite Batholith), based on lithological differences and inferred metamorphic and magmatic genetic events. A tentative evolution of the WDC encompasses an early, ca. 3.5 Ga protocrust possibly forming the basement to the ca. 3.35-3.2 Ga Sargur Group greenstone belts. The latter are interpreted as having formed through accretion of plume-related ocean plateaux. The approximately coeval Peninsular Gneiss Complex (PGC) was possibly sourced from beneath plateau remnants, and resulted in high-grade metamorphism of Sargur Group belts at ca. 3.13-2.96 Ga. At about 2.9-2.6 Ga, the Dharwar Supergroup formed, comprising lower Bababudan (largely braided fluvial and subaerial volcanic deposits) and upper Chitradurga (marine mixed clastic and chemical sedimentary rocks and subaqueous volcanics) groups. This supergroup is preserved in younger greenstone belts with two distinct magmatic events, at 2.7-2.6 and 2.58-2.54 Ga, the latter approximately coincident with ca. 2.6-2.5 Ga granitic magmatism which essentially completed cratonization in the WDC. The EDC comprises 2.7-2.55 Ga tonalite-trondhjemite-granodiorite (TTG) gneisses and migmatites, approximately coeval greenstone belts (dominated by volcanic lithologies), with minor inferred remnants of ca. 3.38-3.0 Ga crust, and voluminous 2.56-2.5 Ga granitoid intrusions (including the Closepet Batholith). An east-to-west accretion of EDC island arcs (or of an assembled arc - granitic terrane) onto the WDC is debated, with a postulate that the Closepet Granite accreted earlier onto the WDC as part of a "central Dharwar" terrane. A final voluminous granitic cratonization event is envisaged to have affected the entire, assembled Dharwar craton at ca. 2.5 Ga. When Dharwar evolution is compared with that of Kaapvaal, while possibly global magmatic events and freeboard-eustatic changes at ca. 2.7-2.5 Ga may be identified on both, the much earlier cratonization (by ca. 3.1 Ga) of Kaapvaal contrasts strongly with the ca. 2.5 Ga stabilization of Dharwar. From comparing only two cratons, it appears that genetic and chronologic relationships between mantle thermal and plate tectonic processes were complex on the Archaean Earth. The sizes of the Kaapvaal and Dharwar cratons might have been too limited yet to support effective thermal blanketing and thus accommodate Wilson Cycle onset. However, tectonically driven accretion and amalgamation appear to have predominated on both evolving cratons.
 
Publisher CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS
 
Date 2014-12-28T12:20:25Z
2014-12-28T12:20:25Z
2014
 
Type Article
 
Identifier CANADIAN JOURNAL OF EARTH SCIENCES, 51(3)312-325
0008-4077
1480-3313
http://dx.doi.org/10.1139/cjes-2013-0145
http://dspace.library.iitb.ac.in/jspui/handle/100/16493
 
Language English