Pb–Pb zircon ages of Archaean metasediments and gneisses from the Dharwar craton, southern India: Implications for the antiquity of the eastern Dharwar craton

Abstract

207 Pb-206 Pb ages of zircons in samples of metasediments as well as ortho-and para-gneisses from both the western and the eastern parts of the Dharwar craton have been determined using an ion microprobe. Detrital zircons in metasedimentary rocks from both yielded ages ranging from 3.2 to 3.5 Ga. Zircons from orthogneisses from the two parts also yielded similar ages. Imprints of younger events have been discerned in the ages of overgrowths on older zircon cores in samples collected throughout the craton. Our data show that the evolution of the southwestern part of eastern Dharwar craton involved a significant amount of older crust (>3.0 Ga). This would suggest that crust formation in both the western and eastern parts of the Dharwar craton took place over similar time interval starting in the Mesoarchaean at ca. 3.5 Ga and continuing until 2.5 Ga. Our data coupled with geological features and geodynamic setting of the Dharwar craton tend to suggest that the eastern Dharwar craton and the western Dharwar craton formed part of a single terrane.

Basement–cover structural relationships in the Kaladgi Basin, southwestern India: Indications towards a Mesoproterozoic gravity gliding of the cover along a detached unconformity

“…The Closepet granite is dated to be of c. 2513 ± 5 Ma (Friend and Nutman, 1991). The Closepet granite is thought to be a part of a widespread NeoArchaean phase of plutonism (Mojzsis et al, 2003;Maibam et al, 2011;Jayananda et al, 2013) in both the Eastern and Western Dharwar Cratons and marks the stabilization age for both (Meert et al, 2010).…”

Carbon isotope studies of auriferous quartz carbonate veins from two orogenic gold deposits from the Neoarchean Chitradurga schist belt, Dharwar craton, India: Evidence for mantle/magmatic source of auriferous fluid

“…To explain this dichotomy, Srinivasan and Naha (1993) and Chadwick et al (2000) have proposed that the eastern schist belts developed from assemblages that accumulated in intra-arc basins while the western belts developed in foreland basins. The foreland basin is considered to be of the nature of retro-arc foreland basin by Maibam et al (2011). The boundary between the intra-arc and foreland basin terrains approximately coincides with a major crustal scale shear zone known as Chitradurga Boundary Shear Zone or Chitradurga eastern shear zone traced along the eastern margin of the Chitradurga schist belt (Swami Nath and Ramakrishnan, 1981).…”

“…Due to granitic magmatism and high temperature-low pressure metamorphism, the basement was largely reworked during amphibolite facies which virtually erased basement-cover relations of the Dharwar Sequence in the EDC. By contrast in the WDC, in the retro-arc region, the late stage granite emplacement was subdued, the gneissic basement was reworked to various degrees with gneissic basement preserved in some places and erased elsewhere (Maibam et al, 2011). The boundary zone between the stiff WDC and weak EDC crust, east of the Chitradurga schist belt, witnessed large-scale reconstitution of the basement and constrictional flow of crustal material (Chardon et al, 2011).…”

New 1.9-2.0 Ga, Pb-Pb (PbSL), Age of Dolomites from Vempalle Formation, Lower Cuddapah Supergroup, Eastern Dharwar Craton, India

“…The ages of detrital zircons in the EDC reveal presence of widespread Archaean crust (3.1-3.3 Ga) which are subsequently affected by later geological activities notably at 2.8 and 2.5 Ga (Maibam et al, 2011). Nagaraja Rao et al, 1987, presented detailed stratigraphy of the basin in which the Cuddapah Supergroup is divided into three groups i.e.…”