Neoarchean greenstone volcanism and continental growth, Dharwar craton, southern India: Constraints from SIMS U-Pb zircon geochronology and Nd isotopes
Date
2013
Authors
Jayananda, M.
Peucat, J-J
Chardon, D
Krishna Rao, B.
Fanning, Christopher
Corfu, F
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
We present SIMS U-Pb zircon ages and Nd isotope data for the felsic volcanic rocks from seven Neoarchean greenstone belts of the Eastern Dharwar craton (EDC) and from the Chitradurga greenstone belt in the Western Dharwar craton (WDC). Zircon ages show bimodal age distribution of felsic volcanism. The ca. 2.70-2.65Ga felsic volcanic event is contemporaneous with 2.7Ga mafic greenstone volcanism and emplacement of juvenile tonalitic to granodioritic crust, while 2.58-2.54Ga felsic volcanics are coeval and spatially (and probably genetically in some cases) linked to the major episode calc-alkaline magmatic accretion in the EDC. The Chitradurga and Veligallu greenstone belts host felsic volcanics of the first generation, the latter showing inheritance at ca. 2.95Ga. Four of the five greenstone belts hosting the second generation of felsic volcanics (Chitradurga, Kolar, Kadiri, Hutti) show crustal inheritance at ca. 2.6, 2.7, 2.9, 3.0, 3.1 and 3.3Ga. e{open}Ndt indicate derivation of the felsic volcanics from juvenile sources or short-lived crustal sources with minor influence of older crust.The new and existing data are consistent with two-stage growth of the Dharwar craton in the Neoarchean. First-stage accretion led to the growth of a 2.7-2.6. Ga juvenile crustal province of mafic volcanics and felsic plutons along the eastern margin of the WDC. Second-stage accretion (2.58-2.52. Ga) led to the emplacement of TTG and calc-alkaline plutons and felsic volcanics throughout the Eastern Dharwar craton. An active margin context could apply for the two-stage accretion scenario considering a west-dipping subducting slab beneath the craton in the framework of long-lived ultra-hot accretionary orogen. But the great width of influence of magmatic accretion and/or reworking, particularly during the second stage, would suggest large-scale mantle flow reorganization that would have generated large plume(s).
Description
Keywords
Keywords: accretion; Archean; emplacement; greenstone belt; mafic rock; neodymium isotope; orogeny; pluton; uranium-lead dating; volcanism; zircon; Dharwar Craton; India Continental growth; Dharwar craton; Felsic volcanics; Nd isotopes; Neoarchean; SIMS zircon geochronology
Citation
Collections
Source
Precambrian Research
Type
Journal article
Book Title
Entity type
Access Statement
License Rights
Restricted until
2037-12-31
Downloads
File
Description