3,360-Myr old gneisses from the South Indian Craton

Beckinsale, R. D.; Drury, S. A.; Holt, R. W.

doi:10.1038/283469a0

Cited by 199 publications

(58 citation statements)

References 10 publications

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“…These sub-horizontal basalts lie unconformably on the crystalline basement, infilling and blanketing a pre-existing shield topography (Jerram & Widdowson, 2005). Our interest is the area south of the Deccan flood basalts (8° -16°N), where the margin is composed of crystalline basement with Archaean basement gneiss and the younger metasediments of the Dharwar system forming the common rock types (Beckinsale et al, 1980;Drury et al, 1983;Naqvi & Rogers, 1987). The southern portion of the margin (i.e.…”

Section: Regional Geology Tectonics and Geomorphologymentioning

confidence: 99%

Sedimentation record in the Konkan–Kerala Basin: implications for the evolution of the Western Ghats and the Western Indian passive margin

et al. 2007

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The Konkan and Kerala Basins constitute a major depocentre for sediment from the onshore hinterland of Western India and as such provide a valuable record of the timing and magnitude of Cenozoic denudation along the continental margin. This paper presents an analysis of sedimentation in the Konkan-Kerala basin, coupled with a mass balance study, and numerical modelling of flexural responses to onshore denudational unloading and offshore sediment loading in order to test competing conceptual models for the development of high-elevation passive margins. The Konkan-Kerala basin contains an estimated 109,000 km 3 of Cenozoic clastic sediment, a volume difficult to reconcile with the denudation of a downwarped rift flank onshore, and more consistent with denudation of an elevated rift flank. We infer from modelling of the isostatic response of the lithosphere to sediment loading offshore and denudation onshore infer that flexure is an important component in the development of the Western Indian Margin. There is evidence for two major pulses in sedimentation: an early phase in the Palaeocene, and a second beginning in the Pliocene. The Palaeocene increase in sedimentation can be interpreted in terms of a denudational response to the rifting between India and the Seychelles, whereas the mechanism responsible for the Pleistocene pulse is more enigmatic.

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Section: Regional Geology Tectonics and Geomorphologymentioning

confidence: 99%

Sedimentation record in the Konkan–Kerala Basin: implications for the evolution of the Western Ghats and the Western Indian passive margin

et al. 2007

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“…3.0 Ga PGC), can possibly be considered as the base of the Sargur Group; however, Ramakrishnan and Swaminatha (1976) and Swami Nath and contend that the basement for the Sargur is not yet recognized. In contrast to this view, some of the older greenstone belts were intruded by the ϳ3.4 Ga Gorur gneisses near Katya in the western part of the Holenarsipur schist belt (Beckinsale et al 1980;Naqvi 1981). The oldest ages documented in the Dharwar craton include a 24-point Rb-Sr whole-rock isochron of 3315 ± 13 Ma (Ri = 0.7006) and an 11-point Pb-Pb isochron of 3305 ± 13 Ma for the Gorur-Hassan tonalitic gneisses of the Holenarsipur region (Glikson 1979).…”

Section: Fig 2 Evolution Of Kaapvaal (Kv) Precambrian Supracrustal mentioning

confidence: 67%

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

et al. 2014

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Abstract: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 lithologi-cal 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-trondhjemitegranodiorite (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.Résumé : L'histoire géologique et l'évolution du craton de Dharwar (ϳ3,5-2,5 Ga) sont examinées et sommairement comparées a` celles d'un second craton, celui de Kaapvaal, afin de permettre une certaine spéculation sur la nature des régimes tectoniques globaux duran...

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“…(Continued) of the data are from the west and south west of the Chitradurga greenstone belt. Beckinsale et al (1980) first dated the Peninsular Gneiss by Rb-Sr method and obtained an age of 3358 ± 66 Ma. Other published ages in nearby areas are 3080 ± 110 Ma and 3175 ± 45 Ma (Taylor et al, 1984 by Rb-Sr method), 3204 ± 30 Ma (Bhaskar Rao et al, 1991 by Rb-Sr method), and 3328 ± 10 to 3200 ± 20 Ma (Peucat et al, 1993 by Pb-Pb method).…”

Section: Discussionmentioning

confidence: 99%

“…Chadwick et al (2000) suggests that the accretion of already formed island arcs and granitic plutons constituted a single landmass (i.e., Dharwar batholith) to the WDC, causing sin- Chardon et al, 2008) showing the locations and ages of Mesoarchean and Neoarchean granitoids referred to in the text. Digits denote ages (Ma) of granitoids and numbers in parenthesis represent the source of age data; (1) Beckinsale et al (1980), (2) Taylor et al (1984), ( istral transpressive shear systems along the margins due to oblique convergence of the landmass. Greenstone belts developed as a result of intra-arc basin associated with the batholiths.…”

Section: Geological Settingmentioning

confidence: 99%

SHRIMP U–Pb zircon ages of granitoids adjacent to Chitradurga shear zone, Dharwar craton, South India and its tectonic implications

Nasheeth

Okudaira

Horie

et al. 2015

Journal of Mineralogical and Petrological Sciences

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We report newly obtained U-Pb SHRIMP ages of zircons from the granitoids in the vicinity of Chitradurga shear zone of Dharwar craton, South India. The analyses yielded two different ages, an older age of ca. 3300 Ma and younger ages of~2600-2650 Ma, those suggest two major igneous activities in the study area. The former activity contemporaneous with the formation of Mesoarchean (~3.3 Ga) basement rocks (i.e., Peninsular Gneiss) and the latter reflects the Neoarchean (~2.6 Ga) regional plutonic activity in the Western Dharwar craton. Field and petrographic observations suggest that the intensity of deformation is high at the boundary between amphibolites and granitoids. Our new age dates imply that the formation of Chitradurga shear zone postdated the magmatic activity in the study area and the deformation structures possibly related to the development of Chitradurga shear zone. The area on either sides of the boundary between Eastern and Western Dharwar cratons experienced a Neoproterozoic event between 700-600 Ma indicated by prominent SHRIMP lower intercepts.

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3,360-Myr old gneisses from the South Indian Craton

Cited by 199 publications

References 10 publications

Sedimentation record in the Konkan–Kerala Basin: implications for the evolution of the Western Ghats and the Western Indian passive margin

Sedimentation record in the Konkan–Kerala Basin: implications for the evolution of the Western Ghats and the Western Indian passive margin

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

SHRIMP U–Pb zircon ages of granitoids adjacent to Chitradurga shear zone, Dharwar craton, South India and its tectonic implications

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