Thrusting in the lower crust: evidence from the Oygarden 
Islands, Kemp Land, East Antarctica

Kelly, Nigel M.; Clarke, Graeme; Carson, Chris; White, R. W.

doi:10.1017/s0016756800004027

Cited by 42 publications

(21 citation statements)

References 59 publications

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“…This is again similar to the timing of zircon growth during the D 3 -D 4 events in rocks from Oygarden area of the Rayner Complex (Kelly et al, 2002). Moreover, a striking similarity between the D 3 structural characteristics in the present study area and D 3 -D 4 structural reworking in the Oygarden area (Kelly et al, 2000) reinforces the notion that the EGB and Rayner Complex shared a common geologic history from ca. 950 Ma to ca.…”

Section: Discussionsupporting

confidence: 85%

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

et al. 2011

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Integrated structural, petrological and geochronological study on a suite of granulites from the central part of the Eastern Ghats Belt (EGB), India unveils polyphase tectonothermal evolution. We document (a) M 1 ultrahigh temperature (UHT) metamorphism ($10008C at 6.5-8.5 kbar) on an anticlockwise P-T trajectory simultaneously with early deformations D 1 -D 2 involving partial melting, (b) cooling down to $ 8008C, 6 kbar that produced a variety of coronae/symplectites (M 1R ), (c) an unrelated compressional orogeny (D 3 ) that produced deep crustal shears and mylonitic foliation (S 3m ) at low angles to D 1 -D 2 structures and was associated with slight loading, and possible partial melt extraction under granulite facies condition (M 2 $7 kbar, 8508C), and (d) localized retrogression (M 3 ) in the presence of melt accompanying D 4 deformation. This is the first record of the prograde P-T path of the superimposed granulite facies metamorphism in the EGB. U-Pb SHRIMP data of zircon preserves an inherited grain domain of ca. 1700 Ma ( 207 Pb age) that traces back the history of EGB with a lineage of the Mesoproterozoic supercontinent, Columbia. The UHT metamorphosed (peak M 1 at ca. 1000 Ma) and subsequently cooled crustal segment (M 1R ) was subjected to strong tectonothermal reworking (M 2 ) along a clockwise P-T path at 953 þ 6 Ma (concordia age) that partially exhumed the rocks to mid-crustal levels. A later fluid-induced retrogressive event vis-à-vis melt crystallization occurred at ca. 900 Ma ( KEY WORDS deep crustal reworking; Eastern Ghats Belt; India; UHT aluminous granulites; zircon U-Pb SHRIMP ages Supporting information (supplementary tables S2-S6) may be found in the online version of this paper.

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Section: Discussionsupporting

confidence: 85%

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

et al. 2011

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“…Mineral assemblages that define S 3 foliations in D 3 shear zones reflect metamorphic conditions of Pz9-11 kbar and Tz800-850 (C (Kelly et al 2000). The D 3 event involved high-grade ductile thrusting with an eastward transport direction, accompanied by tight to isoclinal folding.…”

Section: Geological Settingmentioning

confidence: 99%

Archaean crust in the Rayner Complex of east Antarctica: Oygarden Group of islands, Kemp Land

Kelly

Clarke

Fanning

2004

Earth and Environmental Science Transactions of the Royal Socie

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Archaean zircon grains from the Oygarden Group of islands in Kemp Land, east Antarctica, record evidence for multiple episodes of recrystallisation, dissolution and growth from the Early to Middle Archaean to the Neoproterozoic. Zircon grains in layered felsic orthogneiss have an age of ∼3650 Ma, a minimum protolith age for this rock. These zircon grains were subsequently affected by a ∼3470 Ma Pb-loss event. Homogeneous felsic orthogneiss that cuts S1, but contains an intense S2 foliation, has disturbed ∼2780 Ma metamorphic zircon cores and rims that suggest a minimum age of ∼2780 Ma for the protolith to the orthogneiss. All zircon U-Pb data display considerable disturbance with further Pb-loss at ∼2400 Ma and ∼1600 Ma, and a major episode of isotopic resetting at ∼930 Ma. The highly disturbed data are related to complexly zoned zircon grains that developed through growth and modification during successive metamorphic events. Zircon cores with relic growth zoning patterns are inferred to have resulted from partial annealing or recrystallisation of older magmatic zircon. Highly luminescent zircon rims that embay cores along curved boundaries are interpreted to have formed through recrystallisation of zircon cores, and not new growth. The ages reported here confirm that central Kemp Land is composed of Archaean crust reworked during the Neoproterozoic Rayner Structural Episode.

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“…This belt has dominantly juvenile crustal material of 1650-2180 Ma (Nd isotope depleted mantle model age), which underwent partial melting at~1500 Ma . Intense deformation and granulite facies metamorphism, with peak value of 800-950°C at 9-10 kbar, are reported from the Oygarden Group bordering the Napier Complex and in the adjacent Mawson coast (Kelly et al 2000). Detrital zircons in the Oygarden Group have a weighted mean age of 2567 ± 31 Ma (MSWD = 1.4), which is interpreted as the maximum Figure 6.…”

Section: The Rayner Complexmentioning

confidence: 98%

Precambrian continent assembly and dispersal events of South Indian and East Antarctic Shields

Mohanty

2015

International Geology Review

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An Archaean continent 'SIWA', an acronym for South India-Western Australia, comprising the Bastar-Dharwar craton, the Yilgarn craton, the Napier Complex, and the Vestfold Hills has been identified from palaeomagnetic and spatio-temporal data. This assembly was dispersed in three phases with the development of the proto-Indian ocean. The first and second events~2350 and~2000 Ma were related to the separation of the Yilgarn craton and the Napier Complex, respectively, to form a proto-Indo-Antarctic ocean and the Cuddapah basin. The proto-ocean was closed~1650 Ma by the collision of the Lambert Terrane of East Antarctica and the Bastar-Dharwar craton. This collision, associated with ultra-high temperature (UHT) granulite facies metamorphism, is identified in the southern domain of the Eastern Ghats and the Oygardens domain of East Antarctica. The third extensional event between 1500 and 1200 Ma was associated with the separation of the Vestfold Hills block and a second phase of opening of the proto-Indian ocean, and the development of a series of basins on the western side of the Eastern Ghats (the Chhatisgarh, Khariar, Ampani, Indravati, and Sabari basins). The closing of this ocean basin during the Eastern Ghats-Rayner orogeny at~950 Ma was related to the amalgamation of India and East Antarctica to form the supercontinent Rodinia. During the Neoproterozoic, this part of Rodinia was involved in orogenic collapse/extension and deposition of the Sodruzhesvo Group. The Pan-African Prydz Bay orogeny at~550 Ma caused the closing of the basin to form East Gondwanaland.

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Thrusting in the lower crust: evidence from the Oygarden Islands, Kemp Land, East Antarctica

Cited by 42 publications

References 59 publications

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

Multiple tectonometamorphic imprints in the lower crust: first evidence ofca. 950 Ma (zircon U‐Pb SHRIMP) compressional reworking of UHT aluminous granulites from the Eastern Ghats Belt, India

Archaean crust in the Rayner Complex of east Antarctica: Oygarden Group of islands, Kemp Land

Precambrian continent assembly and dispersal events of South Indian and East Antarctic Shields

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