Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India
The southern boundary of the Singhbhum Craton witnessed multiple orogenies that juxtaposed thin slice of granulite suite of the Rengali Province against the low-grade granite-greenstone belt of the craton along the E–W trending Sukinda Thrust. The strong southerly dipping mylonitic foliation within...
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doaj-34407153a67f4a9a8ebe66553e28f1942020-11-25T01:36:44ZengElsevierGeoscience Frontiers1674-98712015-07-016453755510.1016/j.gsf.2014.09.002Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern IndiaSankar Bose0Susmita Guha1Gautam Ghosh2Kaushik Das3Joydip Mukhopadhyay4Department of Geology, Presidency University, Kolkata 700073, IndiaDepartment of Geology, Presidency University, Kolkata 700073, IndiaDepartment of Geology, Presidency University, Kolkata 700073, IndiaDepartment of Earth and Planetary Systems Science, Hiroshima University, Higashi Hiroshima, JapanDepartment of Geology, Presidency University, Kolkata 700073, IndiaThe southern boundary of the Singhbhum Craton witnessed multiple orogenies that juxtaposed thin slice of granulite suite of the Rengali Province against the low-grade granite-greenstone belt of the craton along the E–W trending Sukinda Thrust. The strong southerly dipping mylonitic foliation within the granulites along with the prominent down-dip mineral lineation, suggest a northerly-verging thrusting. Mylonitized charnockite at the contact zone contains enclaves of mafic and ultramafic granulite, whereas granitoid gneiss contains enclaves of pelitic granulite. Mafic granulite enclaves preserve an early (S1M) foliation that formed during D1M deformation. This rock, along with the host charnockite, were intensely deformed by the D2M thrusting event and resulting S2M foliation development in both rock suites. Geothermobarometric and pseudosection analyses show that the garnet-clinopyroxene-plagioclase-orthopyroxene-ilmenite-quartz assemblage in mafic granulite was stabilized at high-pressure and temperature conditions (10−12 kbar, 860 °C) and was overprinted by a fine-grained assemblage of clinopyroxene-plagioclase ± hornblende that developed during decompression (down to 5.5–7.5 kbar). Matrix hornblende shows incipient breakdown to garnet-clinopyroxene-quartz intergrowth due to a granulite facies reworking. A contrasting P-T history is preserved in the pelitic granulite. The peak assemblage garnet-orthopyroxene-cordierite-quartz-rutile was stabilized at ∼6.0 kbar, 730 °C which resulted from heating of the mid crust magma during the D2M thrusting. The contrasting P-T histories could result from the tectonic juxtaposition of lower- and mid-crustal section during the D2M event. Evidences of an early orogenic imprint within the mafic granulite imply involvement of deep continental crust during southward growth of the Singhbhum Craton.http://www.sciencedirect.com/science/article/pii/S1674987114001297Singhbhum cratonRengali ProvinceGranulite enclaveTectonic juxtaposition |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Sankar Bose Susmita Guha Gautam Ghosh Kaushik Das Joydip Mukhopadhyay |
spellingShingle |
Sankar Bose Susmita Guha Gautam Ghosh Kaushik Das Joydip Mukhopadhyay Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India Geoscience Frontiers Singhbhum craton Rengali Province Granulite enclave Tectonic juxtaposition |
author_facet |
Sankar Bose Susmita Guha Gautam Ghosh Kaushik Das Joydip Mukhopadhyay |
author_sort |
Sankar Bose |
title |
Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India |
title_short |
Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India |
title_full |
Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India |
title_fullStr |
Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India |
title_full_unstemmed |
Tectonic juxtaposition of crust and continental growth during orogenesis: Example from the Rengali Province, eastern India |
title_sort |
tectonic juxtaposition of crust and continental growth during orogenesis: example from the rengali province, eastern india |
publisher |
Elsevier |
series |
Geoscience Frontiers |
issn |
1674-9871 |
publishDate |
2015-07-01 |
description |
The southern boundary of the Singhbhum Craton witnessed multiple orogenies that juxtaposed thin slice of granulite suite of the Rengali Province against the low-grade granite-greenstone belt of the craton along the E–W trending Sukinda Thrust. The strong southerly dipping mylonitic foliation within the granulites along with the prominent down-dip mineral lineation, suggest a northerly-verging thrusting. Mylonitized charnockite at the contact zone contains enclaves of mafic and ultramafic granulite, whereas granitoid gneiss contains enclaves of pelitic granulite. Mafic granulite enclaves preserve an early (S1M) foliation that formed during D1M deformation. This rock, along with the host charnockite, were intensely deformed by the D2M thrusting event and resulting S2M foliation development in both rock suites. Geothermobarometric and pseudosection analyses show that the garnet-clinopyroxene-plagioclase-orthopyroxene-ilmenite-quartz assemblage in mafic granulite was stabilized at high-pressure and temperature conditions (10−12 kbar, 860 °C) and was overprinted by a fine-grained assemblage of clinopyroxene-plagioclase ± hornblende that developed during decompression (down to 5.5–7.5 kbar). Matrix hornblende shows incipient breakdown to garnet-clinopyroxene-quartz intergrowth due to a granulite facies reworking. A contrasting P-T history is preserved in the pelitic granulite. The peak assemblage garnet-orthopyroxene-cordierite-quartz-rutile was stabilized at ∼6.0 kbar, 730 °C which resulted from heating of the mid crust magma during the D2M thrusting. The contrasting P-T histories could result from the tectonic juxtaposition of lower- and mid-crustal section during the D2M event. Evidences of an early orogenic imprint within the mafic granulite imply involvement of deep continental crust during southward growth of the Singhbhum Craton. |
topic |
Singhbhum craton Rengali Province Granulite enclave Tectonic juxtaposition |
url |
http://www.sciencedirect.com/science/article/pii/S1674987114001297 |
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