Geochemical characteristics of the Late Cretaceous radiolarian cherts from North Andaman Island, Bay of Bengal, India

Jafri, S. H.; Sarma, D. Srinivasa; Khan, Tavheed; Singh, Dinesh

doi:10.1007/s12040-020-1368-2

Cited by 2 publications

(1 citation statement)

References 27 publications

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“…Andaman ophiolite comprises of a basal serpentinized and tectonized mantle peridotite unit overlain by ultramafic and mafic cumulate units, basaltic dykes and pillow basalts (Saha et al, 2010). Limited work has been carried out on the various segments of the exposed rocks which include cumulates of ultramafics (serpentinite/dunite, harzbur-gite and spinel lherzolite) (Saha et al, 2010;Pal, 2011;Bhattacharya et al, 2013;Saha et al, 2018), mafic rocks gabbro - (Shastry et al, 2002;Saha et al, 2010;Pal, 2011;Rasool et al, 2015), troctolite - and pillow lavas - (Ray et al, 1988;Vohra et al, 1989;Jafri et al, 1990;Jafri and Charan, 1992;Jafri et al, 1995;Srivastava et al, 2004;Jafri et al, 2006;Jafri et al, 2010;Jafri and Sheikh, 2013;Bhattacharya et al, 2013;Ghosh et al, 2017;Sachin and Pal, 2017;Bandyopadhyay et al, 2020), felsic rocks plagiogranite- (Jafri et al, 1995;Pedersen et al, 2010;Sharma et al, 2010) and sedimentary radiolarian cherts- (Jafri, 1986;Haldar, 1984;Jafri et al, 1993;Ling et al, 1996;Pal et al, 2003;Jafri et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Back-arc basin origin for the basalts of the South Andaman Island Ophiolite (India)

et al. 2022

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Petrological, mineral chemical and geochemical characteristics are reported for the basalts of South Andaman ophiolite suite (India) of Cretaceous age to infer its petrogenesis, magma source characteristics and tectonic setting. In the field, both massive basalts and basalts with wellpreserved pillow morphology are present. The basalts consist of plagioclase, clinopyroxene, Fe-Ti oxide and Cr-spinel. They are tholeiitic in composition with low concentrations of Na 2 O + K 2 O (3 -5 wt.%). The representative samples of these basalts have a nearly flat chondrite-normalized REE pattern [(La/Yb) N = 0.29 -2.27)] with minor Eu anomaly (Eu/Eu* = 0.90 -1). Our findings suggest that the arc-like massive basalts were generated before the back-arc rifting initiated in an earlier stage of back-arc extension as a result of eastward subduction of the Neotethyan oceanic slab. The MORB-like pillow basalts were erupted due to further back-arc spreading in response to the roll-back of the Neotethyan oceanic lithospheric slab. The pillow and massive basalts assemblage in the South Andaman ophiolite records the evolution of a back-arc basin from initial rifting to subsequent spreading, documenting how basaltic magmatism evolves during the formation of the back-arc basin in a suprasubduction zone setting.

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