Mafic rocks with back-arc E-MORB affinity from the Chotanagpur Granite Gneiss Complex of India: relicts of a Proterozoic Ophiolite suite

Abstract The Proterozoic Chotanagpur Granite Gneiss Complex (CGGC) at the northern boundary of Central Indian Tectonic Zone (CITZ) eastern shield preserves relics fossilized oceanic back-arc crust. We describe field, petrographical and geochemical characteristics mafic rocks comprising pillow basalts dolerites from Bathani area fringe CGGC, India. consist plagioclase feldspar, hornblende, opaque minerals (Fe–Ti oxide) chlorite, dolerite consists plagioclase, hornblende minerals. Our data indicate that have tholeiitic to transitional composition are overprinted by greenschist facies metamorphic conditions; however, REE fluid immobile elements preserve their primary signatures. (La/Sm) N ratios (1.38–2.15) chondrite-normalized patterns point an enriched mid-ocean ridge basalt (E-MORB) mantle source. Geochemical a mixed signature MORB arc tholeiite with enrichment Ba, Th, Eu Sr, similar supra-subduction zone ophiolites. These product MORB-like magma derived depleted corresponding < 2% partial melting spinel lherzolite, subduction-induced slab metasomatism melting. representative upper part columnar ophiolite section, which was emplaced onto present-day margin CGGC during suturing southern block c. 1.9 Ga Nuna amalgamation.