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Please use this identifier to cite or link to this item: http://drs.nio.org/drs/handle/2264/605

Title: A petrogenetic model of basalts from the Northern Central Indian Ridge: 3-11°S
Authors: Ray, Dwijesh
Iyer, S.D.
Banerjee, R.
Misra, S.
Widdowson, M.
Citation: Acta Geologica Sinica, vol.81(1), 99-112p.
Issue Date: 2007
Publisher: Geological Society of China
Abstract: Mid-Ocean Ridge Basalts (MORB) from Northern Central Indian Ridge (NCIR) were recovered between latitudes 30 and 110S and are olivine tholeiite with higher abundances of K and Rb. They are of typical transitional MORB (T-MORB) variety and appear to have been generated from an enriched mantle peridotite source. The primitive NCIR MORBs having #Mg > 0.68, are the product of partial melting at an estimated pressure of ~10 kbar. It is inferred that the magma was subsequently modified at a pressure >10 kbar by crystal fractionation and spinel was the first mineral to crystallise followed by separation of relatively Fe-rich olivine with subsequent decrease in pressure. During progressive fractionation at lower pressure (between 10-5 kbar), the bulk composition of the magma became systematically depleted in MgO, and enriched in FeOt, TiO2, P2O5 and Na2O. There was, however, limited gradual depletion in Al2O3 and CaO, and concomitant enrichment in K2O. With the progressive fractionation, these basalts became gradually enriched in V, Co, Y, Zr and to some extent in Sr, and depleted in Ni and Cr. In addition, the SREE of magma also increased with fractionation, without any change in (La/Yb)N value.
Document type: Article
Copyright: An edited version of this paper was published by Geological Society of China. © [2007] China Academic Journal Electronic Publishing House. In case of objection from publisher for the author version, it will be removed without any notification.
URI: http://drs.nio.org/drs/handle/2264/605
Appears in Collections:Geology & Geophysical Sciences

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