Geochemical Stratigraphy of the Deccan Traps at Mahabaleshwar, Western Ghats, India, with Implications for Open System Magmatic Processes

Geochemical stratigraphy of Deccan flood basalts of the Bijasan Ghat section, Satpura Range, India

“…1) in the Western Ghats range, and the stratigraphic framework of this region is now known quite well from extensive field, geochemical (including isotopic) and palaeomagnetic work (e.g. Cox and Hawkesworth, 1985;Beane et al, 1986;Subbarao, 1988;Lightfoot et al, 1990;Peng et al, 1994). On the basis of geochemical characteristics and field markers, the Western Ghats sequence, with a total stratigraphic thickness of , 3,000 m, has been divided into three subgroups and eleven formations (Table 1).…”

Enriched mantle components in Proterozoic continental-flood basalts of the Cape Smith foldbelt, northern Québec

“…Continental flood-basalts usually have fractionated rare-earth-element (REE) profiles and anomalously low Nb concentrations relative to large ion lithophile elements (LIT..E) and light REE when normalized to primitive mantle compositions (e.g., Cox and Hawkesworth, 1985). Several hypotheses have been proposed to account for this distinctive geochemical signature, including mixing between depleted and enriched mantle sources (Campbell and Griffiths, 1990), crustal contamination (Ellam and Cox, 1989), and combinations of enriched mantle comPQnents and crustal contamination (Arndt and Christensen, 1992 (Lightfoot et al, 1990).…”

“…• element profiles characterized by strong negative Nb and Ta anomalies (with respect to chondrite-normalized LlLE and LREE) as a consequence of crustal contamination (Cox and Hawkesworth, 1985). The PG tholeiitic basalts, however, lack significant Nb and Ta anomalies (Fig.…”

Isotope Geochemistry of Leg 115 Basalts and Inferences on the History of the Réunion Mantle Plume

“…Deccan lavas have 87 Sr/ 86 Sr ratios as high as 0.720, and e Nd as low as < -16, values which, along with such other observations as the presence of crustal xenoliths in some lavas, indicate pervasive contamination of magma by continental crust (e.g., Cox and Hawkesworth, 1985;Mahoney, 1988). Most recent studies have concluded that subcontinental lithosphere was also involved in the genesis of some Deccan lavas, either through partial melting of the lithosphere or through assimilation of the lithosphere by plume-or asthenosphere-derived melts (e.g., Lightfoot and Hawkesworth, 1988).…”