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We present the first measurement of bioavailable strontium (87Sr/86Sr) and lead (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) isotope ratios from five cattle bones and one soil sample from Erenda, a Chalcolithic site in coastal east India. Bioavailable 87Sr/86Sr of bones differ from that of the soil. A similar Pb isotope ratio of bones to the soil indicates insignificant diagenesis and local origin of the cattle. Our result suggests a potential influence of marine Sr in modifying the bioavailable 87Sr/86Sr ratio, although the current coastline is 30 km from the site. The finding has implications in archaeological, geological, environmental and ecological research. [ABSTRACT FROM AUTHOR]

• From geochemical proxies, the present study deciphers the addition of a northern (ophiolitic) provenance during Subathu sedimentation as opposed to the sole cratonic input in the case of Nilkanth sedimentation in a passive margin basin setup. The Nilkanth sedimentation was terminated by Cenomanian. • The sediments of the Subathu Formation, particularly Subathu shales, with anomalous Ni (159 ppm) and Cr (301 ppm) concentrations substantiate the addition of an ophiolitic provenance from the north (the Kohistan-Dras Island arc including granitic plutons in the arc roots). • The detrital zircon age data from both Nilkanth and Subathu Formations justify the contention; whereas ∼100 and 120 Ma aged grains from the Nilkanth Formation suggest cratonic input from the south, documentation of ∼91 Ma zircon grain from the Subathu sandstone bear undoubted indication for an additional sediment source present in the north. • The evolution of the Subathu basin in the Garhwal foreland spanned over a period of ∼25 Ma. The fore-bulge created around 55 Ma with the collision between the Indian and Eurasian plates paved the way for foreland sedimentation. The present study involving the sediments of Nilkanth and Subathu formations from the Himalayan foreland basin in Garhwal region, NW-Himalaya, Uttarakhand, India focuses on the tectono-sedimentary evolution of the basin in relation to the India-Eurasia collision using sandstone petrography, sediment geochemistry and detrital zircon geochronology. Geochemical proxies including i) higher concentrations of MgO, Ni, Cr, ii) enriched LILE and LREE and iii) flat HREE in Subathu litho-succession as compared to the Nilkanth mixed clastic-carbonate succession , allowed proposing a northern arc-related supply (in addition to cratonic source) for the Subathu Formation as opposed to supply only from the cratonic side in case of Nilkanth Formation. The presence of ∼90 Ma youngest zircon grain in Subathu sandstone attests to the claim of detrital supply in the Subathu basin from the north. The idea also gets support from the chemical distinction between sandstone samples of the two formations and their tectonic set-ups inferred therefrom. Whereas the upper Cretaceous Nilkanth Formation, deposited in a passive margin set-up at the leading edge of the northward advancing Indian plate, between ∼125 and 100 Ma and received detritus from the Indian peninsula, collision and forebulge formation resulted in the transgression that triggered Subathu sedimentation with the onset of detritus supply from the tectonically uplifted orogen in the north by Late Paleocene. [ABSTRACT FROM AUTHOR]

A N-S trending, lenticular, and dismembered ultramafic unit is found emplaced within the multiply deformed metapelites of the North Singhbhum Mobile Belt, belonging to the Singhbhum Craton, eastern India. Their occurrence in an orogenic belt, lack of evidences of intrusive activity and close proximity to the Singhbhum Shear Zone suggest emplacement by thrust control. These rocks have experienced extensive serpentinization which has obscured and obliterated some of the features of the protolith. Relict areas of the Bangriposi wehrlite rocks indicate that the protolith might have been a cumulate clinopyroxene-dunite/wehrlite from an oceanic magma chamber. Detailed petrography and mineralogy reveal numerous metasomatic features which are separate from the serpentinization event: (i)Very high Ni-content of the relict olivines which does not correlate with Fo contents, (ii) Presence of secondary clinopyroxene (Cpx2) rims around primary olivine and replacing primary clinopyroxene (Cpx1), which have major and trace element compositions similar to clinopyroxenes from diopsidites of crustal origin (iii) Occurrence of secondary calcic hornblendes as tiny blebs within the Cpx2 rims (iv) Occurrence of secondary Mg-chlorite as interstitial patches between olivine rimmed by Cpx2 and inter-mixed with antigorite in the matrix, (v) Modifications of original Cr-spinels to ferri-chromite cores rimmed by magnetite. These features indicate these rocks have experienced fluid-rock interaction at temperatures above the serpentinization process. Primary Cpx1 grains exhibit elevated LREE compositions and can either reflect effects of cryptic metasomatism or crystallization from an enriched melt. Both groups of clinopyroxenes exhibit LILE enrichment and HFSE depletion. P-T estimates from Cpx1 and Cpx2 yield values of ~1200 °C and 0.5–1.2 GPa. The calcic hornblendes provide more realistic estimates of ~1000 °C and ~ 1.0 GPa, which suggest that the Cpx2 + hornblende assemblage formed during high temperature fluid-rock interaction. Presence of interstitial chlorite, chlorite+antigorite in the matrix and Cr-spinel recrystallization suggests successively decreasing temperatures during the fluid-rock interaction episode. Modeled trace element characteristics of fluids which are supposed to be in equilibrium with Cpx2 show similarities with high-temperature, ore-forming basinal brines. Similar basinal brines formed Cu-U ores in the Singhbhum Shear Zone and was likely the metasomatic agent of the Bangriposi wehrlite rocks. These rocks were originally cumulate ultramafic units from an oceanic crustal magma chamber, which experienced prolonged fluid-rock interaction in a retrogressive regime, until its emplacement as a dismembered unit in an orogenic belt. • Dismembered serpentinized wehrlite found emplaced in mobile belt metasediments. • Evidence of prolonged high temperature fluid-rock interaction in retrogression • Secondary clinopyroxene chemically similar to diopsidites • Protolith was a cumulate ultramafic rock belonging to mid to lower oceanic crust. • Modeled metasomatic fluids similar to ore-forming basinal brines [ABSTRACT FROM AUTHOR]