Little is known about the fluids or the microbial communities present within potentially vast hydrothermal reservoirs contained in still-hot volcanic ocean crust beneath the flanks of the mid-ocean ridge. During Alvin dives in 2002, organic material attached to basalt was collected at low, near-ambient temperatures from an abyssal hill fault scarp in 0.5 Ma lithosphere on the western ridge flan...

The North Tabriz Fault is seismologically an active fault with current right lateral strike-slip movements. Restricted mafic to intermediate Late Cretaceous igneous rocks are exposed along the North Tabriz Fault. Whole rock samples and clinopyroxene phenocrysts geochemistry were studied in order to characterize the petrogenesis of these mafic rocks and their possible relation to an oceanic crus...

Bimodal volcanism in the Santa Maria Province of west-central California occurred when segments of the East Pacific Rise interacted with a subduction zone along the California margin during the Early Miocene (about 17 million years ago). Isotopic compositions of neodymium and strontium as well as trace-element data indicate that these volcanic rocks were derived from a depleted-mantle (mid-ocea...

B12A-0755. Langmuir, C. H., J. F. Bender, and R. Batiza (1986), Petrolo-gical and tectonic segmentation of the East Pacific Rise,5300–14 300N, Nature, 322, 422–429, doi:10.1038/ 322422a0.Leybourne, M. I., and N. A. Van Wagoner (1991), Heck and Heckle seamounts, northeast Pacific Ocean: High extrusionrates of primitive and highly depleted mid-ocean ridge basalt on off-ridge s...

The Kermanshah ophiolite complex is a part of the Mediterranean–Zagros–Oman Tethyan ophiolites, located in the structural–tectonic zone of western Iran in the northern part of the Zagros main thrust. Doleritic sheeted dykes are well exposed within the ophiolite in the south of Sahneh. These dykes contain high MgO, Na2O, low TiO2 (2O5, and K2O contents, and high FeOt/MgO and LILE/HFSE ratios. Th...

This contribution assesses the availability of catabolic energy for microbial life during water-rock reactions in the flanks of mid-ocean ridges, where basaltic and ultramafic rocks interact with circulating seawater. In addition to equilibrium thermodynamic computations, results for kinetic reaction paths are presented. In these calculations, it is assumed that dissolution of olivine and basal...

The subarctic North Atlantic Ocean has experienced a complex and gradual magmatic evolution, including continental breakup, mature seafloor spreading, episodic ridge jumps. Here, we present new in situ major-element, trace-element, Sr isotopic compositions for minerals (olivine, clinopyroxene, plagioclase) from the Jan Mayen microcontinent (Integrated Drilling Program [IODP] Sites 907 985), Rey...