[1] Abstract: Peridotite xenoliths erupted in late Miocene basalts ( 8 Ma) in the central Sierra Nevada sample a lithosphere that is vertically stratified in terms of age and thermal history. The deeper portions ( 45–100 km) have asthenospheric osmium isotopic compositons and possess textural and chemical evidence for cooling from >11008 to 700–8208C. The shallower portions (<60 km) have unradi...

The composition of continental subduction-zone fluids varies dramatically from dilute aqueous solutions at subsolidus conditions to hydrous silicate melts at supersolidus conditions, with variable concentrations of fluid-mobile incompatible trace elements. At ultrahigh-pressure (UHP) metamorphic conditions, supercritical fluids may occur with variable compositions. The water component of these ...

Decompression melting of the upper mantle produces magmas and volcanism at Earth's surface. Experimental petrology demonstrates that presence CO2 H2O enhances peridotite anywhere within down to approximately 200–300 km depth. The melts with compositions ranging from carbonate-rich silicate-rich unavoidably affects geophysical signals retrieved mantle. Geochemical investigations erupted intrapla...

Martian basalts identified by rover in-situ analyses and the study of meteorites represent a direct link to melting process in planet's interior can be used reconstruct composition mantle estimate its temperature. Experimentally calibrated numerical models are powerful tools systematically search for compositions conditions that produce melts similar primary basalts. However, currently availabl...

Abstract Mantle peridotites from the External Liguride Jurassic ophiolites (Northern Apennines, Italy) show diffuse occurrence of pyroxenite bands, recording melt migration and crystallization at lithosphere-asthenosphere boundary, during old, pre-Jurassic stages their subcontinental lithospheric mantle evolution. We present coupled microstructural geochemical study profiles across various type...

The metamorphic sole rocks at the base of mantle peridotites from the Mersin ophiolite consist of amphibolites and metasedimentary lithologies. Mineral parageneses in the metamorphic sole rocks exhibit amphibolite and greenschist facies assemblages. Geothermobarometric studies based on mineral assemblages and chemical compositions of minerals indicate that average metamorphic temperature during...

Abstract The iron isotope contrast between mid-ocean ridge basalts and abyssal peridotites is far greater than can be explained by mantle melting alone. Here we investigate a suite of magma chamber rocks sampled the Ocean Drilling Project Hole 735B in Atlantis Bank Indian Ocean. We report major trace element geochemistry from these measure their compositions to potential role fractional crystal...

Chromite oxidation during serpentinization of host peridotites is a well-documented process. Detailed compositional characterization chromites and Cr-rich spinels from three geotectonic settings provided the basis for this study, focused on comparison their patterns as means to evaluate relative mobility spinel components serpentinization-related in those different contexts, namely: (i) tectoni...

New Caledonia is one of the world’s best-exposed subduction/obduction complexes and central to understanding geodynamic evolution southwest Pacific region. We present new geochemical Ar/Ar age dates from in situ eruptive sequences La Conception basaltic-andesite lavas (ca. 29.12 Ma) correlate generation these with Saint Louis Koum/Borindi Massifs 24 provide information on magmatic processes ope...

the nain and ashin ophiolites are located in northeastern isfahan province, in western central-east iranian microplate. pillow lavas are one of the most significant cretaceous rock units. the lower partial melting degree in mantle peridotites of ashin ophiolite, and the derived melt by melting their clinopyroxene caused a more basic (basalt) and enriched nature for the ashin pillow lavas, where...