Abstract Mantle peridotites from three 3 × 3-meter grids sampled at kilometer distances one another in the ca. 497 Ma Leka Ophiolite Complex (LOC), Norway, are examined to investigate chemical and isotopic nature of oceanic mantle domains centimeter scale. The lithology each grid locality is predominantly harzburgite, but includes layers lenses dunite pyroxenite. Major lithophile trace element ...

Abstract Serpentinization of peridotites in Earth’s mantle is associated with the generation hydrogen and low molecular weight organics that could support subsurface life. Studies microbial metabolisms peridotite-hosted environments have focused primarily on methanogenesis, yet DNA sequences, isotopic composition sulfides thermodynamic calculations suggest there potential for sulfate reduction ...

Os-, Nd-, and Pb-isotope measurements were performed on a suite of eleven Kamchatka peridotite mantle xenoliths in volcanics from the southern (Avachinsky) and central (Sheveluch and Kharchinsky) segments of the Kamchatka peninsula. Peridotites with higher Os content (1.3–5.2 ppb) show a narrow Os / Os range between 0.1182 and 0.1272 while the xenoliths with lower Os content (b1 ppb) show a wid...

[1] Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to ≥ 50 m for shipboard multibeam ba...

Xenoliths hosted by Cenozoic volcanic flows and plugs from the Central Sierra Nevada and Eastern Sierra Nevada, Owens Valley, and Inyo Mountains were studied for petrography and thermobarometry. The Central Sierra Nevada suite consists of abundant lower crustal feldspathic granulites, garnet clinopyroxenites, and mantle-derived peridotites and garnet websterites. Mafic crustal assemblages occur...

Mineralogical and geochemical study was performed on peridotite xenolith hosted by amygdaline basalts of Lanzarote Island (Canary archipelago). Their modal composition corresponds to harzburgite. Remarkably, the petrographic rocks is marked presence plagioclase. The isochron shows age 267±35 Ma, which might be initial stage opening a fragment Atlantic Ocean. peridotites were apparently derived ...

[1] Abstract: We studied trace element geochemistry and petrology of the crust-mantle transition zone (MTZ) in the Samail massif of the Oman ophiolite to constrain the location where different primitive magmas mix beneath an oceanic spreading ridge. The MTZ is the deepest location where crystallization took place and thus is an ideal place to determine the compositional diversity of melts leavi...

Orthopyroxene is the second most abundant mineral in upper mantle and, like olivine, can form crystallographic preferred orientations (CPO) during deformation that may influence seismic anisotropy. Here we use a compilation of 21 peridotites which both olivine and orthopyroxene CPOs are preserved to document range CPO types explore their effects on anisotropy peridotites. In addition four previ...

The Lindås Nappe, Bergen Arc, is located in western Norway and displays two high-grade metamorphic structures. A Precambrian granulite facies foliation is transected by Caledonian fluid-induced eclogite-facies shear zones and pseudotachylytes. To understand how a superimposed tectonic event may influence olivine fabric and change seismic anisotropy, two lenses of spinel lherzolite were studied ...