By examining the minor and trace element contents of chromites from three intrusions—the Bushveld Complex (South Africa), Stillwater (USA), Great Dyke (Zimbabwe)—and comparing these chromite compositions with those magmas which they could have formed (komatiites picrites) we conclude that ( i) variations in Ti, V, Sc, Ga across stratigraphy individual layers do not support model magma mixing le...

Zoned plutons, composed of dunites, pyroxenites, and gabbroic rocks, have been referred to as the Ural-Alaskan type complexes (UA-complexes) occur in numerous paleo-arc settings worldwide. Many these are source rocks for economic placers platinum-group metals. Thus, it is important understand how UA-complexes form origin behavior elements (PGEs). It widely assumed that result from differentiati...

Mantle xenoliths in basalt and tuffaceous volcanoes at the Shawran Crater, Bir Ali area, along southeastern coast of Yemen are very useful to elucidate nature lithospheric mantle beneath which is characterised by rift tectonic activity volcanism during Pliocene–Quaternary period. The studied mostly fresh showing igneous textures composed mainly spinel harzburgite lherzolite, addition to, less p...

The hydration of mantle rocks occurs at mid-ocean ridges, in subduction zones and ophiolites where it strongly modifies the properties oceanic lithosphere. nanostructure reaction products is poorly constrained, but very important, as controls fluid transport during solid volume increase, influences phase reactivity further fluid/rock interaction low temperature. We image contacts between olivin...

The proposal by Hubbard et al. (1) that "Very High Alumina basalt" ("VHA basalt") may represent an important primary lunar magma type neglects consideration of certain well-characterized high-magnesium highland rocks, among them spinel troctolite from Luna 20 (2) and Apollo 16 samples (3) and dunite from Apollo 17 samples (4), and the possibility that "VHA basalt" may in fact have originated by...

Ancient lunar volcanic deposits, known as cryptomaria, have been detected by remote telescopic and orbital measurements since the 1970s. Cryptomaria are most easily identified by the presence of darkhalo impact craters and are associated with a mare basalt mineralogy, which is indicated by two pyroxene spectral absorption features near 1 μm and 2 μm in the visible to near-infrared (VNIR) wavele...

Ž . Gabbroic sills intruding dunite in the crust–mantle transition zone MTZ of the Oman ophiolite have textures and compositions very similar to those in modally layered gabbros that form the lower part of the gabbro section in the ophiolite, and different from those in non-layered gabbros near the dike–gabbro transition. The presence of gabbroic sills in the MTZ indicates that modally layered ...