the magnesite veins are located in the beni bousera massif (internal rif, morocco), especially in tafidest region about 103 km sw of the tetouan city. they are hosted by perridotite and serpentinite formations.  the aim of this study is to clarify the origin of this type of orre genesis. geochimical study of magnesite ore reveals that is a cryptocrystalline magnesite, formed by the co2-rich hyd...

Interrogating physical processes that occur within the lowermost mantle is a key to understanding Earth's evolution and present-day inner composition. Among such processes, partial melting has been proposed to explain mantle regions with ultralow seismic velocities near the core-mantle boundary, but experimental validation at the appropriate temperature and pressure regimes remains challenging....

TWO different spinels, analyses of which are given, occur in the layered ultramafic rocks at Dawros. Chrome spinel occurs both as gravity-stratified cumulates and as complex orbs, while an Al-rich spinel is both in rocks of the main Dawros magmatic sequence and in an association with an aluminous bronzite, which may originate by recrystallization. It is concluded that while the chrome spinel is...

Abstract Arc magmatism is thought to be driven by peridotite melting in the mantle wedge. Yet pyroxenites are ubiquitous region beneath magmatic arcs. Because they typically have lower solidi temperatures and higher melt productivities compared peridotite, likely play a significant role magma generation. Here, we use Zn/Fe ratios of global database Pliocene–Holocene primitive arc magmas show th...

To constrain further the Mg isotopic composition of the Earth and chondrites, and investigate the behavior of Mg isotopes during planetary formation and magmatic processes, we report high-precision (±0.06& on dMg and ±0.07& on dMg, 2SD) analyses of Mg isotopes for (1) 47 mid-ocean ridge basalts covering global major ridge segments and spanning a broad range in latitudes, geochemical and radioge...