the subduction of the northern part of the tethys is documented by arc magmatism from upper triassic to lower eocene crosscutting the sanandaj-sirjan zone and from upper eocene to plio-quaternary in the urumieh-dokhtar magmatic zone, situated north of the ssz. neyriz ophiolite is part of middle eatern neo-tethyan ocean of mesozoic that geographically is related to ophiolites of nw-se iran, alon...

Lherzolite is one of the main units in the Ab-Bid ultramafic complex from Esfandagheh-HadjiAbad coloured mélange (South of Iran). The complex contains harzburgite, dunite, lherzolite and pyroxenite dykes and the lherzolites mainly occur in the margins. In the field, lherzolites occur as weakly foliated coarse-grained peridotites with shiny pyroxene grains and cut by neumerous pyroxenitic veins....

We performed melting experiments of hydrous pyrolite at pressures from 3 to 8 GPa and temperatures from 1,100°C to 1,800°C to identify the origin of chemical variation in cratonic garnet peridotites with high contents of magnesian orthopyroxene. In hydrous conditions, the stability field of residual orthopyroxene expands relative to olivine above solidus, and the harzburgitic residue contains l...

ONE petrological approach to upper mant le studies is to determine which ultramafic rocks represent mantle material. Ultramafic rocks occur in a variety of field and petrographic associations : in recent reviews, Wyllie [1967b, 1968] outlined eleven petrographic associations, some with subdivisions. In this summary, it is convenient to consider these in four larger groups: (1) layered, stratifo...

The ophiolites of Othris, northern Greece, and Troodos, Cyprus, are of mixed lherzolite-harzburgite and harzburgite sub-type respectively. Within both ophiolites an entire spectrum of harzburgite, plagioclase harzburgite, lhcrzolite and plagioclase lherzolite interpreted respectively as residual and highly, moderately and slightly modified upper mantle has been recognised. Plagioclase lherzolit...

Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and harzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au...

[1] Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of B and Li in serpentinized peridotites from the Feather River Ophiolite (California) indicates that B is enriched in serpentine minerals compared to the whole-rock and less altered olivine grains, while Li in serpentine is depleted or comparable to whole-rock Li. The high B contents of serpentine minerals cor...

Abundant mafic and ultramafic rocks including basalts, komatiitic basalts, and peridotites occur in the Proterozoic Sibao Group, northern Guangxi Province, China. Whereas the basalts are generally pillow lavas, the komatiitic basalts are typically spinifex-textured and, in a few cases, show pyroxene accumulation associated with Ni Cu (PGE) sulfide deposits. The peridotites occur in the lower po...

Article history: Received 17 November 2009 Received in revised form 25 January 2010 Accepted 26 January 2010 Available online 23 February 2010 Editor: R.W. Carlson