the kuhshah ultramafic complex is located in the south-east of sanandaj-sirjan metamorphic zone, near the probable remnants of neotethys plate in iran. it consists of highly depleted harzburgites, dunites, chromitite bands and altered gabbros. the ultramafic parts have been intruded by numerous clinopyroxenite dykes and veins. in the harzburgites, there are different generations of olivine, ort...

We report new stepped heating He, Ar, CO2 and water data on a petrogenetically diverse suite of lavas from the Manus back-arc basin, where a plume component has previously been identified. The aim of this study is to evaluate the superimposed effects of degassing and contamination in order to identify mantle source characteristics. CO2 abundances and carbon isotopes in both the vesicle ([CO2] u...

Bulk-rock major and trace element geochemistry of a range of eclogite, garnet blueschist and garnet amphibolite rocks from northern New Caledonia has been determined in order to geochemically characterise subducted oceanic crust. The rocks experienced peak metamorphic conditions of 1.9 GPa and 600 jC and represent excellent samples of oceanic crust that was subducted to depths of approximately ...

Leg 135 of the Ocean Drilling Program drilled and cored eight sites across the Lau Basin and adjacent Tonga Ridge to study the geological evolution of a backarc basin and adjacent oceanic arc and forearc. Six sites (Sites 834, 835, 836, 837, 838, and 839) were drilled within the Lau Basin, each within smaller and narrower (<10 km) north-south fault basins and collectively representing a broad e...

west directed subduction zones show common characteristics, such as low structural elevation, deep trench, steep slab and a conjugate back-arc basin that are opposite to those of the east directed subduction zones. the tectonomagmatic and metallogenic setting of the lut block is still a matter of debate and several hypotheses have been put forward. despite some authors denying the influence of ...