the kasian volcanic body is located in the eastern margin of the zagros thrust belt, close to the sanandaj-sirjan metamorphic zone. these volcanic rocks are mainly composed of andesite and andesite-basalt rocks with porphyritic, hypocrystalline porphyritic, hyalo-porphyritic and hyalo-microlitic porphyritic textures. analyses of the distributions of major, rare earth and trace elements reveal a...

The Early Paleozoic Lachlan Fold Belt of eastern Australia is widely regarded as an ancient convergent plate margin beneath which paleo-Pacific (Panthalassic) oceanic lithosphere was continuously subducted. It is cited as the type example of a retreating accretionary orogeny. However, sandstone compositions, the sedimentological nature and timing of chert accumulation and overall stratigraphic ...

Abstmct: Island arc lavas from New Britain and the Marianas have 143 Nd/144 Nd similar to other oceanic basalts and distinctly different from continental flood basalts and thus appear to be derived from a high Sm/Nd, light-REE-depleted reservoir. Consideration of both Nd and Sr isotopes suggests seawater involvement in the generation of some island arc lavas and thus indicates that they may be ...

The Ophiolite Terrane of the Southern Chewore Inliers is comprised of two related, but lithologicallyand geochemically-distinct groups. The Maunde Ophiolite Group comprises a suite of lithologies similar to those within Phanerozoic ophiolites. The Kaourera Island Arc Group contains a suite of silica-variable, extrusive lithologies similar to those within present-day island-arcs. Geochemical ana...

Chaldoran area in NW of Iran has Mesozoic oceanic crust basement. The studied rocks of this region can be divided into three groups: ophiolitic gabbros and pillow lavas, ophiolitic volcanoclastics and Eocene lava flows. Ophiolitic mafic rocks show continental volcanic arc natures and Eocene lava flow shows OIB-like nature. During the Mesozoic,the Chaldoran region was situated in the active cont...

Abstract Ophiolitic mélanges in Anatolia represent Mesozoic subduction-accretion complexes, which are unusually poor land-derived coarse-clastic rocks. A segment of the ophiolitic mélange Beynam region south Ankara was studied. The consists three accretionary units (AUs), distinguished by lithology, structure, age and geochemistry. At base there is a serpentinite mélange, overlain semi-intact U...

chaldoran area in nw of iran has mesozoic oceanic crust basement. the studied rocks of this region can be divided into three groups: ophiolitic gabbros and pillow lavas, ophiolitic volcanoclastics and eocene lava flows. ophiolitic mafic rocks show continental volcanic arc natures and eocene lava flow shows oib-like nature. during the mesozoic,the chaldoran region was situated in the active cont...

Abstract Subduction of oceanic lithosphere is a diagnostic characteristic plate tectonics. However, the geodynamic processes from initiation to termination subduction zones remain enigmatic mainly due scarcity appropriate rock records. We report first discovery early Paleozoic boninitic blueschists and associated greenschists eastern Proto-Tethyan North Qilian orogenic belt, northeastern Tibet,...

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 ...