sahand volcanic-sub-volcanic dome, along with several other magmatic domes in northwest iran and the southern part of tabriz fault show adakitic geochemical characteristics. sahand dome has mainly dacitic composition. the sio2 content and mg number of sahand dome range from 64 to 73 wt% and 27 to 57 respectively. sahand dome can be classified as high silica adakitic (hsa) type. the rocks studie...

in the centeral iranian volcanic belt (civb), north-west of shahre-babak, in area of javazm, dehaj and khabr, about 20 plutonic porphyritic tonalitic to granodioritic masses (1-50 km2) are intruded into a varity of rock sequences from eocene to early miocene in age. tonalitic and granodioritic rocks are some part of dehaj-sardoieh belt and having early miocene age. the civb contains intrusive a...

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...

we present new whole major and trace elements data for a suite of adakitic dacite to rhyolite rocks from the sahand region. these rocks formed in the pliocene to pleistocene during the the collision between the arabian and eurasian plates following subduction of neo–tethys ocean. these subvolcanic intrusions were emplaced into late cretaceous and eocene sedimentary، volcano–clastic and volcanic...

the study of tectonic evolution of the tethyan and se asian regions indicates that these tworegions have each passed through southwardly progressing sequences of similar tectonic events. both regionshave experienced a southward island-arc subduction and back-arc spreading leading to continentaldetachment from gondwanaland, with an earlier southward island arc subduction of palaeotethys (tethyan...

Afghanistan sits on the junction between the Indo-Australasian and Eurasian crustal plates and is composed of a series of terranes (Figure 1) that broke away from the main Gondwana supercontinent before colliding with and being accreted on to the Eurasian plate. The accretionary events began in the Cretaceous and have continued until recent times. The Herat or Hari Rod fault, which runs E-W acr...

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...

The end-Permian mass extinction, ∼252 million years ago, is notable for a complex recovery period of ∼5 Myr. Widespread euxinic (anoxic and sulfidic) oceanic conditions have been proposed as both extinction mechanism and explanation for the protracted recovery period, yet the vertical distribution of anoxia in the water column and its temporal dynamics through this time period are poorly constr...