نتایج جستجو برای: central iranian volcanic belt
تعداد نتایج: 536946 فیلتر نتایج به سال:
A geophysical transect across the central Gulf of Mexico coastal plain shows that the early Paleozoic continental margin of southern Laurentia is preserved in a nearly pristine state beneath younger strata that were emplaced during the late Paleozoic Ouachita orogeny and formation of the modern Gulf of Mexico coastal plain. The thickness of the crystalline crust decreases abruptly across the ma...
Modelling suggests that the UV radiation environment of the early Earth, with DNA weighted irradiances of about three orders of magnitude greater than those at present, was hostile to life forms at the surface, unless they lived in specific protected habitats. However, we present empirical evidence that challenges this commonly held view. We describe a well-developed microbial mat that formed o...
The Muteh gold deposit (NE of Golpaygan) in the central part of intrusive-metamorphic belt of Sanandaj-Sirjan zone comprises NW-SE trending gold-quartz vein occurred in metamorphic complex. Gold mineralization is associated with quartz veins that formed during regional deformation across the mylonitic zones in metamorphic rocks of predominantly meta-volcanic, gneiss and schist. The sulfidation ...
[1] Broadband data from the Meso-America Subduction Experiment (MASE) line in central Mexico were used to image the subducted Cocos plate and the overriding continental lithosphere beneath central Mexico using a generalized radon transform based migration. Our images provide insight into the process of subducting relatively young oceanic lithosphere and its complex geometry beneath continental ...
[1] Based on analysis of data from a trans-Mexico temporary broadband seismic network centered on Mexico City, we report that the subducting Cocos Plate beneath central Mexico is horizontal, and tectonically underplates the base of the crust for a distance of 250 km from the trench. It is decoupled from the crust by a very thin low viscosity zone. The plate plunges into the mantle near Mexico C...
The South Armenian Block (SAB) belongs to the Lesser Caucasus, and it is located where Central Tethyan belt bends from an EW orientation in Turkey NW-oriented Iranian tectonic zones. Magmatism these belts result of convergence, collision post-collision evolution Arabian plate with Eurasian margin. An exhaustive study including whole-rock major, trace element, radiogenic isotope (Sr, Nd, Pb) dat...
Relevant data on the structure and composition of crystalline basement in Central México can be found by means plutonic, metamorphic, sedimentary xenoliths transported Neogene Quaternary volcanic eruptions within Trans-Mexican Volcanic Belt (TMVB). We present detailed major oxide trace elements concentrations, isotopic analysis thermobarometric estimations for a granitic xenolith an Early Mioce...
Investigations have been undertaken to provide constraints on the nature of geochemically active processes in the mantle and their effects on mantle evolution and magma generation. Three types of approaches have been implemented: (1) To study isotopic systematics and trace element abundances in young, mantle-derived volcanic rocks, which, because of their tectonic setting, had little or no chan...
The Makran Subduction Zone is the primary seismic/tsunami hazard of northwestern Indian Ocean, but little known its on-shore seismic structure. We derived a shear wave velocity model extending to 100 km depth beneath ∼400 km-long profile oriented parallel convergence vector Arabian Sea Plate. Receiver function/surface analysis shows that average structure in coastal region comprises ∼22–28 km-t...
The Central Asian Orogenic Belt (CAOB) is the world’s largest accretionary orogenic belt, and its formation related to closure of Paleo-Asian Ocean (PAO). However, time style PAO remain controversial. To address these issues, this paper presents zircon U-Pb dating, whole-rock geochemistry Lu-Hf isotope analyses volcanic rocks in Faku-Kaiyuan area on northern margin North China Craton. results s...
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