نتایج جستجو برای: ophiolitic
تعداد نتایج: 353 فیلتر نتایج به سال:
Chemistry of detrital garnets, chrome spinels and tourmalines of 30 selected samples in combination with the general heavy mineral distribution from 523 sandstone samples of the Upper Cretaceous to Eocene Gosau Group of the eastern part of the Eastern Alps and the western West Carpathians result in an advanced picture of sedimentary provenance and palaeogeographic evolution of that area. Garnet...
Ophiolitic belt of Northern Sabzevar is invaded by basic, intermediate and acidic post-ophiolitic magmtism as dome, dyke and cone. Microscopically, the texture of the studied samples is porphyric and trachytic. Phenocryst mostly consists of amphibole, feldspar and clinopyroxene. All researchers that have investigated basic to acidic post ophiolitic magmatism of northern Sabzevar have consensus ...
Eastern Birjand ophiolitic complex consist of different rock types of a complete ophiolitic sequence. Three groups of amphiboles which exist in metabasites of this ophiolitic complex are of: calcic amphiboles, such as actinolite-tremolite and magnesio-hornblende; calcic-sodic amphiboles, e.g. vinchite and barroisite; and sodic-amphiboles, e.g., glaucophane, magnesio-riebeckite and ferro-glaucop...
The ophiolitic complex of eastern Birjand consists of various rocks of a complete ophiolitic complex. Except for basaltic pillow lavas which are changed to metabasites such as eclogites and blueschists under metamorphic conditions, all other rock types of an ophiolitic complex could be seen in this sequence. Chemistry of garnets and their zoning patterns indicates the occurrence of subduction i...
Compositional fields for spinels from a wide variety of mafic– a wide range of conditions from mafic and ultramafic ultramafic igneous rock types and tectonic environments have been magmas and, in the case of chromites, are often among determined from a global database of over 26 000 analyses. the first phases to crystallize. They also exhibit a wide These fields are defined using contoured dat...
Six minor alluvial chromite placers (Kolkhoznyi Prud, Verkhne-Yaushevo, Sukhoy Izyak, Bazilevo, Novomikhaylovka, Kiryushkino) and one major littoral placer (Sabantuy) were found in sandy sediments of the Kazanian stage Permian System (Late Roadian Wordian Stages) Southern Pre-Urals. It is shown that morphological features chromian spinels are diverse, which not evidence heterogeneity source. Th...
baft ophiolitic – mélange belt is a part of the ophiolite melange belt of central iran whose genesis is considered as an environment related to tethys subduction at upper cretaceous. major part of intrusive masses of baft ophiolitic – melange form gabbros with the inequigranular texture fine to coarse and pegmatitic, plagiogranites also with inequigranular general texture have been developed wi...
The Surk ophiolitic mélange is located at the south west of central Iran and along the Naein-Dehshir-Baft ophiolitic belt. In petrological sequence, peridotites are nominated the undermost part of rock unit, and then gabbros and volcanic rocks are at the following ranks respectively. The predominant peridotitet of this ophiolitic mélange is harzburgite. Lherzolite that is the primitive mantle r...
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...
the kahnuj ophiolitic complex, a part of the jazmurian ophiolitic belt, is located on the western boundary of the jazmurian depression and is bounded by two major fault systems. there is a well-preserved, ophiolite pseudostratigraphy of early cretaceous to early palaeocene age and has a bearing on the mesozoic development of southeastern part of iran and adjacent region. the kahnuj ophiolitic c...
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