نتایج جستجو برای: the lower triassic rocks indicate
تعداد نتایج: 16087334 فیلتر نتایج به سال:
Abstract The petrogenesis and evolution process of continental arc magmatism provide insight into discovering the formation differentiation crust. Therefore, geochemical, isotopic, mineralogical analyses were conducted for coeval igneous rocks in Tengchong Block to clarify their magmatic systems. Middle Triassic appinites Block, southeastern extension Tibet, generated at subduction setting with...
Razdar ultramafic–mafic complex is located in south of Kerman province and contains ultramafic (dunite with chromitite, lherzolite, wehrlite, websterite and olivine websterite) and mafic (gabbro) rocks. The most important minerals in this complex are olivine, chromospinel, orthopyroxene, clinopyroxene, plagioclase and amphibole. Mineralogical studies indicate that chemical composition of these ...
: KC5 copper exploration prospect is located 80 Km to the northwest of Bardaskan and 4 Km to the Northeast of Dahaneh Siah copper mine in Khorasan Razavi. KC5 and Dahaneh Siah areas belong to Sabzevar geological Zone. Copper mineralization is observable mainly as secondary minerals such as Malachite and Chlorite which fills joints and fractures in a faulty contact at the boundary of the volcani...
arghash – ghasem-abad area in ne iran is located in the rim of the sabzevar structural zone. tertiary outcrops include granite and quartz monzodiorite porphyry associated with dacite and andesite volcanic rocks. in the study area, quartz gabbro and quartz monzodiorite dykes intruded the older rocks. granite and volcanic rocks host au-sb-bearing quartz-calcite veins. mineralized veins are mainly...
Concentrations of sulfur and carbon, and isotopic compositions of sulfur were determined in sedimentary rocks from a section across the terrestrial Permian^Triassic (P^Tr) boundary in the northern Karoo Basin, South Africa. High concentrations of sulfide produced by sulfate-reducing bacteria were found in the sedimentary rocks at and just below the perceived P^Tr boundary. The ratios of organic...
We welcome the examination by Marshall (1) of our study (2), particularly his corrected statistical analysis of confidence intervals on stratigraphic ranges, which we accept. We believe, however, that in the process he has misinterpreted both our original data and his own reanalysis. We argued for both gradual and abrupt aspects to the Permian-Triassic (P-T) extinction, whereas Marshall suggest...
Outcrops of the Upper Ordovician igneous rocks, as basaltic lava and microgabbroic dyke and sill, present within the Abarsej and Ghelli formations in north and southwest of Shahrood. These rocks have basaltic, trachybasaltic and basaltic trachyandesitic composition with alkaline nature. Their parallel patterns on the primitive mantle and chondrite normalized spider diagrams indicate the common ...
SahebDivan porphyry copper system is located in Alborz-Azarbaijan magmatic zone at northwest Iran. Based on geological surveys, petrographic and geochemical studies, indicated that mineralized stock in this system mainly cosists of granodiorite, diorite and monzonite rocks. These rocks are peraluminous and belong to high-K calc-alkaline and shoshonitic magma series and plotted in the field of I...
The Ghoshchi batholith, ~150 km2 in size is a granitoidic pluton, which intruded the Permian country rocks, in Sanandaj-Sirjan Zone, NW Iran. This granitoidic pluton is covered by Oligocene-Miocene sedimentary rocks known as Qom Formation. The Ghoshchi batholith comprises five plutons with following compositions: (a) gabbro-diorite (b) biotite granite, (c) alkali granite, (d) syenites, and (e) ...
The conglomerates of Sangestan Formation (Lower Cretaceous) have been metamorphosed in the vicinity of the leucogranitoid rocks of the Shir-Kuh batholith and have created the mineral assemblage of garnetepidote- quartz-calcite-pyrite in the contact halo. Following the contact metamorphism, hydrothermal alteration (pyrite formation and silicification) has likely occurred. Based on the trace...
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