نتایج جستجو برای: 5 si therefore the host rocks
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Scientists from the U.S. Geological Survey are evaluating the potential for undiscovered sulfide deposits containing varying amounts of nickel, copper, platinumgroup metals, and cobalt in the Lake Superior region as part of an ongoing effort to assess the mineral potential of the United States. Similarities between rocks of the Midcontinent rift and rocks that host the Voisey Bay nickel-copper-...
when we return to the concept of poetry and the age-old discussion about the uselessness or the usefulness of the poets to the private and public state of human beings, originating from plato and aristotles views about poets respectively, there emerges the question of the role of poetry in human beings lives. in the same manner, with the advance of technology and the daily progress and improvem...
kuh-e-faryadoon and kouli kosh iron deposits are hosted by regional metamorphic rocks of sanandaj-sirjan zone around deh-bid area. plugs and domes of acid rocks protrude these metamorphic rocks. a mylonitization event is super imposed on acid rock and metamorphic complexes. field, petrological and geochemical studies have shown that (1) iron mineralization have occurred during mylonitization in...
abstract the first purpose of this study was to investigate the effect of consciousness-raising (c-r) activities on learning grammatical structures (simple present tense in this case) by iranian guidance school efl learners. the second one was to investigate the effect of gender on learning the simple present tense through c-r activities and tasks. finally, this study aimed to investigate the ...
The garnet calc-silicates at Baba-Nazar are located in the NE of Takab, Sanandaj- Sirjan zone. Anhedral to euhedral green colored garnets is a characteristic feature of these Calc-silicates. Mineral chemistry shows that garnets are Andradite- Grossular and contain more than 13% uvarovite. The high chromium content garnet, Cr-Spinel that have relatively Cr rich core than the rim, sulfide opaque ...
today, scouring is one of the important topics in the river and coastal engineering so that the most destruction in the bridges is occurred due to this phenomenon. whereas the bridges are assumed as the most important connecting structures in the communications roads in the country and their importance is doubled while floodwater, thus exact design and maintenance thereof is very crucial. f...
The quartz-aluminosilicate veins in the Hamadan region consist of quartz with one, two or three polymorphs of aluminum silicate )andalusite, kyanite and sillimanite(. In some veins other accessory minerals (i.e. garnet, chlorite, muscovite, staurolite, biotite and plagioclase) are present. The petrogenesis of these veins and their country rocks have been previously described; this paper studies...
The polar desert is one of the most extreme environments on Earth. Endolithic organisms can escape or mitigate the hazards of the polar desert by using the resources available in the interior of rocks. We examined endolithic communities within crystalline rocks that have undergone shock metamorphism as a result of an asteroid or comet impact. Specifically, we present a characterization of the h...
Osmium isotope compositions and concentrations of Re, platinum group elements (PGE), and Au were determined for host peridotites (serpentinites and harzburgites) and hydrothermally altered ultramafic wall rocks associated with Mother Lode-type hydrothermal gold-quartz vein mineralization in the Alleghany district, California. The host peridotites have Os isotope compositions and Re, PGE, and Au...
Thermal history and apatite fission-track ages were determined for the Kaleybar, Razgah and Bozqush alkaline intrusions which display Eocene-Oligocene stratigraphic age. These subduction-related intrusions are located in the Alborz-Azarbaijan magmatic belt which is characterized by a Paleogene magmatic flare-up associated with extensional/transtensional tectonism. The mean of Uranium content an...
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