نتایج جستجو برای: alkali basalt
تعداد نتایج: 19800 فیلتر نتایج به سال:
Amphibolite rocks with mylonitic texture exposed in the NE of Yan- Cheshmeh village (SE of Zayandeh-Rud Lake). Mineralogy of rocks include amphibole, plagioclase, quartz, rutile, clinozoesite, chlorite, titanite, biotite and opaque. Amphiboles are seen as fish. Basic igneous rocks are protolith of the amphibolites that have subalkaline nature. Ni (299-370 ppm), Cr (1169-1900 ppm) and SiO2 (44.9...
Sabzevar ophiolitic pillow lavas contain variolitic, porphyritic with microlitic matrix, intersertal and amygdaloidal textures and include plagioclase, clinopyroxene (augite-diopside), olivine, amphibole (magnesiohastingsite) and opaque minerals. The chemical composition of clinopyroxenes show a calc-alkaline magmatic series and a tectonic environment within plate alkaline basalts. Geochemicall...
Eocene volcanic rocks of north Anarak area are as scattered as masses. These rocks cross the Anarak schists and Ashin-Zavar ophiolites but had not metamorphosed them. Their outcrops follow the direction of within the area faults. Mineralogicaly, these rocks are limited in composition from Andesi-Basalt and Andesite to Dacite. These rocks have phenocrysts of amphibole and plagioclase in microcry...
Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that par...
Unraveling a planet's geologic evolution requires knowing what happened and when it happened. Two recent studies of the ages of Martian meteorites illuminate the early and late stages of Martian crust formation. One, by Munir Humayun (Florida State University) and colleagues in Australia and France studied Martian meteorite NWA 7533, an impact melt breccia composed of alkali-rich basalt similar...
Titanium-rich clinohumite and layered structure minerals are observed in kimberlite and as inclusions in pyropic garnets from the Moses Rock dike, a kimberlite-bearing breccia dike in San Juan County, Utah. Associated clinopyroxenes observed as inclusions within similar pyropes and also in kimberlite are estimated to have equilibrated at depths ranging from about 50 to 150 km at modest temperat...
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