نتایج جستجو برای: basaltic composition
تعداد نتایج: 261472 فیلتر نتایج به سال:
Water-rock interactions within the seafloor are responsible for significant energy and solute fluxes between basaltic oceanic crust and the overlying ocean. Permeability is the primary hydrologic property controlling the form, intensity, and duration of seafloor fluid circulation, but after several decades of characterizing shallow oceanic basement, we are still learning how permeability is cre...
The soils at the Opportunity site are fine-grained basaltic sands mixed with dust and sulfate-rich outcrop debris. Hematite is concentrated in spherules eroded from the strata. Ongoing saltation exhumes the spherules and their fragments, concentrating them at the surface. Spherules emerge from soils coated, perhaps from subsurface cementation, by salts. Two types of vesicular clasts may represe...
Introduction: Secondary minerals identified by Mars Science Laboratory (MSL), together with their sedimentological and stratigraphic context, provide an unprecendented opportunity to constrain the nature of martian fluids and habitability. One of the main targets for the MSL mission within the new Extended Mission is the Hematite Ridge on the north, lower slopes of Mt. Sharp (Aeolis Mons). This...
The studied volcanic and pluton rocks are located in west of Nir city in the Ardebil Province and south of Sabalan volcano. Volcanic rocks in the studied area are display basaltic to trachy-andesite composition with microlitic porphyry texture. The main minerals of basalt to trachyandesite rocks are plagioclase, pyroxene and olivine. Bordering to volcanic units, pluton of microgabbroic to micro...
Plio-Quaternary potassic to high potassic basaltic rocks are found in northern part of Uromieh-Dokhtar Magmatic Arc in NW Iran. The mineralogical composition of these rocks characterized with phenocrysts of Cpx, phlogopite, leucite and olivine in groundmass of plagioclase, sanidine, Cpx and biotite. Phlogopite phenocrysts display a euhedral platy form with reaction rims. Based on the Internatio...
Oceanic basalts host diverse microbial communities with various metabolisms involved in C, N, S, and Fe biogeochemical cycles which may contribute to mineral and glass alteration processes at, and below the seafloor. In order to study the microbial colonization on basaltic glasses and their potential biotic/abiotic weathering products, two colonization modules called AISICS ("Autonomous in situ...
Volcanic cinder, also known as scoria, is an extrusive igneous rock that forms when gas-rich magmas of basaltic or andesitic composition cool quickly. It typically dark in color, ranging from black to red depending on its chemical composition. Sometimes fresh cinder samples show a variety shiny metallic colors surface blue gold silver. The origin these has remained unknown up now. Cinder erupti...
Introduction: The nature, origin and evolution of Mars' Noachian crust is relatively unknown [1]. Detailed analyses of meteorites point to an early differentiation event for the planet but the only rock definitively of Noachian age is the Martian meteorite; ALH84001, comprised of >95% orthopyroxene [2]. Our understanding of the composition of the Martian crust is derived mostly from Amazonian-a...
We report the oxygen isotope composition of olivine and orthopyroxene phenocrysts in lavas from the main magma types at Mt Shasta and Medicine Lake Volcanoes: primitive high-alumina olivine tholeiite (HAOT), basaltic andesites (BA), primitive magnesian andesites (PMA), and dacites. The most primitive HAOT (MgO [ 9 wt%) from Mt. Shasta has olivine dO (dOOl) values of 5.9–6.1%, which are about 1%...
introduction the study area is located in the shurab area that is about 50 km southeast of qom. volcanic rocks of the shurab area have basaltic composition that is associated with salt and marl units. igneous rocks of the shurab area have not been comprehensively studied thus far. clinopyroxene composition of volcanic rocks, and especially the phenocrysts show magma chemistry and can help to id...
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