نتایج جستجو برای: felsic composition
تعداد نتایج: 260277 فیلتر نتایج به سال:
New zircon U-Pb-Hf-O isotope, whole rock geochemical and Sr-Nd-Pb isotope data of Variscan felsic to intermediate rocks from the Odenwald-Spessart basement, Mid-German Crystalline Zone, Germany are presented. Peraluminous, high-K calc-alkaline S-type granite in eastern Odenwald basement (Group 1 rocks) formed by partial melting lower crust at c. 425 Ma. Their composition indicates presence sedi...
Abstract The Juomasuo Au–Co deposit, currently classified as an orogenic gold deposit with atypical metal association, is located in the Paleoproterozoic Kuusamo belt northeastern Finland. volcano-sedimentary sequence that hosts was intensely altered, deformed, and metamorphosed to greenschist facies during 1.93–1.76 Ga Svecofennian orogeny. In this study, we investigate temporal relationship b...
Abstract The mineralogy, bulk sediment geochemical composition, and U–Pb ages of detrital zircons retrieved from the Barra del Tordo (Tordo) Tesoro beach sediments in northwestern Gulf Mexico were analyzed to determine their provenance. are mainly composed quartz, ilmenite, magnetite, titanite, zircon, anorthite. weathering proxies such as Chemical Index Alteration (CIA), Weathering (CIW), Plag...
Landslides in tropical and sub-tropical regions are generally associated with weathered rock profiles which often possess chemical and mineralogical heterogeneities at materialand mineral-scales. Such heterogeneities reach a climax by the occurrences of oxyhydroxideand clayrich zones. Weakness and low permeability of these zones makes them ideal for the development of slip zones along which lan...
Seismic structure beneath the contiguous U.S. was imaged with multimode receiver function stacking and inversion of Rayleigh wave dispersion and ellipticity measurements. Crust thickness and elevation are weakly correlated across the contiguous U.S., but the correlation is ~3–4 times greater for separate areas east and west of the Rocky Mountain Front (RMF). Greater lower crustal shear velociti...
Over summer 2017, I continued my research on dikes emplaced during the waning stages of the Neoproterozoic-Ordovician Ross Orogen, a continental arc along the present day location of the Transantarctic Mountains in Antarctica. The dikes intrude calc-alkaline plutons constituting the main intrusive phase as well as metasedimentary rocks formed during early stages of orogenesis. These dikes compr...
Large impacts provide a mechanism for resurfacing planets through mixing near-surface rocks with deeper material. Central peaks are formed from the dynamic uplift of rocks during crater formation. As crater size increases, central peaks transition to peak rings. Without samples, debate surrounds the mechanics of peak-ring formation and their depth of origin. Chicxulub is the only known impact s...
: Despite that, in the Alvand complex, the mafic-intermediate rocks (gabbros, diorites and tonalites) are mostly older than felsic rocks (granodiorites and monzogranites), and mineralogical and geochemical discontinuity is seen between them, there are evidence that indicate they have sometimes been co-existed. With the studies on field relationship of rocks, xenocrysts assemblages, synplutonic ...
The Kashmar granitoid (43.5–42.4 Ma) forms an extensive part of iron–oxide type magmatic belt in northern side of the Doruneh Fault. It includes plutons of tonalite, granodiorite, granite and alkali feldspar granite which are metaluminous (ASI ≤ 1) in nature. They contain dominantly felsic minerals, representing I–type granites with low–temperature and low–pressure characteristics. According to...
در این پایان نامه عملگرهای ترکیبی و ضربی را که بوسیله نگاشتهای عملگر مقدار روی فضاهای بوخنر (لورنتس بوخنر و پایا بازارایشی بوخنر ) تولید می شوند را موردمطالعه قرار داده، بسته بودن برد، فشردگی و طیف آنها را بررسی می نماییم. در ضمن این پایان نامه براساس مرجع زیر تنظیم شده است. s. c. arora, g. datt and s. verma, multiplication and composition operators on lorentz-bochner spaces, osaka j. math. 4...
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