نتایج جستجو برای: Calc-alkaline
تعداد نتایج: 43545 فیلتر نتایج به سال:
the lalezar granitoids crop out within volcanic successions of the urumieh-dokhtar magmatic assemblage (udma). these granitoids have a range from gabbro-diorites to granites in composition. the mineral compositions of the most felsic rocks are characterized by the abundances of na-plagioclase, quartz, alkali feldspar, biotite and hornblende. in the gabbro-diorite rocks, plagioclase (ca-rich), h...
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...
The Pliocene calc-alkaline volcanic rocks are exposed in two areas in southeast and northwest of Isfahan and consist of andesites and dacites. Based on geochemical data and multi- elements pattern, these rocks are medium to high calc-alkaline suite and they show LILE and LREE enriched normalized multi-element patterns, and negative Nb and Ti. Condrite-normalized REE patterns display a steep dec...
The Bazman intrusive rocks are located in northwest of Iranshahr, south of Lut block, and above of Makran subduction zone. The Bazman intrusive rocks are composed of gabbro, diorite, monzodiorite, qurtze monzodiorite, granodiorite and granite. The Composition of clinopyroxenes is in the diopside-augite range and orthopyroxenes are enstatite. The studied amphiboles are classified as calcic (magn...
The clinopyroxene composition of two types of alkaline and calc-alkaline gabbros at Piranshahr pluton was investigated in this study. The major oxides variations are similar in all clinopyroxenes of two types of gabbros and are classified as diopside- augite; but trace element compositions are very different in these two groups. The clinopyroxenes of alkaline gabbros are rich in high field stre...
Smith, D. R. and Leeman, W. P., 1993. The origin of Mount St. Helens andesites. J. Volcanol. Geotherm. Res., 55: 271-303. Mount St. Helens volcano has intermittently produced mainly dacitic products but occasionally erupted a more diverse suite of lavas including basalts and andesites. Petrogenetic relations between these magmas provide insight into the dynamics of the subjacent magma system. M...
Older and younger granitoids are widespread throughout the basement rocks of NE Egypt. Therefore, they are played a significant role in the evolution of the Pan-African crust. The Wadi El Sheikh-Gabal Saint Katherine area comprise three distinctive magmatic granitoid suites, namely: (1) calc-alkaline older quartz monzodiorite-tonalite suite (COG), (2) calcalkaline younger monzogranite suite (CY...
Hornblende occurs in some andesitic and basaltic rocks of calc-alkaline affini1y, where it is commonly associated with olivine. The texture, eruption history, and composition are interpreted to indicate that hornblende commonly forms as a product of reaction between olivine and basaltic and andesitic liquids. The natural hornblendes probably formed within the crust at temperatures between 960o ...
Cenozoic volcanic activity in Morocco started the Miocene and proceeded, after a short break, during Pliocene Quaternary. Calc-alkaline magmatic occurred first was accompanied by eruption of transitional lavas, followed Plio-Quaternary alkali basaltic activity, which emplaced within Neogene sedimentary basins Rif belt its foreland. From calc-alkaline to alkaline magmatism, passing through term,...
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