نتایج جستجو برای: crustal contamination
تعداد نتایج: 61183 فیلتر نتایج به سال:
Since the onset of plate tectonics, continents have evolved through a balance between crustal growth, reworking, and recycling at convergent margins. The term “reworking” involves re-insertion material into pre-existing volumes, while growth respectively represent gains from losses to mantle. Reworking that occurs in mantle wedge (“source” contamination slab material) or within upper (“path” co...
Quchan- Esfarayen magmatic belt (north of Sabzevar) include Neogene adakitic domes with andesite to rhyolite in composition which is cut by Jurasic sedimentary rocks, Eocene volcano-sedimentary rocks, Miocene sedimentary rocks and even occasionally Peliocene conglomerate. The main minerals of these rocks are plagioclase and amphibole with various textures such as felsitic porphyry, microlitic p...
Ellipsoidal huge granitoidic batholiths of Zahedan, with NW-SE trending, located in south of this city which is intruded in low metamorphosed Eocene flysches (eastern Iran flysch zone). This batholith has two compositional terms: an extensive intermediate-acid term includes diorite - granodiorite with igneous source (I- type origin) and a low extent crustal and hybrid origin acidic term (H-type...
The geochemical signatures like discordant variation of major and trace elements among felsic-intermediate and basic rocks and mafic enclaves of Malayer region on binary variation plots, decreasing values of FeOt, TiO2, MgO, MnO and CaO accompanied with increasing of SiO2 content from basic to felsic rocks, and decreasing Ni, Cr and Co with increasing SiO2 are considered as indications of mag...
The studied area is located about 35 KM north-west of Rafsanjan (Kerman Province) and belongs to Hezar volcanic complex (in Uromieh-Dokhtar volcanic belt) and consists of Eocene folded lava flows (basalt, basaltic andesite, andesite) and pyroclastic rocks. Plagioclase phenocrysts show evidences of disequilibrium textures such as sieve texture, resorption and oscillatory zoning. These features c...
Chahrisseh magmatic rocks are located in the northeast Isfahan, in the Sanandaj-Sirjan structural zone and parallel to the Qom-Zefre fault. These magmatic masses are located in a continuous section of Permian-Triassic sediments and rarely enter the Early Triassic beds. These rocks contain anhydrous ferromagnesium minerals (olivine, clinopyroxene and plagioclase), hydrous ferromagnesium minerals...
The crystal-chemistry of the plagioclase, alkali feldspar, biotite, amphibole and whole rock geochemistry of Akapol granitic massif are investigated in this paper. The chemical composition of biotites and amphiboles ploted in the annite-siderophyllite, magnesiohornblende and actinolite fields, respectively. Comparison of the chemical composition of biotites and amphiboles with similar minerals...
The plutonic body of Bostanabad-Meyaneh belt formed during the Cenozoic magmatism on the weast Alborz-Azarbaijan zone. The Oligocene plutonic rocks consist of alkaligranite, granodiorite and biotitegranite, intruded into the Eocene volcanic-sedimentary rocks. The predominant textures are granular, graphic and perthite. Geochemical evidence reveals that they are cogenetic and have features typic...
The alkaline extrusive rocks of Neogene from Nehbandan-Assagie region, eastern Iran, include basanite, hawaiite, mugearite and benmoreite. Relatively low Ni and Cr contents and Mg-numbers of basanites are indicative of olivine and clinopyroxene fractionation from their relevant primary magma. Decreasing of CaO, TiO2, FeOt, HREEs and MREEs with increasing SiO2 indicate fractional crystallization...
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