نتایج جستجو برای: porphyritic texture
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Chaharfarsakh intrusive and extrusive rocks are located in 25 Km northwest of Nehbandan and 165 Km south of Birjand and in terms of geology, suituated in the eastern of Lut block. Chaharfaraskh intrusive rocks with Jurassic age were injected into shales and sandastons Shemshak Formation. Intrusive rocks are gabbro, diorite, synogranite, quartz monzonite, hornblend tonalite, granodiorite, granit...
Introduction: Knowledge of martian igneous and mantle composition is crucial for understanding mantle evolution including early differentiation, mantle convection and the chemical alteration of the surface. Primitive magmas provide critical information on their mantle source regions but most Martian meteorites crystallized from fractionated melts [1]. The new martian meteorite NWA 5789, discove...
Upper Cretaceous intrusives of limited extent crop out in the Coastal Cordillera near Valdivia (39º48’ S), 100 km west main topographic divide Andean Cordillera. Given that plutonic rocks same age at latitudes high Andes coastal emplaced a forearc position upper plate subduction setting. They correspond to hypabyssal displaying mainly porphyritic texture and lithological variations with microto...
A new meteorite find, named Khatyrka, was recovered from eastern Siberia as a result of a search for naturally occurring quasicrystals. The meteorite occurs as clastic grains within postglacial clay-rich layers along the banks of a small stream in the Koryak Mountains, Chukotka Autonomous Okrug of far eastern Russia. Some of the grains are clearly chondritic and contain Type IA porphyritic oliv...
New U-Th-Pb zircon data (SIMS) from three intrusive phases of the Palaeoproterozoic Viterliden intrusion in the western Skellefte District, central Fennoscandian Shield, dates igneous emplacement in a narrow time interval at about 1.89 Ga. A locally occurring quartz-plagioclase porphyritic tonalite, here dated at 1889± 3 Ma, is considered the youngest of the intrusive units, based on the new ag...
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The paper discusses the geochemistry of major (EPMA) and trace (SIMS) elements in olivine porphyritic, nonporphyritic chondrules, matrix equilibrated ordinary chondrite Saratov (L4). Olivine corresponds to forsterite is rather heterogeneous (Fo 73-77). No differences content chondrule meteorite were found. However, within chondrules varies considerably; high values found from barred chondrules....
The 18-km-diameter El’gygytgyn crater is located on the Chukotka peninsula, northeastern Russia. It represents the only currently known impact structure formed in siliceous volcanics, including tuffs. The impact melt rocks and target rocks provide an excellent opportunity to study shock metamorphism of volcanic rocks. The shockinduced changes observed in porphyritic volcanic rocks from El’gygyt...
At the south of Bardsir, Kerman province, Iran, southeastern part Urmia-Dokhtar magmatic arc (UDMA), a large number gabbroic intrusions are intruded into Eocene lava flows and pyroclastic rocks with form small stocks dykes. In this paper, geochemical variations, evolutions, origin these investigated. The studied characterized by fine-grained margins resulting from rapid cooling flow differentia...
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