نتایج جستجو برای: alkaline volcanic
تعداد نتایج: 57247 فیلتر نتایج به سال:
This study investigates petrology and major, minor, and rare earth elements geochemistry of East Iranian Eocene–Oligocene volcanic rocks in Sistan suture zone, to examine their petrogenesis and magma evolution. The volcanic rocks include andesite, trachy-andesite, dacite and rhyolite. These calc-alkaline rocks of high-K series are enriched in Large Ion Lithophile Elements of Rb and Ba a...
The study area is located at 220 km southwest of Mashhad and 80 km south of Neyshabur and is situated between 58° 40' 30" to 58° 43' 30" E longitudes and 35° 47' 30" to 35° 52' 00" N latitudes. The study area is part of Sabzevar zone. The lithology of the area consists mainly of volcanic rocks with trachyte, trachy andesite, and basaltic trachy andesite composition and in some parts has been su...
The study area is located in Tertiary plutonic belt of Lut Block. Tertiary intrusive injection in Cretaceous limestone caused the formation of skarn in this region. Injection intrusive changes the texture and mineralogy of limestone and skarn or marble formed. A lens-shaped iron mineralization mainly occurred in the border of intrusions and calcareous unit. Petrological studies show that the w...
The Chersky seismic belt (NE-Russia) forms the modern plate boundary of the Eurasian-North American continental plate. The geodynamic evolution of this continent-continent setting is highly complex and remains a matter of debate, as the extent and influence of the Mid-Arctic Ocean spreading center on the North Asian continent since the Eocene remains unclear. The progression from a tensional st...
Amphibole (Amp) plays a crucial role in the study of several earth and planetary processes. One its most common applications is thermobarometry, especially for volcanic-magmatic systems. However, many thermobarometers require input melt composition, which not always available volcanic products (e.g., partially crystallized melts or devitrified glasses), show rather high errors characterizing de...
Mehrabad bentonite deposit appears to be derived from the volcano- sedimentary materials of Oligo-Miocene age by transformation in a lagoon environment. Based on analysis, bentonite samples contain minerals such as montmorillonite, albite, clinoptilolite, quartz, cristobalite, calcite, gypsum, halite, muscovite and nantronite. Conversion of shard glasses to bentonite and zeolite has occurred un...
Evidence for a c. 600 Ma rifted passive margin in eastern Australia exists in the form of multiple belts of mafic volcanic rocks preserved along the western margin of the Tasman Fold Belt System, and giving rise to elongate magnetic anomalies. Outcrop, drillhole and geophysical evidence points to piles of lavas, volcaniclastic and intrusive rocks up to 6 km thick, extending for strike lengths o...
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