The most frequent and voluminous eruptive Kurasawa, 1983], (4) partial melting of the lower crust products at Mount St. Helens are dacitic in composition, [e.g., Grant et al., 1984; Reid and Cole, 1983], and (5) although a wide variety of magma types (basalt to formation of compositional gradients in response to rhyodacite) is represented. To address the petrogenesis of convective and diffusive...

introduction the study area is a small part of the urumieh-dokhtar structural zone in the markazi province, located in the northeastern part of the farmahin, north of arak (hajian, 1970). the volcanic rocks studied from the area include andesite, dacite, rhyodacite, ignimbrite and tuff of middle to late eocene age (middle lutetian to upper lutetian) (ameri et al., 2009). it seems that folding a...

There have been presented the results of study a thick (no less than 2–3 km), extended (for more 200 km) volcanogenic formation (Tsetsen-Uul or Yargait) in south Zavkhan terrane Central Asian fold belt. The is an assemblage frequently intercalating effusive rocks subalkaline basalt-andesite-dacite-rhyolite series, their tuffs, tuffites, ignimbrites, and terrigenous rocks. Felsic dominate over b...

arghash – ghasem-abad area in ne iran is located in the rim of the sabzevar structural zone. tertiary outcrops include granite and quartz monzodiorite porphyry associated with dacite and andesite volcanic rocks. in the study area, quartz gabbro and quartz monzodiorite dykes intruded the older rocks. granite and volcanic rocks host au-sb-bearing quartz-calcite veins. mineralized veins are mainly...

hydrothermal alteration processes are extensively took place on volcanic and pyroclstics of takestan area. existence of abundant, deep fracturing and subvolcanic intrusions are enhanced extend hydrothermal alteration zones. the following alteration zones are determined: propylitic, argillic, advanced argillic and sillicic. there are outcropped and widespread in different size and limit. formati...

The study of building materials is important for a better conservation built heritage. Worldwide, volcanic stones (including basalt, andesite and dacite) are among the least studied materials. In this research, decay red basalt due to wet atmospheric deposition was studied. Red exposed artificial rain solutions, prepared from samples collected weekly 2014–2019. stone-built heritage indirectly e...

Abstract The Ruwai skarn deposit is the largest polymetallic in Borneo and located Schwaner Mountains. skarns massive orebodies are hosted marble of Jurassic Ketapang Complex, which was intruded by Cretaceous Sukadana granitoids. prograde-stage garnet retrograde-stage titanite yielded U-Pb ages 97.0 ± 1.8 to 94.2 10.3 Ma 96.0 2.9 95.0 2.0 Ma, respectively. These similar Re-Os obtained on sulfid...

The Setouchi volcanic rocks include high-Mg andesites (HMAs) and garnet-bearing dacite–rhyolite, are sporadically distributed along the Median Tectonic Line, Japan. New U–Pb zircon ages geological geochemical data presented for those in Western region (W-Setouchi). Previous studies referred to altered andesite W-Setouchi as “pre-Setouchi rocks.” However, on basis of new age (14.4 Ma ± 0.3 Ma) c...

The Carboniferous volcanic reservoirs in the Shixi area of Junggar Basin are complex and diverse. Identifying characteristics main factors controlling high-quality is key to increasing oil gas reserves production this area. Through core observations, thin section identification, physical property pore structure analyses, combined with data, development modes were analysed. results show that str...