نتایج جستجو برای: dacite
تعداد نتایج: 251 فیلتر نتایج به سال:
The Tertiary volcanic rocks in the north and west of Birjand are dacite; andesite, basaltic andesite, trachyandesite and rhyolite.They belong to calc- alkaline from magmatic series. Mineralogcal, petrographcal and geochemical evidence show that they have formed in active continental margins. Most andesites and dacites are appeared as volcanic domes or subvolcanic dykes that injected older units...
The Beshgaz manganese-bearing veins are located in ~45 km northeast of Birdjand, South-Khorasan, and east of Iran. These veins with 0.1-1.5 m thickness and 4-7 m length are engulfed discordantly within Paleocene (Eocene-Oligocene) volcanic-pyroclastic rocks. The host of Mn-bearing veins are dacite to rhyo-dacite tuff, lapilli tuff with andesitic and andsi-basaltic fragments in shear zones. The...
Nodoushan clay deposit is located about 130km southwest of Yazd city in the Uromieh-Dokhtar volcano-plutonic belt. Based on the field, mineralogical and geochemical studies, the rocks of Nodoushan area are of volcanic type and are composed of dacite, andesite and olivine-basalt, the pyroclastic type (crystalline tuff), and the microgranodioritic intrusive rocks. According to Zr/TiO2 versus SiO2...
Gazestan deposit is located about 185 km of Yazd, in the Bafgh – Posht e Badam Metallogenic belt, consists of Infracambrian carbonate, shale, tuff, sandstone and volcanic rocks. Acid to basic green rocks (rhyolite, dacite and basalt) are host for iron and phosphate mineralization. The alteration process is more intence in the volcanic rocks including, actinolite, chloritization, silicification ...
Groundmass pyroxene crystals in pumice from the 1914 eruption of Sakurajima Japan show varied combinations crystallographic faces (i.e., ‘tracht’). To investigate whether groundmass tracht depends on magma decompression conditions, we performed isothermal single–step experiments hydrous dacite magma. The was held under water–saturated conditions at 920 °C, 120 MPa, and oxygen fugacity no more o...
High-level natural radioactivity, geochemical, geological, and radiological hazard assessment of the poorly investigated Wadi Gebeiy Dokhan volcanics rocks are discussed. located in Southwestern Sinai, Egypt, covering an area ~1.3 km2. represented by porphyritic dacite. Geochemically, they have medium-k characters originate from calc-alkaline magma within a arc environment. Along fault plane st...
A new patented lightweight aggregates is tested. This type is given the name Flashag. The only solid raw material used to manufacture these aggregates is fly ash. The aggregates are sintered but not pelletized and the process is easy and inexpensive. This paper describes these patented aggregates and compares them with other lightweight and normal-weight aggregates that are used for concrete. T...
Sado Island is floating offshore of Niigata on Sea of Japan. This island is 855km2 and composed of Ko-sado (Small Sado) and O-Sado (Large Sado), and both them are arranged in a direction of NNE-SSW. This arrangement are parallel to Kakuda-Yahiko Range, south of Niigata City in the main land. O-Sado has the highest peak of more than 1100 m (Kinpokusan: 1172m), and Ko-Sado of 600 m high peak (Dai...
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