introduction more than 30 fluorite occurrences with approximately 1.35 million tons of reserves have been recognized in iran (ghorbani, 2013). the atashkuh fluorite-barite (±sulfide) deposit is one of four occurrences located south of the city of delijan in markazi province, about 80 km se of arak city. the atashkuh deposit occurs between the central iran structural zone on the north and the sa...

Piezoelectric (strain) coefficients dij of quartz are calculated in terms of molecular dynamics as a function of pressure and temperature. We review the necessary formulas for the computation of electromechanical materials coefficients obtained at constant stress and temperature, and discuss how to overcome complications of the definition of polarization variations due to fluctuating box geomet...

introduction arefi quartz-bearing conglomerate (middle jurassic) is situated within binalud structural zone. the unit is trending nw-se located 25 km south of mashhad. more than 97% of the pebbles are quartz as mono-crystalline, poly-crystalline, and minor fragments of chert, quartzite, and mica schist. less that 3% of the remaining minerals are feldspar, mica, chlorite, hornblende, tourmaline,...

Serpentinization is a widespread process that affects large-scale geodynamic processes along plate boundaries, including continental breakup, seafloor spreading, and subduction. Documenting the timing of serpentinization is critical for our understanding of these processes, but direct dating of serpentinites has been challenging or impossible. We present the first application of magnetite (U-Th...

Liquidus phase relationships determined on the join anorthite-forsterite-quartz at 20 kbar show primary phase fields for quartz (q), forsterite 0Co), enstatite (en), spinel (sp), anorthite (an), sapphirine (sa), and corundum (cor). Increasing pressure causes (1) the f o and an primary phase fields to contract, (2) the en, q, and cor fields to expand, (3) t h e f o e n boundary line to move away...

The solubility of quartz in H2O-NaCl solutions was measured at 2, 4.35, 10 and 15 kbar and 500–900°C, and at NaCl concentrations up to halite saturation, usually greater than 75 wt.%. Quartz solubility was also measured in CO2-H2O solutions at 10 kbar and 800°C. Solubilities were determined by weight loss of ground and polished quartz crystal fragments which were equilibrated with solutions in ...

The high-temperature rate of reaction of the homogeneous, reverse water-gas shift reaction, rWGSR, has been evaluated in quartz reactors with rapid feed pre-heating at low-pressure and high-pressure conditions. The form of the powerlaw rate expression was consistent with the Bradford mechanism. The Arrhenius expressions for the reaction rate constant corresponding to the empty reactor were in v...

Liquidus phase relationships determined on the join CaAIzSi20 8 (anorthi te)-MgzSiO 4 (forsteri te)-SiO 2 (quartz) at 10 kbar show that increasing pressure causes the forsterite and anorthite primary phase fields to shrink and the spinel, enstatite and silica fields to expand. The boundary line between the enstatite and forsterite fields and that between the enstatite and quartz fields both mov...

compared to quartz sand, the shear behavior of carbonate sand differs in  appearance, origin, and kind. carbonate sand is found mainly in the northern coast of the persian gulf and the oman sea. in this research, a comparison is made between the shear behavior of carbonate sand retrieved from the eastern region of the chabahar port, located north of the oman sea, and quartz sand obtained from f...