late miocene–pliocene calc-alkaline volcanic rocks are exposed southeast of isfahan in the urumieh-dokhtar magmatic belt. volcanic rocks consist of lava flows and domes, chiefly basaltic andesites, andesites and dacites. minerals in the volcanic rocks exhibit degrees of disequilibrium features. plagioclase as dominant mineral in these rocks generally displays reverse and oscillatory zoning; sie...

The magmatic-hydrothermal evolution of porphyry-style mineralization in the shallow crust that is linked to magmatic processes at depth has been extensively studied using bulksample isotopic analysis combined with relative timing constraints. However, a lack of evaluation of the fluid evolution process against an absolute time frame limits further understanding of the ore-forming process. Here,...

From (3. F. Becker's and L. V. Pirsson's early enunciations linking the dynamics of magma chambers to the rock records of sills and plutons to this day, two features stand at the centre of nearly every magmatic process: solidification fronts and phenocrysts. The structure and behaviour of the envisioned solidification front, however, has been mostly that akin to non-silicate, non-multiply-satur...

Large Ra excesses in a number of mafic arc magmas, and geophysical observations of earthquake hypocenters locations, indicate that mafic melts can get transferred from source to surface within days to ~1 kyr. Decreasing Ra–Th disequilibria with increasing SiO2 in co-magmatic suites of individual arc volcanoes suggest that magma differentiation often occurs on timescales of a few thousand years ...

The Wadi Dib magmatic complex is the oldest known alkaline ring complex in the Egyptian part of the Pan-African orogenic belt. Rb-Sr isotope data for seven samples suggest a Vendian age of 578=k16 Ma, and a 87Sr/S6Sr initial ratio of 0.7048±0.0010. The igneous complex has a diameter of 2 km and was emplaced within granodioritic Pan-African host rocks at the intersection of two faults. It shows ...

Chemical and isotope data were obtained for the active gas and noble gas of inclusion fluids in coarse-grained samples of magmatic-hydrothermal and magmatic-steam alunite from well-studied deposits (Marysvale, Utah; Tambo, Chile; Tapajós, Brazil; Cactus, California; Pierina, Peru), most of which are discussed in this Volume. Primary fluid inclusions in the alunite typically are less than 0.2 Am...

salafchegan-khorhe volcanic rocks are exposed within urumieh-dokhtar magmatic belt. different kinds of volcanic and subvolcanic rocks of calc-alkaline to alkaline character have been reported throughout this magmatic belt. since, isotopic investigations are very useful for detection of magma petrogenesis and because no isotopic studies have been done in this area, so a geochemical and isotopic ...

Subduction-related magmatic arcs represent immense accumulations of intermediate, calc-alkaline igneous rocks and are considered the main factories of continental crust on Earth. Estimating the pace at which these giant volumes of magmatic rock were added to the crust and the mechanisms responsible for magmatic addition are fundamental issues for the disciplines of igneous petrology and contine...