Petrology
Asma Nazarinia; Seyed Mohsen Mortazavi; Mohsen Arvin; Mohammad Poosti
Abstract
The Oligocene Sarduiyeh batholith with NW-SE trend is located in the southeast of the Urumieh-Dokhtar magmatic zone in the Kerman province. This batholith intruded into the Eocene volcanic rocks that comprises of andesite, andesite basalt and subordinate basalt with pyroclastics rocks. The batholith ...
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The Oligocene Sarduiyeh batholith with NW-SE trend is located in the southeast of the Urumieh-Dokhtar magmatic zone in the Kerman province. This batholith intruded into the Eocene volcanic rocks that comprises of andesite, andesite basalt and subordinate basalt with pyroclastics rocks. The batholith consists of acidic-intermediate rocks such as diorite, tonalite, granodiorite and monzogranite. Mineral Chemistry of plagioclase crystals indicate that their composition varies between oligoclase and andesine with An 24-43 and calcic amphibole have magnesiohornblende compositions. Field, petrological and geochemical studies show that the Sarduiyeh batholith magma is I-type, metaluminous to weakly peraluminous and its belonging to calc-alkaline series. On the primitive mantle-normalized spider diagram, all samples are enriched in large ion lithophile elements such as U, K, Pb and Sr and depleted in high field strength elements such as Ti, Ta and Nb which are characteristics of the volcanic arc setting formed in an active continental margin. Based on geochemical studies, the Sarduiyeh batholith formed as a result of partial melting from metabasic rocks of lower crust.
D. Raeisi; S. Dargahi; H. Moeinzadeh; M. Arvin
Abstract
Gandom Beriyan, as a part of Quaternary volcanism of Iran, is a kind of messa which is covered by very dark lava flows. The flows are generally fresh to rarely altered alkali olivine basalts and cover an area around 480 km2 in southern part of the Lut desert in northeast of Kerman. The common textures ...
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Gandom Beriyan, as a part of Quaternary volcanism of Iran, is a kind of messa which is covered by very dark lava flows. The flows are generally fresh to rarely altered alkali olivine basalts and cover an area around 480 km2 in southern part of the Lut desert in northeast of Kerman. The common textures of basaltic lava flows are porphyry to glomeroporphyry with an intersertal to intergranular groundmass. Their major minerals are olivine and clinopyroxene phenocrysts along with plagioclase microlites. Plagioclase microlites are recognized as the major silicate phase in these rocks. Three-dimensional shape of plagioclase crystals and also rate of nucleation and growth time was estimated by thin section image processing and using crystal size distribution (CSD) method. Based on this, it is revealed that the shape of plagioclase microlites is tablet with aspect ratio of 1:10:10 for short: intermediate: long axes, respectively. The uniformity of CSD graph and its constant slope show that the effect of physical processes such as magma mixing was limited during ascent of basaltic magma toward the surface. Based on these calculations, growth time (t) and rate of nucleation (J) were estimated 2.53 to 3.21 years and 10.17×10-9 to 9.53×10-9 mm-3/s-1, respectively. The results are completely matched with nature of alkali basalt magmas.
