فهرست مطالب a .partabian

The mineralogical composition and geothermobarometry of the peridotites from the Marivan-Kamyaran ophiolitic complex, as a part of the Neo-Tethyian ophiolites in the Zagros Mountains, western Iran, are investigated. The studied samples are belonged to mantle and crustal peridotite types. Results of electron probe microanalysis in peridotites indicate that olivine is forsterite (Fo87-Fo92), clinopyroxene is augite-diopside (En48-56Fs3-6Wo39-49) and orthopyroxene is enstatite (En90-91). Cr-number (Cr#) and Al-number (Al#) in spinels of the mantle peridotites are 33-59 and 41-67, respectively. The same values in spinels of the crustal peridotites are 67-98 and 2-32, respectively. Geothermobarometry calculations for the mantle peridotites show average temperature of ~1104°C and average pressure of ~14 kbar. The crustal peridotites are formed at ~900 °C and ~7 kbar. Two distinct mineral chemistry of the mantle peridotites indicate existence of two types of mantle peridotites in the area, suggesting the possibility of the influence of melt-rock interaction on the chemical composition of the mantle peridotites in the area.

Tozki volcanic cone located in west of Sistan fold-and-thrust belt in north of Zahedan. In this study morphometric charactristic, field properties and relationship to Neogene strike-slip faults of this cinder-cone have been studied for first time. The composition of the Tuzaki cone lithography is named "Andesite" on the geological map of the ChehelKureh region. However, according to the petrographic studies of this research, its composition includes lava flows, and volcanic agglomera. Tozki volcanic cone and related minor cones emplaced on a branch of Chehelkoureh strike-slip fault related to strike-slip fault system of eastern Iran. Petrology and field properties shows that this cone emplaced into Paleocene-Eocene sedimentary rocks during single intercontinental erupting. Rocks of this cone composed of basaltic lava flow and minor volcanic pumice. In order to calculate Morphometric parameter such as crater diameter, base diameter, cone high, cone volume, ratio of crater cone/base cone, ratio of high/ base diameter and cone angle digital elevation model have been used. These data show the Tozki cone is yang and less eroded with elliptical crater and superelliptical base shape. Estimated  Morphometric age suggest a 0.2  Ma. (Pleistocene) to formation of  this cone.   Another Minor Crater located  at  near  Main Crater show they erupted along the Chehelkureh basement fault but not dislocated by this Neogene fault, Indicates  the activity of these cinder cones occurred after the last activity of the Quaternary faults. These evidences suggest that Tozki is a young monogenetic Quaternary volcanic cone that After the last activity, the main and secondary faults of the region have erupted.