World Journal of Environmental Biosciences
World Journal of Environmental Biosciences
2020 Volume 9 Issue 2

Mineralogical Characteristics and Estimating the Depth of the Formation of Gabbroic Rocks in Dehsard Area

Mehdi Ebrahimnejad, Mohsen Arvin, Sara Dargahi

The upper Triassic gabbroic magmatism is located in the southernmost of the Sanandaj-Sirjan zone, in the southwest of Kerman, Iran. Based on field observations and petrographic studies, this mafic body is Hornblende-gabbro. The general texture of the samples is hypidiomorphic granular; but porphyry, intergranular and poikilitic textures also occasionally occur in mafic samples. Mineralogically the gabbroic rocks include plagioclase, clinopyroxene, amphibole, titanite, apatite, epidote, calcite, and chlorite. Mineral chemistry studies demonstrate that the composition of plagioclases is albite to oligoclase and clinopyroxenes are composed of diopsides. The composition of clinopyroxenes includes an iron-magnesium-calcium type. The amphiboles are calcic and plotted in the magnesium hornblende and actinolite field. The petrogenesis of parental magma is the arc type related to the subduction environment. Based on geothermobarometry studies on amphiboles and clinopyroxenes, the average temperatures of 1000-1200 °C with pressure ranges of 2.05 to 5.58 Kbar were estimated for gabbroic samples. The calculated pressures are equivalent to near the surface conditions to the depth of approximately 14 km.

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