Mineralogical & Geochemical studding of ChromiteDeposits which are in Ophiolite Melange of Birjand Nehbandan area.
|Category||Economic geology & mineral exploration|
|Location||21th symposium on geosciences|
|Holding Date||21 May 2008|
Chromite is one of the major ore deposits in the ophiolite melange of Birjand?Nehbandan area. Four chromite mines are exploring in the Bandan, Hematabad, Chahpanjsar and Cheshmehanjir.
There is also a few chromite in the Kalateh Pagodar, Noferest and Dahaneh-e-Nasfandeh with a low reserve. These mines have podiform lenses and badinages shapes, and these helps for easily exploration. Furthermore, in some places, ore has been filled fractures and faults have an important role in ore deposits. For example, Chahpanjsar chromite has been occurred in fault zone, because in the wall of ore deposits slicken slides are seen clearly. Mineralogical and chemical studies show that serpentinization is more common in these ultramafic rocks, so we can not see any evidence of the primitive minerals. Olivine (forsterite), pyroxene, amphibole, plagioclase, clinochrysotile, chromite and magnetite are major minerals in thin and polished sections. Based on XRF analysis there is 22 percent SiO2 in chromite, thus it is difficult to use the minerals in industry. Furthermore, chemical data shows that aluminum has also more than % 10 in chromites, and because host rocks of chromites in this area, is from upper mantle harzburgite, chromite of the studied area is Al-Alpine type, and ophiolites are a kind of harzburgitic (HOT).