سال انتشار: ۱۳۸۵

محل انتشار: دهمین همایش انجمن زمین شناسی ایران

تعداد صفحات: ۷

نویسنده(ها):

Fritz Ebner – University of Leoben, A-8700 Leoben, Austria, Department Applied Geosciences and Geophysics
Amir Azimzadeh – University of Leoben, A-8700 Leoben, Austria, Department Applied Geosciences and Geophysics

چکیده:

Magnesite ore occurs as sparry magnesite (SM, Veitsch type deposits) in carbonatic rocks and as cryptocrystalline magnesite (CM) hosted in ultramafic rocks (Kraubath type) or within young clastic sedimentary basins in the neighborhood of ultrabasic rocks (Bela Stena type deposits).
The proven global magnesite resources are about 12400 Mt (92 % SM, 8 % CM). Based on the current magnesite production ten magnesite provinces of commercial value are defined worldwide. The Tethyan ophiolite magnesite province, ranging from the former Jugoslavia in the west as far as to Pakistan in the east, is the most important province with CM-type deposits. These are generally of high quality but smaller than SM-type deposits. Nevertheless in the light of the increasing steel, iron and cement industry in the Near and Middle East these deposits will certainly become highest importance for the future and exploration activities should be directed to the ultramafic rock domains within the Tethyan opiolite belts. The paper is focused to the distribution of the global magnesite resources and the geological characteristics of magnesite deposits in general and with special reference to the Tethyan ophiolite magnesite province and the magnesite deposits in Iran. The variable formation of magnesite in Iran is identified as a topic for discussion and for advanced geochemical investigations. As Iran´s current magnesite production (130 Kt) is too low to cover the increasing domestic demand on refractory raw materials additional magnesite exploration is recommended. Because all Iran´s magnesite deposits are of CM-type and part of the Tethys ophiolite province the ophiolite zones and especially the East Iran ophiolite belt should be regarded as a prosperous target for integrated magnesite exploration in the future.