Habib Mollai - Department of Geology, Faculty of Sciences, Mashhad Branch, Islamic Azad University, Mashhad, Iran.

Bauxite deposits in Iran occurring in three zones ,the first zone is Alborz in the north the second is Central Iran and the third zone is Zagros. Most of the bauxite deposits in Iran belong to the PrmoTeriass age (36.53%), Permian (26.92%),Teriassic-Jurassic(17.3%),Teriass (11.53%) and Cretaceous (7.9%). But the Gush kamer bauxite deposit is belong to the upper Devonian age .They are mediteranian types and the bed rocks of most these deposits are dolomitic,few of these are lateritic with various size of karst and sink hole. The Gushkamer bauxite deposit un conformability overly the Bahram limestone formation as lenses and small karsts All of the bauxite deposits in the Alborz and East Central Iran have all most the same cover rocks that is Shemshak Formation . The present structural feature of these bauxite deposits were created by the Alpian Orogeny's in Cretaceous and Tertiary time of the Middle East. The thickness of the bauxites varies from few miter up to more than 25 meter. The quality of bauxite show positive relation with the thickness of bauxite. Classification of bauxite deposits show that ther range from bauxite to clayic or clayic iron rich bauxite but. All of the bauxite deposits show politomorphic, micro granular with several secondary textural elements. Mineralogical most the deposits are diasporci type but Gush kamer is topical a gibbsite type . In general the Al2O3 content ranges (22.- 57.7%, ) SiO, (16.82 - 35.87 %,) and Fe2Osis (9.08 - 38.9 %,).In comparison the Gushkamer bauxite contain lower Al2O3 and high concentration of iron and silicate. These prove the various stages and degree of bauxitization for these deposits.

Geology, bauxite mineralogy, texture, geochemistry, bauxite of Iran