QE248 : Study of Mineralogy, Geochemistry and the formation of Tash bauxite deposits, North West of Shahrood
Thesis > Central Library of Shahrood University > Geosciences > MSc > 2015
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Abstarct: Tash bauxite deposit is located in 40 km NW Shahrood in NE of the Alborz structural zone. the
study area are affected by faults and folds with general trend of NE – SW. The Tash bauxite in
the Aliabad 1/100000 geological sheet is situated between 54° 41' to 54° 48 ' eastern
longitudes, and 36° 32' to 36° 37' northern latitudes. The main stratigraphic Formations in this
area are including Mubarak, Dorud , Ruteh Elika and Shemshak F.. Bauxite is created by
erosion and weathering of basalts. Basalt rocks resulted in Eo-Cimmerian orogenic phase in
Upper Triassic. The recent rocks limited stratigraphicaly to baxse of Shemshak F. The bauxite
horizon over lying karstic carbonates of Elika F. and its upper border as angular unconformity is
covered by Shemshak F.. Thin sections mineralogical studies display that oolitic, pisolitic,
plitomorphic, collomorphic-fluidal and dissolution textures indicating to authigenic origin. The
results of X-ray diffraction studies show that the the main minerals are diaspore, boehmite,
kaolinite, hematite, shamosite, anatase and quartz. Also polished sections identify pyrite,
chalcopyrite, goethite and hematite as ore minerals. Textural and mineralogical observations
indicate that bauxite laxyer are individed into four separate units: Lower kaolinite, shale bauxite,
hard bauxite and upper kaolinite units. The geological and geochemical documents and
calculations of accumulation coefficient of trace elements demonstrate that source rocks of
bauxite have the characteristics of intermediate mafic rocks. Silica and iron releaching as
secondary and epigenetic processes is also observed in area. According to the proposed genetic
model, under suitable climatic conditions in the Late Triassic, basalt rocks weathering created
the soil bauxite. The subsequent stage the soil bauxite carried in short – distance and finally
deposited into karstic cavities of Elika Formation.
Keywords:
#Basalt #Weathering and Erosion #Upper Triassic #Tash bauxite #Northwest Shahrood Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
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