MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF MARBLE: A CASE STUDY FROM THE MUSTAFA KEMALPASA-BURSA AREA, NORTHWEST TURKEY.

The marbles of the Upper Jurassic-Lower Cretaceous period are located in an area between the Kabulbaba and Sogutalan villages of Mustafa Kemalpasa-Bursa in the Marmara region, northwest Turkey. The basis of the Paleozoic-Triassic Kiziltepe Metamorphic rocks in the Sakarya Composite Unite was formed here. The Karakaya Group composed of the Lower Triassic sandstone, conglomerate, mudstone, radiolarite, spilitic basalt, tuff, and limestone alternation unconformably overlies the Unite. The Jurassic-Lower Cretaceous Inatlar limestone unconformably covers this group. The Inatlar limestone with economic significance is worked by many companies and is known commercially as dark-light and fossiliferous beiges, emperor and rosalia marble species. The mineral assemblage indicates that the rosalia marble consists of calcite, fossiliferous beiges and emperor types of the calcite and dolomite minerals. Except for the CaO content (36.70%) of emperor marble, CaO contents of the other types vary between 54-56% and their mineral content is composed of pure calcite. MgO concentration of emperor marble with low CaO content is 16.71% and fossiliferous dark beige marble 1.30%. MgO contents of the other types vary between 0.32-0.98%. The presence of dolomite or magnesite minerals in these samples indicates that emperor marble is rich in magnesium. Fe2O3 contents of fossiliferous light and dark beiges are very low at 0.07 to 0.08% and those of other types vary between 0.15-0.20%. SiO2 content is 1.28% in siliceous dark beige marble and varies between 0.15-0.84% in other marble types. The high SiO2 amount in siliceous dark beige marble probably results from chert in the limestone. [ABSTRACT FROM AUTHOR]