EVALUATION OF THE PILA SPI FORMATION CARBONATE ROCKS FOR DIMENSION STONE, QARA DAGH AREA, KURDISTAN REGION, NE IRAQ

Abstract

The Kurdistan Region has an enormous number of different carbonate rock units, which vary widely in their geological age and sedimentary depositional environment. Limestone quarried from the exposures has a wide range of usages and applications, such as dimension stone, crushed stone, building stone and paving stones. Since antiquity, limestone was used as building materials in areas where they were naturally available and abundant. Little work has been done to indicate the physical and mechanical properties of the limestone, especially under humid environment. In this study, the physical and mechanical properties of some carbonate rocks of the Pila Spi Formation (Eocene) are investigated. samples are collected from the Pila Spi Formation in the Qara Dagh area at two sites close to each other to assess their suitability for use as dimension stone. Geological, petrographical, geochemical and geotechnical properties of the carbonate rocks in the study area are determined based on field studies and laboratory tests. The field studies indicate that the carbonate rocks of the Pila Spi Formation in the studied area are mostly well-bedded to massive, crystalline, white in color, sometimes become chalky towards the top with small oxidation signs on the surface. Petrographical study reveal that the carbonate rocks are characterized as dolomitic limestone and have a grayish and yellowish-white color after polishing. The carbonate rocks are mostly dolomites or recrystallized dolomitic limestone. Geochemical analyses of the studied samples show that CaO and MgO are the most abundant oxides and the rocks can be classified as impure limestones. According to the American Standard for Testing and Materials, ASTM C568-03 (2006) the carbonate rocks in the studied sites are acceptable for use as dimension stone.