Physical and chemically changes in limestone intruded by trachytic dyke: implications for cement raw material

Limestone samples intruded by trachyte dike from the Tonasa Formation in Bantimurung, Indonesia have been investigated for their suitability for cement manufacturing. The objective of this study is to analyze the physical and chemical characteristics of the limestone surround an intrusion with the petrographic and XRF methods. Field observation shows a gradation of color (reddish to grey) away from intrusion contacts. Petrographic analysis shows metasomatic indication by the presence of garnet and wollastonite within the limestone at 0 - 20 meters from the intrusion contact. The geochemical analysis shows a decreasing degree trend of CaO₂, and Fe₂O₃, however SiO₂, Al₂O₃, and MgO increase towards the intrusion contact. According to the petrographic and geochemical characteristics indicate the limestone fulfills requirements as raw material for cement, even though the ideal composition for the cement industry is the limestone which is located between 20 - 70 meters from the intrusion contact