Petrogenetic Analysis of Ultramafic Peridotite Rocks Case Study: Tinanggea Area, Southeast Sulawesi Province

Abstract

Ultramafic rocks in the ofiolite complex of the Southeast Arm of Sulawesi have a fairly wide distribution in the Tinanggea Region. Administratively, the research area is located in Tinanggea District, Southeast Sulawesi Province. Geographically, it is located at coordinates and 4˚ 22' 15“to 4˚ 24' 14” South latitude (LS) dan 122˚10' 16.88“to 122˚12' 22” East Longitude (East). This study aims to determine the characteristics of ultramafic rocks, the type and origin of magma, and the environment that forms ultramafic rocks in the study area. This research was conducted on ten (10) ultramafic rock surface samples from the results of field mapping activities then carried out petrographic mineralogical analysis and geochemical analysis using XRF (X-Ray Flouresence). From the results of the data analysis, it was found that the types of ultramafic rocks in the study area consist of lherzolite and wehrlite. Based on major rock element data, ultramafic rocks in the Tinanggea area have ultramafic magma types with low SiO₂, with a thoellitic magma series that has high total MgO and FeO values. Ultramafic rocks in the study area were formed in the tectonic environment of the expansion of the ocean floor of the ocean ridge and floor and the ocean islands of the ocean island.