40Ar/39Ar Geochronology of Rumbia Schist Complex: New Implications For Timing and Hydrothermal Activity in The Southeast Sulawesi Gold Prospect, Indonesia

The Rumbia Mountains, which in this study named Rumbia Complex is an east-west oriented, composed by a high-pressure/low-temperature, and a medium-pressure/low-temperature metamorphic rocks. The complex is identified as mica schist, glauchopane schist, and green schist. Rumbia Complex known as the location of gold deposits prospects discovered by local communities since 2007. The results of research showed that the metamorphic rocks are as hosts. There are two period of gold mineralization that occurs in this area, namely: 1) Associated with tectonic deformation and metamorphic rocks exhumation as a first period, and 2) Gold deposits related to post-tectonic as a result of hydrothermal activity in the Rumbia Complex. Radiometric age dating used 40Ar/39Ar geochronology, indicate that the first period of gold mineralization in the Rumbia Complex occurred ≈23 million years ago (MA), and the second period were subsequently overprinting at ≈6.8 million years ago (MA).