Petrography study of hot spring sinter in Gunung Talang District, Solok Regency, West Sumatera

This study conducted a petrographic study of sinter found in hot springs in Gunung Talang District, Solok Regency. This area has many surface manifestations in the form of hot springs which have sinter deposits, either silica sinter or carbonate sinter. This petrographic test aims to investigate and identify geothermal potential based on the type of hydrothermal material that may be brought to the surface through hot springs. This study compares the alteration minerals from sintered silica deposits which represent a high hydrothermal system and a combination of sintered carbonate and sintered silica deposits which have the potential to have a medium hydrothermal system. Sinter consists of predominantly silica and carbonate-predominant materials. Slices of samples with high silica content showed volcaniclastic texture, hypocrystalline with massive structure, angular-subangular grain shape, grain size <0.1-3.5 mm. Rocks are composed of plagioclase, pyroxene, biotite and opaque minerals in a volcanic glass matrix. Samples with carbonate predominance showed grain size <0.05-0.8 mm, composed of calcite and amorphous silica. Other hot springs which also contain high amounts of carbonate have a grain size of <0.03-0.9 mm, composed of calcite and feldspar.