Geological Lineament Pattern and Geomorphic Indices Characteristic Related To Geothermal Manifestation Appearance: A Case Study from Gunung Talang District and Its Surroundings, Solok Regency, West Sumatra Province, Indonesia

Abstract

The study area is located in Gunung Talang District and its surroundings, Solok Regency, West Sumatra Province, Indonesia. This area has a potential volcanic geothermal system and is generally covered by the Quarternary rocks which are deformed due to the tectonic activity of the Sumatran Fault System. Geological structure traces are not well preserved in such an area. This study aims to determine the geological lineament pattern associated with geological structure, the geomorphic indices characteristic related to the tectonic activity and rock permeability, and the geothermal manifestation appearance based on these two factors. Geological lineament pattern is identified using the remote sensing method. Geomorphic indices characteristic is calculated through the quantitative analysis of bifurcation ratio (Rb), drainage density (Dd), mountain front sinuosity (Smf), and lineament density (Ld). Geothermal manifestation appearance is evaluated through geospatial analysis using the overlay method on the geological lineament pattern and the geomorphic indices characteristic, which are then correlated with the distribution of geothermal manifestations. The main geological lineament patterns associated with the geological structures in the study area are north-northwest–south-southeast (NNW-SSE) and northeast-southwest (NE-SW). These lineament patterns indicate synthetic and antithetic strike-slip faults around the Sumani Segment of Sumatran Fault System successively. The geomorphic indices characteristics imply deformed areas (Rb values: 1.14-5.45), rough (Dd values: 2.00-2.66 km/km2), moderate (Dd values: 3.14-4.00 km/km2), and slightly fine landform textures (Dd values: 4.32-5.51 km/km2), active (Smf values: 1.05-1.64) and moderate to slightly active tectonisms (Smf values: 1.74-2.52), low (Ld values: 0.00-0.84 km-1), moderate (Ld values: 0.84-1.68 km-1), and high lineament densities (Ld values: 1.68-2.52 km-1) over the study area. The geothermal manifestations in the study area are divided into four groups based on their appearance characteristics, namely group I (Songsang and Garara hot springs), group II (Padang Damar, Bukit Gadang, and Batu Bajanjang hot springs), group III (Bukit Kili and Bawah Gunuang hot springs), and group IV (Gabuo Atas and Bawah Betung hot springs).