GEOLOGY AND HYDROGEOLOGY OF TUK TUK, SAMOSIR REGENCY, NORTH SUMATERA

• Main Author: Gurning, Ferdinand
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/37301
• Institution: Institut Teknologi Bandung

The research area is located in Ronggur Nihuta District and Simanindo District, Samosir Regency, North Sumatera. Geographically, the research area is located at UTM coordinates 474000 - 488000 mT and 287000 – 296000 mT (Zone 47 N). The research area is 107.07 km2. According to the Bentuk Muka Bumi (BMB) classification, the research area can be divided into three geomorphological units, Ronggur Nihuta Fault Block Ridge Unit, Tuk-Tuk Lava Dome Unit, and Simanindo Alluvial Plain Unit. The research area is in young geomorphic stage. Stratigraphically, the research area can be divided into five non-formal rock units which were formed during Late Pleistocene – Recent, deposited in lacustrine and terrestrial environment. The sequence from older to younger strata are Welded Tuff Unit, Rhyolite Lava Unit, Siltstone-Sandstone Unit, Breccia Unit, and Alluvial Deposit Unit. Geological structures in the research area are Sijambur Normal Fault, Simanindo Normal Fault, and Hutaginjang Normal Fault. These structures was formed in Late Pleistocene, at the same time with the uplift of the three oldest unit in the research area. Aquifer in the research area is in the Welded Tuff Unit, Rhyolite Lava Unit, Siltstone- Sandstone Unit, Breccia Unit, and Alluvial Deposit Unit. The type of aquifer in the research area is unconfined aquifer. Quality of groundwater in the research area are suitable for drinking according to PERMEN No.492/MENKES/PER/IV/2010 based on pH and TDS value criteria. The pH value ranges from 6.5 – 8.39 while TDS value ranges from 3.2-197 mg/L.