GEOLOGY AND HYDROTHERMAL ALTERATION STUDY IN CISEUTI AND SURROUNDING AREA, PURWAKARTA DISTRICT, WEST JAVA

• Main Author: HAKIM DEWANGGA (NIM :12009051), AMRAN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17913
• Institution: Institut Teknologi Bandung

This research has been conducted on the southern part of Jatiluhur Dam, Purwakarta. The result of geomorphological analysis showed there are distinguishing differences in <br /> <br /> <br /> <br /> <br /> <br /> lithologies. It can be seen from the morphology of mountain which is consist of resistant rocks, andesite lava unit and the andesite intrusion unit. There is also valley morphology be composed of claystone and tuff, the less resistant rocks. The mountain morphology is <br /> <br /> <br /> <br /> <br /> <br /> interpreted as the trace of old volcanoes, that cause the appearance of hydrothermal alteration and economic minerals. The result of hydrothermal alteration study indicate that the research area is the deposit high sulfidation. This high sulfidation deposit characterized by the Muscovite-Pyrophyllite Alteration Zone with vuggy texture. The presence of traditional open mines in this area show that Muscovite-Pyrophyllite Alteration Zone is the zone of alteration with high number of gold deposits. Beside that, there are also found Sphalerite, Galena, and Cinnabar. Moreover, there are also rocks unit which is not altered, the andesite intrusion unit and tuff <br /> <br /> <br /> <br /> <br /> <br /> unit. This case indicatethat the alteration process happened before those units are formed. The andesite intrusion is predicted as source of hydrothermal fluid.The analysis of microfossil also has been done. It bring out that the Claystone Unit was deposited in Middle Miocene at Neritic Depositional Environment. After that, the up lift process occurred until Jatiluhur turned into land. In the Late Miocene – Pliocene, Jatiluhur Volcano activity produced Andesite Lava Unit and Andesite Intrusion. The geological structure formed in Pliocene – Pleistocene. After that, the volcanic arc changed over in <br /> <br /> <br /> <br /> <br /> <br /> Quaternary. This event resulted in the deactivate of Jatiluhur Volcano. After the deposition of Tuff Unit which is presented from the activity of Quartenary volcanoes, the research area went through exogenous process which is formed today’s morphology.