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BASEMENT KOMPLEK BAYAH, KABUPATEN LEBAK, PROPINSI BANTEN Patonah, Aton; Helmi, Faisal; Prakoso, Jodi; Widiaputra, Taufiq
Bulletin of Scientific Contribution Vol 13, No 3 (2015): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1254.822 KB) | DOI: 10.24198/bsc.v13i3.8405

Abstract

Researching metamorphic rocks in Bayah and in its surrounding area has slight data so it has not been clear yet how the stratigraphic position, the age and the metamorphic rocks characteristic is in the study area. By using geological mapping and petrographic method, it showed that the metamorphic rock is believed to be the basement of Bayah complex which accreted because of reverse fault in the northwest so that the rock appeared together with the relatively younger rocks in the south (Bayah Formation and Granodiorite Cihara). These rocks showed that there are foliation, boudinage and crenulation structure consisting of various types of metamorphic rocks which are different in degrees of metamorphism (low grade – high grade metamorphism) and in protoliths as well, so these interpret as a result of orogenic processes of intermediate pressure metamorphism.
ALTERASI DAN MINERALISASI PADA BATUAN PORFIRI ANDESIT DAN PORFIRI GRANODIORIT DI DAERAH CIGABER DAN SEKITARNYA, KABUPATEN LEBAK, PROVINSI BANTEN Prakoso, Jodi; Patonah, Aton; Helmi, Faisal
Bulletin of Scientific Contribution Vol 14, No 1 (2016): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1715.243 KB) | DOI: 10.24198/bsc.v14i1.9789

Abstract

Geographically, the study area is located in the Cihara Region, Lebak District, Banten Province. The purpose of this research is to determine alteration zone and  mineralization of porphyry andesite and porphyry granodiorite. The research method is fieldwork and laboratory analysis (petrography and minegraphy analysis). Result of research area, there are seven alteration zone; such as chlorite-sericite-quartz zone, chlorite-sericite-carbonate zone, chlorite-sericite-carbonate-quartz zone, sericite-quartz zone, chlorite-epidote-sericite zone, chlorite-epidote-sericite-carbonate zone, and chlorite-actinolit-biotite zone. Alteration type in research area is devided into three alteration type philic zone, phropilitic zone, and potasic zone. Ore mineral assemblages of research area are dominated by pyrite and calcopyrite according to type model mineral deposite the research area included of epithermal intermediete sulfidation and porphyry type. Keyword : Alteration, Mineralization, Ephitermal Intermediete Sulfidation, porphyry typeSecara Geografis daerah penelitian termasuk dalam Kecamatan Cihara, Kabupaten Lebak, Provinsi Banten. Penelitian ini dilakukan untuk mengetahui tipe alterasi dan mineralisasi daerah penelitian serta sebarannya. Metode penelitian yang dilakukan adalah pemetaan geologi dan analisis laboratorium (analisis petrografi dan minegrafi). Hasil penelitian lapangan dan analisis laboratorium daerah penelitian terbagi menjadi tujuh zona alterasi yaitu zona klorit-serisit-kuarsa, zona klorit-serisit-karbonat, zona klorit-serisit-karbonat-kuarsa, zona serisit-kuarsa, zona klorit-epidot-serisit, zona klorit-epidot-serisit-karbonat, dan zona klorit-aktinolit-biotit. Tipe alterasi daerah penelitian terbagi menjadi tiga tipe alterasi yaitu tipe alterasi filik, propilitik, dan potasik. Mineral bijih yang berkembang pada daerah penelitian didominasi oleh mineral pirit dan kalkopirit menurut model endapan mineral termasuk kedalam tipe endapan epitermal sulfida menengah dan endapan porfiri.           Kata Kunci : Alterasi, Mineralisasi, Epitermal Sulfida Menengah, endapan porfiri