Studi Petrogenesis Batuan Vulkanik Menggunakan Analisis Petrografi pada Formasi Jampang, Daerah Bodjong, Kabupaten Ciamis, Provinsi Jawa Barat
Abstract
Daerah penelitian secara fisiografi termasuk dalam Zona Pegunungan Selatan Jawa Barat. Penelitian ini bertujuan untuk memahami karakteristik batuan vulkanik dan proses pembentukannya pada Formasi Jampang, Daerah Bodjong, Kabupaten Ciamis, Provinsi Jawa Barat. Penelitian ini memerlukan observasi lapangan guna mendapatkan data primer dari data yang ditemui pada singkapan yang kemudian dilakukan analisis petrografi dari sampel batuan vulkanik yang didapatkan saat melakukan pemetaan geologi. Terdapat dua metode yang digunakan pada penelitian ini yaitu analisis petrografi dengan cara mengamati tekstur khusus pada sayatan tipis batuan. Kemudian dengan analisis DEM (Digital Elevation Model) yang bertujuan mengetahui persebaran fasies vulkanik, serta untuk mengetahui pembentukan satuan batuan pada daerah penelitian. Terdapat tiga jenis satuan batuan yang diperoleh oleh aktivitas vulkanik selama periode Tersier di daerah telitian. Satuan batuan tersebut antara lain berupa satuan breksi gunungapi, satuan batuan andesit, dan satuan tuf. Pada satuan breksi gunungapi ditemukan tekstur khusus berupa zoning dan vitrofirik. Selanjutnya pada satuan batuan lava andesit ditemukan tekstur khusus seperti trakitik dan zoning.
The research area is physiographically included in the Southern Mountainous Zone of West Java. This study aims to understand the characteristics of volcanic rocks and the process of their formation in the Jampang Formation, Bodjong Region, Ciamis Regency, West Java Province. This research requires field observations to obtain primary data from data found in outcrops which are then carried out a petrographic analysis of volcanic rock samples obtained during geological mapping. There are two methods used in this study, namely petrographic analysis by observing special textures on thin sections of rock. Then the DEM (Digital Elevation Model) analysis aims to determine the distribution of volcanic facies, as well as determine the formation of rock units in the study area. There are three types of rock units obtained by volcanic activity during the tertiary period in the study area. These rock units include volcanic breccia units, andesite rock units, and tuff units. In volcanic breccia units, special textures are found in the form of zoning and vitrophyric. Furthermore, the andesite lava rock unit found special textures such as trachytic and zoning.
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DOI: https://doi.org/10.31284/j.semitan.j.2022.v1i1.4987
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