Identifikasi Alterasi Epitermal Low Sulphidation pada Batuan Vulkanik Formasi Jampang Daerah Cikondang, Kabupaten Tasikmalaya, Provinsi Jawa Barat

Rizka Chintya Ramadona, Endang Wiwik Dyah Hastuti

Abstract


Secara fisiografi, daerah penelitian termasuk ke dalam zona Pegunungan Jawa Selatan yang mana beberapa formasi penyusunnnya telah mengalami alterasi hidrotermal yang diakibatkan karena adanya intrusi magma yang lebih muda. Penelitian ini dilakukan dengan tujuan mengetahui prospek endapan epitermal low sulphidation pada batuan vulkanik Formasi Jampang yang terdapat di daerah Cikondang, Kabupaten Tasikmalaya, Provinsi Jawa Barat. Metode penelitian yang digunakan yaitu analisis petrografi dengan cara mengamati keterdapatan mineral sekunder yang ada pada suatu sayatan tipis batuan. Alterasi yang terjadi di daerah penelitian terbagi menjadi tiga zona yaitu zona argilik, zona subpropilitik, dan zona propilitik. Berdasarkan hasil analisis, didapatkan rentang suhu keterbentukan yang berkisar antara 125o C – 200o C dengan pH asam hingga netral. Tekstur khusus urat yang ditemukan di daerah penelitian berupa tekstur saccharoidal dan tekstur cockade mencirikan endapan epitermal low sulphidation.

 

Physiographically, the study area is included in the South Java Mountains zone where several of its constituent formations have undergone hydrothermal alteration caused by the intrusion of younger magma. This research was conducted with the aim of knowing the prospect of low sulphidation epithermal deposits in volcanic rocks of the Jampang Formation located in the Cikondang area, Tasikmalaya Regency, West Java Province. The research method used is petrographic analysis by observing the presence of secondary minerals in a thin section of rock. Alteration that occurred in the study area was divided into three zones, namely the argillic zone, sub-propylitic zone, and propylitic zone. Based on the results of the analysis, the formation temperature ranges from 125o C - 200o C with an acidic to neutral pH. The special texture of veins found in the study area in the form of saccharoidal texture and cockade texture characterizes low sulphidation epithermal deposits.


Keywords


Alterasi; epitermal; Jampang; low sulphidation; petrografi

Full Text:

PDF

References


V. Bemmelen, The Geology of Indonesia, vol. 1A, General Geology of Indonesia and Adjacent Archipelageos, 2nd ed,. 2013, Guidebook Volcanic Petroleum Play AAPG UGM-SC, 1970.

Marcoux and Miles, Epithermal gold deposit in West Java, Indonesia, In : Van Leeuwen: Geology, age and crusta source, 1994.

T. Budhistrina, Geologi Lembar Tasikmalaya, Jawa Barat, Bandung : Pusat Penelitian dan Pengembangan Geologi, Jenderal Geologi dan Sumberdaya Mineral, 1986.

F. Hilmi, “Pola Struktur Regional Jawa Barat,” Bulletin of Scientific Contribution, pp. Volume 6, Nomor 1 : 57-66, 2008.

J. Lagat, “Hydrothermal Alteration Mineralogy in Geothermal Fields with Case Examples from Olkaria Domes Geothermal Field,” Short Course IV on Exploration for Geothermal Resources, UNU-GTP, Kenya, 2009.

P. Browne, Hydrothermal Alteration and Geothermal Systems, Auckland: Geothermal Institute (Unpublished), 1989.

Corbett and Leach, “Southwest Pacific Rim Gold-Copper Systems : Structure, Alteration, and Mineralization,” Southwest Pacific : SEG Special Publication, p. No. 6, 2008.

G. A. Reyes, “J. Volcanol,” Geotherm, pp. Res. 43 279-304, 1990.

F. Pirajno, Hydrothermal Processes and Mineral System, Australia: Springer, 1992.

A. Thompson, Atlas of Alteration, a Field and Petrographic Guide to Hydrothermal Alteration Minerals, Geological Association of Canada, 1996.

Hedenquist and Houghton, “Epithermal Gold Mineralization and its Volcanc Environments, Mt. Mangani, Sumatra, Indonesia,” p. 415 hal, 1988.

Hedenquist, “Epithermal Gold Deposits : Styles, Characteristics And Exploration,” Society of Economic Geologists Newsletter 23, pp. hal. 1-13, 1995.

Whitney D. L, “Abbreviations for names of rock-forming minerals,” American Mineralogist, pp. Volume 95. pages 185-187, 2010.

N. W. Bambang, “Mineralisasi Emas Epitermal di Kecamatan Cineam. Tasikmalaya, Jawa Barat-Indonesia,” in Pertemuan CASM Asia-Pasifik, Bandung, Indonesia, 2006.

W. Widyatmanti, “Identification of topographic elements composition based on landform boundaries from radar interferometry segmentaton (preliminary study on digital landform mappin,” in IOP Conference Series : Earth and Environmental Science, 37, https://doi.org/10.1088/1755-1315/37/1/012008, 2016.

R. J. Hugget, Fundamental of Geomorphology (4th edition), USA and Canada: Routledge, 2017.

B. B. Bandono, “Klasifikasi Bentuk Muka Bumi (Landform) untuk Pemetaan Geomorfologi pada Skala 1 : 25.000 dan Aplikasinya untuk Penataan Ruang,” Geoaplika, Vols. Volume 1, Nomor 2, pp. 071 - 078, 2006.




DOI: https://doi.org/10.31284/j.semitan.j.2022.v1i1.4982

Refbacks

  • There are currently no refbacks.