Karakteristik Mineralisasi dan Geokimia Skarn Pb-Zn-Cu-Ag, Ruwai, Kabupaten Lamandau Provinsi Kalimantan Tengah

Siti Rahmawati H. Budiawan, Waterman Sulistyana Bargawa, Arifudrin Idrus

Abstract


Endapan skarn merupakan batuan yang tersusun oleh silika Ca-Fe-Mg-Mn terbentuk oleh penggantian batuan kaya karbonat selama proses metamorfisme regional atau kontak dan metasomatisme sebagai respon pada intrusi batuan beku dari bermacam-macam komposisi (Einaudi et al., 1981) [2]. Keberadaan endapan skarn di Indonesia salah satunya berada di Ruwai, Kabupaten Lamandau, Kalimantan Tengah. Tujuan dari penelitian ini untuk mengetahui karakteristik mineralisasi dan geomikia bijih endapan skarn Pb-Zn-Cu-Ag dengan menggunakan metoda analisis petrografi, mikroskopis bijih, dan geokimia bijih ICP-MS. Hasil penelitian ini menunjukan bahwa mineralisasi skarn Ruwai terbagi dalam dua kategori yaitu mineral prograde kumpulan mineral yang terbentuk pada suhu tinggi dan retrograde kumpulan mineral yang terbentuk pada suhu rendah. Mineral prograde dicirikan oleh kuarsa, sedangkan mineral retrograde dicirikan adanya klorit dan kalsit. Mineral bijih dikarakterisasi oleh adanya galena (PbS), sfalerit (ZnS), kalkopirit (CuFeS2) dan pirit (FeS2). Secara geokimia memiliki kadar logam dasar Pb-Zn-Cu-Ag yang tinggi. tetapi dari ke empat unsur tersebut kadar logam Zn yang paling tertinggi yaitu 50.000 ppm.

Skarn deposits are rocks composed of Ca-Fe-Mg-Mn silica formed by the replacement of carbonate-rich rocks during regional of contact metamorphism in response to igneous intrusion of various compositions (Einaudi et al., 1981). One of the skarn deposits in Indonesia is in Ruwai, Lamandau Regency, Central Kalimantan. The purpose of this study was to determine the mineralization and geochemical characteristics of Pb-Zn-Cu-Ag ore skarn deposits by using petrographic analysis, microscopic ore analysis, and ICP-MS ore geochemistry. The results of this study indicate that the Ruwai skarn mineralization is divided into two categories, namely prograde mineral assemblages formed at low temperatures. Prograde minerals are characterized by quartz, while retrograde minerals are characterized by the presence of chlorite and calcite. The ore minerals are characterized by the presence of galena (PbS), sphalerite (ZnS), chalcopyrite (CuFeS2) and pyrite (FeS2). Geochemically it has a high base metal content of Pb-Zn-Cu-Ag but of the four elements, the highest Zn metal content is 50,000 ppm.


Keywords


Skarn;Mineralisasi;Geokimia Bijih

Full Text:

PDF

References


Dana, C.D.P., Jordan R.S., Putu, G.S., Aditya, Anggara, W., 2019, Hydrothermal Alteration Zoning and Mineralization Style in Southwest Gossan Block of Ruwai Skarn Zn-Pb-Ag Deposit, Lamandau, Central Borneo: an implication to ore genesis and exploration, Proceesing Joint Convention Yogyakarta 2019, hal 1-6

Einaudi, M.T., Meinert, L.D., and Newberry, R.J., 1981, Skarn deposits: ECONOMIC GEOLOGY 75TH ANNIVERSARRY VOLUME, p. 317-391.

Idrus, A., Setijadji, L,d., Thamba, F., 2011 Geology and Characteristics of Pb-Zn-Cu-Ag Skarn Deposit at Ruwai, Lamandau Regency, Central Kalimantan. Jurnal Geologi Indonesia, hal 191-201.

Lim, E., Yoo, B., Shin, D, 2016, Skarnization and Fe Mineralization at the Western Orebody in the Manjang Deposit, Goesan, J. Miner. Soc. Korea, v. 29 hal. 141-153

Meinert, L. D., 1992, Skarn and Skarns Deposits, Geoscience Canada, v.19, hal. 145–162.

Mollaei, H., Yaghubpur, A.M., dan Attar, R.S., 2009, Geology and Geochemistry of Skarn Deposits in the Northern Part of Athar Batholith, East Azarbaijan, NW Iran, Iranian Journal of Earth Sciences, hal. 15-34.

Pirajno, F., 2013, Chapter 7. Effects of Metasomatism on Mineral Systems and Their Host Rocks: Alkali Metasomatsm, Skarn, Greisens, Tourmalinites, Rodingites, Black-Wall Alteration and Listyenites, In Harlov, D. E., Austrheim, H. (eds) Metasomatism and the Chemical Transformation of Rock: The Role of Fluids in Terrestrial and Extraterrestrial Processes, Springer- Verlag, hal. 203-251.

Ridley, J., 2013, Ore Deposit Geology, Cambridge University Press, USA, 398 hal.

Robb, L., 2005, Introduction to Ore-Forming Processes, Blackwell Science Ltd, 373 hal.

Setijadji, L. D., Basuki, N. I., Prihatoko, S., 2010, Kalimantan Mineral Resources: An Update on Exploration and Mining Trends, Synthesis on Magmatism History and Proposed Models for Metallic Mineralization: Prosiding PIT IAGI Lombok 2010, hal. 14-28.

Morrison, K., 1997, Important Hydrotermal Minerals and their Significance, Mineral services, p. 58-63

Setijadji, L, D., Idrus, A., Thamba, F., 2011, Geology of the Ruwai Iron Zn-Pb-Ag Skarn Deposits Lamandau District, Central Kalimantan, Majalah Geologi Indonesia, vol 26, hal. 143-154.

Simbolon, D.R., Cendi D.P., Laurie E.W., 2019, Metallogenic Model of Ruwai Fe-Zn-Pb-Ag Skarn Deposit, Central Kalimantan: Understanding the Complexity from Proximal to Distal Base Metal Mineralization, Proceeding of MGEI Unlocking Concealed and Complex Deposit, hal. 115-122.

Sverdrupa, U., Olafsdottira, A.H., Ragnarsdottirb, K.V., 2019. On the long-term sustainability of copper, zinc and lead supply, using a system dynamics model Harald. Resources, Conservation & Recycling X, 1-21.

Whitney, D.l., Evans, B., 2010, Abbreviations for Names of Rocks-forming Minerals, American Mineralogist, v.95, hal. 185-187.

Williams-Jones, A.E., Samson, I.M., Ault, K.M., Gagnon, J.E., Fryer, B.J., 2010, The Genesis of Distal Zinc Skarns: Evidence from the Mochito Deposit, Honduras, Society of Economic Geologists, v.105, hal. 1411-1440.




DOI: https://doi.org/10.31284/j.semitan.j.2022.v1i1.4926

Refbacks

  • There are currently no refbacks.