Alteration Alteration, Mineralization and Geochemistry of Metamorphic Rocks Hosted Hydrothermal Gold Deposit at Rumbia Mountains, Bombana Regency, Southeast Sulawesi, Indonesia
DOI:
https://doi.org/10.25299/jgeet.2019.4.2.2346Keywords:
Alteration, ore mineralogy, geochemistry, hydrothermal gold deposit, metamorphic rocks, Rumbia mountainsAbstract
In Indonesia, gold is commonly mined from porphyry, epithermal and skarn type deposits that are commonly found in volcanic/magmatic belts. However, were recently numerous gold prospects discovered in association with metamorphic rocks. This paper is intended to describe an alteration and ore mineralogy hosted by metamorphic rocks at Rumbia mountains, Bombana regency, Southeast Sulawesi province, Indonesia. The study area is found the placer and primary gold hosted by metamorphic rocks. The placer gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). This study is conducted in three stages, three stages including desk study, field work and laboratory analysis. Desk study mainly covers literature reviews. Field work includes mapping of surface geology, alteration and ore mineralization as well as sampling of representative rocks types, altered rocks and gold-bearing veins. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section, XRD (X-ray diffraction), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), ICP-MS (Inductively Coupled Plasma Emission Mass Spectrometry and FA/AAS (Fire Assay/Atomic Absorbtion Spectophotometry) analysis. The results shows that the alteration characteristics of hydrothermal gold deposits in Mendoke and Rumbia mountain consist of 3 (three) alterations namely sericitic, argillic dan propylitic. Characteristics of mineralization hydrothermal gold deposits in the research area are generally p related to gold-bearing quartz veins/veinlets consist of chalcopyrite, pyrite, chrysocolla, covellite, cinnabar, magnetite, hematite and goetite in rocks categorized into greenschist facies. There are three generations of veins identified including the first is parallel to the foliations, the second crosscut the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. The quartz veins commonly deformed, segmented, massive, laminated, irregular, brecciated, and occasionally sigmoidal. The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18,4000 at found in third generation veins which are laminated quartz±calcite in argillic alteration. ppm. The protoliths of metamorphic rocks in Rumbia Mountain, which comes from sedimentary rocks, spesifically pelitic rocks and graywacke. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposits type. The orogenic gold deposit is one of the new targets for exploration in Indonesia.
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References
Gebre-Mariam, M., Hagemann, S.G., and Groves, D.I., 1995. A Classification Scheme for Epigenetic Archaen Lode-Gold Deposits. Mineralium Deposits, 30, 408-410.
Goldfarb, R.J., and Groves, D.I., 2015. Orogenic Gold : Common or Evolving Fluid and Metal Sources Through Time. Lithos, 233, 2-26
Goldfarb, R.J., Baker, T., Dube, B., Groves, D.J., Hart, C.J.R., and Gosselin, P., 2005. Distributioncharacter and genesis of gold deposits in metamorphic terrains. In: Hedenquist, J.W., Thompson, J.F.H., Goldfarb, R.J., Richards, I.P (Eds.), Economic Geology. One Hundredth Anniversary Volume, p. 407-450.
Groves, D.I., 1993, The crustal continuum model for late-Archaean lodegold deposits of the Yilgarn block, Western Australia: Mineralium Deposita, v. 28, p. 366–374.
Groves, D. I., Goldfarb, R. J., and Robert, F., 2003. Gold deposit in metamorphic belts: Overview or current understanding, outstanding problems, future research, and exploration significance. Economic Geology, 98, p.1-29.
Groves, D. I., Goldfarb, R. J., Gebre-Mariam, M., Hagemann, S. G., and Robert, F., 1998. Orogenic gold deposit: A proposed classification in the context or their crustal distribution and relationship to other gold deposit types. Ore Geology Review, 13, p.7-27.
Hasria., Idrus, A., Warmada, I.W. 2017. The Metamorphic Rocks-Hosted Gold Mineralization at Rumbia Mountains Prospect Area in the Southeastern Arm of Sulawesi Island, Indonesia. Journal of Geoscience, Engineering, Environment, and Technology, 2, 213-227.
Idrus, A., 2009. Potensi Sumberdaya Mineral Bijih pada Busur Magmatik Sulawesi bagian Barat dan Utara, Invited speaker on National Seminar “Geologi Sulawesi dan Prospeknya”, Makassar, 3 Oktober 2009, 26pp.
Idrus, A., Fadlin., Prihatmoko, S., Warmada, I.W., Nur, I., and Meyer, F.M., 2012. The metamorphic rock-hosted gold mineralization at Bombana, Southeast Sulawesi: a new exploration target in Indonesia. Jurnal Sumber Daya Geologi, (22) 1: 35-48.
Idrus, A., Hakim, F., Warmada, I.W., Aziz, M., Kolb, M and Meyer, F.M., 2015. Geology and ore mineralization of Neogene sedimentary rock hosted LS epithermal gold deposit at Paningkaban, Banyumas Regency, Central Java, Indonesia.Journal of Southeast Asian Applied Geology,Volume 7(2), pp. 73-79.
Idrus, A., Kolb, J., and Meyer, F.M., 2007. Chemical composition of rock-forming minerals in copper-gold- bearing tonalite porphyry intrusions at the Batu Hijau deposit, Sumbawa Island, Indonesia: Implications for crystallization conditions and fluorine-chlorine fugacity, Special Issue. Resource Geology, 57 (2), p.102-113.
Idrus, A., Kolb, J., and Meyer, F.M., 2009. Mineralogy, Lithogeochemistry and Elemental Mass Balance of the Hydrothermal Alteration Associated with the Gold-Rich Batu Hijau Porphyry Copper Deposit, Sumbawa Island, Indonesia. Resource Geology, 59, 215-230.
Idrus, A., Nur, I., Warmada, I W., and Fadlin., 2011. Metamorphic rock-hosted orogenic gold deposit type as a source of Langkowala placer gold, Bombana, Southeast Sulawesi. Jurnal Geologi Indonesia, (6) 1: 43-49.
Idrus, A., Prihatmoko, S., Hartono, GH., Idrus., Ernowo, Franklin, Moetamar and Setiawan, I., 2014. Some Key Features and Possible Origin of the Metamorphic Rock-Hosted Gold Mineralization in Buru Island, Indonesia. Indonesian Journal on Geoscience, 1, 9-19.
Idrus, A. and Prihatmoko, S., 2011. The metamorphic-hosted gold mineralization at Bombana, Southeast Sulawesi. A new exploration target in Indonesia. Proceedings MGEI Conference Mineral Resources of Sulawesi, Manado, 2011
Imai, A. and Ohno, S., 2005. Primary ore mineral assemblage and fluid inclusion study of the Batu Hijau porphyry Cu-Au deposit, Sumbawa, Indonesia. Resource Geology, 55, p.239-248.
O'Connor, F.A., Lucey, B.M., Batten, J.A., and Baur, D.G., 2015. The financial economics of gold-A survey. International Review of Financial Analysis, 1-20p.
Simandjuntak, T.O., Surono, and Sukido., 1993. Peta Geologi Lembar Kolaka, Sulawesi, skala 1 : 250.000. Pusat Penelitian dan Pengembangan Geologi, Bandung.
Surono., 2013. Geologi Lengan Tenggara Sulawesi. Badan Geologi, Kementerian Energi dan Sumber Daya Mineral. Bandung, 169p.
Thompson, A.J.B, and Thompson, J.F.H. 1996. Atlas of Alteration A Field and Petrographic Guide to Hydrothermal Alteration Minerals. Geological Association of Canada, Mineral Deposits Division, Department Of Earth Sciences, 118p.
Van Leeuwen, T.M. and Pieters, P.E. 1992. Mineral Deposits of Sulawesi, Geological Agency, Bandung.
Wadji, M.F., Santoso, S.T.J., Kusumanto, D., and Digdowirogo, S., 2011. Metamorphic Hosted Low Sulfidation Epithermal Gold System at Poboya, Central Sulawesi : A General Descriptive Review, Proceedings of The Sulawesi Mineral Seminar, Manado 28-29 November 2011, p. 201-210.
Warmada, I W., 2003. Ore mineralogy and geochemistry of the Pongkor epithermal gold-silver deposit, Indonesia. Dissertation. Papierflieger, Clausthal-Zellerfeld. ISBN: 3-89720-658-7.
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