Metamorphic Rock-Hosted Orogenic Gold Deposit Type as a Source of Langkowala Placer Gold, Bombana, Southeast Sulawesi

Arifudin Idrus, I. Nur, I. W. Warmada, Fadlin Fadlin


DOI: 10.17014/ijog.v6i1.114

In 2008, placer gold was discovered in Langkowala area (Bombana Regency), Southeast Sulawesi, Indonesia, and more than 60,000 traditional gold miners in the early 2009 have been operating by digging vertical pits and panning active stream sediments. The grade of placer gold ranges from 50 to 140 g/t. Local geological framework indicates that the placer gold is not related to volcanic rock-related hydrothermal gold deposit, e.g. epithermal, skarn or porphyry. This paper describes a preliminary study on possible primary deposit type as a source of the Langkowala (Bombana) secondary placer gold. A field study indicates that the Langkowala (Bombana) placer/paleoplacer gold is possibly related to gold-bearing quartz veins/veinlets hosted by metamorphic rocks particularly mica schist and metasediments in the area. These quartz veins/veinlets are currently recognized in metamorphic rocks at Wumbubangka Mountains, a northern flank of Rumbia Mountain Range. Sheared, segmented quartz veins/veinlets are of 2 cm to 2 m in width and contain gold in a grade varying between 2 and 61 g/t. At least, there are two generations of the quartz veins. The first generation of quartz vein is parallel to foliation of mica schist and metasediments with general orientation of N 300oE/60o; the second quartz vein generation crosscut the first quartz vein and the foliation of the wallrock. The first quartz veins are mostly sheared/deformed, brecciated, and occasionally sigmoidal, whereas the second quartz veins are relatively massive. The similar quartz veins/veinlets types are also probably present in Mendoke Mountain Range, in the northern side of Langkowala area. This primary gold deposit is called as ‘orogenic gold type’. The orogenic gold deposit could be a new target of gold exploration in Indonesia in the future.


placer gold; orogenic gold deposit; Langkowala; Bombana; Southeast Sulawesi


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. DOI:10.1016/S0169-1368(97)00012-7

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. DOI:10.2113/gsecongeo.98.1.1

Hamilton, W. B. 1979. Tectonics of the Indonesian region. USGS Prof. Paper 1078, 345 pp.; reprinted with corrections 1981 and 1985.

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 crystallisation conditions and fluorine-chlorine fugacity, Special Issue. Resource Geology, 57 (2), p.102-113. DOI:10.1111/j.1751-3928.2007.00010.x

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.

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. DOI:10.1111/j.1751-3928.2005.tb00245.x

Kompas Daily, 2008. Bombana Diserbu Penambang Liar, Published, online, 18th September, 2008.

Makkawaru, A. and Kamrullah, 2009. Laporan inventarisasi prospek emas daerah Bombana dan sekitarnya, Propinsi Sulawesi Tenggara. Unpublished, 10p.

Surono and Tang, H.A., 2009. Batuan pembawa emas primer dari endapan emas sekunder di Kabupaten Bombana, Sulawesi Tenggara berdasarkan interpretasi inderaan jauh. Prosiding PIT IAGI Semarang 2009, 11pp.

Simandjuntak, T.O., Surono, and Sukido, 1993. Peta Geologi Lembar Kolaka, Sulawesi, skala 1 : 250.000. Pusat Penelitian dan Pengembangan Geologi, Bandung.

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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