Occurrences and Characteristics of Gold Mineralization in Rampi Block Prospect, North Luwu Regency, South Sulawesi Province, Indonesia

https://doi.org/10.22146/jag.26962

Arifudin Idrus(1*), Suaib Mansur(2), Ahmad Ahmad(3), Rahmayuddin Rahmayuddin(4), Abdul Abdul(5)

(1) Geological Engineering Department, Faculty of Engineering, Gadjah Mada University
(2) Mining and Energy Agency, North Luwu District, South Sulawesi Province
(3) Mining and Energy Agency, North Luwu District, South Sulawesi Province
(4) Mining and Energy Agency, North Luwu District, South Sulawesi Province
(5) Mining and Energy Agency, North Luwu District, South Sulawesi Province
(*) Corresponding Author

Abstract


This study is aimed to identify the occurences, characterisatics and genetic type of gold mineralization, and to elucidate the preliminary gold potential in the study area. Research method includes field observation of prospect geology, hydrothermal alteration and ore mineralization. Laboratory analysis consists of petrography, ore microscopy and ore chemistry. Geologically, quartz ± gold veins were found in Rampi block prospect, which are mainly hosted by metamorphic and metasediment rocks. The quartz veins has structurally segmented with massive, brecciated and laminated textures. Orientation and distribution of veins is controlled by NW–SE and NE–SW trending structures. Sulfides are present with minor abundance (<1 %). Pyrite is obviously observed and partially oxidized. Arsenopyrite and stibnite are minor, while basemetal (Pb, Zn) sulfides are very rare. Gold mineralization occurred in quartz veins and closely related to silica-clay and silicic alteration. Gold grade varies from 0.1 to 11 ppm Au (29 samples). Quartz veins contained high gold grade (>9 ppm) commonly show laminated and brecciated texture and has been undergone a supergene enrichment. According to several characteristics above, gold deposit in Rampi block prospect tends to meet the criteria of orogenic/mesothermal gold type (cf. Groves et al., 2003). The deposit shares similarities with Awak Mas prospect, which is already confirmed to be a mesothermal type in Luwu district (cf. Querubin and Walters, 2011). Therefore, discoveries of economic mesothermal gold deposits are still open in the metamorphic terrains, and thus, it requires a systematic exploration based on the genetic model of the deposit.


Keywords


Gold · Orogenic/mesothermal · Rampi block prospect · North Luwu · Sulawesi · Indonesia.

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References

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: 1-29.

Harjanto, E., Meyer, F.M., Idrus, A. (2015) Geology and Mineralization of Awak Mas Gold Deposit and Challenges for New Exploration Targeting in the Metamorphic Rock Terrain of Eastern Indonesia, 13th SGA Meeting, Nancy, France, 24-27 August, 2015, p. 103-106.

Idrus, A., Kolb, J., Meyer, F.M. (2007) Chemical composition of rock-forming minerals in coppergold-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: 102-113.

Idrus, A., Warmada, I.W., Setyawan, I., Raditya, B., Kurnia, M. (2009) Endapan Urat Epitermal di Tirtomoyo, Kabupaten Wonogiri, Propinsi Jawa Tengah: Studi Awal mengenai Alterasi Hidrotermal, Mineralisasi Bijih dan Inklusi Fluida. Majalah Geologi Indonesia 24(1): 13-20.

Idrus, A., and Prihatmoko, S. (2011) The metamorphic rock-hosted gold mineralization at Bombana, Southeast Sulawesi: A new exploration target in Indonesia, Proceedings of The Sulawesi Mineral Seminar, Manado 28 29 November 2011, p. 243-258.

Idrus, A., Sufriadin, Nur, I. (2011) Hydrothermal Ore Mineralization in Sulawesi: A Point of View of Tectonic Setting and Metallogenesis, Proceeding JCM Makassar 2011, The 3th HAGI and 40th IAGI Annual Meeting, Makassar 26-29 September 2011, p. 298-310

Idrus, A., Prihatmoko, S., Hartono, H.G., Fadlin, Ernowo, Franklin, Moetamar, 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(1): 9-19.

Imai, A. and Nagai, Y. (2009) Fluid inclusion study and opaque mineral assemblage at the deep and shallow part of the Batu Hijau porphyry Cu-Au deposit, Sumbawa, Indonesia. Resource Geology, 59: 231-243.

Marshall, D., Anglin, C.D., Mumin, H. (2004) Ore Mineral Atlas, Geological Association of Canada, Mineral Deposits Division, St. Johns Newfoundland, 112 p.

Querubin, C.D., and Walters, S. (2011) Geology and Mineralization of Awak Mas: A Sedimentary Hosted Gold Deposit, South Sulawesi, Indonesia, Proceedings of The Sulawesi Mineral Seminar, Manado 28-29 November 2011, p. 211-229.

Simandjuntak, T.O., Rusmana, Surono, Supanjono (1991) Peta Geologi Lembar Malili, Majene dan Palopo Bagian Barat, P3G Bandung.

Thomson, A.J.B., Thomson, J.F.H. (1998) Atlas of Alteration, A Field and Petrographic Guide to Hydrothermal Alteration Minerals, Geological Association of Canada, Mineral Deposits Division, St. Johns Newfoundland, 119 p.

Warmada, I W. (2003) Ore mineralogy and geochemistry of the Pongkor epithermal gold-silver deposit, Indonesia, Dissertation. Papierflieger, Clausthal-Zellerfeld.

 



DOI: https://doi.org/10.22146/jag.26962

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