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Journal : Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources)

THE METAMORPHIC ROCK-HOSTED GOLD MINERALIZATION AT BOMBANA, SOUTHEAST SULAWESI: A NEW EXPLORATION TARGET IN INDONESIA Idrus, Arifudin; Fadlin, Fadlin; Prihatmoko, Sukmandaru; Warmada, I Wayan; Nur, Irzal; Meyer, Franz Michael
Jurnal Geologi dan Sumberdaya Mineral Vol 22, No 1 (2012): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (533.652 KB)

Abstract

Placer gold has been discovered in Bombana, SE-Sulawesi, Indonesia. The placer gold is not associated with volcanic rock-related gold deposits. This paper discusses the primary gold mineralization as the source of the placer gold. The placer gold is possibly derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). Pyrite, chalcopyrite, cinnabar, stibnite and tripuhyite are present. Sheared, segmented vein varies in thickness from 2 cm to 2 m. The veins contain erratic gold in various grades from below detection limit (0.005 g/t) to 134 g/t. At least three generations of veins are identified. The first is parallel to the foliations, the second crosscuts the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. The first veins are mostly massive to crystalline, occasionally brecciated and sigmoidal, whereas the second veins are narrower than the first and relatively brecciated. Gold grades in the second and third veins are relatively higher than that in first veins. Fluid inclusion study of quartz veins indicates abundant H2O-NaCl and a small amount of H2O-NaCl-CO2 inclusions. Temperature of homogenization (Th) and salinity of the first vein vary from 184.7 to 245.3 ºC and 5.26 to 9.08 wt.% NaCl eq., respectively. The second generation vein was originated at Th of 132.1-283.4 ºC and salinity of 3.55-5.86 wt.%NaCl eq., whereas the third generation vein formed at lowest Th varying from 114 to 176ºC and less saline fluid at salinity range between 0.35 and 4.03 wt.% NaCl eq. Gold is mainly identified in the form of 'free gold' among silicate minerals. Mineralogically, gold is closely related to cinnabar, stibnite, tripuhyite and possibly minor arsenopyrite. Metamorphogenic gold deposits would be the new target of gold exploration in Indonesia.Keyword: Gold mineralization, orogenic-type, Bombana, Southeast Sulawesi, Indonesia
Karakteristik Fluida Hidrotermal Endapan Emas Orogenik di Pegunungan Rumbia, Kabupaten Bombana, Provinsi Sulawesi Tenggara Hasria, Hasria; Idrus, Arifudin; Warmada, I Wayan
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 2 (2019): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (239.487 KB) | DOI: 10.33332/jgsm.geologi.20.2.111-117

Abstract

Recently, gold exploration activities  are not only focused along volcanic-magmatic belt but also starting to shift along metamorphicand sedimentary terrains. The purpose of this study is to analyses the characteristics hydrothermal fluids gold deposits t in the Rumbia Mountains, Bombana Regency, Southeast Sulawesi. There are three generations of veins identified including the first is parallel to the foliations, the second crosscuts the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. Temperature of homogenization (Th) and salinity at Rumbia Mountain of the first vein vary from 220 to 355.30oC and 6.74 to 10.11 wt. % NaCl eq., respectively. The second generation vein was originated at Th of 157 to 255.50oC and salinity of 3.39 to 6.88 wt.%NaCl eq., whereas the third generation vein formed at lowest Th varying from 104.40 to 265.90oC and less saline fluid at salinity range between 0.18 and 6.30 wt.% NaCl eq. The result of temperature formation value correlation to the depth of the formation of orogenic gold deposits in Rumbia Mountain is indicated to form on sub-greenschist to greenschist facies at depth of about 4-8 kilometers and formation temperature between 104.40 - 355.30oC at zone epizonal and mesozonal. Based on characteristics fluids inclusion discussed above, the primary metamorphic-hosted gold mineralization type at Rumbia Mountain tends to meet the criteria of orogenic gold type.  Keyword : fluid iclusion, quartz veins, Rumbia mountain, orogenic gold deposits.
Co-Authors A. Harijoko A. Imai A. Imai A. M. Imran A. W. Yogatama Agung Harijoko Agus Prasetya Ahmad Aminuddin, Muhammad Irman Khalif bin Akira Imai Al-Furqan, Reza Aldian Fahrialam Alvian Rizky Yanuardian Anastasia Dewi Titisari Anita Yuliyanti Anita Yuliyanti Ariffin, Kamar Shah Arifudin Idrus Arifudin Idrus Arifudin Idrus Arifudin Idrus Atmaja, Ammar Dwi Aulia Rahmah Karunianti Aung Tay Zar Aung Tay Zar, Aung Tay Bhakti H. Harahap Bhakti H. Harahap Bunchoeun Pich Chusni Ansori Denizar Rahman Dian Novia Sartika Dian Yesy Fatimah Diyan Aditya Putra Pratama Doni Prakasa Eka Putra Ega Gita Prasastia Endah Retnaningrum Endah Retnaningrum Endang Tri Wahyuni F. Pratiwi Fadlin Fadlin Fadlin Fadlin Fadlin Fadlin Fadlin, Fadlin Franz Michael Meyer Franz Michael Meyer Franz Michael Meyer, Franz Michael Gevor, Even Hakim, Fahmi Haryono, Septiawan Nur Hasria Hasria Hasria Hasria Hasria Hasria, Hasria Herry Yogaswara Heru Hendrayana Hideki, Ohta Himawan Tri Bayu Murti Petrus Hirajima, Tsuyoshi Htun, Tin May I Gde Budi Indrawan I. G. Sukadana I. Nur I. Nur I. Nur Ilham, Muhamad Imai, A. Imai, Akira Irzal Nur Irzal Nur, Irzal Iwan Setiawan Jochen Kolb Johan Syafri Mahathir Ahmad Kaharuddin Kaharuddin Kaharuddin, Kaharuddin Kamar Shah Ariffin Kant, Win Kha Yay Oo Khant, Win Koichiro Watanabe Koichiro Watanabe Koichiro Watanabe Koichiro Watanabe Koichiro Watanabe Koichiro Watanabe, Koichiro Kolb, Jochen Kotaro Yonezu Kusumaningrum, Serafica Btari Christiyani Kyaw Linn Zaw Leonardo Anthony Wijaya Linn Zaw, Kyaw Listiyastuti, Riana Lucas Donny Setijadji Makruf Nurudin Martadiastuti, Vanadia Maulana, Deviana Shinta Mochammad Aziz Mochammad Aziz, Mochammad Mudinillah, Adam Muhammad Irman Khalif bin Ahmad Aminuddin Muhammad Zulfikrie Mutiara Selvina Myo Min Tun Myo Min Tun Myo Min Tun Naing Oo, Toe Nugroho Imam Setiawan Nur, I. Nur, I. Okki Verdiansyah Okki Verdiansyah Okki Verdiansyah Oo, Than Than Pich, Bunchoeun Pramumijoyo, Pranayoga Pramumijoyo, S. Pranayoga Pramumijoyo Prasastia, Ega Gita Putra Pratama, Diyan Aditya Rahman, Denizar Retno Hartati Reza Al-Furqan Riyadi, Hasan Rodhie Saputra S. Pramumijoyo S. Pramumijoyo Salafudin Salafudin, Salafudin Sang Kompiang Wirawan Saputra, Rodhie Sartika, Dian Novia Seang Sirisokha Septiawan Nur Haryono Shinta Maulana, Deviana Simamora, Lestari Sutra Sirisokha, Seang Soewondo, Widiasmoro Subagyo Pramumijoyo Subagyo Pramumijoyo, Subagyo Sufriadin, Sufriadin Sukmandaru Prihatmoko Sukmandaru Prihatmoko Syafruddin Maula Syafruddin Maula T. B. Adimedha Takemura, Jiro Tetsuro Yoneda Than Than Oo Tin May Htun Toe Naing Oo Tsuyoshi Hirajima Tsuyoshi Hirajima Tun, Myo Min Ubaidillah, Aji Syailendra Vanadia Martadiastuti Wahyu Wilopo Wawan Budianta Widiasmoro Soewondo Win Kant Win Khant Yoneda, Tetsuro Yonezu, Kotaro Yonezu, Kotaro