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The Metamorphic Rocks-Hosted Gold Mineralization At Rumbia Mountains Prospect Area In The Southeastern Arm of Sulawesi Island, Indonesia Hasria Hasria; Arifudin Idrus; I Wayan Warmada
Journal of Geoscience, Engineering, Environment, and Technology Vol. 2 No. 3 (2017): JGEET Vol 02 No 03 : September (2017)
Publisher : UIR PRESS

Recently, in Indonesia gold exploration activities are not only focused along volcanic-magmatic belts, but also starting to shift along metamorphic and sedimentary terrains. The study area is located in Rumbia mountains, Bombana Regency, Southeast Sulawesi Province. This paper is aimed to describe characteristics of alteration and ore mineralization associated with metamorphic rock-related gold deposits. The study area is found the placer and primary gold hosted by metamorphic rocks. The gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). These quartz veins are currently recognized in metamorphic rocks at Rumbia Mountains. The quartz veins are mostly sheared/deformed, brecciated, irregular vein, segmented and relatively massive and crystalline texture with thickness from 1 cm to 15.7 cm. The wallrock are generally weakly altered. Hydrothermal alteration types include sericitization, argillic, inner propylitic, propylitic, carbonization and carbonatization. There some precious metal identified consist of native gold and ore mineralization including pyrite (FeS2), chalcopyrite (CuFeS2), hematite (Fe2O3), cinnabar (HgS), stibnite (Sb2S3) and goethite (FeHO2). The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18.4 ppm. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposit type. The orogenic gold deposit is one of the new targets for exploration in Indonesia

Alteration Alteration, Mineralization and Geochemistry of Metamorphic Rocks Hosted Hydrothermal Gold Deposit at Rumbia Mountains, Bombana Regency, Southeast Sulawesi, Indonesia Hasria Hasria; Arifudin Idrus; I Wayan Warmada
Journal of Geoscience, Engineering, Environment, and Technology Vol. 4 No. 2 (2019): JGEET Vol 04 No 02 : June (2019)
Publisher : UIR PRESS

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.

Characteristics of Ultramafic Igneous Rock Ofiolite Complex in Asera District, North Konawe Regency Southeast Sulawesi Province, Indonesia Hasria; Erzam S. Hasan; Deniyatno; L M Iradat Salihin; Asdiwan
Journal of Geoscience, Engineering, Environment, and Technology Vol. 5 No. 3 (2020): JGEET Vol 05 No 03 : September (2020)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2020.5.3.4113

The research area is located in Asera District, North Konawe Regency, Southeast Sulawesi Province which has ultramafic rock lithology. The purpose of this study is to determine the characteristics of ultramafic igneous rocks using petrographic and geochemical analysis. Petrographic analysis aims to determine the types and abundance of minerals present so that rock types can be determined based on the classification of Travis (1955) and Streckeisen (1976). The geochemical analysis aims to determine the oxide/major element so that it can determine the type of magma based on the AFM classification according to Irvine and Baragar (1971) and the origin of the magma / original rock formation environment based on Pearce (1977). Petrographic analysis results showed that ultramafic rocks in the study area consisted of 2 types of rocks namely peridotite consisting of wherlit and lherzoite and serpentinite. The results of geochemical analysis indicate that the type of magma in the study area is thoellitic series and the origin of the magma/rock formation environment comes from the expansion of the oceanic floor or mid oceanig ridge (MOR) which is ultramafic.

Analysis of Ultramafic Rocks Weathering Level Using the Magnetic Susceptibility in Konawe Regency, Southeast Sulawesi, Indonesia Jahidin; LO. Ngkoimani; LM. Iradat Salihin; Hasria; Erzam S. Hasan; Irfan Ido; Suryawan Asfar
Journal of Geoscience, Engineering, Environment, and Technology Vol. 5 No. 2 (2020): JGEET Vol 05 No 02 : June (2020)
Publisher : UIR PRESS

The Konawe region is part of the Sulawesi Southeast Arm ophiolite belt where ultramafic rocks are exposed in the form of dunite and peridotite. The formation of nickel deposits is closely related to the weathering process of ultramafic rocks as a source rock. Ultramafic rocks exposed to the surface will experience weathering which is influenced by many factors, including in the form of climate change, topography, and existing geological structures. The weathering process in the source rock can influence variations in chemical elements and magnetic properties in laterite soil profiles. For example, the chemical weathering might affect magnetic mineralogy and the physical weathering could affect granulometry as well as the quantity of magnetic minerals in the soil. Condition of weathering of ultramafic rocks (initial, moderate and advanced) can affect nickel content in laterite sediments. The weathering profile study of serpentine mineral is an indication of the lateralization process that occurs in ultramafic rocks and is carried out through petrographic analysis of thin cuts and polish cuts. Determination of weathering level like this is based on the level of weathering of the mineral serpentine. In this study, the determination of the weathering level of ultramafic rocks (initial, moderate, and continued) uses magnetic susceptibility parameter. A total of 232 ultramafic rock core samples obtained from 34 hand samples were taken from different places and weathered levels were analyzed. The results of the research have shown that the magnetic susceptibility of ultramafic rocks in the study area varies, from 580 x 10-6 SI to 4.724 x 10-6 SI. Based on the value of magnetic susceptibility, magnetic minerals contained in ultramafic rock samples are hematite and geotite minerals. This means that the weathering level of ultramafic rock samples is the continued weathering level. The level of continued weathering that occurs in ultramafic rocks in the study area produces nickel laterite deposits with a nickel content of 1.65 - 2.40% in the saprolite zone, 0.42% in the saprock zone, and 0.20 - 0.51% in the basic rock zone (bedrock).

Characteristics of Chromite Deposits at North Kabaena District, Bombana Regency, Southeast Sulawesi Province, Indonesia Hasria; Masri; Suryawan Asfar; Arisona; Ali Okto; La Ode Restele; La Ode Ngkoimani; Rika Yustika
Journal of Geoscience, Engineering, Environment, and Technology Vol. 6 No. 2 (2021): JGEET Vol 06 No 02 : June (2021)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2021.6.2.6424

The study area is located in North Kabaena District, Bombana Regency, Southeast Sulawesi. This paper is aimed to describe characacristics of chromite deposits. 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 and sampling of representative rocks types. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section. The results of petrographic analysis show that olivine minerals are generally replaced by minerals orthopyroxene and has been alterated by lizardite type serpentine veins with a fractured structure. The mineral olivine is also replaced by the mineral chrysotile as a secondary mineral with a fibrous structure. Based on ore microscopy analysis show that chromite has generally experienced a lateritification process and has been replaced by magnetite, hematite and geotite minerals. Chromite has experience process of weathering and alteration from its source rock caused by tectonics that occurred in the study area. The results shows that the characteristics of chromite deposits in North Kabaena District Chromite deposits has generally encountered in peridotite rock which have a grain size of 0.3-20 cm. Furthermore, chromite deposits in the study area are also encountered in podiform deposits, distributed locally and shows podiform to tubular shape with the dimensions of 30-60cm.

Serpentinization Study On Ultramafic Rock at Morombo Area, Lasolo Islands District, North Konawe Regency, Southeast Sulawesi, Indonesia Hasria; Febiyanti; Masri; Ali Okto; Erzam S. Hasan; La Hamimu; Sawaludin; La Ode Muhammad Iradat Salihin; Wahab
Journal of Geoscience, Engineering, Environment, and Technology Vol. 7 No. 1 (2022): JGEET Vol 07 No 01 : March (2022)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25299/jgeet.2022.7.1.6643

The research is in Morombo area, North Konawe Regency, Southeast Sulawesi. The purpose of this study was to determine the characteristics of serpentinized ultramafic rock and serpentine paragenesis. Research was conducted using field observations and laboratory analysis consisting of petrographic and geochemical analysis in the form of X-Ray Fluorosence (XRF). Petrographic analysis was carried out to identify the mineral content and textures in the rock and to determine the percentage of serpentine mineral presence. Both of these rocks are petrographically dominated by primary minerals olivine and clinopyroxine and secondary minerals namely lizardite, chrysotile, antiorite and opaque minerals. The XRF analysis was to determine the elements of Ni, Fe, Co, MgO, SiO2, CaO, Al2O3 and P in ultramafic rocks. The results of petrographic analysis show that serpentinized ultramafic rocks in the study area consist of serpentinized dunite and serpentinized peridotite. The formation of clay minerals in rocks does not occur because of the low serpentinization process in the rock. The results of XRF analysis showed that all samples in the bedrock showed Ni content above 0.2%. This is caused by the enrichment of Ni which is interpreted as a result of the serpentinization process along with the formation of lizardite in the rock. The serpentinization sub-processes in the study area comprised by hydration, serpentine recrystallization, and deserpentinization. Serpentine paragenesis is formed from the mid-oceanic ridge ocean floor, the orogenic phase to weathering. Substitution of Mg by Ni in ultramafic rocks will produce Ni-Serpentin. It is estimated that in the research area lizardite and chrysotile lizardite and chrysotile are the causes of Ni enrichment in bedrocks. The serpentinization characteristics of ultramafic rocks in the study area show a low to moderate level of serpentinization.

Preliminary Study Gold Mineralization Hosted By Metamorphic Rocks In The Southeastern Arm Of Sulawesi, Indonesia Hasria Hasria; Arifudin Idrus; I Wayan Warmada
UNEJ e-Proceeding 2016: Proceeding The 1st International Basic Science Conference
Publisher : UPT Penerbitan Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar

This paper is intended to describe an preliminary study of geological setting and gold mineralization hosted by metamorphic rocks in the southeastern arm of Sulawesi. The stratigraphy consists of three constituent rocks are continental terrain composed of metamorphic rocks, ophiolite complex are dominated by mafic and ultramafic rocks and Sulawesi Molasse composed of clastic sediments and carbonate. The origin of gold mineralization at Mendoke and Rumbia mountains only preliminary studies. A field study indicates that the Langkowala placer/paleoplacer gold is possibly related to gold-bearing quartz veins hosted by metamorphic rocks particularly mica schist, phyllite and metasediments in the area. These quartz veins are currently recognized in metamorphic rocks at Wumbubangka Mountains, a northern flank of Rumbia Mountain Range. At least, there are three generations of the quartz veins. The first generation of quartz vein is parallel to foliation of mica schist, phyllites and metasediments in up to 10 m wide zones. The second quartz vein generation crosscut the first quartz vein and the foliation of the wallrock. 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. The similar quartz veins types are also probably present in Mendoke mountain range, in the northern side of Langkowala area. The wallrock are generally weakly altered. Alteration types include argillic, silification, carbonate and carbonization alteration. This primary gold deposit is called as orogenic gold type and product of hydrothermal activity. The orogenic gold deposit is one of the new target of gold exploration are being developed in Indonesia.

Karakteristik batugamping Formasi Wapulaka dan pemanfaatannya sebagai bahan galian industri di Desa Wuna, Kabupaten Muna, Sulawesi Tenggara Ali Okto; Masri Masri; Marwan Zam Mili; Hasria Hasria
Jurnal Mineral, Energi dan Lingkungan Vol 5, No 1 (2021): Juni
Publisher : Fakultas Teknologi Mineral, Universitas Pembangunan Nasional (UPN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/jmel.v5i1.4030

Daerah penelitian merupakan kawasan karst yang tersusun atas batugamping terumbu berumur Plistosen. Secara administrasi, daerah penelitian terletak pada Desa Wuna, Kabupaten Muna, Sulawesi Tenggara. Hamparan batugamping terumbu tidak hanya dapat dimanfaatkan dalam geokonservasi, namun juga sebagai bahan industri. Metode yang digunakan adalah metode lapangan geologi dan pekerjaan laboratorium dengan data luaran utama adalah deskripsi sayatan tipis batugamping dan kandungan senyawa mayor batugamping. Pengolahan data lapangan menggunakan analisis petrografi dalam pemerian batuan dan analisis geokimia senyawa mayor untuk mengetahui jenis pemanfaatan batugamping. Batugamping dijumpai pada satuan perbukitan karst dan pedataran. Litologi penyusun berupa wackestone dan packstone yang kaya akan fragmen bioclast, kalsit, aragonit, mineral sekunder, dan porositas yang intens. Batugamping didominasi oleh CaO (kalsium oksida) dengan kadar rata-rata 94,44%. Beberapa sampel memiliki kadar MgO (magnesium oksida) tinggi hingga mencapai 4,4% yang mengindikasikan proses dolomitisasi. Data geokimia menunjukkan batugamping dapat digunakan untuk berbagai keperluan bahan industri seperti: industri semen, bata silika, soda abu, karbit, dan pemurnian baja. Batugamping packstone dan wackstone untuk bahan industri dicirikan oleh kelimpahan lumpur karbonat dan aragonit, serta minimnya mineral sekunder.

Fasies Batuan Metamorf Daerah Wumbubangka, Kecamatan Rarowatu Utara, Kabupaten Bombana, Provinsi Sulawesi Tenggara hasria hasria; Suryawan Asfar; Adriyansyah Adriyansyah; Masri Masri; Muliddin Muliddin; Arisona Arisona; Al Firman; Ali Okto; Laode M Golok Jaya
Jurnal Geomine Vol 9, No 1 (2021): Edisi April 2021
Publisher : Universitas Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33536/jg.v9i1.896

Daerah penelitian terletak di daerah Wumbubangka, Kecamatan Rarowatu Utara, Kabupaten Bombana, Provinsi Sulawesi Tenggara.Penelitian ini bertujuan untuk mengindentifikasi jenis batuan metamorf dan fasies metamorfisme yang terdapat di daerah penelitian. Metode penelitian yang digunakan terdiri dari studi pustaka, pengambilan sampel di lapangan, analisis labroratorium serta interpretasi data. Hasil penelitian menunjukkan bahwa litologi daerah penelitian umumnya terdiri dari sekis mukovit dan marmer. Sekis muskovit memiliki tekstur berupa lepidoblastik, struktur schistose, sedangkan marmer memiliki tekstur sisa dan struktur non foliasi. Adapun komposisi mineralnya terdiri dari kalsit, klorit, kuarsa, muskovit, biotit, glukofan dan mineral opak. Adapunfasies metamorfime batuan metamorf di daerah penelitianadalah fasies sekis hijau yang dicirikan dengan kehadiran mineral muskovit, klorit, biotit, kalsit dan kuarsa.Fasies sekis hijau ini diinterpretasikan terbentuk pada temperatur 300°C-500°C.

Karakteristik batugamping Formasi Wapulaka dan pemanfaatannya sebagai bahan galian industri di Desa Wuna, Kabupaten Muna, Sulawesi Tenggara Ali Okto; Masri Masri; Marwan Zam Mili; Hasria Hasria
Jurnal Mineral, Energi dan Lingkungan Vol 5, No 1 (2021): Juni
Publisher : Fakultas Teknologi Mineral, Universitas Pembangunan Nasional (UPN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/jmel.v5i1.4030

Daerah penelitian merupakan kawasan karst yang tersusun atas batugamping terumbu berumur Plistosen. Secara administrasi, daerah penelitian terletak pada Desa Wuna, Kabupaten Muna, Sulawesi Tenggara. Hamparan batugamping terumbu tidak hanya dapat dimanfaatkan dalam geokonservasi, namun juga sebagai bahan industri. Metode yang digunakan adalah metode lapangan geologi dan pekerjaan laboratorium dengan data luaran utama adalah deskripsi sayatan tipis batugamping dan kandungan senyawa mayor batugamping. Pengolahan data lapangan menggunakan analisis petrografi dalam pemerian batuan dan analisis geokimia senyawa mayor untuk mengetahui jenis pemanfaatan batugamping. Batugamping dijumpai pada satuan perbukitan karst dan pedataran. Litologi penyusun berupa wackestone dan packstone yang kaya akan fragmen bioclast, kalsit, aragonit, mineral sekunder, dan porositas yang intens. Batugamping didominasi oleh CaO (kalsium oksida) dengan kadar rata-rata 94,44%. Beberapa sampel memiliki kadar MgO (magnesium oksida) tinggi hingga mencapai 4,4% yang mengindikasikan proses dolomitisasi. Data geokimia menunjukkan batugamping dapat digunakan untuk berbagai keperluan bahan industri seperti: industri semen, bata silika, soda abu, karbit, dan pemurnian baja. Batugamping packstone dan wackstone untuk bahan industri dicirikan oleh kelimpahan lumpur karbonat dan aragonit, serta minimnya mineral sekunder.

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