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ORE MINERALOGY AND MINERAL CHEMISTRY OF PYRITE, GALENA, AND SPHALERITE AT SORIPESA PROSPECT AREA, SUMBAWA ISLAND, INDONESIA Win Kant; I Wayan Warmada; Arifudin Idrus; Lucas Donny Setijadji; Koichiro Watanabe
Journal of Applied Geology Vol 4, No 1 (2012)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3683.914 KB) | DOI: 10.22146/jag.7191

Abstract

The Soripesa prospect area is located at Maria village, Wawo district, Bima region in the East Sumbawa Island, Indonesia. Lithology is dominantly composed of a lithic-crystal tuff of andesitic and dacitic composition and bedded limestone. The polymetallic epithermal quartz veins are hosted by andesitic volcaniclastic rocks. Within these veins, multiphases, colloform-crustiform, bedding to massive textures with pyrite, sphalerite, galena, chalcopyrite, chalcocite, azurite, and malachite are observed. Selected samples were analyzed by using ore microscopy and SEM-EDX. Ore minerals show replacement, ex-solution, colloform, and zonal textures. The paragenesis diagram was made from a careful study of polished sections and thin sections. Textures of ore minerals such as banded, exsolution, replacement, and zone, have been interpreted to correspond to the order of deposition. In pyrite, the average content of Co (0.45 wt.%) is higher than Ni content (0.14 wt.%) and it means that their origin may be hydrothermal origin. Average content ratio, Co:Ni is 2.81. Galena shows a low Ag content of 0.07 %in average. But they show a high Au content of 1.48 %in average. Sphalerite shows a low Fe content of 1.04 %in average and occasionally chalcopyrite inclusion/disease also occurred. Ga and Ge contents are also high in sphalerite. Co>Ni in pyrite, low content of Ag in Galena, low content of Fe and mole % FeS in sphalerite, high content of Ga and Ge, and log (Ga/Ge) in sphalerite, show that pyrite, galena, and sphalerite from Soripesa prospect area were formed under low temperature condition of hydrothermal fluid. Keywords: Ore textures, paragenesis, deposition, hydrothermal fluid, low temperature
Fluid Inclusion Study Of The Polymetallic Epithermal Quartz Veins At Soripesa Prospect Area, Sumbawa Island, Indonesia Win Kant; I Wayan Warmada; Arifudin Idrus; Lucas Donny Setijadji; Koichiro Watanabe
Journal of Applied Geology Vol 4, No 2 (2012)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3344.355 KB) | DOI: 10.22146/jag.7199

Abstract

The Soripesa prospect area is located at Maria village, Wawo district, Bima region in the eastern part of Sumbawa Island, Indonesia. This area is a part of Cenozoic Calc-alkaline volcanic inner Banda-Sunda Arc. The dominant lithology of Soripesa prospect area are a lithic-crystal tuff of andesitic and dacitic composition and bedded limestone. There have five main polymetallic epithermal quartz veins in the Soripesa prospect area, namely, Rini vein, Jambu air vein, Dollah vein, Merpati vein, and Arif vein. Those quartz veins are hosted mainly in andesitic volcaniclastic rocks. Fluid inclusion study on those quartz veins is vey important to know the condition of hydrothermal fluids and their origin. Fluid inclusion study is conducted at the laboratory of Earth Resources Engineering Department, Kyushu University, Japan. Homogenization temperature, freeze temperature, eutectic temperature, and melting temperature can be known from fluid inclusion study. Based on fluid inclusion study, formation temperatures of all veins are between 250–260◦C. Melting temperature is between -0.2 to -3◦C. Based on the melting temperature, salinity (wt.% NaCl equiv.) of fluid inclusions is calculated by using Bodnar’s equation. Paleodepth of formations and pressure of trapping are also estimated by using formation temperature and salinity. Based on Hass (1971) diagram, estimated paleodepths of formations are 270 m for Merpati vein, 400 m for Dollah vein, 480 m for Rini vein, 570 m for Arif vein, and 680 m for Jambu Air vein, respectively. Pressure of trapping can also be estimated from depth of formation, density of lithostatic overburden, and gravity; 72 bars for Merpati vein, 106 bars for Dollah vein, 127 bars for Rini vein, 151 bars for Arif vien, and 180 bars for Jambu Air vein, respectively. Keywords: Soripesa, polymetallic quartz veins, homogenization temperature, salinity.
HOST ROCKS’ GEOCHEMISTRY AND MINERALIZATION POTENTIAL OF POLYMETALLIC EPITHERMAL QUARTZ VEINS AT SORIPESA PROSPECT AREA, SUMBAWA ISLAND, INDONESIA Win Khant; I Wayan Warmada; Arifudin Idrus; Lucas Donny Setijadji; Koichiro Watanabe
Journal of Applied Geology Vol 5, No 1 (2013)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2935.663 KB) | DOI: 10.22146/jag.7205

Abstract

The Soripesa prospect area is located at Maria village, Wawo district, Bima region in the eastern part of Sumbawa Island, Indonesia. This area is a part of Cenozoic Calc-alkaline volcanic inner Banda- Sunda Arc. There are five main polymetallic epithermal quartz veins in the Soripesa prospect area, namely, Rini vein, Jambu air vein, Dollah vein,Merpati vein, and Arif vein. The dominant lithology is a lithic-crystal tuff of andesitic and dacitic composition and bedded limestone. Major oxides and trace elements were analyzed by using X-Ray Fluorescence (XRF) to identify the host rock geochemistry. The main veins are hosted by andesitic and andesitic/ basaltic volcanic host rocks. Major elements compositions are affected by alteration. Based on the trace element data, host rocks of all veins were formed in the volcanic arc basalt (VAB) and island arc basalt (IAB) tectonic settings. Host rocks of Rini vein contain higher amount of precious and base metal elements (Zn, Cu, Pb, and Ag.etc.) than those of other host rocks. Keywords: Soripesa prospect area, lithology, tectonic setting, mineralization.
OVERVIEW OF DEEP GEOLOGICAL CO2 STORAGE AND ITS AREA SELECTION METHOD Lucas Donny Setijadji
Journal of Applied Geology Vol 1, No 1 (2009)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (271.087 KB) | DOI: 10.22146/jag.7225

Abstract

Geological sequestration of CO2 inside deep geologic formations is revolutionary among several other initiatives to combat the global warming. This method is already approved globally as a reliable and likely to be the only option that will allow removing CO2 in large enough quantities over short enough times to make a real difference. The first step of any geological CO2 storage projects is to select appropriate sedimentary basins in which CO2 will be injected and stored temporarily or permanently within permeable geological layers. The criteria for site selection methods are here explained based on summary from stateof-the-art research findings now exist. This method is planned to be applied for a more detailed mapping of potential sedimentary basins in Indonesia and neighboring regions. Keywords: Sequestration, sedimentary basin, geological layers.
MERCURY AND ARSENIC CONTAMINATION FROM SMALL SCALE GOLD MINING ACTIVITIES AT SELOGIRI AREA, CENTRAL JAVA, INDONESIA Agung Harijoko; Tin May Htun; Rodhie Saputra; I Wayan Warmada; Lucas Donny Setijadji; Akira Imai; Koichiro Watanabe
Journal of Applied Geology Vol 2, No 1 (2010)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1689.074 KB) | DOI: 10.22146/jag.7235

Abstract

Small scale gold mines discussed here are located at Selogiri area, Central Java, Indonesia which was mined by local community mainly during gold rush in 1990s. This Selogiri gold deposit genetically is characterized by porphyry mineralization overprinted by epithermal system. The ore minerals assemblage consists of pyrite, sphalerite, chalcopyrite, galena, chalcocite and rare arsenopyrite. Chemical analysis of soil and stream sediment sampled over 1.5 km across at the Selogiri gold extraction site indicates that the site has been contaminated with mercury due to mining activities. The mercury concentrations in soil and stream sediments collected during dry season range from 0.01 to 481 ppm and 0.01 to 139 ppm, respectively, higher than background value of 0.05 ppm. In contrast, mercury concentration in stream sediments collected during rainy season from the same location as dry season sampling ranges from 0.01 to 13.42 ppm, and one sample has anomalous value of 331 ppm. This result show that rain water may disperse and decrease mercury concentration in stream sediments. In case of arsenic, although the ore contains rare arsenic minerals, arsenic concentration in bulk rock and ore is high ranging from 8 to 59 ppm, while the arsenic concentration in tailing is much higher ranging from 5.8 to 385 ppm. Chemical analyses on pyrite reveal that the pyrite grains contain arsenic and might be the source of arsenic in Selogiri mine site. However, analysis of dug-well water demonstrates that the mercury and arsenic content is still lower than the maximum allowable concentration. Keywords: Mercury, arsenic, contamination, Selogiri, gold mine
Hydrothermal Alteration and Mineralization of the Randu Kuning Porphyry Cu-Au and Intermediate Sulphidation Epithermal Au-Base Metals Deposits in Selogiri, Central Java, Indonesia Sutarto Sutarto; Arifudin Idrus; Agung Harijoko; Lucas Donny Setijadji; Franz Michael Meyer; Sven Sindern; Sapto Putranto
Journal of Applied Geology Vol 1, No 1 (2016)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (23220.401 KB) | DOI: 10.22146/jag.26951

Abstract

The Randu Kuning Porphyry Cu-Au prospect area is situated in the Selogiri district, Wonogiri regency, Central Java, Indonesia, about 40 km to the South-East from Solo city, or approximately 70 km east of Yogyakarta city. The Randu Kuning area and its vicinity is a part of the East Java Southern Mountain Zone, mostly occupied by both plutonic and volcanic igneous rocks, volcaniclastic, silisiclastic and carbonate rocks. Magmatism-volcanism products were indicated by the abundant of igneous and volcaniclastic rocks of Mandalika and Semilir Formation. The Alteration zones distribution are generally controlled by the NE–SW and NW–SE trending structures. At least eight types of hydrothermal alteration at the Randu Kuning area and its vicinity had been identified, i.e. magnetite + biotite ± K-feldspar ± chlorite (potassic), chlorite + sericite + magnetite ± actinolite, chlorite + magnetite ± actinolite ± carbonate (inner propylitic), chlorite + epidote ± carbonate (outer propylitic), sericite + quartz + pyrite (phyllic), illite + kaolinite ± smectite (intermediate argillic), illite + kaolinite ± pyrophyllite ± alunite (advanced argillic) and quatz + chlorite (sillisic) zones. The Randu Kuning mineralization at Selogiri is co existing with the porphyry Cu-Au and intermediate sulphidation epithermal Au-base metals. Mineralization in the porphyry environment is mostly associated with the present of quartz-sulphides veins including AB, C, carbonate-sulphides veins (D vein) as well as disseminated sulphides. While in the epithermal prospect, mineralization is particularly associated with pyrite + sphalerite + chalcopyrite + carbonate ± galena veins as well as hydrothermal breccias. The Randu Kuning porphyry prospect has copper gold grade in range at about 0.66–5.7 gr/t Au and 0.04–1.24 % Cu, whereas in the intermediate sulphidation epithermal contain around 0.1–20.8 gr/t Au, 1.2–28.1 gr/t Ag, 0.05–0.9 % Zn, 0.14–0.59 % Pb and 0.01–0.65 % Cu.
Geochemistry, Hydrothermal alteration and Ore mineralogy of Skarn Mineralization at Wethey-Pheshey area, Thabeikkyin Township, Mandalay Region, Myanmar Toe Naing Oo; Lucas Donny Setijadji; I Wayan Warmada; Than Than Oo
Journal of Applied Geology Vol 1, No 2 (2016)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (17878.483 KB) | DOI: 10.22146/jag.26961

Abstract

Wethey-Pheshy area is located 80 km north of Mandalay at Thabeikkyin Township, Mandalay Region. X-ray Diffraction (XRD) Analysis and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were applied in this study. Geochemical studies on the host rocks indicate that major and minor oxides compositions of metamorphicrocks show some degree of variation. CaO, MgO, FeO, TiO2 and P2O5 concentration of the metamorphic rock samples show a coherent negative correlation with SiO2 whereas Na2O is positively correlated with SiO2. The metamorphic rocks are strongly enriched in light rare earth elements (LREE) and relatively depleted in heavy rare earth element (HREE). The depleted Eu-nomalies in the chondrite-normalized REE diagrams indicate a plagioclase-depleted Eu crustal source or fractionation during magmatic differentiation. Intrusion of granitic rocks in the diopside marble caused the base metal ore mineralization and associated skarn alterations. Granite shows the sub-alkaline nature and peraluminous character. It is identified as I-type granite (magnetite series) developed in the volcanic arc setting. Hydrothermal alteration types associated with gold and skarn mineralization in the study area include calc-silicate alteration, propylitization, sericitization (argillitization) and hematization. Based on the nature and characteristics of host rocks, mineralization and alteration style and geochemical characteristics in the study area is identified as intrusion-related skarn mineralization. Common ore minerals include chalcopyrite, galena, sphalerite, pyrite, gold and Fe-oxides. 
MINERALOGY, GEOCHEMISTRY, AND SEQUENTIAL EXTRACTION EXPERIMENT OF REE IN WEATHERED ANGGI GRANITE, MANOKWARI REGENCY, WEST PAPUA, INDONESIA Ega Gita Prasastia; Lucas Donny Setijadji; I Wayan Warmada
Journal of Applied Geology Vol 7, No 1 (2015)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2238.743 KB) | DOI: 10.22146/jag.26978

Abstract

This research objective is to identify geochemical andmineralogical characteristics of Rare earth elements(REE) in the weathering products of Anggi Granite, which is located in Manokwari Regency, WestPapua, Indonesia. The research is conducted on 7samples of fresh rocks and 7 samples of weatheredrocks of Anggi Granite. The research analysis consists of petrography, XRD, XRF, and sequential extraction experiment, supported by secondary dataand references. Anggi Granite is S-type and peraluminous granite that contains zircon, monazite andapatite as a rare earth bearing minerals. Weathering products of Anggi Granite do not have a significant enrichment of REE, even some of the samplesare depleted in REE. REE in weathered Anggi Granite are dominantly present in the primary minerals,mostly in zircon and monazite. Extractable formof geochemical fractions include crystalline Fe-oxideoccluded fraction (ilmenite, hematite and goethite),and ion-exchangeable (illite, kaolin and chlorite).Enrichment of REE in the weathered Anggi Granite is influenced by the presence of resistant REEbearing minerals, in the forms of zircon and monazite, degree of weathering related to the presenceof secondary minerals, and other factors such as pHand Eh
MINERAL POTENTIAL MAPPING USING GEOGRAPHIC INFORMATION SYSTEMS (GIS) FOR GOLD MINERALIZATION IN WEST JAVA, INDONESIA Seang Sirisokha; Lucas Donny Setijadji; I Wayan Warmada
Journal of Applied Geology Vol 7, No 2 (2015)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (13444.738 KB) | DOI: 10.22146/jag.26980

Abstract

Western Java is a part of the Sunda Banda magmatic belt. This belt is well known to be host for several gold deposits in Indonesia, the distribution of 107 Au occurrences in this area was examined in terms of spatial association with various geological phenomena. The goal of this project is to use GIS to conduct weights of evidence (WofE) model for gold mineralization in West Java, Indonesia. A Geographic Information System (GIS) is a computer system for capturing, storing, querying, analyzing, and displaying geospatial data and weight of evidence method is one of the most important datadriven methods for mapping in GIS. The method is a probability based on technique for mapping mineral potential using the spatial distribution of known mineral occurrences. Therefore this method is very useful for gold potential mapping. There are six evidences maps such as NE–SW lineaments NW–SE Lineament, host rocks, heat sources, clay alteration and limonitic alteration, have been combined using a weights of evidence model to predict gold potential in West Java. The best predictive map generated by this method defines 21.62% (9902 km) of study area as favourable zones for gold mineralization further exploration work. It predicts correctly 74 (92.5%) of the 80 model deposits and predicts correctly 26 (96.35%) of the 27 validation deposits, has 6 main 2 prospective target for future exploration are located in Bayah Dome, southern mountain, Honjie Igneous Complex and Bogor zone, Purwakarta. Bayah Dome is highest potential area for gold deposit like Gunung Pongor, Cikidang, Cirotan, Ciawitali, Cikotok destricts and other deposits. The potential area of Au occurrences in research area is associated with NE–SW and NW–SE structure/ lineaments, dominated surrounding the Tertiary intrusive rock unit and hosted in Miocene to Pleistocene lithology rock unit.
VEINS AND HYDROTHERMAL BRECCIAS OF THE RANDU KUNING PORPHYRY Cu-Au AND EPITHERMAL Au DEPOSITS AT SELOGIRI AREA, CENTRAL JAVA INDONESIA Sutarto Sutarto; Arifudin Idrus; Agung Harijoko; Lucas Donny Setijadji; Franz Michael Meyer
Journal of Applied Geology Vol 7, No 2 (2015)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (20215.791 KB) | DOI: 10.22146/jag.26982

Abstract

The Randu Kuning prospect is situated at Selogiri area, Wonogiri, Central Java, Indonesia. This location is about 40 km to the south-east from Solo city or approximately 70 km east of Yogyakarta city. Many Tertiary dioritic rocks related alterationmineralisation were found at the Randu Kuning area and its vicinity, including hornblende microdiorite, hornblende-pyroxene diorite and quartz diorite. Mineralisation type of the Randu Kuning prospect was interpreted as porphyry Cu-Au and a number epithermal Au-base metals deposits in its surrounding. The closed existing of porphyry Cu-Au and epithermal Au-base metals type deposits at the Randu Kuning area produced a very complex of veins and hydrothermal breccias crosscutting relationship. A lot of porphyry veins types were found and observed at the Randu Kuning area, and classified into at least seven types. Most of the porphyry veins were cross cut by epithermal type veins. Many epithermal veins also are found and crosscut into deeply porphyry vein types. There are genetically at least two type of hydrothermal breccias have recognized in the research area, i.e. magmatic-hydrothermal breccia and phreatomagmatic breccia. Magmatic hydrothermal breccias are mostly occured in contact between hornblende microdiorite or quartz diorite and hornblende-pyroxene diorite, characterized by angular fragments/clasts supported or infilled by silicas, carbonates and sulphides matrix derived from hydrothermal fluids precipitation. Phreatomagmatic breccias are characterized by abundant of the juvenile clasts, indicated contact between hot magma with fluid or water as well as many wall rock fragments such as altered diorites and volcaniclastic rock clasts set in clastical matrix. The juvenile clasts usually compossed by volcanic glasses and aphanitic rocks in rounded-irregular shape. Both veining and brecciation processes have an important role in gold and copper mineralisation of the Randu Kuning Porphyry Cu-Au and epithermal Au-base metals deposits, mostly related to the presence of quartz veins/veinlets containing significant sulphides, i.e., quartz with thin centre line sulphides (Abtype) veins, pyrite±chalcopyrite (C type) veinlets, pyrite+quartz± chalcopyrire±carbonate (D type) veins of porphyry types as well as epithermal environment quarts+ sulphides+carbonate veins.