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Geology, Geochemistry and Hydrothermal Fluid Characteristics of Low Sulfidation Epithermal Deposit in the Sangon Area, Kokap, Special Region of Yogyakarta Pramumijoyo, Pranayoga; Idrus, Arifudin; Warmada, I Wayan; Yonezu, Kotaro
Journal of Applied Geology Vol 2, No 1 (2017)
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Abstract

On the basis of the previous studies and reconnaissance survey in the studyarea covering Sangon, Kalirejo, Kokap Sub-district, Kulon Progo Regency, Special Region of Yogyakarta, it reveals some facts of the occurrence of quartz veins with massive, crustiform, comb, drusy cavity, saccharoidal, granular, and reniform/mammillated textures, the appearance of lattice bladed barite and hydrothermal breccia veins. Referring to those characteristics, the deposit type in the study area is interpreted to be low sulfidation epithermal type. This study is aimed to understand and characterize the geological condition, rock and ore geochemistry and the mineralizing fluids. The alteration and ore mineralization are almost observed in entire rock units particularly the intrusive andesite 1. Their formation is controlled by the tension fractures (NW–SE and NE–SW) which associate with sinistral strike slip faults (NE–SW), dilational jog (NNW–SSE), oblique normal fault (WNW–ESE), and predictable normal fault at the NE of study area (NW–SE). The alteration zones are developed to be silica-clay (quartz-illite-kaolinite-kaolinite/smectite), argillic (smectite-illite/smectite), and propylitic (chlorite-calcite±epidote). The precipitationof ore minerals is controlled by boiling, mixing, and wall-rock alteration, and canbe found in the quartz veins (quartz-adularia-sericite) and disseminated in the alteration zones, which their high variability is only can be found in the quartz veins, including pyrite, sphalerite, chalcopyrite, galena, marcasite, and arsenopyrite. Based on the ICPAES measurement of 5 quartz vein samples, the Cu, Zn, Pb, and As grade reach about 5,171 ppm, 8,995 ppm, 6,398 ppm, 34.1 ppm, and 1,010.5 ppm, respectively. Gold is not detected. Fluid inclusion microthermometric analysis shows Th of 242.1–257.6 °C and salinity of 1.57–3.87 wt.% NaCl equiv., which indicate a depth below the paleosurface of 384–516 m, and pressure of 101.7–136.6 bar. The ore deposit in the study area is interpreted to be a deep basemetal low sulfidation epithermal type. Gold might be depleted in this epithermal type.
MINERAL POTENTIAL MAPPING USING GEOGRAPHIC INFORMATION SYSTEMS (GIS) FOR GOLD MINERALIZATION IN WEST JAVA, INDONESIA Sirisokha, Seang; Setijadji, Lucas Donny; Warmada, I Wayan
Journal of Applied Geology Vol 7, No 2 (2015): Current Issue
Publisher : Geological Engineering Department Universitas Gadjah Mada

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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.
MINERALOGY, GEOCHEMISTRY, AND SEQUENTIAL EXTRACTION EXPERIMENT OF REE IN WEATHERED ANGGI GRANITE, MANOKWARI REGENCY, WEST PAPUA, INDONESIA Prasastia, Ega Gita; Setijadji, Lucas Donny; Warmada, I Wayan
Journal of Applied Geology Vol 7, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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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
COPPER (Cu2+) REMOVAL FROM WATER USING NATURAL ZEOLITE FROM GEDANGSARI, GUNUNGKIDUL, YOGYAKARTA Wilopo, Wahyu; Haryono, Septiawan Nur; Eka Putra, Doni Prakasa; Warmada, I Wayan; Hirajima, Tsuyoshi
Journal of Applied Geology Vol 2, No 2
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Development of indusrialization and urbanization not only increase economic growth but also contribute to the environmental degradation, especially contamination of heavy metals in water. In other side, there are many geological materials have capability to immobilize heavy metals. Therefore, the objective of this research is to know the maximum capacity of natural zeolite from Trembono area, Gunung Kidul regency to immobilize copper (Cu2+) from water and to understand their mechanism. This experiment was carry out by a batch test. The result showed that the maximum capacity of zeolite to immobilize Cu (qmax) is 63,69 mmolCu/kg Zeolite according to Langmuir adsorption equilibrium model. In addition, the capability to immobilize Cu will increases due to decreasing the grain size. The result of this research can be used as an alternative for waste water treatment, especially Cu. Keywords: Removal, copper (Cu2+), natural zeolite, Langmuir isotherm
Studi Kimia Fisika Fluida Hidrotermal Endapan Emas Organik Daerah Wumbubangka, Kabupaten Bombana, Sulawesi Tenggara Fadlin, Fadlin; Idrus, Arifudin; Warmada, I Wayan
Dinamika Rekayasa Vol 12, No 1 (2016): Dinamika Rekayasa Februari 2016
Publisher : Jenderal Soedirman University

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Penelitian ini di latar belakangi oleh karena masih sangat minimnya studi mengenai sifat kimia-fisik fluida hidrotermal pembentuk bijih pada endapan emas yang berasosiasi dengan batuan metamorf khususnya endapan emas orogenik yang ada di indonesia. Tujuan dari penelitian ini untuk mengetahui bagaimana suhu dan tekanan pembentukan endapan, serta karakteristik fluida pembentuk endapan emas pada batuan metamorf tersebut. Penelitian ini menggunakan metoda pemetaan geologi dan dikombinasikan dengan hasil analisis kimia-fisik fluida hidrotermal (inklusi fluida). Ada 3 generasi urat yang ditemukan yaitu generasi pertama, urat yang sejajar foliasi, urat tipe ini terbentuk pada 221,9 oC, dengan nilai salinitas rata-rata 7,17 wt.% NaCl ek. Urat generasi kedua adalah urat kuarsa yang memotong foliasi, urat ini terbentuk pada temperatur 188,4 oC, salinitas rata-rata 3,87 wt.% NaCl ek. Sedangkan urat generasi ke tiga yaitu urat kalsit-kuarsa, merupakan fase akhir dari endapan emas tersebut, terbentuk pada temperatur 138,2 oC dan salinitas rata-rata 1,91 wt.% NaCl ek. Secara umum evolusi fluida hidrotermal pada endapan emas orogenik yang ada dilokasi penelitian ada 2 (dua) fase yaitu fase isothermal mixing with fluids of constracting salinity, kemudian fase kedua menunjukan evolusi fluidanya lebih kearah mixing with cooler, less saline fluids. Kata kunci-Emas orogenik, tekstur urat, inklusi fluida, Bombana, Sulawesi Tenggara.
Mineralogical Characteristics of Hydrothermally-altered Andesite in Kalirejo Village and The Surrounding Areas, Indonesia Putra Pratama, Diyan Aditya; Indrawan, I Gde Budi; Warmada, I Wayan
Journal of Applied Geology Vol 3, No 2 (2018)
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Type and intensity of hydrothermal alterations affect rock engineering properties and slope stability. Identification of mineralogical characteristics of rocks is essential in determination of rock slope failure mechanism in a hydrothermal alteration zone. This research was conducted to identify mineralogical characteristics of hydrothermallyaltered andesite in Kalirejo Village and surrounding areas, Indonesia. The research was conducted by field observation and laboratory analyses involving petrographic and X-ray Powder Diffraction (XRD) analyses. The results showed that the research area was dominated by argillic alteration type and high alteration intensity implying high susceptibility to slope failures
Preliminary Study Gold Mineralization Hosted By Metamorphic Rocks In The Southeastern Arm Of Sulawesi, Indonesia Hasria, Hasria; Idrus, Arifudin; Warmada, I Wayan
UNEJ e-Proceeding 2016: Proceeding The 1st International Basic Science Conference
Publisher : UPT Penerbitan Universitas Jember

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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.
CHATODOLUMINESCENCE MICROSCOPIC ANALYSIS TO INTERPRET THE REDOX CONDITION DURING THE FORMATION OF CARBONATE VEIN Warmada, I Wayan; Hartati, Retno
Journal of Applied Geology Vol 2, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Abstract

Cathodoluminescence (CL) is generated by an electron gun coupled to an optical microscope. There are two types of chatodoluminescence, i.e., cold CL and hot CL. In the cold cathode microscopic equipment, the electrons are generated by an electric discharge between two electrodes under a low gas pressure, whereas in the hot CL microscope, the electrons are generated by heating a filament (2000–3000°C). In this paper we utilize cold CL combine with electron microprobe analysis (EMPA). The CL microscopy of carbonate shows at least three carbonate generations, i.e., rhodochrosite with dull or no luminescence, Mg-rich calcite with dark red luminescence, manganese-bearing calcite with up to 0.04 wt.% Mn with bright orange luminescence, and pure calcite and Mn-rich calcite (> 0.15 wt.% Mn) with dull or no luminescence. The result also suggests that the luminescence pattern of calcite is controlled by the amount of Mn2+. Sectoral zoning and chevron-shape growth zoning exist in some coarse-grained calcite aggregates. The sectorial zoning of calcite as reflected by dull to bright CL color indicated that slightly to more reducing environment during calcite deposition. Keywords: Chatodoluminescence, rhodochrosite, calcite, sectorial zoning
MERCURY AND ARSENIC CONTAMINATION FROM SMALL SCALE GOLD MINING ACTIVITIES AT SELOGIRI AREA, CENTRAL JAVA, INDONESIA Harijoko, Agung; Htun, Tin May; Saputra, Rodhie; Warmada, I Wayan; Setijadji, Lucas Donny; Imai, Akira; Watanabe, Koichiro
Journal of Applied Geology Vol 2, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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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
MODIFIED NATURAL ZEOLITE AND BENTONITE AS ADSORBENTS OF HEAVY METAL IONS FROM POLLUTED GROUNDWATER IN YOGYAKARTA URBAN ARE, INDONESIA Pich, Bunchoeun; Warmada, I Wayan; Hendrayana, Heru; Yoneda, Tetsuro
Journal of Applied Geology Vol 2, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Abstract

Groundwater quality in Yogyakarta city has become the major concern due to the presence of heavy metals originated from batik home industries, slaughterhouses, and leather factories, especially in shallow groundwater. In response to the above problems, the naturally abundant zeolite and bentonite in Sidomulyo and Bandung areas were respectively sampled along with the metal-containing groundwater in Yogyakarta urban area for batch adsorption experiment. Before put into experiment, the zeolite and bentonite were characteristically investigated by means of XRD, SEM, chemical composition, and physical property analyses. Also, they were thermally activated to improve their qualities in terms of increase in CEC, whereas the groundwater was analyzed for heavy metal concentrations (Cd, Cr, Cu, Fe, Zn) and its physical property. Five logarithmic amounts of this modified zeolite or bentonite were separately and incrementally introduced into the same three solutions of heavy metals. After the experiment, all the solutions were re-analyzed for the rest of heavy metals to figure out the optimum adsorption capacity of zeolite and bentonite. The outcomes of this experiment will be beneficial in enhancing the groundwater quality for consumptions in Yogyakarta city as well as other places in Indonesia, and will also imply the zeolite and bentonite in commercialization. Keywords: zeolite, bentonite, groundwater, heavy metal, adsorption