Indonesian Journal of Economic Geology最新文献

{"title":"Study of Active and Fossil Hydrothermal Systems in Ijen Caldera Complex and Merubetiri Mountains, East Java","authors":"Mardhiawan Tri Susetyono, L. D. Setijadji","doi":"10.51835/ijeg.2021.1.1.340","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.340","url":null,"abstract":"Ore deposits formed at subduction zone are associated with magmatism activities that are represented by volcanic activities at the surface. In the Eastern Sunda Arc, one of active volcanic activity can be found in Ijen Caldera Complex. The complex has hydrothermal volcanic manifestations with a very acidic pH. Meanwhile in the south of Ijen Complex, there is ancient volcanic complex called Merubetiri Mountains that is proven to be well-mineralized at Tumpangpitu as high sulfidation and porphyry-style mineralizations. An understanding of hydrothermal activity and volcanic landforms in active volcanic systems can be used as a powerful tool to understanding hydrothermal systems. This paper presents the distinction between active hydrothermal systems and fossil hydrothermal systems as an exploration’s tool in ancient volcanic systems. The method used in this study is remote sensing with focus on volcanic landforms, geological structures, and distribution of alteration minerals. ASTER satellite imagery, Landsat 8 satellite imagery, and DEMNAS are used in this study. ASTER and Landsat 8 images are processed with Principle Component Analysis (PCA) and Direct Principle Component (DPC) methods to determine the distribution of alteration minerals that are associated with propylithic, argillic, advanced argillic, and silisic alterations. Semi-quantitative method is used to identify geological structures by automatic lineament detection. Meanwhile, qualitative method is used by manual lineaments delineation on the DEM imagery. Delineations of volcanic landforms in active and ancient volcanic complex use semi-quantitative methods include ridge lineaments and flow pattern. Then, volcanic landform is manually delineated by determining the distribution pattern of ridges, flow pattern, morphological texture, and cross-cutting relationship of volcanic products as a key in determine the eruption centers. The results show a relationship between volcanic distribution and the main stresses in the Ijen Caldera Complex with NE-SW direction, which is represented by the elliptic and elongation of volcanic depression zone, monogenetic volcano, and intrusion distribution. Geological structures that are found in the Ijen Caldera Complex show E-W and NE-SW directions. Meanwhile, Merubetiri complex shows E-W, NW-SE, and N-S structural direction patterns. The distribution of alteration minerals associated with silisic, argillic, and advance argillic in the Ijen Caldera Complex are found in the central zone of stratovolcano, intra-caldera zone, and structural zone that intersects the caldera. This shows that active hydrothermal system is related to volcanic activity and geological structures. Meanwhile, in the Merubetiri complex, alteration minerals are associated with the eruption centers, diorite/granodiorite intrusions, and NW-SE strike slip fault. The understandings of volcanic setting and volcanic landforms are very important in the early stages of exploration to determine ","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"34 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114030934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Study of Gajah and Ijo Volcano Mineralization in Kulon Progo Dome based on Textural and Mineralogical Characteristics","authors":"Habil Abdillah, Wahyu Ardiansyah Nugraha, F. Hakim","doi":"10.51835/ijeg.2021.1.1.341","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.341","url":null,"abstract":"Gajah Volcano and Ijo Volcano are two tertiary volcanoes located in the Kulon Progo Dome area, Yogyakarta. Gajah Volcano is located in the middle of the Kulon Progo Dome which is the oldest in the complex and belongs to Early Oligocene volcanism period (± 29 mya). On the other hand, Ijo Volcano is a product of younger volcanism period, occurred in the Late Oligocene (± 25 mya). The tectonic deformation occurred during the Late Oligocene-Early Miocene led to the formation of geological structures like faults and joints, which also serve as pathway for acid-intermediate intrusion rocks. The intrusions are associated with hydrothermal alteration and ore mineralization in both volcanoes. There has been no research comparing the characteristics of hydrothermal deposits that formed on Gajah Volcano and Ijo Volcano. This will be the main objective of this research. The research was carried out at two mineralization prospect locations representing each volcano, namely the Kaligono area (Gajah Volcano) and the Hargorojo area (Ijo Volcano). The results were obtained from geological and alteration mapping as well as representative rocks/veins sampling...Petrology,..petrography, mineragra- phy, and XRD analyzes conducted on altered rock and vein samples from the two prospects indicated some differences. Kaligono prospect area (Gajah Volcano) consists various of alteration types ie. phylic (quartz-sericite-illite-pyrite),..propylitic..(chlorite-calcite-pyrite±epi- dote±actinolite), and argillic (illite-smectite-kaolinite±quartz). The mineralized veins found on Gajah Volcano show vein swarm, brecciated, stockwork, and massive vein structure with massive vein textures. The veins in Kaligono show NE-SW and NW-SE trends and hosted by Andesite, Dacite, and Andesite Lava. Gangue minerals that are found in the vein samples are quartz, illite, iron oxide, pyrite, and carbonate minerals. The ore minerals consist of magnetite, chalcopyrite, and sphalerite. Meanwhile in Hargorojo prospect area (Ijo Volcano), the types of alteration found including phylic (quartz-sericite-pyrite),..propylitic..(pyrite-calcite±ch- lorite), and argillic (illite-smectite-kaolinite-quartz). The mineralized veins found on Ijo Volcano have a massive vein structure, brecciation, and stockwork with comb, drussy, and massive vein textures. The veins have NNE-SSW and E-W trend and hosted by Andesite and Dacite. The gangue minerals are carbonate minerals, oxide minerals, pyrite, barite, quartz and chalcedony. The ore minerals include chalcopyrite, silver, galena, and sphalerite. Based on the vein characteristics of Kaligono prospect, such as a complex stockwork structure, hydrothermal breccia, and massive vein texture, which contain high temperature hydrothermal minerals, ie. epidote, actinolite, and magnetite, maybe indicate this deposit is controlled by deep..structure..related..to..the..porphyry miner alization. Whereas in the Hargorojo prospect shows the typical textures of shallow epithermal s","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131393530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis of Pre-Tertiary A-Type Granitoid in Jambi Area and its Implications of Rare Earth Element Potential on Main Range Sumatra Belt","authors":"A. Najili, P. Sendjaja, B. Priadi, V. E. Setiawan, B. M. Hartono","doi":"10.51835/ijeg.2021.1.1.342","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.342","url":null,"abstract":"Granitoid rocks are one of the main sources of rare earth elements (REE). This makes granitoid characterization become important in the early stages of REE exploration. Almost all granitoids in Indonesia have been mapped. However, more detailed granitoid studies in Indonesia are still focused on Bangka and Belitung granites (tin belt granite). In contrast to Bangka and Belitung granites, studies related to petrogenesis and granite characteristics on the mainland of Sumatra Island (Sumatra Main Range) are rarely done, such as granitoid in Jambi area. The aim of this study is to determine the characteristics of the Pre-Tertiary granitoids located in the Tigapuluh and Duabelas Mountains, Jambi. The Tanjungjabung Barat granitoid represent the Tigapuluh Mountains area while the Sarolangun granitoid represent the Duabelas Mountains area. These two granitoids interpreted to be Triassic to Jurassic in age. Granitoid characteristics include petrological and geochemical characters. This study also focuses on the petrogenesis of Pre-Tertiary granitoid and its implications for the abundance of REEs. Megascopic observation, petrographic, and geochemical analysis are done in this study. Geochemical analysis was done at the Center of Geological Survey Laboratory, Bandung using the ICP-MS Thermo Icap-Q and XRF ADVANT XP Thermo ARL9900 instruments. Based on megascopic and petrographic observations, both of the granitoids are classified as granite. Geochemically, these two granitoids show the character of A-type granite which is formed in the post-collision environment, and derived from the crustal melting with ferrous alkalic to alkali-calcic peraluminous affinities. This crustal melting happened due to the collision of the Sibumasu Block with Indochina resulting in crustal thickening and crustal melting. The magma then contaminated effectively in the rift environment due to the subduction roll-back of Meso-Tethys in the Late Triassic. Subduction in the West Sumatra also play roles in the genesis and it is shown by the geochemical character of the Sarolangun granitoid. Effective contamination derives the characteristics of A-type granite so that the REE content in both granites are abundant. The abundance of REE is indicated by the presence of the allanite, monazite, apatite, zircon, and titanite. The REE concentration of the Sarolangun granitoid reaches 330 ppm, while the Tanjungjabung Barat granitoid reaches 261 ppm. The REE concentrations of A-type granitoid in Jambi then compared with A-type granitoids from the world and showed relatively the same REE concentrations. The REE concentrations of these granitoids are also higher than the other type granitoids in Indonesia. However, the REE concentrations of Jambi granitoids are similar to the fractionated S-type granite in Bangka. With a recent study showing the presence of A-type granitoid in Sarudik (North Sumatra) and Bukit Batu (South Sumatra), the A-type granitoid in this study indicates the existence of A-t","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129775425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Preliminary Economic Evaluation of Rare Earth Element and Yttrium (REY) in Indonesian Coal: Progress and Future Prospect","authors":"A. Patria, F. Anggara","doi":"10.51835/ijeg.2021.1.1.339","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.339","url":null,"abstract":"Coal deposits have fascinated much attention in recent years due to its by-product waste as promising alternative sources for rare earth metals. Rare earth metals concentration in many coals and coal ashes are known have equal to or higher than those found in conventional ore. Indonesia is one of the most extensive coal-bearing sedimentary basins in SE Asia with unique tectonic and geological control that might be significance as prospective country of rare metals recovery from coal. This study shows recent progress from several Indonesian coal-bearing sedimentary basins: Ombilin, South Sumatra and Pasir basin. Surprisingly, the REY concentration in Ombilin, South Sumatera and Pasir basin has higher than the average world-coal with 126.15 ppm, 203.72 and 285.53 ppm, respectively. Based on the relationship market demand and supply of individual REY in recent years proposed by Seredin and Dai (2012), all of coal samples were clustered into Promising (II) type with base of critical outlook is 0.7 and cut-off grade is 1000 ppm in coal ashes. It comprises the various REY distribution types and can be regarded as promising REY raw metrials for economic development. REY-enrichment processes in Indonesian coal are different due its tectonic and geological processes that control the basin formation, both of pre-, syn- and post-forming. Genetically, major REY-enrichment processes in Indonesian coal are controlled by tuffaceous; infiltrational; and terrigenous process. Tuffaceous process is related to volcanism that produce tonstein layer during coal peatification, this type is determined in South Sumatera and Pasir basin. Terrigenous process is controlled by provenance sediment-source during coal-bearing formation is formed; basaltic-igneous basement is major controlled REY-enrichment in Ombilin and Pasir basin. Injections of marine water during coal peatification also known that lead REY-enrichment, this type called infiltrational type and its presence in all three basins. Recent study about REY-rich in Indonesian coal shows significance prospect for future rare earth metals recovery. Further study is needed in unexplored coal-bearing sedimentary basin such as Tarakan, Asem-asem, Barito, Ketungau, Melawi, Salawati and Bintuni basin.","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125659059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrology and Fluid Inclusion Study of W+Sb±Au Quartz Vein Mineralization in Sebuku Island, South Kalimantan, Indonesia","authors":"Arvida Noviana, A. Idrus, Yoseph Calasanctius Amita Swamidharma, I. Setiawan, Chunkit Lai","doi":"10.51835/ijeg.2021.1.1.347","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.347","url":null,"abstract":"Sebuku Island in South Kalimantan province has hosted one of the largest Fe-Ni laterite deposits in Indonesia. Surface mapping has discovered new ore deposit types, notably quartz-bearing W+Sb±Au ore veins in the northern Sebuku. This study aims to characterize this newly-discovered deposit type and understand its origin. We present geological mapping, petrographic and ore microscopic observations, and data from XRD, bulk-ore major and trace element (XRF and ICPMS), as well as fluid inclusion microthermometric analyses. The results show that the host rocks are composed of metasandstone and metapelitic rocks. The quartz veins are associated with narrow alteration zones, comprising silicic, sericite and argillic types, which are strongly controlled by NE-trending dextral and SE-trending sinistral strike-slip faults. The veins trend approximately N120oE, and have massive, brecciated, drusy, comb and bladed textures. Ore minerals comprise mainly wolframite, stibnite, kermesite, tripuhyite, and minor arsenopyrite, pyrite and Fe-Ti oxides. The ores contain up to 958 ppm W and 1,220 ppm Sb, with wolframite and stibnite being the main ore minerals. Medium homogenization temperatures (Th) were found for the fluid inclusions, ranging from 238 to >350°C, which correspond to moderate fluid salinity of 1.4 to 5.4 wt.% NaCl eq. Based on those characteristics, the W+Sb±Au mineralization in Sebuku is similar to a mesothermal type","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124071420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Potential Enrichment of Scandium in Bauxite Deposit for the Emerging Green Technology Needs","authors":"Adinda Ramadhani Haka Putri, L. D. Setijadji, D. Sunjaya","doi":"10.51835/ijeg.2021.1.1.343","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.343","url":null,"abstract":"Scandium (Sc) becomes one of critical raw materials as principal uses are now in the production of scandium-aluminum alloys and also in Solid Oxide Fuel Cells (SOFCs). Scarcity of scandium resources has led the urgency to discover new potential sources of scandium to meet the supply and demand. One of the possible sources of scandium is from bauxite deposit. Tayan area is part of West Kalimantan laterite belt with the potency for scandium resources in Indonesia as a result of the altered granitoid rocks, namely bauxite. This study presents integrated geological and modes of occurrences study to elucidate the potential enrichment of scandium in the study area including through several laboratory analyses: petrography, XRD, XRF, ICP-MS, and SEM-BSE-EDS. Our study concludes that the concretion textures of bauxite samples are dominated by Fe and Al oxide-hydroxide. The ore is composed of gibbsite and goethite. The result of scandium concentration analysis is equal to 50.9 ppm. Systematic SEM–EDS mapping confirms the presence of scandium as mainly from substitution of Fe3+ and Al3+ by Sc3+. Sc is hosted in goethite, where Sc3+ substitutes Fe3+ in goethite crystal lattice. Sc3+ also substitutes Al3+ in gibbsite crystal lattice. Understanding the enrichment in which scandium occurs in bauxite deposit will hopefully open the new possibility to meet the needs for critical materials for green technology development.","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121477937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coal Geometry Modeling and Resources Estimation in Darmo and Surrounding Area, Muara Enim, South Sumatra","authors":"P. Kurniawan","doi":"10.51835/ijeg.2021.1.1.344","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.344","url":null,"abstract":"This research is located in Darmo, Muara Enim, South Sumatra, while in geological spatial it is located in the Muaraenim Anticlinorium zone. The purpose of this study is to build coal geometry model and calculating coal resources estimation in the study area. The methods applied in this study include field observations, laboratory analysis and studio analysis. Coal geometry modeling is doing by krigging method, as well as the calculation of coal resources using the circular method. The results obtained from this study are in the form of stratigraphic sequence of the youngest namely the Kasai Formation and the Muaraenim Formation. Geometry of coal seams in the study area has a thickness that is quite varied from 0.5 meters - 12.8 meters, in general is continuous, has the characteristics of the roof and floor in the form of sandy coal and muddy coal and interburden in the form of sandstone and claystone. The form of coal seams in the study area is included in the classification of horseback, fault and fold. Estimated coal resources in the study area consist of inferred resources 74677959 m3 or equivalent to 104549142 tons, indicated resources 69043012 m3 or 96660216 tons and measured resources 68041837 m3 or 95258571 tons which is a calculation of estimated coal resources from seam A, seam B, seam C and seamless C and seam D.","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127508466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial Delineation of Gold Resource Planning Regions Based on Multi-Objectives","authors":"Yuhan Zhang","doi":"10.51835/ijeg.2021.1.1.2","DOIUrl":"https://doi.org/10.51835/ijeg.2021.1.1.2","url":null,"abstract":"Current gold resource management in China has faced dual challenge from guaranteeing metal supply (quantity) and resource upgrade and transformation (quality). Although China has proposed the setup of seven gold resource planning regions to resolve this challenge, how to spatially-delineate these regions has not been specified. In this study, we identify three criteria for the spatial delineation of these 7 planning regions, i.e., (i) geographic distance from any mining right to the center of its planning region is shorter than to the center of any adjacent planning region; (ii) the size of each planning region should be similar; (iii) the amount of gold production capacity in each planning region should reach a certain proportion threshold of the national total (namely the “goal value”). Referenced from the existing spatial delineation methods, Voronoi diagram and buffer analysis are used to calculate the spatial scope necessary to satisfy these three objectives, from both resource development (mining right-level) and management (administrative county-level) perspective. The results show that with the goal value rising from 40 to 60%, the planning region size, the number of mining right and the administrative county involved in the planning regions all increase substantially, but the growth rates are different. Our work integrates the mineral resource management and geographic analysis, and such methodology is also applicable on other commodities.","PeriodicalId":283305,"journal":{"name":"Indonesian Journal of Economic Geology","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133651282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}