EKSPLORIUM最新文献

{"title":"Indikasi Sesar Naik di Plampang, Pulau Sumbawa Berdasarkan Analisis Gempa Bumi 13 Juni 2020","authors":"P. Priyobudi, M. Ramdhan","doi":"10.17146/eksplorium.2021.42.2.6273","DOIUrl":"https://doi.org/10.17146/eksplorium.2021.42.2.6273","url":null,"abstract":"ABSTRAK. Keberadaan sesar aktif dengan pola sesar naik di daerah Plampang berhasil diungkap dari sebaran hiposenter terelokasi, hasil inversi momen tensor, dan pemodelan perubahan tegangan Coulomb. Studi ini juga berhasil mengungkap sumber gempa pada sesar aktif tersebut dengan kedalaman relatif dangkal yang bisa menjadi ancaman di Pulau Sumbawa jika magnitudo maksimumnya rilis di masa yang akan datang. Hasil relokasi hiposenter menunjukkan sebaran episenter berarah barat daya–timur laut. Hal ini didukung juga oleh hasil inversi momen tensor yang menunjukkan bidang sesar berarah barat daya–timur laut (N2240E) dengan dip cukup curam (490). Penampang seismisitas vertikal pada arah dip menunjukkan adanya pola sesar naik yang semakin landai seiring bertambahnya kedalaman. Bidang sesar yang landai menunjukkan struktur decollement pada kedalaman 10–15 km dan berangsur menjadi curam sebagai struktur splay fault pada kedalaman 0–10 km. Hal tersebut konsisten dengan hasil inversi momen tensor yang menunjukkan mekanisme pergerakan sesar naik terjadi pada kedalaman 7 km. Pemodelan perubahan tegangan Coulomb menunjukkan adanya penambahan stress di luar area bidang sesar sehingga memicu terjadinya aftershocks. Sebaran gempa susulan menunjukkan adanya bidang sesar hipotetik dengan panjang 19 km dan lebar 12 km. Sesar sebesar ini berpotensi membangkitkan gempa dengan kekuatan Mw 6,4. Gempa Sumbawa 13 Juni 2020 dengan magnitudo M 5,3 disebabkan oleh sebagian kecil aktivitas dari bidang sesar tersebut.ABSTRACT. The existence of an active fault with a reverse fault mechanism in the Plampang area is successfully delineated from the distribution of the relocated hypocenter, the moment tensor inversion, and the Coulomb stress changes. This study also reveals the source of the earthquake in the active fault with a relatively shallow depth which can be a threat on Sumbawa Island if the maximum magnitude is released in the future. Seismicity from hypocenter relocation shows the distribution of the epicenter with a southwest–northeast direction. It is also supported by the moment tensor inversion result which shows the fault plane trending southwest–northeast (N2240E) with a steep dip (490). The vertical section of seismicity in the dip direction shows that the slope of the plane has a lower angle with increasing depth. The lower angle of a fault plane shows a decollement structure at a depth of 10–15 km and gradually becomes steep as a splay fault structure at a depth of 0–10 km. It is consistent with the result of moment tensor inversion which shows the mechanism of a reverse fault that occurred at a depth of 7 km. The Coulomb stress changes show the stress increasing outside the fault plane area, which triggers aftershocks. The distribution of aftershocks shows a hypothetical fault plane of 19 km long and 12 km wide. A fault of this size has the potential to generate an earthquake with a magnitude maximum of Mw 6.4. The Sumbawa earthquake on June 13, 2020, having M 5.","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72846014","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":"Karakterisasi Geoteknik Fondasi Kandidat Tapak PLTN dengan Metode Seismik Refraksi","authors":"Dwi Haryanto, Yoshi Rachael, Dhatu Kamajati, Gagah Hari Prasetyo, Heri Syaeful, Frederikus Dian Indrastomo","doi":"10.17146/eksplorium.2021.42.2.6538","DOIUrl":"https://doi.org/10.17146/eksplorium.2021.42.2.6538","url":null,"abstract":"ABSTRAK. Pemerintah Indonesia dalam Peraturan Presiden (Perpres) Nomor 38 Tahun 2018 tentang Rencana Induk Riset Nasional Tahun 2017–2045, menetapkan beberapa bidang utama yang akan menjadi prioritas penelitian nasional, salah satunya adalah bidang energi. Dalam tema riset teknologi kelistrikan berbasis energi baru dan terbarukan rendah/nol karbon terdapat topik riset teknologi Pembangkit Listrik Tenaga Nuklir (PLTN) skala komersial. Pada topik riset tersebut, ditetapkan bahwa dalam jangka waktu penelitian tahun 2020–2024, dihasilkan purwarupa PLTN. Pada penelitian ini, karakterisasi geoteknik tapak PLTN dilakukan dengan menggunakan metode seismik refraksi guna melengkapi data penelitian sebelumnya. Tujuan penelitian ini adalah untuk mengetahui profil perlapisan batuan bawah permukaan untuk estimasi pekerjaan terkait fondasi PLTN. Pemetaan geologi dan akuisisi data geofisika, pengolahan, serta interpretasi tanah/batuan berdasarkan parameter kecepatan gelombang kompresi (Vp). Hasil pemetaan geologi menunjukkan adanya 2 satuan batuan beku yaitu diorit kuarsa dan andesit. Hasil pengolahan dan interpretasi data seismik refraksi menghasilkan model penampang Vp pada lapisan batuan bawah permukaan. Terdapat 3 lapisan batuan di lokasi penelitian yaitu lapisan tanah (Vp = 361–715 m/s), lapisan batuan beku lapuk (Vp = 1.386–2.397 m/s), dan lapisan beku segar (Vp = 3.789–6.133 m/s). Perkiraan densitas batuan beku segar berdasarkan perhitungan adalah 2,43–2,74 g/cm3. Hasil pemodelan dapat menunjukkan kedalaman dan struktur bawah permukaan lapisan batuan beku segar yang dapat menjadi fondasi bangunan PLTN.ABSTRACT. Presidential Regulation (Perpres) number 38 of 2018 concerning the National Research Master Plan for 2017–2045, the Government of Indonesia establishes several main areas that will become national research priorities, one of which is the energy sector. In the research theme of electricity technology based on new and renewable low/zero carbon energy, there is the topic of research on commercial-scale Nuclear Power Plant (NPP) technology. On the research topic, it was determined that within the research period of 2020–2024, a prototype nuclear power plant would be produced. Research related to the geotechnical characterization of the nuclear power plant site using the seismic refraction method was carried out to complement the previous research data. The purpose of this study was to determine the subsurface rock layer profile for estimation of work related to nuclear power plant foundations. Geological mapping and geophysical data acquisition, processing, as well as soil/rock interpretation based on the compression wave velocity (Vp) parameter are carried out to achieve this goal. The results of geological mapping show that there are 2 igneous rock units, namely quartz diorite and andesite. The results of processing and interpreting seismic refraction data produced a cross-sectional model of Vp in the subsurface rock layers. There are 3 rock layers i","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"18 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91479731","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":"Aplikasi Metode Geolistrik dan Analisis X-Ray Diffraction (XRD) untuk Investigasi Longsor di Pidada, Kecamatan Panjang, Bandar Lampung","authors":"Rahmi Mulyasari, Suharno Suharno, Nandi Haerudin, Hesti Hesti, Ida Bagus Putu Prajna Yogi, S. Saputro","doi":"10.17146/eksplorium.2021.42.2.6304","DOIUrl":"https://doi.org/10.17146/eksplorium.2021.42.2.6304","url":null,"abstract":"ABSTRAK. Bandar Lampung merupakan wilayah perkotaan padat penduduk yang terdiri atas daratan dan perairan dengan beberapa dataran tinggi dan pegunungan yang terbentang di wilayah ini. Untuk mendukung pembangunan yang berkelanjutan di sebuah kawasan kota diperlukan konsep penataan wilayah yang mempertimbangkan segala aspek, salah satunya adalah aspek potensi bencana. Salah satu bencana yang berpotensi terjadi di Bandar Lampung, khususnya di Kecamatan Panjang, adalah gerakan massa/longsoran. Berdasarkan penelitian sebelumnya, daerah ini terekam memiliki beberapa titik sejarah longsor tetapi belum ada mitigasi/penanggulangan yang diaplikasikan khusus untuk jenis bencana tersebut. Tujuan dari penelitian ini adalah untuk mengetahui susunan batuan yang berada pada zona rawan longsor Kecamatan Panjang menggunakan metode geolistrik resistivitas serta untuk mengetahui hasil penilaian keteknikan tanah yang diperoleh dari hasil analisis litologi menggunakan X-Ray Diffraction (XRD). Hasil analisis dua lintasan geolistrik mengindikasikan adanya tiga lapisan litologi pada daerah penelitian, yaitu sedimen tuf dengan nilai resistivitas dan kedalaman antara (1–40 Ωm; 0,4–4 m), zona kontak atau bidang gelincir (40–120 Ωm; 2–4 m), dan breksi padu dengan komponen batuan beku (> 120 Ωm; 2–22 m). Selanjutnya berdasarkan hasil analisis penilaian keteknikan tanah, sedimen tuf sebagai lapisan permukaan yang mengalami longsoran diidentifikasi memiliki sifat keteknikan litologi yang rentan karena telah mengalami oksidasi dan pelapukan yang cukup intensif. Data yang diperoleh ini diharapkan dapat dimanfaatkan sebagai data dukung penataan wilayah berbasis potensi bencana.ABSTRACT. Bandar Lampung is a densely populated urban area consisting of land and water with several plateaus and mountains that stretch across this region. To support sustainable development in a city area, it is necessary to have a regional arrangement concept that considers all aspects, one of which is the potential disaster aspect. One of the potential disasters in Bandar Lampung, especially in Panjang District is a mass movement/landslide. Based on previous research, this area has been recorded as having several historical points of landslides, but there is no mitigation/response specifically for this type of disaster. The purpose of this study was to determine the arrangement of rocks that are in the landslide-prone zone in Panjang District using the geoelectric resistivity method and to analyze the soil engineering assessment obtained from the results of lithological analysis using X-Ray Diffraction (XRD). The results of the geoelectric analysis indicate that there are three lithological layers in the study area; namely tuff sediments with resistivity values and depths between (1–40 Ωm; 0.4–4 m), clay sand (40–120 Ωm; 2–4 m), and solid breccias with igneous rock components (>120 Ωm; 2–22 m). Furthermore, based on the results of the analysis of soil engineering assessments, tuff sediment as a surface l","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78097988","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":"Identifikasi Deformasi Tektonik Aktif Berdasarkan Ekstraksi Kelurusan Morfologi dan Seismisitas di Sukabumi, Jawa Barat","authors":"R. Mahbub, Candra Ragil","doi":"10.17146/EKSPLORIUM.2021.42.1.6139","DOIUrl":"https://doi.org/10.17146/EKSPLORIUM.2021.42.1.6139","url":null,"abstract":"ABSTRAK Pusat gempa bumi di Sukabumi telah membentuk deformasi bawah permukaan dan kini terekam juga di permukaan. Hal itu termanifestasi melalui geomorfologi kelurusan gawir dan sungai. Ekstraksi kelurusan-kelurusan akibat deformasi geologi tersebut dapat digunakan untuk mengidentifikasi deformasi tektonik aktifnya. Tujuan penelitian ini adalah untuk mengetahui hubungan antara struktur sesar aktif dengan arah dominan kelurusan di daerah penelitian. Metode Edge Enhancing Filtering digunakan untuk menginterpretasi kelurusan secara manual dan semi-otomatis. Data geospasial kelurusan diekstraksi menggunakan formula Sastratenaya untuk mengetahui kronologi kelurusan yang terbentuk. Hasil analisis menggunakan formula Sastratenaya menunjukkan kelurusan-kelurusan yang terekam melalui olah data peta DEM, yaitu segmen 1 berarah N315°E dan segmen 2 berarah N10°E yang diinterpretasikan sebagai hasil reaktivasi sesar. Hal ini dapat diinterpretasikan bahwa Sesar Cimandiri, yang merupakan sesar aktif dengan pergerakan oblique-slip sinistral N88°E/85° rake 33°, memengaruhi arah dua segmen kelurusan di daerah penelitian wilayah Sukabumi, Jawa Barat.ABSTRACT The epicenter of the earthquake in Sukabumi has formed subsurface deformation which is now also recorded on the surface area. This is manifested through the geomorphology of the scarp and river lineaments. Extraction of lineaments produced by geological deformation can be used to identify its active tectonic deformation. The research objective is to determine the relationship between the active fault structure and the dominant direction of lineaments in the study area. The Edge Enhancing Filtering method is used to interpret lineaments manually and semi-automatically. The lineament geospatial data was extracted using the Sastratenaya formula to determine the chronology of the lineaments formed. The Sastratenaya formula results showed the lineaments recorded by DEM images data processing, the first segment direction is N315°E and the second is N10°E, both are interpreted as the result of fault reactivation. It can be interpreted that the Cimandiri Fault, which is an active fault that has an N88°E/85° rake 33° sinistral oblique-slip fault movement, affects the lineaments direction of two segments in the research area of Sukabumi, West Java.","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"204 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74832748","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":"Eksplorasi Geokimia untuk Menentukan Daerah Prospek Mineralisasi Emas Tipe Urat Epitermal: Studi Kasus di Daerah Tompaso, Kabupaten Minahasa Selatan, Sulawesi Utara","authors":"A. Idrus, Fadlin Fadlin, H. G. Hartono","doi":"10.17146/eksplorium.2021.42.1.6230","DOIUrl":"https://doi.org/10.17146/eksplorium.2021.42.1.6230","url":null,"abstract":"ABSTRAK Sulawesi Utara termasuk daerah Tompaso, Kabupaten Minahasa Selatan merupakan jalur magmatik yang potensial menghasilkan endapan bijih hidrotermal. Penelitian ini bertujuan menentukan daerah prospek mineralisasi emas khususnya tipe urat epitermal berdasarkan eksplorasi geokimia meliputi geokimia batuan dan sedimen sungai, khususnya metode BLEG (Bulk Leach Extractable Gold). Metode penelitian meliputi pemetaan geologi, alterasi dan jalur urat, percontoan (bijih/batuan dan sedimen sungai), dan analisis geokimia. Sampel bijih dianalisis dengan metode FA/AAS untuk emas dan metode AAS untuk unsur lain, sedangkan analisis sampel sedimen sungai dilakukan dengan metode cyanide leach dan AAS. Hasil penelitian menunjukkan batuan induk mineralisasi berupa lava andesit dan intrusi diorit. Batuan ini mengalami alterasi silica-clay, argilik, dan propilitik. Perpaduan antara pemetaan geologi, zona alterasi, dan jalur urat dengan eksplorasigeokimia batuan dapat menentukan daerah prospek mineralisasi yaitu Prospek Asam dan Polangkok. Pada Prospek Asam, sampel bijih memiliki kandungan emas sampai 0,03 ppm dengan anomali emas pada sampel BLEG menunjukkan nilai threshold 13,52 ppb Au. Pada Prospek Polangkok ditemukan 2 jalur urat (P1 dan P2) berarah baratlaut-tenggara dengan lebar sampai 5 m. Urat P1 memiliki kadar Au mencapai 0,31 ppm dan pada urat P2 mencapai 0,16 ppm Au. Mineralisasi pada Prospek Polangkok didukung oleh anomali Ag pada sampel BLEG dengan nilai threshold 67,18 ppb. Kedua daerah prospek tersebut direkomendasikan untuk eksplorasi lanjut (follow-up exploration). ABSTRACT North Sulawesi, including the Tompaso region, South Minahasa district, is a part of the magmatic belts hosting potential hydrothermal ore deposits. This study is aimed to determine the prospect area for epithermal vein-type gold mineralization, based on geochemical exploration including rock and BLEG (Bulk Leach Extractable Gold) stream sediment geochemistry. Mapping of geology, alteration and vein direction, sampling (ore/rock and stream sediment), and geochemical analysis were performed. Gold in rock samples was analyzed by FA/AAS, and other elements were detected by AAS, while BLEG samples were analyzed using the cyanide leach and AAS methods. The study area is occupied by andesitic lava and diorite, which are suffered by silica-clay, argillic and propylitic alteration. An integration of geological mapping, alteration zones and vein direction with lithogeochemical survey enables to determine the prospect areas, which consist of Asam and Polangkok prospects. At the Asam prospect, the ore sample contains gold up to 0.03 ppm, where the gold anomaly in BLEG samples show a threshold of 13.52 ppb Au. At the Polangkok prospect, two NW-SE trending veins (P1 and P2 Veins) were discovered with a width of up to 5 m. Vein P1 and P2 contains of up to 0.31 and 0.16 ppm Au, respectively. Mineralization at the Polangkok prospect coincides with Ag anomaly of BLEG samples with a threshold of","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"115 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72835034","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":"Pengendapan Uranium pada Monasit Bangka sebagai Ammonium Diuranate (ADU) Menggunakan Gas NH3","authors":"Riesna Prassanti, Ahmad Fauzan, Aditya Widian Putra, Afiq Azfar Pratama, Erlan Dewita, Rachmat Hidayat, Budi Yuli Ani, Y. Permana","doi":"10.17146/eksplorium.2020.41.1.5879","DOIUrl":"https://doi.org/10.17146/eksplorium.2020.41.1.5879","url":null,"abstract":"ABSTRAK Monasit, sebagai produk ikutan penambangan timah, mengandung unsur-unsur logam tanah jarang (LTJ) serta unsur radioaktif seperti uranium (U) dan torium (Th). Penelitian dan pengembangan pengolahan monasit di Pusat Teknologi Bahan Galian Nuklir-Badan Tenaga Nuklir Nasional (PTBGN-BATAN) telah berhasil memisahkan LTJ sebagai senyawa hidroksida dengan recovery 85%. Unsur radioaktif U dan Th masing-masing diperoleh sebagai produk dalam bentuk konsentrat senyawa ammonium diuranate (ADU)/(NH4)2U2O7 dan torium hidroksida (Th(OH)4). Pada penelitian sebelumnya, pemisahan U sebagai ADU pada monasit dilakukan dengan proses pengendapan menggunakan larutan NH4OH. Pada penelitian, U ini akan diendapkan sebagai ADU menggunakan reagen gas NH3 dengan tujuan memperoleh kondisi optimum pengendapan. Umpan pengendapan berupa larutan (U,Th,LTJ) sulfat diperoleh dari proses pengolahan monasit secara basa yaitu dekomposisi menggunakan NaOH, pelarutan parsial menggunakan HCl, dan pelarutan total menggunakan H2SO4. Parameter yang diteliti meliputi pengaruh laju alir gas NH3, temperatur proses, dan waktu kontak terhadap recovery U. Hasil penelitian menunjukkan bahwa pada kondisi statis pH-7, kondisi optimum pengendapan U menggunakan gas NH3 adalah pada laju alir gas NH3 150 ml/menit, temperatur proses 30oC, dan waktu kontak 15 menit dengan recovery pengendapan U 100%, Th 99,97%, dan LTJ 99,93%. Hasil tersebut menunjukkan bahwa unsur U sudah terambil seluruhnya akan tetapi masih bercampur dengan unsur lain yaitu Th dan LTJ, sehingga diperlukan penelitian berikutnya untuk memperoleh U dengan kemurnian yang tinggi pada kondisi pH optimum.ABSTRACT Monazite, as a by-product of tin mining, contains rare earth elements (REE) and radioactive elements like uranium (U) and thorium (Th). The monazite processing Research and Development at the Center for Nuclear Mineral Technology-National Nuclear Energy Agency (PTBGN-BATAN) has succeeded in separating REE as a hydroxide compound with an 85% recovery. The radioactive elements U and Th are each obtained as a product in the form of concentrated compounds of ammonium diuranate (ADU)/(NH4)2U2O7 and thorium hydroxide (Th(OH)4). In previous studies, the separation of U as ADU in monazite was carried out by the precipitation process using NH4OH solution. In this research, U will be precipitated as an ADU using NH3 gas reagents to obtain precipitation optimum conditions. Precipitation feed in the form of (U, Th, REE) sulfate solution derived from the monazite processing using the alkali or base method, which includes decomposition using NaOH, partial dissolution using HCl, and total dissolution using H2SO4. The parameters studied include the effect of NH3 gas flow rate, process temperature, and contact time on U recovery. The results showed that on the static pH-7 condition, the optimum state of U precipitation using NH3 gas is at NH3 gas flow rate of 150 ml/minutes, processing temperature of 30oC, and 15 minutes contact time with pre","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73736321","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":"Konsentrasi Radon-222 dalam Gas Tanah untuk Deteksi Distribusi Permeabilitas di Daerah Panas Bumi Tampomas, Jawa Barat","authors":"Rasi Prasetio, Neneng Laksminingpuri, E. R. Pujiindiyati","doi":"10.17146/eksplorium.2020.41.1.5642","DOIUrl":"https://doi.org/10.17146/eksplorium.2020.41.1.5642","url":null,"abstract":"ABSTRAK Daerah upflow dalam sistem panas bumi merupakan daerah dengan permeabilitas yang tinggi sebagai lintasan naiknya fluida panas bumi ke permukaan, yang umumnya ditandai dengan adanya fumarol di permukaan. Gunung Tampomas, Jawa Barat, merupakan salah satu lokasi potensi panas bumi yang memiliki manifestasi berupa mata air panas, namun tidak memiliki fumarol atau steam vent. Zona permeabel atau upflow sulit untuk diidentifikasi. Isotop 222Rn merupakan isotop geogenik yang konsentrasinya di dalam gas tanah dapat menunjukkan permeabilitas, baik permeabilitas primer maupun sekunder (struktur). Serangkaian pengukuran 222Rn dalam gas tanah telah dilakukan pada 56 titik di sekitar Gunung Tampomas untuk melihat anomali kandungan 222Rn dengan menggunakan metode statistik, serta relasinya antara daerah dengan permeabilitas tinggi dengan struktur geologi dan manifestasi panas bumi. Hasil pengukuran dan evaluasi statistik menunjukkan bahwa konsentrasi 222Rn terbagi menjadi konsentrasi rendah (latar), konsentrasi tinggi, dan anomali. Nilai latar berada di 16 lokasi berada di bawah 825 Bq/m3, sementara konsentrasi tinggi di 32 lokasi antara 825–7688 Bq/m3 dan anomali di 8 lokasi di atas 7688 Bq/m3. Sebagian besar lokasi dengan konsentrasi 222Rn tinggi dan anomali letaknya tidak berdekatan dengan kelurusan struktur, Seluruh pengukuran yang berdekatan dengan mata air panas memiliki konsentrasi 222Rn tinggi dan anomali. Mata air panas Ciseupan merupakan pengecualian yang mengindikasikan air panas tersebut keluar secara lateral (outflow). Selain itu, tidak ada indikasi korelasi antara konsentrasi 222Rn dengan elevasi lokasi pengukuran. Proses perpindahan 222Rn dari reservoir ke permukaan diperkirakan melalui mekanisme gas pembawa yang berasal dari reservoir panas bumi melalui zona permeabel.ABSTRACT Upflow zone in the geothermal system is a zone with high permeability that serves as a path for geothermal fluid to ascend to the surface, which usually marked with fumarole at the surface. Mount Tampomas, West Java, is a potential geothermal site with some thermal manifestation in the form of hot springs, but no fumarole or steam vent exists. The up-flow or the permeable zone is difficult to identify. 222Rn isotope is a radiogenic isotope that its concentration in soil gas can infer primary permeability as well as secondary permeability (structure). Series of 222Rn measurement in soil gas has been performed from 56 sampling positions around Mount Tampomas to evaluate 222Rn anomaly by a statistical method and its relation with high permeability area, geological structure, and geothermal manifestation. The measurement and statistical evaluation results show that 222Rn concentration clustered into low (background), high, and anomaly concentration. The background values in 16 places are below 825 Bq/m3, while a high level in 32 areas between 825–7688 Bq/m3 and anomaly in 8 places above 7688 Bq/m3. Most of the locations with high and anomaly 222Rn concentrations did n","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78891167","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":"Karakteristik Alterasi dan Mineralisasi Tipe Epitermal Daerah Gunung Budheg dan Sekitarnya, Tulungagung, Jawa Timur","authors":"Rinal Khaidar Ali, Tri Winarno, Muhammad Ainurrofiq Jamalulail","doi":"10.17146/eksplorium.2020.41.1.5676","DOIUrl":"https://doi.org/10.17146/eksplorium.2020.41.1.5676","url":null,"abstract":"ABSTRAK Penemuan bongkah-bongkah vuggy quartz di sekitar Desa Pojok, daerah Gunung Budheg, Tulungagung, Jawa Timur, mengindikasikan adanya proses endapan mineral di daerah tersebut. Tujuan penelitian ini adalah untuk membahas lebih detail karakteristik alterasi dan mineralisasi serta tipe endapan mineral di daerah penelitian. Metode penelitian berupa pengamatan lapangan dilengkapi dengan analisis laboratorium petrografi, X-ray Difraction (XRD) dan mineragrafi. Satuan batuan di daerah penelitian tersusun atas enam satuan litologi yaitu satuan intrusi dasit, satuan lava andesit, satuan breksi andesit, satuan breksi polimik, satuan batugamping terumbu dan aluvium. Tipe alterasi di daerah penelitian adalah alterasi profilitik, argilik, argilik lanjut, dan silisifikasi. Alterasi profilitik dicirikan oleh melimpahnya mineral klorit. Alterasi argilik dicirikan dengan melimpahnya mineral kaolin, sementara argilik lanjut dicirikan oleh hadirnya mineral kaolinit dan alunit. Alterasi silisifikasi yang dicirikan oleh melimpahnya mineral kuarsa. Mineral logam yang ditemukan di daerah penelitian didominasi oleh kelompok mineral sulfida seperti kovelit, kalkosit, enargit, kalkopirit, pirit,  dan jarosit. Emas native ditemukan berasosiasi dengan enargit. Sistem endapan mineral pada daerah penelitian merupakan sistem epitermal sulfidasi tinggi dicirikan oleh kuarsa berongga (vuggy quartz) yang termineralisasi dan kehadiran mineral kaolin sebagai mineral hasil alterasi.ABSTRACT The discovery of vuggy quartz boulders around Pojok Village, Gunung Budheg area, Tulungagung, East Java, indicates the presence of mineral deposits process in this area. This study aims to discuss detailed characteristics of alteration and mineralization as well as mineral deposits type in the study area. The research methods are field observations completed with petrography, X-ray Diffraction (XRD), and mineragraphy laboratory analysis. The rock unit in the study area consists of six lithology units, a dacitic intrusion, andesitic lava, andesitic breccia, poly-mix breccia, reef limestone, and alluvium. The study area's alteration types are profilitic alteration, argillic alteration, advanced argillic, and silicification alteration. The profilitic alteration characterized by the abundance of chlorite minerals. The argillic alteration characterized by the abundance of kaolin minerals, while the advanced argillic alteration by the presence of kaolinite and alunite minerals. The silicification alteration characterized by abundance quartz minerals. The metallic minerals dominated in the area are sulfide minerals such as covellite, chalcocite, enargite, chalcopyrite, pyrite, and jarosite. The native gold found in an association with enargite. The study area's mineral deposit system is an epithermal high sulfidation system characterized by mineralized vuggy quartz and the presence of kaolinite mineral as an alteration mineral.","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"93 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73904414","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":"Pendugaan Potensi Volume Akuifer Menggunakan Metode Geolistrik di Pulau Gili Ketapang, Probolinggo, Jawa Timur","authors":"Dino Gunawan Pryambodo, J. Prihantono","doi":"10.17146/EKSPLORIUM.2019.40.1.5415","DOIUrl":"https://doi.org/10.17146/EKSPLORIUM.2019.40.1.5415","url":null,"abstract":"ABSTRAKPengukuran geolistrik dengan menggunakan konfigurasi schlumberger telah dilakukan di Pulau Gili Ketapang, sebuah pulau kecil yang memiliki kepadatan penduduk mencapai 12.356 jiwa/km2. Pengukuran dilakukan di 8 lokasi menggunakan metode pada 8 titik Vertical Electrical Sounding (VES). Hasil pengolahan data geolistrik menunjukkan nilai tahanan jenis akuifer berkisar antara 2,71–206 Ωm pada litologi batugamping pasiran. Potensi volume akuifer terbesar berdasarkan model 2D akuifer air tanah berada di lokasi K-03 dan K-17. Model 3D akuifer air tanah menunjukkan bahwa volume akuifer sebesar 27.689.400 m3 atau sekitar 27.689.400.000 liter. Air tanah di dalam akuifer dapat bertahan selama 68 tahun jika tidak terjadi kenaikan populasi. Selain itu, air tanah juga akan bertahan meskipun tidak terjadi penambahan air di dalam akuifer, baik secara alami ataupun buatan.ABSTRACTGeoelectric measurement using Schlumberger configuration was carried out in Gili Ketapang Island, a small island with a population density of 12,356 people/km2. The measurement conducted at 8 locations using a vertical electrical sounding (VES) method. The result of geoelectric data processing shows aquifer resistivity value ranging from 2.71–206 Ωm at the sandy limestone lithology. The largest aquifer volume potency based on the 2D groundwater aquifer model is in the K-03 and K-17 location. The 3D groundwater aquifer model shows that the aquifer volume is 27,689,400 m3 or about 27.689.400.000 liters. The groundwater inside the aquifer will last within 68 years in a condition where there is no population increase. Besides, the groundwater also lasts even there is no water addition inside the aquifer, by natural or artificial","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84557218","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":"Estimasi Sumber Daya Uranium Tipe Batupasir di Sektor Aloban, Sibolga, Tapanuli Tengah","authors":"Roni Cahya Ciputra, A. Muhammad, Tyto Baskara Adimedha, Heri Syaeful, I. Sukadana","doi":"10.17146/EKSPLORIUM.2019.40.1.5360","DOIUrl":"https://doi.org/10.17146/EKSPLORIUM.2019.40.1.5360","url":null,"abstract":"ABSTRAKEksplorasi uranium di daerah Sibolga telah dilakukan sejak tahun 1978 oleh BATAN dan berhasil menemukan mineralisasi uranium tipe batupasir. Penelitian mengenai konsep mineralisasi uranium pada batupasir dan konglomerat di Sektor Aloban, Sibolga, telah dilakukan melalui data 22 titik bor yang menghasilkan penampang geologi, peta sebaran anomali, serta data cacahan radiometri dan geokimia. Penelitian ini bertujuan untuk mengetahui sumber daya uranium di Sektor Aloban dengan mencari hubungan antara nilai cacahan radiometri dan data geokimia pada data hasil penelitian sebelumnya menggunakan pendekatan geostatistik. Pengolahan geostatistik menggunakan perangkat lunak SGeMS menunjukkan nilai koefisien korelasi 0,5 sehingga data radiometri dan geokimia diinterpretasikan memiliki korelasi yang baik. Estimasi sumber daya uranium dihitung pada Satuan Konglomerat I dan Batupasir I yang memiliki sebaran lapisan mineralisasi tebal dan luas. Nilai kadar rata-rata uranium untuk Satuan Konglomerat I dan Satuan Batupasir I adalah 173,03 ppm U dan 161,54 ppm U secara berurutan. Estimasi sumber daya uranium di Sektor Aloban adalah 415 ton uranium sebagai sumber daya tereka.ABSTRACTUranium explorations in Sibolga Area have been conducted since 1978 by BATAN and successfully result in sandstone-type uranium mineralization. Research related to uranium mineralization concept on sandstone and conglomerate at Aloban Sector, Sibolga has been conducted through 22 boreholes data which resulted in the geological section, anomaly distribution along with radiometry counting and geochemistry data. This research objective is to obtain uranium resources in Aloban Sector by correlating radiometry counting and geochemical data from previous research by using a geostatistic approach. Geostatistical processing using SGeMS software shows a correlation coefficient of 0.5 so that the radiometry and geochemical data are interpreted to have a good correlation. Uranium Resources estimation was measured on Conglomerate I and Sandstone I units which are considered to have thick and wide mineralization distribution. The average uranium grade for Conglomerate I and Sandstone I units are 173.05 ppm U and 161.54 ppm U respectively. Uranium resource estimation at Aloban Sector is 415 tons as inferred resources.  ","PeriodicalId":11616,"journal":{"name":"EKSPLORIUM","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91344784","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}