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Identifikasi Pola Struktur Geologi Sebagai Pengontrol Sebaran Mineral Radioaktif Berdasarkan Kelurusan Pada Citra Landsat-8 di Mamuju, Sulawesi Barat Indrastomo, Frederikus Dian; Sukadana, I Gde; Suharji
EKSPLORIUM Vol. 38 No. 2 (2017): NOVEMBER 2017
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2017.38.2.3874

Abstract

Mamuju area and its surrounding are composed of volcanic rock containing uranium (U) and thorium (Th) elements. Radioelements concentrations in the area reach 1,529 ppm eU and 817 ppm eTh. Radioactive minerals identified in the area are thorianite, davidite, gummite, and autunite. The geological structures were formed by tectonic activities which controlled the creation of volcanic complex and U-Th mineralization in the complex. Identification of geological structure in the field is very difficult due to densely vegetation and higly degree of weathering. The interpreted lineaments from Landsat-8 imagery are the manifestation of geological structures which have controlled the existence of U and Th. Lineaments analysis using Sastratenaya formula is used to obtain the relative age and chronologies of the lineaments. Dose rate measurements in the area show the trend of radioactivitiy anomalies are trending northwest–southeast. The Sastratenaya formula results the formed structures are relatively older and dominantly directing northwest–southeast (N 140o–150o E). Based on the linement interpretation, the dominant direction has similliarity with volcanic and radioactivity distribution. Structures which controlling the volcanic formation and related to U and Th mineralization generally are the northwest–southeast trending structures, which were created along with U and Th mineralization.
Inventarisasi Potensi Sumber Daya Uranium Daerah Kawat, Mahakam Hulu, Kalimantan Timur Tahapan Prospeksi Detil Ngadenin, Ngadenin; Sukadana, I Gde; Muhammad, Adi Gunawan; Suripto, Suripto
EKSPLORIUM Vol. 32 No. 2 (2011): NOVEMBER 2011
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2011.32.2.2813

Abstract

Result of the general prospecting in East Kalimantan has found several radioactivity outcrop anomalies at upper Mahakam in the acid volcanic rock area which is approximately 25 km2 in wide. The objective of the research is to know detailed geological information and characteristic of uranium mineralization. Method of this research are detailed geological, radiometric and geochemical mapping 1:10.000 on scale. The lithology of Kawat area is composed of seven units of rock. They are black clay unit, feldspatic sandstone unit, Nyaan rhyolite unit, lower andesite unit, Kawat rhyolite unit, upper andesite unit and tuffaceous sandstone unit. Evolving fault is dextral fault and normal fault. The trending of dextral fault is west-east and southwest-northeast, meanwhile the trending of normal faults is west-east and southwest - northeast. There are two period of uranium mineralization occurrences in the area, the first is connected with the eruption of Nyaan rhyolite magma and the second is connected with the eruption of Kawat rhyolite magma. Uranium mineralization occurred in the stage of hydrothermal process and including in the pneumatogenic class of volcanogenic uranium deposits. This investigation has yielded two sites of potential uranium sector are the Nyaan sector with an area of about 6 km2 and Kawat sector with an area of about 10 km2.
Geologi dan Mineralisasi Uranium di Sektor Sarana Kalan, Kalimantan Barat Berdasarkan Data Pemboran Sartapa, Sartapa; Sukadana, I Gde
EKSPLORIUM Vol. 32 No. 2 (2011): NOVEMBER 2011
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2011.32.2.2816

Abstract

Favourable zone of uranium mineralization in Sarana Sector with NE-SW direction are contained in metapelite rock and some in muscovite quartzite. Mineralization of uranium is occurred fill in the fields of parallel fractures with schistosity by ENE-WSW direction, and moderate to strong inclination to the north. Three points drilling with the depth of 126.6, 174.50, and 150.90 meter has been conducted. This study is aimed to obtain the knowledge of geology, and geometry of sub-surface uranium mineralization. Geologically, research area are consists of metapelite, muscovite quartzite and biotite quartzite with millimetric - centimetric thicknesses. Uranium mineralization are in forms of veins or tabular as uraninite and pitchblende associated with pyrite, chalcopyrite, pyrrhotite, ilmenite and molydenite. Uranium Mineralization on the surface could be correlated with sub-surface from bore-hole data, with the result that zone of uranium mineralization in lenses or tabular form with sub-vertical dip may be identified.
Kombinasi Pengukuran Radioaktivitas Batuan dan Geofisika dalam Menentukan Akuifer Airtanah Potensial di Desa Sumbermanjing Kulon, Pagak, Malang, Jawa Timur Sukadana, I Gde; Indrastomo, Frederikus Dian
EKSPLORIUM Vol. 32 No. 2 (2011): NOVEMBER 2011
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2011.32.2.2820

Abstract

The study area is an area with difficulties in fresh water supply. This study aimed to investigate geological characteristics, stratigraphical traps and sub surface geophysical characteristics to identify aquifer existance, depth and distribution. The purpose of this study is to determine the potencial location for groundwater drilling to fulfill the needs of fresh water in this area. Stages of activities include topography mapping, geological mapping, soil/rocks radioactivity measurements, geoelectric (resistivity) surveys and potential location determination analysis for drilling. The study area is an area with undulating terrain, litologically composed with sandstone unit and limestone unit. Radioctivity value of limestone ranged from 30c/s to 45c/s, carbonaceous sandstone ranged from 20c/s to 30c/s, and tuffaceous sandstone lower than 20c/s. Based from geoelectrical measurements analysis, lithologically this area devide into 4 rock layers, i.e. limestone (>100Wm), claystone (1Wm - 7 Wm), sandstone-1 (10Wm - 33Wm), and sandstone-2 (14Wm - 17 Wm). Integrated analysis resulted 2 potential location for drilling with coordinates for location 1 UTM 49M 664327mT, 9082526mU, 346 mdpl and location 2 UTM 49M 664333mT, 9082750mU, 349 mdpl.
Mobilitas Uranium pada Endapan Sedimen Sungai Aktif di Daerah Mamuju, Sulawesi Barat Mu’awanah, Frida Rosidatul; Priadi, Bambang; Widodo; Sukadana, I Gde; Andriansyah, Rian
EKSPLORIUM Vol. 39 No. 2 (2018): NOVEMBER 2018
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2018.39.2.4953

Abstract

Mamuju is an area that has a high dose rate (radioactivity) value. The research area consists of 6 sectors namely Ahu, Orobatu, Takandeang, Botteng, Pangasaan, and Taan Sector. Lithological distribution does not represent the distribution of uranium; therefore geochemical method is needed to observe the distribution of uranium in the drainage system. The aim of this research is to provide an overview of the mobility and distribution of uranium in the drainage system using stream sediment. Uranium mobility analysis uses labile percent obtained from the ratio of total uranium and labile uranium, the total uranium value obtained from the measurement of X-Ray fluorescence spectrometry and the value of labile uranium obtained from measurement of labile fluorimetry. The sample taken from 4 potential areas based on radiometric value Map. The result of analysis shows that Ahu Sector has labile uranium anomaly >113.44 ppm, Pangasaan Sector with labile uranium anomaly >168.63 ppm, Takandeang Sector with uranium labile anomaly values >74.36 ppm, and Botteng Sector with uranium labile anomaly >84.23 ppm. The anomaly types identified from two sectors, namely Ahu Sector anomaly is related to the precipitation of dissolved uranium hydrolysates in stream deposit originating from Ahu lava and Tapalang breccia, while Takandeang Sector anomaly is related to the enrichment of in situ uranium in soil and Takandeang lava.
Geologi dan Mineralisasi Uranium Sektor Nyaan Mahakam Hulu Kalimantan Timur Sukadana, I Gde
EKSPLORIUM Vol. 33 No. 2 (2012): NOVEMBER 2012
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2012.33.2.2663

Abstract

Nyaan Sector covered 0.5 km2 area. The aim of research is to understand the geological setting, mineralization and potency of uranium in Nyaan Sector. The research activities involved topography measurement, soil radioactivity measurement by grid of 20x20 m2, stratigraphic and detailed geological structure observation, the making of peels at any anomaly area and radioactivity anomaly area. There are 3 (three) significant radiometric anomaly locations at Nyaan Sector. They are anomaly Sungai Marta, Marta Hulu and Aloha with radiometric value ranges from 8000 c/s to > 15000 c/s with background value of 100 c/s. In these areas, the making of peels, trench and test pit were conducted by sampling mineralization using systematic channel sampling system by the sum of 15 channels sampling and 8 chieps sampling. The petrography and mineralogy analysis exhibited that mineralization of pitchblende, monazite, autunite were associated with bornite, chalcocite, chalcopyrite, lolingite, pyrite, sphalerite, ilmenite, limonite, magnetite, marchasite, rutile, malnicovite, hematite and iron oxide. Results of geochemical analysis for total uranium content in the rocks ranged between 345 to 11.425 ppm of uranium.
Pengukuran Geolistrik dan Intensitas Gas Radon pada Penentuan Daerah Potensial untuk Pemboran Air Tanah-Dalam Desa Lebeng Barat Pasongsongan, Sumenep, Jawa Timur Sukadana, I Gde
EKSPLORIUM Vol. 34 No. 1 (2013): MEI 2013
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2013.34.1.715

Abstract

Lebeng Barat village, Pasongsongan sub-district is a village which has insufficient of fresh water, particularly in dry season. This region has a fairly dense population and equitable distribution of the population, therefore a sufficient supply of clean water for consumption and other needs are required. The purpose of study is to find out the ground-water potential zone in determination of exploration drilling points to develop ground-water’s well production. The methods used in this study as follow: Geological/hydrogeological mapping, measurement of radon intensity and geo-electric sounding survey with Schlumberger’s configuration. Exposed rocks within work areas can be classified into 5 (five) rocks unit, namely claystone with intercalation of limestone unit, inter bedded of calcareous sandstone and limestone unit, mudstone unit and limestone-claystone unit. The potential rock’s layer as aquifer is a layer of calcareous sandstone which has characteristic of pale yellow to brown, medium-coarse grained, sufficient permeability rocks (in the section exposed at the surface) include the limestone unit. Rock aquifers that serve on the bottom are included in inter bedded of calcareous sandstone and limestone unit. Potential points recommended for drilling exploration / production are the point of LBR-29 with the thickness of the aquifer 1 (shallower) 33.86 m and aquifer 2 (deeper) 23.72 m.
Peran Kontaminasi Kerak pada Diferensiasi Magma Pembentuk Batuan Vulkanik Sungai Ampalas, Mamuju, Sulawesi Barat Draniswari, Windi Anarta; Kusuma, Sekar Indah Tri; Adimedha, Tyto Baskara; Sukadana, I Gde
EKSPLORIUM Vol. 41 No. 2 (2020): NOVEMBER 2020
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2020.41.2.6040

Abstract

Anomalous radiometry has been found in Ampalas River Area on volcanic rock boulder. The values measured from gamma spectrometer are 787 ppm eU and 223 ppm eTh. This discovery is promising for exploration development. Further study need to figure the radioactive mineral bearing rock characteristic from in-situ samples. The research aim is to determine the petrology and geochemical characteristics of Ampalas volcanic rocks as preliminary study to find radioactive mineral accumulation process of Ampalas volcanic rocks. The methodologies are field observation, rock sampling, petrography, and X-Ray fluorescence (XRF) analyses. The Ampalas volcanic rocks consist of phonolite, phoidite, and phoid syenite. Their textures are porphyritic, flow, pyroxene rim, zoning, pseudo-leucite, corrosion, mafic inclusions, and sieve. The geochemical characteristics show high alkalinity and radioactive mineral enrichment disseminating on rock. The magmatic processes which play a significant role in radioactive mineral-bearing rocks formation are crystal fractionations (leucite and alkaline feldspar fractionations), continental crust assimilation, and magma mixing. Long interaction between magma and crust creates advanced magma differentiation causing higher uranium and thorium accumulation.
Indikasi Mineralisasi Tipe Porfiri di Daerah Sumbersari, Kompleks Pengunungan Kulon Progo, Purworejo, Indonesia Verdiansyah, Okki; Muharif, Damas; Sukadana, I Gde
EKSPLORIUM Vol. 41 No. 2 (2020): NOVEMBER 2020
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2020.41.2.5959

Abstract

Kulon Progo Mountain is Sunda-Banda Arc magmatism product composed of an old andesite formation. Sumbersari Area is part of the Gajah volcanic, which is the oldest rock of Kulon Progo volcanics. Indication of porphyry type mineralisation has been found in the area which makes the area interested for further research. The research methodologies are geological mapping, petrography and ore microscopy, and geochemical analysis using XRF and ICP-MS. Geology of the area located in central-proximal facies of Khuluk Gajah, consist of microdiorite, quartz-microdiorite, andesite, basaltic-dioritic andesite intrusions, and limestone. Hydrotermal alteration is developing into certain groups like illite-sericite ± secondary biotite, epidote-actinolite-calcite ± illite, epidot-calcite ± illite, and illite-sericite ± quartz. Some mineralisation phases are developed like epidote-actinolite followed by magnetite-chalcopyrite mineralisation, biotite-magnetite-chalcopyrite-bornite phase and the late phase of sericite-clay-pyrite replacing the entire system. Geochemical analysis on altered rocks show Cu-Au mineralisation indication ranging from 491-1,447 ppm (0.14%) and 0.02-0.3 ppm respectively, with Cu:Au ratio is 1.01. Geochemical characteristic shows strong correlation of Cu to Au.
Distribution and Mineralogical Characteristic of Raya Volcanics, West Kalimantan Draniswari, Windi Anarta; Pratiwi, Fadiah; Ngadenin; Sukadana, I Gde; Adimedha, Tyto Baskara; Ciputra, Roni Cahya; Argianto, Ekky Novia Stasia; Aminarthi, Erwina; Supraba, Vertika Dhianda
EKSPLORIUM Vol. 42 No. 2 (2021): NOVEMBER 2021
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2021.42.2.6511

Abstract

There are several volcanic rocks in a radius of 150 km from where the Nuclear Power Plant (NPP) site project in West Kalimantan. The Mesozoic volcanic rocks have not been characterized for volcanic hazard evaluation purposes due to their old age. However, the distribution of Raya Volcanic Rocks that covers the site area and the wider area up to 150 kilometers from the site makes this rock group quite important to be characterized to find out how its activities in the past. This paper’s objective is to comprehend the distribution and characteristics of Raya Volcanic Rocks for NPP site volcanic hazard evaluation purposes. Fieldwork and lineament analyses were conducted to map and interpret the distribution of Raya Volcanic Rocks while mineralogical analysis using petrography and micro XRF were conducted to characterize the Raya Volcanic Rocks. The distribution of Raya Volcanic Rocks that relatively show NNW–SSE orientation is probably controlled by the NNW–SSE fault system. The analyses resulted that Raya Volcanic Rocks erupted as lava flows derived from mafic magma as a product of mantle partial melting that underwent crystal fractionation, injection of hotter/more Ca-rich magma, and magma mixing on an open-system magmatic process.