Journal of Geoscience, Engineering, Environment, and Technology
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Geomorphosite Assessment at North Karangsambung -Karangbolong Geopark Kebumen, as Tools of Geotourism Development
Get PDFGeopark is a sustainable regional development concept that combines geological, biological, and cultural diversity through conservation and education activities to improve the community's welfare. Kebumen Regency has a National Geopark Karangsambung-Karangbolong (GNKK) covering 543,599 Km2 with 41 geosites, ten cultures, and eight biosite since 2018. The northern part of the area is a geological heritage that is widely used for field geological education.
The study aims to identify and assess geosites and geomorphosite in the north area, describing the region's geomorphological processes and geological evolution. Field research was conducted to get an overview of geological diversity, geomorphology, and geosite and determine the selected geomorphosite. Geomorphosite assessment is done quantitatively using the Kubalikova method by assessing five main parameters that include; Intrinsic and scientific value, the value of education, economic value, conservation value, and added value.
The scientific and intrinsic value of Pentulu Indah (PI) = 4, while Wagirsambeng = 3. Educational value of PI = 4, while Wagirsambeng = 2. Economic value is still not satisfactory, but P.I. = 2, while Wagirsambeng = 1.5. Conservation value of P.I. = 3.5, while Wagirsambeng = 2.5. Added value PI = 2.75 while Wagirsambeng = 1.5. Based on those, geomorphosite Pentulu Indah is 16,26 point or a good value (87.83 %) while Wagirsambeng is 10.5 point or fairly level (56.75 %)
Hydrocarbon Prospectivity in the undrilled area of AIMA Field in the Niger Delta Basin, Nigeria.
No full textField development is a very costly endeavor that requires drilling several wells in an attempt to understanding potential prospects. To help reduce the associated cost, this study integrates well and seismic based rock physics analysis with artificial neural network to evaluation identified prospects in the field.
Results of structural and amplitude maps of three major reservoir levels revealed structural highs typical of roll over anticlines with amplitude expression that conforms to structure at the exploited zone where production is currently ongoing. Across the bounding fault to the prospective zones, only the D_2 reservoir possessed the desired amplitude expression, typical of hydrocarbon presence. To validate the observed amplitude expression at the prospective zone, well and seismic based rock physics analyses were performed. Results from the analysis presented Poisson ratio, Lambda-Rho and Lambda/Mu-Rho ratio as good fluid indicator while Mu-Rho was the preferred lithology indicator.
These rock physics attributes were employed to validate the observed prospective direct hydrocarbon indicator expressions on seismic. Reservoir properties maps generated for porosity and water saturation prediction using Probability Neural Network gave values of 20-30% and 25-35% for water saturation and porosity respectively, indicating the presence of good quality hydrocarbon bearing reservoir at the prospective zone
Hydrothermal Alteration and Ore Metal Mineralisation at Temon, Pacitan, East Jawa, Indonesia.
No full textPacitan area is known as Tertiary volcanic arc in Java, as the result of subduction zone of the Indian-Australian Plate beneath the Eurasian Plate since Oligocene. It was superimposed volcanism which formed a wide area of hydrothermal alteration zone, resulting potential ore metals mineralization, such at Temon and its vicinities, Pacitan Regency, East Java Province, Indonesia. The aim of study was to analyze hydrothermal alteration and ore metal mineralization zones. Method was surface mapping, thin section analyses, mineragraphic analyses and X-Ray Diffraction (XRD) analyses. Field study observed denuded and deformed volcanic crater geomorphology. There are ore placer deposits within the sand dunes of Grindulu River, which it consists of andesitic lava and breccia of Early Oligocene Mandalika Formation; Early Miocene lithic and vitric tuffs; and dacitic intrusion. The dikes of dacite as the last of volcanism was the host rock controlling the zonation of alteration and mineralization stages. Oblique normal faults and shear faults were cross over dilating formed fractures, which were as bodies to depositing the ore metals. There are (zone 1st) the argillic clay consists of quartz+alunite+dickite+kaolinite±illite with vuggy structures, (zone 2nd) the argillic clay consists of quartz+montmorillonite±illite zone with quartz vents, brecciated and sulfide massive, and (zone 3rd) as the chloritized zone with low grade and supergene on the edge of hydrothermal alteration. It was fluid overprinted that very acid to the core of zone 1st (pH2-4) into more netral pH 4-6 (zone 2nd) and (pH5-6) in the edge zone 3rd. The potentials ore metal mineralization are Fe and Cu by pyrite, chalcopyrite, hematite, and covellite. Other potential ore metal mineralization was also from enargite by the supergene alteration
Interpretation of Subsurface Fault Through Multi-Level Second Vertical Derivative Gravitational Data in Bittuang Geothermal Working Area, South Sulawesi, Indonesia
Get PDFThe research was conducted in Bittuang, Tana Toraja Regency, South Sulawesi Province, as one of the geothermal prospect areas and targets for the initial stage of the Government exploration drilling program for the 2020-2024 period. One aspect of geothermal is the manifestation control structure as a fluid migration path from below the surface. Therefore, identification of existing structures in the Bittuang geothermal area was carried out and confirmed the surface geological structure contained in the Bittuang geothermal geological map. In determining the presence of a fault and knowing its characteristics such as the type of fault, the direction of the dip, and the magnitude of the dip of the fault, the gravity data is processed using the multi-level second vertical derivative (ML-SVD) method. To strengthen the interpretation, the results from the ML-SVD were matched with the data from the horizontal gradient (HG) method and the geological data of the structure of the study area. From this process, there are 27 faults in the Bittuang geothermal area, two of which are indicated as controlling faults for the manifestation of the Balla group and the Cepeng group. This research is expected to describe faults in the Bittuang geothermal area, which can support detailed exploration activities
The Soft Layer Thickness Estimation using Microtremor Measurement to Identify Landside Potential in Watukumpul, Central Java, Indonesia.
No full textWatukumpul is an area that is prone to landslides, so determining the soft layer thickness is very important to identify the landslide potential. The soft layer thickness can be estimated using microtremor signal measurements which analyzed using the Horizontal to Vertical Spectral Ratio (HVSR). In this study,we measured microtremor signal of 33location around Watukumpul, Pemalang, Central Java area to determine soft layer thickness. Micretremor signal was analyzed based on theHVSR method using Geopsy software and follow the standard of the Sesame Europan Project. The results of the HVSR method are the HVSR curve that fulfills the reliable curve standard. HVSR curve shows that the dominant frequency of soft layer ranges from 1.36 – 7.62 Hz and the amplification values ranges from 9.00 – 41.45. The soft layer thickness value in the study area ranges from 17.58 - 103.60 meters. The high landslide potential area are located at W7, W8, W18, W30 and W32 where has thin soft layer and high soil slope
Proxapertites from Walat Formation, Sukabumi, West Java, Indonesia
No full textProxapertites have become one of the most significant indicators of ancient rock in Indonesia. Walat Formation is one of the oldest rocks exposed in Sukabumi, West Java, Indonesia. These Proxapertites have not been described in detail about their characteristics in previous studies, especially on Walat Formation. Therefore, knowing the characteristics of Proxapertites becomes interesting, especially in Walat Formation, which can be a reference for the characteristics of the late Eocene Proxapertites (37.8 - 33.9 million) in Indonesia. Acetolysis method was carried out for the preparation of pollen and spores; description and determination were carried out to see the characteristics of Proxapertites that present in Walat Formation. Result, there are three types of Proxapertites. Proxapertites operculatus have sizes 23 – 86 µ with average 40.5 (P) and 51.1 (E) µ, index PE 0,43 - 1, Peroblate – Subspheroidal – Oblate Spheroidal, Fine-Reticulate ornamentation, and Asymmetric Monosulcate aperture. Proxapertites cursus have sizes 23 – 86 µ with average 39.8 (P) and 49.8 (E) µ, index PE 0.51 - 1, Oblate – Subspheroidal – Oblate Spheroidal, Reticulate ornamentation, and Asymmetric Monosulcate aperture. Whereas Proxapertites psilatus have sizes 29 – 75 µ with average 42.3 (P) and 52.5 (E) µ, index PE 0.58 - 1, Oblate – Subspheroidal – Oblate Spheroidal, Psilate ornamentation, and Asymmetric Monosulcate aperture. These three Proxapertites can be distinguished by their type of ornamentation. Meanwhile, other aspects have similar characteristics and are affected by the appearance of individual pollen on the slide during preparation
The Transitional Gabbroic Rocks in Bayah Geological Complex, Western part of Java, Indonesia, Inferred from XRF, ICP-MS, and Microprobe Analysis
Get PDFGabbro, is a fossil remnant of oceanic crust in western part of Java, found at Bayah Geological Complex (BGC) and Ciletuh Melange Complex (CMC), Indonesia. It has been studied by using petrographic, X-Ray Fluorescence (XRF), and inductively coupled plasma-mass spectrometry (ICP-MS) and mineralogical (microprobe) analyses. Mineral and geochemical composition of these rocks provide important clues to their origins since the rocks have been deformed and gone through auto metamorphism, beside they contain the economic mineral and or rare earth elements (REE). Gabbroic rocks in these two areas generally shows phaneritic to porphyritic texture, granular texture. These rocks in CMC are dominated by plagioclase (oligoclase to albite), hornblende, pyroxene, partly altered to tremolite, actinolite, chlorite, epidote, and sericite; meanwhile those of BGC dominantly consist of plagioclase, pyroxene, hornblende, some present of chlorite, actinolite, epidote and biotite as secondary minerals. In multi-element diagrams, gabbroic rocks in CMC show strong negative Sr and Zr, but positive Nb anomaly, while those of BGC show strong negative anomaly of Nb and Zr. In addition, based on rare earth elements (REE) diagrams, gabbroic rocks in CMC show depleted of light rare earth elements (LREE) with negative Eu anomaly, while gabbro’s in BGC show enrichment of LREE. These characteristics indicate that GBC’s and CMC’s gabbroic rocks came from different magma sources, one was formed by partial melting of depleted upper mantle reservoir while the other one was formed by partial melting of mantle wedge with active participation of subducted slab in an arc tectonic setting, suprasubduction zone which were formed at started Upper Cretaceous to Paleogene, and they had retrograde metamorphism to epidote amphibolite facies
Groundwater Conservation Strategy Based on Water Balance at Muarabungo Groundwater Basin, Indonesia
Get PDFMuarabungo Groundwater Basin,is locateed in Jambi and West Sumatra Province. Based on the four rainfall stations in Muaratebo, Dusun Rantau Pandan, Sungai Bengkal and Komplek Pengairan PU Station recorded in 2008 to 2011, the precipitation (ppt) in study area is 1799.09 mm/year. Value of evapotranspiration (Evpt) in the study area is equal to 1261.26 mm / year (70.1%). Groundwater Basin of Muarabungo has an infiltration debit of 2,516,791,750 m3 / year and run-off debit (Ro) of 798 042 638 m3 / year. Rock composer in the Muarabungo Groundwater Basin are dominated by Alluvium Deposition, Quaternary rocks, and also the surrounding areas are composed by igneous and metamorphic rocks. Aquifer with a good productvity can be found on Alluvium and sedimentary rocks such as tuff sandy, whereas region without exploitable groundwater are composed by igneous rocks and metamorphic rocks. Based on groundwater quality, Groundwater Basin is divided into 13 facies, namely Ca; Cl, Mg; Cl, Na + K, Cl, Ca; HCO3, Mg; HCO3, Na + K; HCO3, Ca; No. dominant type, Mg; Nodominan type, Na + K; No. dominant type, No. dominant type; Cl, No. dominant type; HCO3, Nodominan type; SO4, and No. dominant type; No. dominant type. The result of water balance measurement in research area is used to show the areas for crisis and secure area. The water balance calculation and determining recharge and discharge areas are needed for developing conservation strategy