Jambura Geoscience Review
ISSN / EISSN : 26230682 / 26560380
Current Publisher: Universitas Negeri Gorontalo (10.34312)
Total articles ≅ 13
Latest articles in this journal
Jambura Geoscience Review, Volume 2, pp 50-57; doi:10.34312/jgeosrev.v2i1.2468
Abstract:The Bayang Sani Watershed has an area of 1267.97 hectares with an average rainfall of 3117 mm/ year. The topography of this watershed have varies slopes. In the rainy season, the river water is a muddy color and both soil and rocks are contained in the river’s water that causes channel damage and reduced river capacity. It is caused by the wider distribution of land erosion in the Bayang Sani Watershed. The purpose of this study was to analyze the soil erodibility. The method of this study is a quantitative study and field survey method. The data was collected by field survey and sample points were determined using purposive random sampling techniques. The sample was analyzed in the BPTP laboratory to determine the types and colors of the soil sample, depending on the quality of the soil's erosive value. The results show that soil erodibility in the Bayang Sani Watershed range 0.15-0.28. The low soil erodibility level found in land units F3.II.Kc.Qal.Lat (0.16), V2.II.Kc.Tomp.Lat (0.15) and V2.II.Sm.Tomp.Lat. (0.16) the moderate of soil erodibility was found in the land unit V3.III.Ht.Tomp.Lat (0.28).
Jambura Geoscience Review, Volume 2, pp 41-49; doi:10.34312/jgeosrev.v2i1.2639
Abstract:The study of soil minerals structure has been conducted in the Sawaru village, Maros regency, South Sulawesi which is locally known to be the landslides-prone area. The aim of this research is basically to determine the mineral characteristics of the soil. The samples were taken randomly in three points with a depth of 75 cm at point 1 and 100 cm for the other. The structure of the samples was analyzed using X-Ray Diffraction (XRD) where the samples were placed in the high temperature and airtight containers. The results of XRD analysis showed that minerals contained at point 1 (75 cm in depth) were illite (69.3%) with a monoclinic structure, albit mineral (25.6%) with a triclinic structure and kaolinite (5.0%) with a triclinic structure. Samples at point II (100 cm depth) contained illite (67.2%), feldspar (23.9%) with monoclinic and merrillit (8.9%) with trigonal structures. Samples at point III (100 cm in depth) contained illite (55.9%), bobtraillite (22.2%) with a trigonal structure and feldspar (21.9%) with a monoclinic structure. The minerals observed at the sampling points are dominated by illite which is clay in nature. Such a mineral has been known to have an ability to initiate high plasticity in soil, leading to the slope instability.
Jambura Geoscience Review, Volume 2, pp 30-40; doi:10.34312/jgeosrev.v2i1.2671
Abstract:Landslide occurrence can be influenced by physical factors and human activities. Thus, research related to the provision of information about landslide distribution in Alo watershed is needed as a basis in enhancing community preparedness in dealing with disasters. The method used in this study is the scoring method based on the Minister of Public Works Regulation No.22 / PRT / M / 2017 which is processed through a geographical information system through the overlay of all physical parameters. The result shows that the Alo watershed area is divided into three vulnerability categories. "Low" category covers 7171.8 ha, "medium" category covers 12008.7 ha, and "high" category covers 5039.5 ha out of 24.221 ha the total area of Alo watershed. Information provided in this research is expected to be able to help the local government in making policies in managing the Alo watershed area and enhancing the understanding of the local community in Alo watershed in dealing with disasters.
Jambura Geoscience Review, Volume 2, pp 1-15; doi:10.34312/jgeosrev.v2i1.2472
Abstract:Gold is one of the precious metals with high economic value, so the exploration process becomes an important stage to find new resources so that gold production remains optimal. The research was aimed at investigating the geological condition and characteristics of hydrothermal alteration and mineralization developed in the research site. The research site was included in the area CoW of PT. Gorontalo Sejahtera Mining exactly lied in Hulawa Village, Gorontalo, Indonesia. This research integrated the fieldwork with laboratory tests and analysis, including petrography, Analytical Spectral Devices, and mineragraphy. Based on data that had been conducted and data analysis results, it can be concluded that the research site consisted of lithology in the form of Oligocene granodiorite and Pliocene rhyodacite and diatreme breccia that rolled as host rock’s mineralization. Normal right-slip fault directing E-W is interpreted as a pre-mineralization structure, while normal left-slip fault directing NNE-SSW is interpreted as syn-mineralization structure or controlling structure during alteration and mineralization process. Alteration developed in research area consisted of the phyllic zone (sericite + quartz ± pyrite ± montmorillonite ± chlorite ± carbonate), argillic zone (illite + kaolinite ± smectite ± montmorilonite), and chloritic zone (chlorite + carbonate + pyrite ± quartz ± illite ± sericite ± montmorillonite). Hydrothermal deposits controlled by geological structure and volcanic mechanism. Mineralization in the research site was found in stockwork quartz veins and hydrothermal breccia, and some were found in dissemination with ores such as pyrite, chalcopyrite, arsenopyrite, galena, sphalerite, bornite, covelite, gold, and electrum. Based on its alteration and mineralization characteristics, the epithermal deposits in the research site was the type of low sulphidation deposite in-depth level in the model of open-vein and breccia.
Jambura Geoscience Review, Volume 2, pp 16-29; doi:10.34312/jgeosrev.v2i1.2682
Abstract:Gorontalo City is one of the regions in Gorontalo Province. Urban development and population growth, causing pressure on land use patterns. Changes in land use are carried out to meet the community's needs for infrastructure. At present, development in Gorontalo City is still ongoing. The increase in temperature is expected to continue and can trigger heat island. This is very important to be studied for the Gorontalo City development planning that is more environmentally friendly. This study aims to analyze the heat island phenomenon through the relationship of the spatial distribution of surface temperature with various types of land cover and vegetation characteristics. The object of this research is the Gorontalo City area on Landsat path-row 121- 65 satellite imagery media. The research material is the wavelength of visible light, near-infrared and moderate infrared and thermal wavelengths on satellite imagery of Landsat TM and OLI TIRS. The results showed an increase in temperature in Gorontalo City since 1990, 2003, and 2017. The correlation between surface temperature and land cover is negative. The value of the correlation coefficient (r) in 1990 was -0.41. The correlation coefficient (r) in 2003 was -0.448. The correlation coefficient (r) in 2017 is -0.402. Changes in surface temperature in Gorontalo City are influenced by changes in the land cover which is marked by the similarity of patterns of changes in surface temperature distribution with patterns of land cover changes.
Jambura Geoscience Review, Volume 1, pp 87-101; doi:10.34312/jgeosrev.v1i2.2474
Abstract:In Gorontalo City there have been 11 landslides in 2017 which are spread in 3 sub-districts namely Hulonthalangi, Kota Barat, and Dumbo Raya. While in 2018 there was a landslide in Tenda village which claimed two lives. The research site is located in coordinate 00°29'00" - 00°31’51" N and 123°3'00" - 123°5'27" E with the wide of area 2,531 Ha consisting of 1,745 Ha of the mainland and 786 Ha of the sea. The research area administratively is located in Dumbo Raya Sub-district, Gorontalo city, Gorontalo Province. The purpose of this study was to determine the level of landslide susceptibility in the study area and make zonation maps of landslide prone area. This research method applied in this study was integration of field survey and GIS analysis. The parameters which influence the landslide are lithology, precipitation, slope, lineament density, type of soil, and the land use. Based on the analysis of landslide susceptibility, the level of susceptibility in the research site consists of 3 classes; low, moderate, and high. The low class of landslide susceptibility has the area of 217.46 Ha, the moderate class of landslide susceptibility has the area of 338.93 Ha with the biggest spread is in Leato Selatan village; 102.68 Ha. The high class of landslide susceptibility has the area of 1,188.70 Ha with the biggest spread in Leato Selatan Village; 288.66 Ha.
Jambura Geoscience Review, Volume 1, pp 77-86; doi:10.34312/jgeosrev.v1i2.2349
Abstract:Information on household poverty level in Wonosari Sub-district area is still very difficult to access by all parties. Therefore, this study aims to analyze poverty level and map of the spatial distribution of webGIS-based poor households in the site area. In determining the number of samples, descriptive statistical analysis techniques focused on assessing and describing the poverty level of each household. GIS analysis used GIS Application 2.18 to map the spatial distribution of poor households and regional poverty levels. GIS Application has been equipped with 2 web tools that are able to display webGIS-based maps. The results shows that the poverty level of households is in the poor category with a percentage of 72% of households, 14% of households are in the extremely poor category and 14% are in the fairly poor category. and 1 village is in a fairly poor category. This is a village that was built with a view that can be accessed by various PCs, laptops and android media so that the maps information from an analysis of household poverty levels and the spatial distribution of poor households can be accessed on the webGIS that has been built.
Jambura Geoscience Review, Volume 1, pp 68-76; doi:10.34312/jgeosrev.v1i2.2380
Abstract:Limestone is a sedimentary rock composed by calcium carbonate derived from the rest of marine organisms and the main materials of cement so exploration and calculation of limestone resources need to be done. The research area is administratively located at the Biluhu Timur Village and its surroundings, Batudaa Pantai District, Gorontalo Regency. The purpose of this study is to observe the geological conditions of the study area to determine distribution of limestones in the study area to be used as cement industrial materials with the geological mapping, and the analysis limestone geochemical using XRF (X-Ray Flourescence). Based on the result of this research can be concluded that the research area was devided into four geomorphological units, consisting of volcanic hills unit, denudational hills and plain unit, and the coastal plain unit. The litology arranged by granodiorit, basal, and the limestone (packstone and wackestone). Based on the result of geochemical analysis using XRF and calculation of volume using Surpac softwere can be devided into three blocks. The A block have limestones (packstone) with the content of CaO 51.79% and MgO 1.98% that meets the requirement materials of portland cement with total volume 423 107 230 tons. The B block have limestones (wackestone) with the content of CaO 4.92% and MgO 5.28% that not meets the requirement materials of portland cement with total volume 729 263 008 tons. The C block have limestones (packstone) with the content of CaO 52.85% and MgO 0.98% that meets the requirement materials of portland cement with total volume 539 883 150 tons.
Jambura Geoscience Review, Volume 1, pp 50-67; doi:10.34312/jgeosrev.v1i2.2056
Abstract:The research area located in the lowland zone and the corrugated hilly zone which is dominated by sedimentary rocks. Therefore, this study aims to determine the geological features of the research area and the study of depositional environmental facies of the Lake Deposits Formation as an analysis of the depositional environment of Limboto Lake. The research method used is the surface geological mapping, measuring a section of stratigraphic and laboratory analysis. Field data consists of stratigraphical features of the research area. Laboratory analysis consists of petrography and stratigraphy-sedimentology analysis. It can be concluded facies and stratigraphy of research from older to youngest, consists of clastic limestones unit formed in Late Miocene-late Early Pliocene age, reef limestones formed in Late Miocene-early Late Pliocene age, sandstones unit formed in Late Pliocene-Pleistocene age, clay unit, and sandy clay unit are deposited in Holocene. Overall the study site consisted of marine, transitional and terrestrial deposition environment with Lake Deposits Formation facies is lake margin clastic deposits and meandering-stream environment deposits.
Jambura Geoscience Review, Volume 1, pp 40-49; doi:10.34312/jgeosrev.v1i2.1756
Abstract:Crime is an unplanned change due to the process of urban development. The geographical approach is able to analyze spatial interactions of criminogenic factors into crime phenomenon. This study aims to explain the spatial interaction between socio-economic conditions and crime risk in Bandung City. The crime risk is obtained through Kernel Density Estimation (KDE) method based on The Annual Crime Data from Bandung Police Department, whereas the socio-economic condition data is revealed from interview and questioner with 176 respondents who determined by multistage random sampling in 37 hamlets. Variable interactions are analysed based on Geographically Weighted Regression (GWR) with Gaussian Distance Function type of cross validation as optimum weight. The results show the socio-economic conditions has a positive and significant effect on crime risk. This model shows that the independent variable acts as a crime attractor. Partially its known that economic conditions have a stronger interaction with crime risk than the social climate. The strongest interaction between variables are concentrated in the southern of Kebon Pisang Urban Village, precisely in the area passed by arterial roads at southern of Sumur Bandung. Crime prevention efforts are conducted using environmental interventions by the formal security personnels and strengthening the social climate of the community.