Journal of Applied Geology
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HOST ROCKS’ GEOCHEMISTRY AND MINERALIZATION POTENTIAL OF POLYMETALLIC EPITHERMAL QUARTZ VEINS AT SORIPESA PROSPECT AREA, SUMBAWA ISLAND, INDONESIA
Get PDFThe Soripesa prospect area is located at Maria village, Wawo district, Bima region in the eastern part of Sumbawa Island, Indonesia. This area is a part of Cenozoic Calc-alkaline volcanic inner Banda- Sunda Arc. There are five main polymetallic epithermal quartz veins in the Soripesa prospect area, namely, Rini vein, Jambu air vein, Dollah vein,Merpati vein, and Arif vein. The dominant lithology is a lithic-crystal tuff of andesitic and dacitic composition and bedded limestone. Major oxides and trace elements were analyzed by using X-Ray Fluorescence (XRF) to identify the host rock geochemistry. The main veins are hosted by andesitic and andesitic/ basaltic volcanic host rocks. Major elements compositions are affected by alteration. Based on the trace element data, host rocks of all veins were formed in the volcanic arc basalt (VAB) and island arc basalt (IAB) tectonic settings. Host rocks of Rini vein contain higher amount of precious and base metal elements (Zn, Cu, Pb, and Ag.etc.) than those of other host rocks. Keywords: Soripesa prospect area, lithology, tectonic setting, mineralization
IMPROVEMENT OF EXPANSIVE SOIL BY ELECTRO-KINETIC METHOD
Get PDFThe roadway in Karangjati, Ngawi Regency, East Java, Indonesia, which is underlain by expansive soil, is susceptible to damage due to volume change. This research aims to improve the engineering properties, such as consistency limits, compressibility, and undrained shear strength of the montmorillonite dominated soil in this area using an electrokinetic stabilization method. Four electro-kinetic experiments were conducted using different electrolytes (calcium chloride or pure water) under different conditions (no-flow or flow water). The results show that, pH values of all soil samples decreased at anolyte and increased at catholyte. Atterberg limits of the soil samples were found to increase, where the liquid limit (LL) range of 79.72– 86.14%, plastic limit (PL) 25.22–30.80%, and plasticity index (PI) 53.28–60.92, liquidity Index (LI) 0.91–1.08. The compression index Cc was 0.50– 0.742. Undrained shear strength of treated soil range of 7–11 kPa. Moreover, strengthening degree of the treated soils achieve 304–556%. The soil improvement was achieved by decreasing the Atterberg limits, and compressibility and increasing the undrained shear strength. Applying calcium chloride and flow water condition were the most effective methods for the soil improvement. The mineralogical compositions of the soil samples did not change after the treatment. Keywords: Electro-kinetic stabilization, electro chemical injection, clayey soil improvement
CHEMICAL COMPOSITION AND HYDRAULIC CONNECTIVITY OF SPRINGS IN THE SOUTHERN SLOPE OF MERAPI VOLCANO
Get PDFSprings are easily found in the southern slope of Merapi volcano, Sleman Regency, Yogyakarta Special Province, Indonesia. Springs origins on this location are commonly related to the existing of Merapi Aquifer System, but importance question of all these springs are hydraulic connectivity among them. In response to the issue, the objective of this research is to determine hydraulic connectivity of springs based on their chemical composition. To answer the objectives, measurement of spring discharge and physicochemical properties of spring’s water and sampling of selected spring’s water were conducted on this research in the study area. Water chemistry composition was classify by Kurlov formula and displayed by Fingerprint diagram and Composition diagram. Results show that the chemical compositions of most all spring samples are almost similar and does not significantly different for most properties from upstream to downstream, which are Na–Ca–HCO3 water, only one spring of Umbul Jatiningsih spring had different chemical composition of Ca–Na–Mg– HCO3 water. Based on the Fingerprint diagram and Composition diagram evaluation, the spring’s water can be differentiated into three groups. Group 1 consists of ten springs which have similar chemical composition of Na–Ca–HCO3 and with electrical conductivity ranges between 150 to 200 mS/cm. Group 2 consists only one spring “Umbul Pajangan” which contain similar chemical composition to Group 1 but has significantly higher ions concentration (EC value about 400 mS/cm) and Group 3 consists also only one spring “Umbul Jatiningsih” which has significantly different ionic composition with Group 1 and 2. Regarding on this condition, it can be concluded that Group 1 spring is hydraulically connected and relate to the shallow aquifer system of Merapi Aquifer System. In other side, water of spring “Umbul Pajangan”possibly comes from deeper aquifer system of Merapi Aquifer System and this argument is supported by the spring discharge evaluation. Finally, spring “Umbul Jatiningsih” is originate mainly from different aquifer system of porous limestone aquifer. Keywords: Merapi aquifer system, spring, chemical composition, geological conditio
Site Investigation For Construction Of Emergency Spillway At The Jatigede Dam
Get PDFAn emergency spillway has been planned to be constructed at the Jatigede Dam, West Java, to allow floodwater to flow downstream and to prevent the capacity of the main spillway to be exceeded during large flood events. The complex geology of theJatigede Dam area, however, poses a challenge to determine the suitable location for the emergency spillway construction, either in the area to the west or to the east of the embankment dam. An engineering geological mapping and landslide susceptibilityzoning were conducted to determine the engineeringgeological characteristics of the area surrounding theJatigede Dam. The site investigation showed that thearea to the west of the embankment dam tended tohave a lower slope inclination than the area to theeast of the embankment dam. Both areas to the westand to the east of the embankment dam were found tobe composed of less erosion resistant rock units. Theexistence of the earth retaining structures for slopestabilization in the area to the east of the embankment dam will, however, likely limit the flexibility in developing the emergency spillway route. With respect to the existence of fault systems, both areas to the west and to the east of the embankment dam will likely be influenced by similar conditions. The areato the west of the embankment dam tended to be lesssusceptible to landslide as compared to the area tothe east of the embankment dam. The undevelopedland use of the area to the west of the embankmen dam as compared to the area to the east of the embankment dam will provide more flexibility in construction of the emergency spillway. Due to the morefavorable engineering geological conditions, the area to the west of the embankment dam is proposed forthe location of the emergency spillway construction.Keywords: Emergency spillway, Engineering geological mapping, Jatigede Da
VEINS AND HYDROTHERMAL BRECCIAS OF THE RANDU KUNING PORPHYRY Cu-Au AND EPITHERMAL Au DEPOSITS AT SELOGIRI AREA, CENTRAL JAVA INDONESIA
Get PDFThe Randu Kuning prospect is situated at Selogiri area, Wonogiri, Central Java, Indonesia. This location is about 40 km to the south-east from Solo city or approximately 70 km east of Yogyakarta city. Many Tertiary dioritic rocks related alterationmineralisation were found at the Randu Kuning area and its vicinity, including hornblende microdiorite, hornblende-pyroxene diorite and quartz diorite. Mineralisation type of the Randu Kuning prospect was interpreted as porphyry Cu-Au and a number epithermal Au-base metals deposits in its surrounding. The closed existing of porphyry Cu-Au and epithermal Au-base metals type deposits at the Randu Kuning area produced a very complex of veins and hydrothermal breccias crosscutting relationship. A lot of porphyry veins types were found and observed at the Randu Kuning area, and classified into at least seven types. Most of the porphyry veins were cross cut by epithermal type veins. Many epithermal veins also are found and crosscut into deeply porphyry vein types. There are genetically at least two type of hydrothermal breccias have recognized in the research area, i.e. magmatic-hydrothermal breccia and phreatomagmatic breccia. Magmatic hydrothermal breccias are mostly occured in contact between hornblende microdiorite or quartz diorite and hornblende-pyroxene diorite, characterized by angular fragments/clasts supported or infilled by silicas, carbonates and sulphides matrix derived from hydrothermal fluids precipitation. Phreatomagmatic breccias are characterized by abundant of the juvenile clasts, indicated contact between hot magma with fluid or water as well as many wall rock fragments such as altered diorites and volcaniclastic rock clasts set in clastical matrix. The juvenile clasts usually compossed by volcanic glasses and aphanitic rocks in rounded-irregular shape. Both veining and brecciation processes have an important role in gold and copper mineralisation of the Randu Kuning Porphyry Cu-Au and epithermal Au-base metals deposits, mostly related to the presence of quartz veins/veinlets containing significant sulphides, i.e., quartz with thin centre line sulphides (Abtype) veins, pyrite±chalcopyrite (C type) veinlets, pyrite+quartz± chalcopyrire±carbonate (D type) veins of porphyry types as well as epithermal environment quarts+ sulphides+carbonate veins
Mineral paragenesis and fluid inclusions of the Bincanai epithermal silver-base metal vein at Baturappe area, South Sulawesi, Indonesia
Get PDFThe Baturappe prospect located at southern part of Sulawesi island, Indonesia, is a hydrothermal mineralization district which is characterized by occurrence of epithermal silver-base metal deposits. The mineralization is hosted in basaltic-andesitic volcanic rocks of the late Middle-Miocene Baturappe Volcanics. More than 20 units of quartz – base metal veins are distributed in the area, and one of the most significant is the Bincanai vein. This study is aimed to characterize the mineral paragenesis and to elucidate the physicochemical conditions of the formation of the deposit on the basis of mineral assemblage and fluid inclusion mictrothermometry. Sulphide assemblages in the vein indicate an intermediate sulfidation state epithermal; beside galena and sphalerite as the early stage minerals, chalcopyrite, tennantite, and tetrahedrite are also identified as the later stage. Microthermometric study of fluid inclusions in quartz indicates formation temperature of the vein ranges from about 230 to 280°C Histogram of homogenization temperature suggests that there are two generations of hydrothermal fluid responsible for the ore mineralization in the vein; the higher temperature range represents formation temperature of the base metal (galena, sphalerite), while the lower temperature range is correlate with the precipitation of the rest relatively lower temperature sulphides (chalcopyrite, pyrite, tetrahedrite, tennantite, polybasite, and Bi-Ag-Cu-Fe-bearing sulfide). The sequence is also consistent with the mineral paragenetic. The mean of salinity (2.0–2.5 wt.% NaCl eq.) indicates that fluid responsible for the mineralization in the Bincanai vein is relatively low-salinity fluid
Removal Of Copper From Water Using Columns Experiment Of Lignite, Shale, And Ironsand
Get PDFExperimental studies using column testing of lignite, shale, and ironsand in copper solution were carried out to determine the adsorption capacity of lignite, shale, and ironsand in remediation of water contaminated with copper. Lignite, shale, and ironsand were analyzed using XRD, SEM/EDX, and XRF. The treatment process by column adsorption was carried out over a period of 24 hours at a stable velocity of 0.005ml/s. After treatment, the remaining copper in the solution was recorded, thus allowing the adsorption capacity of lignite, shale, and ironsand to be calculated. The results revealed that when the solution was treated by lignite and shale there was a good degree of copper removal, while the ironsand had very poor degree of copper removal. The best material for copper removal was lignite with 25-mesh grain size. Pyrite, graphite, calcite, and illite were found in lignite and smectite, calcite, pyrite, hematite, and illite were found in shale. These materials were also shown to contain an abundance of high-valence elements in Al2O3, SiO2, and Fe3O4 which contributes to additional adsorption capacity. CAC values for lignite and shale reached nearly to 100%, suggesting that lignite and shale have a high adsorption capacity. In contrast, ironsand, which has mostly sand minerals with little clay and organic content, caused the pollutant to move rapidly to the water table, reducing the adsorption potential. CAC values treated by ironsand were shown to be negative which showed an increasing of Cu2+ in natural ironsand into solution. Keywords: Copper, ironsand, shale, lignite, column experimen
GROUND MOTION IN YOGYAKARTA CITY, YOGYAKARTA SPECIAL PROVINCE, INDONESIA ON DENSELY MICROTREMOR OBSERVATIONS AND SHEAR WAVE VELOCITY
Get PDFMicrotremor is currently considered the foremost tool in site effect studies. The ground motion is estimated with microtremor observations, meaning that subsoil mechanical properties and geometry are evaluated and from them an estimate of local amplification is computed. Here, the ground motion is studied by the site effects of seismic hazard zonation of urban areas in Yogyakarta City. The main purpose of this paper is zoning the geological engineering features and assessing seismic of the research urban area. In this regard, the microtremors are measured at 274 sites by single station sampling method and Nakamura technique. The microtremors of all over the city are processed by a model of Mitutoyo-GPL-6A3P. The amplification factor generally ranges between 0.70 and 5.56 and the natural frequency normally varies between 0.40 and 3.30 Hz. The information layers are prepared in GMT used for detecting the zonation of potential seismic hazard. The shear wave velocity is calculated in 12 existing drilling sites based on the geotechnical approach of SPT for soil condition. To study the ground motion, geological engineering condition is investigated using amplification factor, natural frequency, shear wave velocity maps which are analyzed using densely single microtremor observation and SPT from existing drilling sites. Keywords: Ground motion, amplification factors, natural frequency; H/V spectral ratio, microtremor observations, Yogyakarta Urba
MODIFIED NATURAL ZEOLITE AND BENTONITE AS ADSORBENTS OF HEAVY METAL IONS FROM POLLUTED GROUNDWATER IN YOGYAKARTA URBAN ARE, INDONESIA
Get PDFGroundwater quality in Yogyakarta city has become the major concern due to the presence of heavy metals originated from batik home industries, slaughterhouses, and leather factories, especially in shallow groundwater. In response to the above problems, the naturally abundant zeolite and bentonite in Sidomulyo and Bandung areas were respectively sampled along with the metal-containing groundwater in Yogyakarta urban area for batch adsorption experiment. Before put into experiment, the zeolite and bentonite were characteristically investigated by means of XRD, SEM, chemical composition, and physical property analyses. Also, they were thermally activated to improve their qualities in terms of increase in CEC, whereas the groundwater was analyzed for heavy metal concentrations (Cd, Cr, Cu, Fe, Zn) and its physical property. Five logarithmic amounts of this modified zeolite or bentonite were separately and incrementally introduced into the same three solutions of heavy metals. After the experiment, all the solutions were re-analyzed for the rest of heavy metals to figure out the optimum adsorption capacity of zeolite and bentonite. The outcomes of this experiment will be beneficial in enhancing the groundwater quality for consumptions in Yogyakarta city as well as other places in Indonesia, and will also imply the zeolite and bentonite in commercialization.
Keywords: zeolite, bentonite, groundwater, heavy metal, adsorptio
JATIBARANG LANDFILL OF SEMARANG CITY: IS IT POTENTIAL AS THE WATER CONTAMINATION SOURCE?
Get PDFLike other million inhabitants Cities, Semarang which is the capital city of Central Java Province in Indonesia has a problem in solid waste management. One biggest landfill in the City is the Jatibarang Landfill. The landfill operated since 1992 and currently receives the domestic waste of about 337 ton/day with total volume of about 5.2 million m3 of solid waste. It located on the hill slope of sandstone tertiary rocks and relatively closed to the river of Kreo (which is the main source of drinking water for Semarang City). In order to evaluate the potentiality of landfill as the contamination source to groundwater and surface water, the quality of leachates were analyzed and the hydrogeology of the area was re-studied. Result of the study show that the leachates contain high chloride concentration of about 2600 mg/L however low concentration of heavymetals. Hydrogeology study show evidence that this leachate is already enters the groundwater system. However its load to the river can be neglected due to the fact that the chloride mass flux derived from the study area was significantly low comparing to the net river loads.
Key Word: landfill, water contamination, chloride, groundwater and surface water interactio