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Geochemical Characteristics of Limestone of Wonosari-Punung Formation, Gunungkidul Regency, Yogyakarta, Indonesia Atmoko, Didik Dwi; Titisari, Anastasia Dewi; Idrus, Arifudin
Indonesian Journal on Geoscience Vol 5, No 2 (2018)
Publisher : Geological Agency

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DOI: 10.17014/ijog.5.2.179-197A geochemical study was carried out to determine the geochemical characteristics of limestone in Wonosari-Punung Formation, and to suggest its depositional conditions and the source of rare earth elements. The study was conducted at Ponjong Area, Gunungkidul Regency, Daerah Istimewa Yogyakarta, Indonesia. White limestone which contains more abundant calcite is characterized by the highest CaO concentration. Red limestone which is associated with impure minerals such as siderite, rodochrosite, hematite, and titanite is typified by depleted CaO but higher SiO2, Fe2O3, MnO, and TiO2 concentrations. Grey limestone characterized by depleted CaO and higher MnO contents is considered to be influenced by the presence of impure minerals of manganite (Mn2O3.H2O) and/or pyrolusite (MnO2). Depletion of Sr concentration in the coloured limestone indicates that the diagenetic process increases from the white limestone to the coloured limestone. The process possibly occurred post-deposition of the limestones. The limestones show positive Mn* values (2.46 - 2.95) and authigenic U values (0.89 - 3.38) that suggest an oxidative environment. The Ce/Ce* values (0.57 - 0.80), Eu/Eu* values (1.04 - 1.88), high Y/Ho ratio, and low LaN/YbN ratio are indications that the rare earth elements in the limestones were derived from terrigenous materials. The positive Eu anomaly and enrichment of Cr and Mn of the limestones are indications of hydrothermal fluid activity taking place in the studied area. Based on the geochemical characteristics of the Punung-Wonosari limestones, the depositional environment and the source of rare earth elements of the limestones were therefore influenced by a combination of hydrothermal fluid activity with small amount of terrigenous material input and post depositional diagenetic process.
MINERALOGI DAN GEOKIMIA BATUGAMPING MERAH PONJONG, GUNUNGKIDUL, DAERAH ISTIMEWA YOGYAKARTA – INDONESIA Atmoko, Didik Dwi; Titisari, Anastasia Dewi; Idrus, Arifudin
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 26, No 1 (2016)
Publisher : Indonesian Institute of Sciences

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Batugamping berwarna merah yang tersebar secara setempat-setempat dan berasosiasi dengan batugamping berwarna putih hingga abu-abu yang dijumpai di Daerah Ponjong, Kabupaten Gunungkidul, Daerah Istimewa Yogyakarta, termasuk dalam Formasi Wonosari-Punung. Batugamping tersebut perlu diteliti karakteristik mineralogi dan geokimianya, yang sangat diperlukan dalam memahami genesa batugamping di daerah tersebut. Hasil penelitian ini diharapkan dapat menambah data khususnya batugamping di daerah penelitian maupun Formasi Wonosari-Punung di daerah Pegunungan Selatan. Pengamatan petrografi dan XRD pada batugamping merah menunjukkan hadirnya mineral kalsit, kuarsa, siderit, hematit, dan titanit. Analisis geokimia oksida mayor batugamping merah memperlihatkan tren pengkayaan senyawa SiO2, TiO2, Fe2O3 dan MnO yang diinterpretasikan berhubungan dengan kehadiran mineral-mineral titanit (CaTiSiO5), siderit (FeCO3), hematit (Fe2O3), dan diduga rodokrosit (MnCO3). Mineral-mineral tersebut mempunyai karakteristik warna coklat kekuningan, merah muda sampai merah sehingga dimungkinkan dapat memberikan warna merah pada batugamping. Ada tiga proses yang diinterpretasi berperan dalam genesa batugamping merah Ponjong yaitu pengaruh material terigenus yang mengandung oksida SiO2, Al2O3, Fe2O3, dan TiO2 saat pengendapan batugamping, proses diagenesis oleh air meterorik yang mengkayakan senyawa Fe2O3 dan proses bekerjanya larutan hidrotermal.Red limestone, which is sporadically distributed and associated with white to grey limestone is located in Ponjong area, Gunungkidul District, Daerah Istimewa Yogyakarta. This limestone belongs to the member of Wonosari-Punung Formation. It is necessary to study the mineralogy and geochemistry chracteristics, which are important in understanding the genesis of the limestone. The result of this study might add the geological data for limestone in this study area and Wonosari-Punung Formation as well. The petrographical observation and X-ray diffraction results of red limestone indicated the presence of calcite, quartz, siderite, hematite and titanite. Major element analysis of the red limestone showed enrichment of SiO2, TiO2, Fe2O3 and MnO, which have considered to have relation to the presence of titanite (CaTiSiO5), siderite (FeCO3), hematite (Fe2O3), and rhodochrosite (MnCO3) in the red limestone. The minerals are typically yellowish brown, pink to red in colour, and are therefore interpreted to be responsible in giving red colour of the limestone. There are three processes that are considered in the genesis of the Ponjong red limestone, which are: impact of terrigenous material when deposition of the limestone, diagenesis process of meteoric water that enriched Fe2O3, and processof hidrotermal fluid activity. 
GEOCHEMICAL VARIATIONS ON HOSTED VOLCANIC ROCKS OF CIBALIUNG EPITHERMAL GOLD MINERALISATION, BANTEN – INDONESIA: IMPLICATIONS FOR DISTRIBUTION OF SUBDUCTION COMPONENTS Titisari, Anastasia Dewi; Phillips, David; Hartono, Hartono
Journal of Applied Geology Vol 6, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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Subduction of the Indo-Australian Plate beneath the Eurasian Plate formed at least seven magmatic arcs in Indonesia. One of the magmatic arcs is the Neogene Sunda-Banda arc hosts various style of gold mineralisation such as Cibaliung epithermal gold mineralisation. Major and trace element data for host volcanic rocks to the Cibaliung epithermal gold mineralisation is provided by this study to identify the magmatic arc system and the distribution of subduction components. Enriched LILE (Large Ion Lithopile Element) and LREE (Light Rare Earth Element) compositions for basaltic andesite – rhyodacitic samples from the Cibaliung district are characteristic of calc-alkaline arcs. In this typical volcanic arc, the subduction component can be shown to make a dominant contribution to its content of LILE such as Rb, K, Th, and Ba enriched (more than 88%) relative to the mantle and within plate inputs. The incompatible elements (Hf, Zr, and Nb) cannot be observed in the subduction component and thus assumed to be derived from trace element enriched sub-continental lithosphere. These incompatible elements are defined as conservative elements therefore it suggests that the magma occurrence is related to a hydrous slab component. Keywords: Subduction, Indo-Australian plate, magmatic arcs, volcanic rocks, Cibaliung, epithermal gold.
Characteristics and genesis of montmorilonitic claystone from Bandung area, Wonosegoro, Boyolali, Central Java, Indonesia Yuliyanti, Anita; Warmada, I Wayan; Titisari, Anastasia Dewi
Journal of Applied Geology Vol 3, No 1
Publisher : Geological Engineering Department Universitas Gadjah Mada

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The Bandung bentonite deposit is located in Wonosegoro District, Boyolali Regence, Central Java. Characteristics of bentonite in this area are very important due to increase demand on bentonite in the industry. Several methods are used to characterize the bentonite in this area, such as PLM (polarizing light microscope), X-Ray Diffraction and Scanning Electron Microscope combined with EDX measurements. The montmorilonitic claystone belongs to Kerek Formation from Banyuurip Member. This deposit consists of mainly montmorilonitic claystone interbedded with tuffaceous sandstone. Petrographical analysis shows that montmorilonitic claystone consists of mostly clay minerals with small amount of calcite, volcanic glass, feldspar, quartz, and opaque minerals. The clay minerals are likely as alteration product of volcanic glass. The oriented XRD analyses show that the clay samples consist of Ca-montmorilonite, illite, and kaolinite. Physico-chemical analyses of montmorilonitic claystone display that the initial CEC (cation exchange capacity) is 20 mgrek.Na2O/200gr (54 mg.Na2O/100gr) and low swelling ability for about 2 times of its initial volume. Based on its mineralogical association, textures, and stratigraphic position, the montmorilonite is formed from devitivication of volcanic glass in a diagenetic environment with over 2 km thicks of overburden. Keywords: Bentonite, montmorillonitic claystone, devitrivication, diagenesis, montmorillonite
Fluid Inclusion Study of The Tumpangpitu High Sulfidation Epithermal Gold Deposit in Banyuwangi District, East Java, Indonesia Myaing, Yu Yu; Idrus, Arifudin; Titisari, Anastasia Dewi
Journal of Geoscience, Engineering, Environment, and Technology Vol 3 No 1 (2018): JGEET Vol 03 No 01 : March (2018)
Publisher : UIR PRESS

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The Tumpangpitu high sulfidation (HS) epithermal gold deposit is located in the south coast of East Java, Banyuwangi District, East Java Province, Indonesia. This area lies within the central portion of the Cenozoic Sunda‐Banda magmatic arc which trends southeast from northern Sumatra to west Java then eastward through east Java, Bali, Lombok, Sumbawa and terminating at Banda sea. The geology of the Tumpangpitu is predominantly occupied by Late Oligocene to Middle Miocene low-K calc-alkaline to alkaline andesitic volcanic rocks and interbedded with volcaniclastic rock sequences, which are associated with low-K intermediate intrusions. The mineralization style at the Tumpangpitu area is composed of a high‐sulfidation (HS) epithermal gold-copper system which is typically associated with concealed gold-rich porphyry copper system. The HS epithermal mineralization is hosted by volcanic and volcaniclastic rocks in this research area. The mineralization domains are divided into Zone A, Zone B and Zone C which are situated along NW-SE-trending silica ledges zones. The HS epithermal mineralization is texturally occurs as vuggy replacements mineralization as well as stockworks, disseminated forms, fractures and veins. Fluid inclusion study was conducted for 6 quartz vein samples which petrographically entrapped fluid inclusions. Homogenization temperature (Th) and melting temperature (Tm) can microthermometrically be determined by fluid inclusion analysis. The average homogenization temperature (Th) of the fluid inclusions gives 180˚C to 342˚C and melting temperature are from -0.1 ˚C to -1.4˚C. Tm corresponds to the salinities ranging from 0.1 to 4.5 wt% NaCl equivalent. The paleodepth of ore formation can be estimated from the salinity of fluid. Since the deposit was not formed at boiling condition, the minimum paleodepth of ore (quartz) samples taken from both shallow level (53.35 m) and deep level (135.15 m) is determined at 650m and 1,220 m, respectively. The microthermometric data point out that the Tumpangpitu deposit formed at moderate temperature and low salinity by magmatic fluid mixing and dilution by meteoric water during the hydrothermal fluid evolution. On the basis of the fluid inclusion microthermometric data and its other key characteristics, the Tumpangpitu gold mineralization shares some similarities compared to other typical HS-epithermal gold deposits worlwide although it also shares few differences.
Geochemical Characteristics of Limestone of Wonosari-Punung Formation, Gunungkidul Regency, Yogyakarta, Indonesia Atmoko, Didik Dwi; Titisari, Anastasia Dewi; Idrus, Arifudin
Indonesian Journal on Geoscience Vol 5, No 2 (2018)
Publisher : Geological Agency

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DOI: 10.17014/ijog.5.2.179-197A geochemical study was carried out to determine the geochemical characteristics of limestone in Wonosari-Punung Formation, and to suggest its depositional conditions and the source of rare earth elements. The study was conducted at Ponjong Area, Gunungkidul Regency, Daerah Istimewa Yogyakarta, Indonesia. White limestone which contains more abundant calcite is characterized by the highest CaO concentration. Red limestone which is associated with impure minerals such as siderite, rodochrosite, hematite, and titanite is typified by depleted CaO but higher SiO2, Fe2O3, MnO, and TiO2 concentrations. Grey limestone characterized by depleted CaO and higher MnO contents is considered to be influenced by the presence of impure minerals of manganite (Mn2O3.H2O) and/or pyrolusite (MnO2). Depletion of Sr concentration in the coloured limestone indicates that the diagenetic process increases from the white limestone to the coloured limestone. The process possibly occurred post-deposition of the limestones. The limestones show positive Mn* values (2.46 - 2.95) and authigenic U values (0.89 - 3.38) that suggest an oxidative environment. The Ce/Ce* values (0.57 - 0.80), Eu/Eu* values (1.04 - 1.88), high Y/Ho ratio, and low LaN/YbN ratio are indications that the rare earth elements in the limestones were derived from terrigenous materials. The positive Eu anomaly and enrichment of Cr and Mn of the limestones are indications of hydrothermal fluid activity taking place in the studied area. Based on the geochemical characteristics of the Punung-Wonosari limestones, the depositional environment and the source of rare earth elements of the limestones were therefore influenced by a combination of hydrothermal fluid activity with small amount of terrigenous material input and post depositional diagenetic process.
Penentuan Zona Kerentanan Longsor Berdasarkan Karakteristik Geologi dan Alterasi Batuan Titisari, Anastasia Dewi; Khul Husna, Hitznaiti Zaidini'; Putra, Ilham Dharmawan; Indrawan, I Gde Budi
Jurnal Pengabdian kepada Masyarakat (Indonesian Journal of Community Engagement) Vol 4, No 2 (2019): Maret
Publisher : Direktorat Pengabdian kepada Masyarakat Universitas Gadjah Mada

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ABSTRACT Landslide is one of the most frequent disasters in Indonesia. The occurrence of landslides is heavily controlled by geological conditions especially in areas with composed by altered rocks. Hargotirto Village, Kokap District, Kulon Progo Regency, DIY is composed by altered rocks so that many landslides occur.It is necessary, thereforeto determine the landslide susceptibility zone based on the geological characteristics and rock alteration in the area as one of disaster mitigation efforts to reduce the risk of landslide disaster. The research method used is data collection in the field such as inclination data of slope, geological condition, and land cover; and laboratory analysis such as petrographic analysis, XRD (X-Ray Diffraction) analysis, and rock geochemical analysis using ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectroscopy).The collected data are used as parameters for landslide zonation determination using Analytical Hierarchy Process (AHP) method.The results showed that the lithology of the research area is andesite and porphyry diorite with alteration type of argillic and propylitic alteration. Their intensity are categorized as low to moderate alteration.Based on these conditions can be categorized into4 levels of landslide susceptibility namely the very high landslide susceptibility that dominates 35% of research areas in the north and northwest; the high landslide susceptibility of 20% spreads over the center of the study area; the moderate landslide susceptibility of 20% distributed in the center southernof the study area; and the low landslide susceptibility of 25% spread over the southern part of the study area.Therefore, residents who live in the area are advised to always be alert to the possibility of landslide because it is included in the zone of very high and high landslide susceptibility. Keywords: argillic alteration; Hargotirto; landslide susceptibility; prophyllitic alteration
Penentuan Zona Kerentanan Longsor Berdasarkan Karakteristik Geologi dan Alterasi Batuan Titisari, Anastasia Dewi; Khul Husna, Hitznaiti Zaidini'; Putra, Ilham Dharmawan; Indrawan, I Gde Budi
Jurnal Pengabdian kepada Masyarakat (Indonesian Journal of Community Engagement) Vol 4, No 2 (2019): Maret
Publisher : Direktorat Pengabdian kepada Masyarakat Universitas Gadjah Mada

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ABSTRACT Landslide is one of the most frequent disasters in Indonesia. The occurrence of landslides is heavily controlled by geological conditions especially in areas with composed by altered rocks. Hargotirto Village, Kokap District, Kulon Progo Regency, DIY is composed by altered rocks so that many landslides occur.It is necessary, thereforeto determine the landslide susceptibility zone based on the geological characteristics and rock alteration in the area as one of disaster mitigation efforts to reduce the risk of landslide disaster. The research method used is data collection in the field such as inclination data of slope, geological condition, and land cover; and laboratory analysis such as petrographic analysis, XRD (X-Ray Diffraction) analysis, and rock geochemical analysis using ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectroscopy).The collected data are used as parameters for landslide zonation determination using Analytical Hierarchy Process (AHP) method.The results showed that the lithology of the research area is andesite and porphyry diorite with alteration type of argillic and propylitic alteration. Their intensity are categorized as low to moderate alteration.Based on these conditions can be categorized into4 levels of landslide susceptibility namely the very high landslide susceptibility that dominates 35% of research areas in the north and northwest; the high landslide susceptibility of 20% spreads over the center of the study area; the moderate landslide susceptibility of 20% distributed in the center southernof the study area; and the low landslide susceptibility of 25% spread over the southern part of the study area.Therefore, residents who live in the area are advised to always be alert to the possibility of landslide because it is included in the zone of very high and high landslide susceptibility. Keywords: argillic alteration; Hargotirto; landslide susceptibility; prophyllitic alteration
Aplikasi Principle Component Analysis dan Directed Principal Component untuk Pemetaan Alterasi Hidrotermal menggunakan Citra ASTER di Kecamatan Kokap, Kulon Progo Raharja, Bayu; Setianto, Agung; Titisari, Anastasia Dewi
Jurnal Geologi dan Sumberdaya Mineral Vol 20, No 3 (2019): Article in Press
Publisher : Pusat Survei Geologi

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Endapan emas di daerah Kokap, Kabupaten Kulon Progo yang berasosiasi dengan endapan tipe epitermal terbentuk akibat adanya proses alterasi hidrotermal. Pemanfaatan data penginderaan jauh untuk pemetaan alterasi telah berhasil dilakukan diberbagai lokasi. Penelitian ini bertujuan untuk mengkaji kemampuan citra ASTER saluran visible near infrared (VNIR) dan saluran shortwave infrared (SWIR) dalam memetakan jenis alterasi menggunakan metode Principle Component Analysis (PCA) dan Directed Principal Component (DPC). Klasifikasi multispektral selanjutnya dilakukan untuk membedakan tipe alterasi hidrotermal menggunakan kombinasi saluran hasil PCA dan DPC. Keberhasilan pemetaan alterasi hidrotermal dievaluasi secara statistik menggunakan confusion matrix. Tingkat akurasi yang dapat diterima adalah sebesar 85% dengan koefisien kappa lebih besar dari 0.8. Hasil penelitian menunjukkan metode DPC memiliki akurasi lebih baik dari PCA dalam memetakan tipe alterasi meskipun tingkat akurasi keduanya dibawah batas yang ditentukan. Saluran ASTER yang paling baik digunakan untuk memetakan tipe alterasi hidrotermal di lokasi penelitian adalah 1, 2, 4, dan 6.
Karakteristik Marmer Daerah Mata Wawatu dan Sanggula, Kecamatan Moramo Utara, Kabupaten Konawe Selatan, Provinsi Sulawesi Tenggara Titisari, Anastasia Dewi; Azzaman, Muhammad Arba
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 29, No 1 (2019)
Publisher : Indonesian Institute of Sciences

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Sulawesi Tenggara memiliki potensi marmer terbesar di Indonesia. Salah satu daerah potensi marmer di Sulawesi Tenggara adalah Mata Wawatu dan Sanggula, Kecamatan Moramo Utara Kabupaten Konawe Selatan. Namun belum ada penelitian rinci mengenai karakteristik marmer yang ada di daerah ini. Karakteristik marmer di daerah penelitian yaitu berwarna abu – abu dengan struktur non foliasi dan tekstur lensa atau augen texture. Secara petrografi, mineral penyusun marmer didominasi dengan ukuran kristal ≤ 0.1 – 1 mm, yaitu mineral kalsit, dolomit, kuarsa, hematit, dan mineral opak. Marmer daerah penelitian memberikan kenampakan tekstur yang bervariasi, yaitu tekstur subidioblastik dan xenoblastik (berdasarkan bentuk individu Kristal), tekstur kristaloblastik (berdasarkan ketahanan terhadap metamorfismenya), tekstur nematoblastik dan granuloblastik (berdasarkan bentuk mineralnya), dan saccaroidal texture dan mortar texture (berdasarkan tekstur khususnya). Sifat keteknikan marmer memberikan nilai yang bervariasi, di mana nilai kuat tekan sebesar 235.718 kg/cm2 – 389.338 kg/cm2, nilai ketahanan aus sebesar 0,0414 mm/menit – 0,0498 mm/menit, dan nilai serapan air sebesar 0,275 % - 0,763 %.  CaO merupakan senyawa yang paling melimpah pada marmer dengan kelimpahan 50,44 % - 55,90 %. Berdasarkan sifat keteknikannya, marmer di daerah penelitian dapat direkomendasikan sebagai batu hias / batu tempel. Berdasarkan spesifikasi senyawa oksida utamanya, marmer bagian timur laut daerah penelitian direkomendasikan untuk industri kertas, pewarna tekstil, penyaringan gula, dan produksi semen sedangkan marmer bagian barat daya daerah penelitian kurang dapat dimanfaatkan. Southeast Sulawesi has the greatest marble potential in Indonesia. One of the marble potential areas in the Southeast Sulawesi is Mata Wawatu and Sanggula, North Moramo District of the South Konawe Regency. However, there is no detailed research on marble characteristics in this area. The marble characteristics in the study area are grey with non-foliation structures and lens texture or augen texture. Petrographically, constituent minerals of the marble are dominated by crystal size ≤ 0.1 - 1 mm which are calcite, dolomite, quartz, hematite, and opaque minerals. The research area's marble provides varied texture features, namely subidobobastic and xenoblastic textures (based on individual form crystals), crystalloblastic textures (based on resistance to metamorphism), nematoblastic and granuloblastic textures (based on their mineral form), and saccharoidal texture and mortar texture (based on texture in particular). The properties of marble engineering give varying values, where the compressive strength value is 235.718 kg / cm2 – 389.338 kg / cm2, the wear resistance value is 0.0414 mm / min - 0.0498 mm / min, and the water absorption value is 0.275% - 0.763%. CaO is the most abundant compound on marble with an abundance of 50.44 - 55.90 wt. %. Based on its engineering properties, marble in the research area can be recommended as an ornamental stone. Based on the specification of the main oxide compound, the northeastern marble of the research area are recommended for the paper industry, textile dyes, sugar screening, and cement production whereas the southwestern marble of the research area is less utilizable.