Indonesia Conference Directory

Corresponding Author
Hidartan Hidartan

Institutions
1 Program Studi Teknik Geologi, FTKE,Universitas Trisakti, Jl.KyaiTapa No1 Grogol, Jakarta Barat
2 Lit Bang Jalan PUPR Bandung

Abstract
The geological condition of Indonesia consisting of various geological formation units, one of which is volcanic products with tropical climate with different characteristics, allowing the discovery of rock-mixed soil media conditions such as the construction of the Sumedang toll road tunnel, where the media has an average Vp 2015m / s and CF1.1403 which are included in the soft rock category (category D II) . The condition of the media can cause various instability problems when doing tunnel excavation, especially the collapse of the crown with a deformation value of 65.6 cm. Therefore, an initial reinforcement system is needed in the form of forepoling with fillers less than 5 meters in length and the distance between forepoling 0.5-0.8 m before excavation to increase the shear strength of the soil / rock on the crown so as not to collapse.

Keywords
Tunnels, initial reinforcement, mixed media

Topic
Geology

Link: https://ifory.id/abstract/CrWwZJtpVaME

Corresponding Author
Rizki Amelia Sasqia Putri

Institutions
Sriwijaya Univerity
Jl. Srijaya Negara Bukit Besar, Palembang, South Sumatera, Indonesia 30139
*rsasqia[at]gmail.com

Abstract
The research area is located in Lubuk Tarok Village, Sijunjung Regency, West Sumatra and is geologically part of the Ombilin Basin. Previous researchers examined Sawahtambang Formation as part of Ombilin Basin stratigraphy on a regional basis. The purpose of this study is to characterize sediment deposition, interpret and model the depositional environment. The method carried out in this study is the making of outcrop stratigraphic profiles with detailed observations of lithofacies and architectural elements in eight observation locations divided in two north-south oriented segments. The observation location is positioned in a geological cross section to find out the stratigraphic position of the unconformity with the Sangkarewang Formation below it. Interpretation of the lithofacies and architectural elements characteristics are carried out to know the process and its depositional environment. The final stage is making comparative modeling, refers to Nichols (2009) to show the vertical and lateral relation of lithofacies. Both segments in the west and east of the research area showed similarities in types of litofacies, there are Scourfills (Ss), Sandy through crossbeds (St), Sandy planar crossbeds (Sp) and Sandy horizontal (Sh). Ss is sandstones that fill the scour surface. St is found in the channel migration part. Sp is found above the channel migration, and Sh is fine deposits at the top of the runoff flow deposits. The architectural element shows repetitions and combination of channel and sandy bedform sedimentary geometry. Litofasies changes show how the the deposition process changed by the cause of channels that intersect each other. The deposit formed by this channel activity is called multistorey channels which are interpreted as the result of braided river environmental deposits with paleocurrent direction to the west. The characteristics of the Sawahtambang Formation which has very thick sandstones are significant value for the study of reservoirs in Ombilin Basin.

Keywords
lithofacies, architectural element, multistorey, amalgamated sandstones, braided river

Topic
Geology

Link: https://ifory.id/abstract/hYM2A8etpHaV

Corresponding Author
mira meirawaty

Institutions
a) Lecturer of Geological Engineering Dept, Universitas Trisakti
Jl. Kyai Tapa No.1, Jakarta Barat-11440
b) PT. Star Energy Geothermal

Abstract
Epidote is a Calc-silicate mineral which is important in geothermal system because it shows high temperature reservoir when the reservoir in neutral pH fluids condition. The presence of epidote in the Wayang Windu geothermal field is very interesting because it comes in two forms, the epidote that replacing primary felsic minerals and the epidote that have been replaced by low temperature calcite-anhydrite minerals. This research is carried out by microscopic analysis (petrographic observation and XRD) of cutting samples from wells in southern area that represent liquid dominated system, and one in the northern that represent the vapor dominated system. The calcite and anhydrite overprinting epidote occur in all three reservoir-s wells, their occurance show abundance of CO2 and H2S gas in the reservoir. These type of epidotes occur right above the heat loss zone in reservoirs well with liquid dominated system, its being intrepeted associate with the boiling zone in the past. Whereas its occurrence in vapour dominated reservoir that present continuesly from certain depth was intrepreted associate with water condensate that move downward to the reservoir. The Calc-silicate minerals in vapour dominated reservoir reflects earlier alteration episodes when the system was more liquid-dominated. The vapor dominated system in the northern area is well indicated by a thick cap rock consist of smectite-cristobalite, whereas this zone is become thinner to the liquid dominated system in the southern. The reservoir of vapor dominated system are composed of acidic pyrophyllite and sericite-illite alteration, meanwhile the reservoir of liquid dominated composed of Calc-alkali mineral that show neutral pH fluids. This research is supported by fluid inclusion analysis to see further fluid evolution in the study area.

Keywords
Epidote, Geothermal, Wayang Windu, Vapour dominated, Liquid dominated

Topic
Geology

Link: https://ifory.id/abstract/KWpxrFaAm4zH

Corresponding Author
FX Delova Christama

Institutions
Universitas Pembangunan Nasional "Veteran" Yogyakarta

Abstract
The research area is located nearby Batutegi Dam in Batutegi Village, Air Naningan District, Tanggamus Regency, Lampung. This area is predominantly occupied by metamorphic rock, namely mica schist, which is part of Paleozoic Gunungkasih Complex. The geological fieldwork which has been conducted reveals the existence of mineralization potential. Altered rocks found in this area are an evidence of past hydrothermal activity during the orogeny tectonic event of Sumatra Island formation which might have deposited some ore minerals. The altered rocks have experienced argillic alteration type with the presence of illite and secondary quartz. This kind of rocks is mostly associated with iron oxide druzy quartz veins. The structures controlling this area are mainly oriented in NW - SE direction.

Keywords
gold mineralization, metamorphic rock, Sekampung River

Topic
Geology

Link: https://ifory.id/abstract/FVnqxXJhw9tj

Corresponding Author
Agus Harjanto

Institutions
Universitas Pembangunan Nasional Veteran Yogyakarta

Abstract
Based on the administrative location the research was located in Tomohon Selatan District, Tomohon, North Sulawesi Province. In the study area, there was a pattern of diverter that developed so that it could be of two types, namely the radial drainage pattern and parallel flow pattern. Through these drainage patterns and geomorphological aspects in the study area, one origin form is in the form of volcanic origin, which can then be grouped into five land forms. The research area is composed of volcanostratigraphic units arranged from old to young, namely, Khuluk Post - Tondano which is composed of Gumuk Lengkoan, Guml Panglombian, Gumuk Kasuratan, and Gumuk Linau. The presence of "Patriot" geothermal surface manifestations in the form of hot springs, warm springs, ponds / hot mud and fumaroles which have a temperature of 47 - 90⁰C. - Chloride waters have geothermal fluid equilibrium in the immature waters which is interpreted that the process is dominated by meteoric water and formed in a fluid forming environment in the form of riolytic and andesitic composition. It can be seen that the characteristics of surface manifestations are included in high temperature systemic manifestations. Fluid equilibrium in MNA-5 wells is in partial equilibrium which has a temperature of 260⁰ C so that it can be categorized as a high-temperature convective geothermal system with liquid domination. The "Patriot" geothermal system is interpreted by conducting petrographic analysis based on cutting and cores accumulated into mineral distributions that can be interpreted that the "Patriot" geothermal system has the characteristics of past and present reservoir temperature traces which are characterized by the presence of adularia, anhydrite, epidote, and mineral illite that forms at high temperatures and has an acidic pH and presence at different depths. So that based on data on mineral distribution of MNA-5 and MNA-23 wells there were three alteration zones consisting of the zone of argectic hematite + hematite alteration type, propylytic alteration zone chlorite + calcite + anhydrite so that the two zones can be interpreted as capillary rocks (caprock ), and epidemic zones + ilit ± wairakit as propylitic alteration types which are interpreted as top reservoirs. The presence of diorite intrusion in the MNA-5 well is interpreted as a heat source and magma body

Keywords
Goethermal, alteration, geochemistry

Topic
Geology

Link: https://ifory.id/abstract/weMAbnRhFY3K

Corresponding Author
Stevanus Nalendra Jati

Institutions
Geology Study Program, Faculty of Engineering, Sriwijaya University

*s.nalendra[at]unsri.ac.id

Abstract
Observation on the Tanjung Enim coal outcrops has been conducted to evaluate coal and cleat characteristics, particularly those occurring at Suban and Air Laya Putih (ALP) sites. Tectonically, the region is located in the South Palembang Sub-basin. In this region, there are four to five coal seams dipping to the SW direction. The dips of coal beds in ALP are commonly steeper than those in Suban, implying that the ALP seams had been more deformed tectonically and hence underwent more shortening. The samples analyzed reveal that the coals are medium in rank with the ash content relatively constant along strike, but distinctive vertically. Most seams have high values of inherent moisture, fixed carbon, and volatile matter. Deformation of the seams has resulted in two types of fractures known as face and butt cleats. The present study employed a scanline method to measure cleat attributes such as spacing, aperture, and bedding orientation. A total of 3,241 face and butt cleats were measured from 12 scanlines. The face cleats are predominantly oriented to NNE-SSW, suggesting peleostress direction. The general trend of butt cleats is NW-SE, likely coincident with the releasing stresses. Face cleats have spacing and aperture more tightly than butt cleats. This suggests that face cleats developed in response to the maximum stresses, and butt cleats formed due to the minimum in situ stresses. Scanning Electron Microscope (SEM) analysis reveals that microcleats in seam show a number of apertures that are connected to form a network system within the analyzed samples.

Keywords
Coal properties, cleat attributes, face cleat, butt cleat

Topic
Geology

Link: https://ifory.id/abstract/ZQHjeXwYb7g4

Corresponding Author
Wisnu Aji Dwi Kristanto

Institutions
Universitas Pembangunan Nasional Veteran Yogyakarta

Abstract
The hydrogeological system of Menoreh Hills, Purworejo Regency area is generally built by fissure aquifers consisting of volcanic pyroclastic breccia, lava, intrusion, and laharic breccia intensively jointed. On the other hand, there are also semi karstic and intergranular aquifer systems compiled by carbonate clastic sedimentary rocks of the Sentolo Formation. Hydrogeologically, the presence of groundwater is inserted in rock crevices (fissure aquifers), and occupying either cavities or inter-granular pores (semi karstic - intergranular aquifer). In general, the value of groundwater pressure is relatively high, proven from the fact that the hydraulic head in volcanic fissure aquifer ranges 150 m – 400 m, while in carbonate aquifer is about 110 m – 150 m above sea level. Groundwater pressure is one of the triggerring factors for landslides. Influenced by hilly topography with moderate to steep slope inclination of 4o – 35o (13% - 70%), thick soil (2m - 5m), high rainfall (>2000mm/year), and saturated soil (water content = 13% – 39%), the Menoreh Hills represents a high potential for landslides. The potential grades can be grouped into low, medium, and high categories. Based on hydrogeological studies, there is a correlation between the hydrogeological system represented by the types of aquifer with the potential of landslides. Volcanic fissure aquifer type indicates higher landslide potential than the carbonate intergranular aquifer type.

Keywords
hydrogeological system, aquifer types, landslide potential, correlation

Topic
Geology

Link: https://ifory.id/abstract/fHtQEDTFJx9B

Corresponding Author
asmoro widagdo

Institutions
Universitas Gadjah Mada

Abstract
The Kulon Progo Mountains, which are on the southern side of Java Island, have the dominant influence of N-S compressional stress, the result of the subduction of the Indian Ocean plate at southern of. To the east of the Kulon Progo Mountains, there is Yogyakarta area, which has tectonic interaction with the Southern Mountain of Java. This tectonic interaction has an influence on the geological structure of Kulon Progo Mountains. This research was conducted by mapping and analyzing the geological structure found in the Kulon Progo Mountains. Analysis of the geological structure using stereographic method was carried out on the structure of faults which were found in the field so that the stress direction forming them was obtained. Kulon Progo Mountains have compressional stress from the East (E) to Southeast (SE) direction or from Yogyakarta and the Southern Mountain of Java. The East to Southeast compressional directions gives effect to the Kulon Progo Mountains in addition to the main compressions of the N-S direction.

Keywords
compressional, stress, structure, stereographic, fault

Topic
Geology

Link: https://ifory.id/abstract/9tPEf3CXNn78

Corresponding Author
Achmad Rodhi

Institutions
Geology Engineering Study Program , University of Pembangunan Nasional “Veteran” Yogyakarta

Abstract
Abstract Gunung Pindul, Bejiharjo, Karangmojo is a nature tourism area that utilizes the presence of underground caves and rivers. In the last 5 years this area often occurs flooding and subsidence. Geological Structure Mapping shows that there are 3 groups of burly and fault structures, most of which have undergone a process of dissolution to form diaclas, sinkhole, dolena, cave, polje and flow valleys on the surface and subsurface. Calcimetric analysis shows that the carbonate content of the Oyo Formation ranges from 76% to 92%. The etching analysis shows that the carbonates present are formed by calcite minerals. Petrophysical analysis shows the average percentage of rock pores ranging from 27.6% to 39.1%, with the lowest value around Watu Plengkung Kluwo and the highest around the Tanding Cave. Analysis of rock mechanics Unconfined Compressive Strength dry conditions obtained limestone shear angle values ranged from 10.9 MPa to 22.1 MPa with the lowest values around Tanding Cave and Suruh Cave while the highest value around Watu Plengkung, Kluwo. Unconfined Compressive Strength wet conditions show the value of limestone shear angle ranges from 5.6 MPa to 16.6 MPa with the lowest value around the Tanding Cave and Suruh Cave while the highest value in Beji Dolena. Weighting of subsidence susceptibility value using geological structure parameters, form of dissolution results, porosity percentage value, density value, shear angle value, obtained with an average score ranging from 14 to 34. The subsidence susceptibility zoning shows that the area around Pindul Cave, Tanding Cave, until Suruh Cave is a watchful zone for subsidence, especially in the rainy season.

Keywords
Structure, mapping, dissolution, subsidence, potential zoning

Topic
Geology

Link: https://ifory.id/abstract/LqajCdczJyP7

Corresponding Author
Untung Sumotarto

Institutions
Universitas Trisakti

Abstract
A geological survey has been performed at Arjosari geothermal area, Pacitan, East Java. Hot springs, rock alteration, and other surface manifestations indicate possible geothermal energy potential of the area. Geologically four main rocks are found in the area. Those are sandstone and volcanic breccia of Mandalika Formation, volcanic rocks of Arjosari Formation, igenous rocks on the bottom of the area and alluvium deposit. Regionally many igneous rocks are exposed as intrusive genetic. The volcanic and igneous rocks found in that area are faulted and have fractures making conductive and convective heat transfer happened causing the formation of hot springs, rock alteration and other natural geothermal characteristics. With the existence of various volcanic and igneous rocks, the surface manifestation of hot springs and other rock signs, it can be concluded the geothermal system of the area.

Keywords
volcanic and igneous rocks, rock alterations, hot springs

Topic
Geology

Link: https://ifory.id/abstract/jk7qrhUJvnbx

Corresponding Author
HERU SIGIT PURWANTO

Institutions
Geological Engineering of University Pembangunan Nasional Veteran Yogyakarta, Indonesia

Abstract
Mineralization of gold and other ore minerals in Arinem area and its surrounding was found in the quartz vein. The research area is in Arinem area and its surrounding, Garut Regency, West Java. Arinem and the vicinity was the location for early stage of research program of mineralization in Papandayan area. This area has good mineralization, and according to previous studies, is a low sulfidation area with the presence of pyrite, chalcopyrite, galena and sphalerite (Antam, 2014). The presence of galena and sphalerite mineral has suggested that instead of low sulfidation, the area may be in intermediate sulfidation zone state supported by other data such as quartz breccia, banded quartz and shear as control structure. Lithology in the area consists of breccia Quaternary and lava unit of Jampang formation in Miocene and unit of andesite and basaltic in Quaternary and intrusion of dacite, andesite and diorite. The alteration and mineralization of research area was classified as propylitic alteration zone with the presence of chlorite, epidote and calcite mineral, argillic alteration zone with montmorillonite, kaolinite mineral, silicic alteration zone with the presence of quartz-sericite, a bit of calcite mineral. Observed ore minerals are pyrite, chalcopyrite, galena, sphalerite. The geological structure was controlled by horizontal fault in almost north-south direction of N 170O-180O E and northeast – southwest horizontal fault in N 40O – 50O E, while the mineralization zone was controlled or following fault pattern of N 170O - 175O E.

Keywords
Mineralization, alteration, sulfidation, sheared

Topic
Geology

Link: https://ifory.id/abstract/FhfY8NXZPd4U

Corresponding Author
Riza Fahmi

Institutions
1Research Group of Earth Resource Exploration, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology (ITB), Indonesia, Ganesha 10, Bandung, Indonesia
2Research Group of Petrology, Volcanology, and Geochemistry, Faculty of Earth Sciences and Technology, Bandung Institute of Technology (ITB), Indonesia, Ganesha 10, Bandung, Indonesia
Corresponding author*: rizafahmi90[at]gmail.com

Abstract
Alteration is the key aspect in exploration, after alteration model in one prospect area has been determined. It could be reference to us how to find information for the next analysis to find any prospect area for mining. The important aspect for determining alteration zone was mineral associations in the rock samples. It was a challenge for the explorer to determine the alteration not only based on the theory, but also how the laboratory testing was managed properly. In this paper, we demontrated a process how the alteration in selected area could be interpreted from field investigation and delineated alteration zone based on mineral association. The petrography and XRD analyses were performed to confirm field investigation. The analyses were used to determine the information about alteration intensity, primary, and secondary mineral. Each petrography and XRD sample testing result was interpreted to identify the alteration zone. Following the Petrography and XRD analyses, we classified the mineral association to five areas, Lawe Sikap, Lawe Pinish, Salim Pinim, Nembak Alas, and Lawe Sigala.The alteration zones in the five areas were dominated by Skarn, Prophylitic, Advance Argillic, and Phylic.

Keywords
Alteration, Exploration, Petrography, XRD, Interpretation

Topic
Geology

Link: https://ifory.id/abstract/Jk3ATrbxvDyX

Corresponding Author
sofyan rahman

Institutions
university of trisakti

Abstract
Abstract In the tunnel construction process, good planning is needed regarding the support system that matches the rock class in the tunnel. One of the support systems is shotcrete. Shotcrete is a mortar that is sprayed with high strength towards a surface. However, to get the thickness of the required shotcrete, the rock class in the tunnel must be obtained. To find out this, an empirical method is needed that approaches the rock mass classification. Based on the analysis that has been done, there is 1 type of lithology that is traversed in the tunnel, namely metamorphic rock in the form of schist with RMR ranging from 39-50 and high debris load of 4.27-3.5 meters.

Keywords
tunnel, support system , RMR, high debris load

Topic
Geology

Link: https://ifory.id/abstract/c9qkdA4FvLng

Corresponding Author
Sutarto Sutarto

Institutions
1)Universitas Pembangunan Nasional “Veteran” Yogyakarta
2)Universitas Gadjah Mada Yogyakarta
3)RWTH Aachen University Germany

Abstract
The Randu Kuning Porphyry Cu-Au prospect area is situated at Selogiri district, Wonogiri regency, Central Java, Indonesia, approximately 70 km east of Yogyakarta city. The area is a part of the East Java Southern Mountain Zone, mostly occupied by both plutonic and volcanic igneous rocks, volcaniclastic, silisiclastic and carbonate rocks. Magmatism-volcanism products were indicated by the abundant of igneous and volcaniclastic rocks of Mandalika and Semilir Formation and many dioritic intrusive rocks of the Late Eocene-Early Miocene magmatism. Porphyry Cu-Au and intermediate sulphidation epithermal Au-base metals mineralisation at Randu Kuning have strong genetic correlation with the magmatism-volcanism processes. The mineralized dioritic intrusive rocks at the area, are distributed at the centre of the depression of an ancient volcanic crater. There are many intermediate sulphidation epithermal prospect area sourrounding the Randu Kuning porphyry Cu-Au. Most mineralizations both porphyry and epithermal environments are associated with the present of quartz- sulphides veins, but not all porphyry vein types contribute in copper and gold mineralization. The early quartz-magnetite veins (particularly A and M vein types) generally not contain Cu-Au or barren, while the later sulphide bearing veins such as quartz-sulphides (AB type) veins, chalcopyrite-pyrite (C type) veins, quartz-sulphides-carbonate (D type) veins are mineralized. Mineralization contain copper and gold deposits in range at about 0.66-5.7 g/t Au and 0.04-1.24 % Cu. Whereas the epithermal level, mineralization mostly related with the present of pyrite+sphalerite+chalcopyrite+quartz+carbonate veins and hydrothermal breccias. The epithermal veins and breccia lead to the occurences of silver, zinc and lead mineralization, it commonly contain around 0.4-1.53 g/t Au, 0.8-8.5 g/t Ag, 0.17-0.39% Cu, 0.003-0.37% Zn, 00089-0.14% Pb. In porphyry environment, copper and gold are likely transported together as chloride complexes (CuCl0 and AuCl2-) in magnetite stability field. The chlorite complexes then react with existing magnetite to produce free gold and chalcopyrite. On the other hand, the epithermal environment, gold and copper usually are transported in a different ion complexes. Au is transported as the thio complexe [Au(HS)2-; Au2(HS)2-S2- and HAu(HS)2-] in phyrite stability field, while Cu is preferably transported as chloride complex in the hematite stability field.

Keywords
Mineralization style, Porphyry, Epithermal, vein, hydrothermal breccia

Topic
Geology

Link: https://ifory.id/abstract/DTzjMKedrLxV

Corresponding Author
sutarto sutarto

Institutions
1)Universitas Pembangunan Nasional Veteran Yogyakarta, Indonesia
2)Universitas Gadjah Mada Yogyakarta, Indonesia
3)RWTH Aachen University Germany

Abstract
Abstract. The Randu Kuning Porphyry Cu-Au prospect area is situated at Selogiri district, Wonogiri regency, Central Java, Indonesia, about 40 km to the south-east from Solo city, or approximately 70 km east of Yogyakarta city. The Randu Kuning area and its vicinity is a part of the East Java Southern Mountain Zone, mostly occupied by both plutonic and volcanic igneous rocks, volcaniclastic, silisiclastic and carbonate rocks. Magmatism-volcanism products were indicated by the abundant of igneous and volcaniclastic rocks of Mandalika and Semilir Formation and many dioritic intrusive rocks as part of the Late Eocene-Early Miocene magmatism. Porphyry Cu-Au and intermediate sulphidation epithermal Au mineralisation at Randu Kuning Prospect have strong genetic correlation with the magmatism-volcanism processes. The mineralized dioritic intrusive rocks at the Randu Kuning Prospect, are distributed at the centre of a half-circular depression are thought to be a feeder of an ancient volcanic crater. There are many intermediate sulphidation epithermal mineralization Au-base metals prospect area sourrounding the Randu Kuning porphyry Cu-Au. Most mineralizations both porphyry and epithermal environments are associated with the present of quartz- sulphides veins, but not all porphyry vein types contribute in copper and gold mineralization. The early quartz-magnetite veins (particularly A and M vein types) generally not contain Cu-Au or barren, while the later sulphide bearing veins such as quartz-sulphides (AB type) veins, chalcopyrite-pyrite (C type) veins, quartz-sulphides-carbonate (D type) veins, and lack of disseminated of sulphides. Mineralization contain copper and gold deposits in range at about 0.66-5.7 g/t Au and 0.04-1.24 % Cu. Whereas the epithermal level, mineralization mostly related with the present of pyrite+sphalerite+chalcopyrite+quartz+carbonate veins and hydrothermal breccias. The epithermal veins and breccia lead to the occurences of silver, zinc and lead mineralization, it commonly contain around 0.4-1.53 g/t Au, 0.8-8.5 g/t Ag, 0.17-0.39% Cu, 0.003-0.37% Zn, 00089-0.14% Pb. In porphyry environment, copper and are likely transported together as chloride complexes (CuCl0 and AuCl2-) in magnetite stability field. The chlorite complexes then react with existing magnetite to produce free gold and chalcopyrite. On the other hand, the epithermal environment, gold and copper usually are transported in a different ion complexes. Au is transported as the thio complexe [Au(HS)2-; Au2(HS)2-S2- and HAu(HS)2-] in phyrite stability field, while Cu is preferably transported as chloride complex in the hematite stability field.

Keywords
Mineralization style, Porphyry, Epithermal, Vein, Hydrothermal breccia

Topic
Geology

Link: https://ifory.id/abstract/3ZUgKQAhmWtr

Corresponding Author
Siti Umiyatun Choiriah

Institutions
1Department of Geology Engineering, Pertamina University, Jakarta
2Department of Geology Engineering, UPN Veteran Yogyakarta

Abstract
Nannofossil analyses of Miocene to Pleistocene, section of Nglebur river, Jiken, Blora of Central Java included of Rembang Zone, North East Java Basin. This research have been performed on 70 samples collected from this section. The result of this analysis consist of 18 genera were obtained with 57 species of nannoplankton. The research method used of field study (measure section) and quantitative analysis. The samples from taken include fine-grained rock (marl, shale) and carbonaceous. The river section that have been selected consist of a continuous sediment sequence from Miocene (Wonocolo, Ledok and Mundu Formation) to Pleistocene (Lidah Formation). The sample preparation has been carried out using smears slide method and nannotex determination. The biostratigraphy consist of 11 zones, there are consist of 2 Partial Zones and 9 Hose Zones. These Zona are Discoaster hamatus and Discoaster neorectus Partial zone / NN9, Hoze Zone of Discoaster hamatus- Discoaster neorectus with Discoaster quinqueramus/ NN10, Zone of Discoaster quinqueramus - Ceratolithus armatus/ NN11, Zone of Ceratolithus armatus - Ceratolithus rugosus/ NN12, Zone of Ceratolithus rugosus-Discoaster asymmetricus/ NN12, Zona of Discoaster asymmetricus - Oolithotus fragilis and Pseudoemiliania lacunosa/ NN14, Zona of Oolithotus fragilis - Pseudoemiliania lacunosa with Discoaster pansus-Reticulofenestra pseudoumbilicus/ NN15, Zona of Discoaster pansus-Reticulofenestra pseudoumbilicus with Discoaster surculus/ NN16, Zona of Discoaster surculus - Discoaster asymmetricus/ NN17, Zona of Discoaster asymmetricus- Discoaster brouweri/ NN18, Partial Zone Discoaster brouweri and Gephyrocapsa oceanica/ NN19.

Keywords
Biostratigraphy, Nannofossil, Rembang zone

Topic
Geology

Link: https://ifory.id/abstract/MgDhvX8CLHp9

Corresponding Author
Lloyd Thomas White

Institutions
1.GeoQuEST Research Centre, School of Earth, Atmospheric and Life Sciences, Northfields Avenue, University of Wollongong, Australia, 2522.

2. Southeast Asia Research Group, Royal Holloway University of London, Egham, Surrey, UK, TW20 0EX.

3. CGG Robertson, Tynycoed, Llanrhos, Llandudno, UK,

4. Institut Teknologi, Bandung, Jalan Ganesha 10 Bandung, Indonesia.

Abstract
Our understanding of the geological evolution of West Papua (or the Bird-s Head Peninsula and Bird-s Neck) predominantly stems from a systematic mapping campaign conducted by Indonesian and Australian geologists during the 1970-s and 80-s, together with the findings of mineral and hydrocarbon exploration by Dutch geologists in the early 1900-s. Most of the research that has been conducted since these initial, but comprehensive studies have been associated with continued exploration for hydrocarbons (e.g., around the Salawati and Bintuni Basins) and precious metals (e.g., associated with Grasberg–Ertsburg). Here we present an overview of research conducted over the past five years that was largely funded by several oil exploration companies. Our research did not focus on oil exploration, but instead attempted to update our understanding of the age of magmatic, metamorphic and deformation events, and to improve our knowledge of the regional stratigraphy of West Papua. These new data have been used to develop new tectonic models and paleogeographic maps that provide a framework for future studies in the region to build upon.

Keywords
Irian Jaya; Birds Head; Geology; Tectonics; Geochronology; Indonesia; New Guinea

Topic
Geology

Link: https://ifory.id/abstract/GhUTVZnFj3ce

Corresponding Author
Agus Sutiono

Institutions
Geological Engineering, University of Pembangunan Nasional “Veteran” Yogyakarta
Center for Volcanology and Geological Hazard Mitigation, Geological Agency of Indonesia

Abstract
The Opak Fault is famous as known as active fault in the South of Java which particularly is importance because accordingly historical noted, its fault has been experienced 3 times large earthquake events that claimed many victims and is being straddled Bantul regency of Yogyakarta. Usually producing uplifts only a few tens cm at a time, the cumulative effect has been to create in Gunung Kidul mountains range over the last million years. It coincides with producing Bantul basin faults fill including their confinements. The location is a site of intense deformation associated with convergence between plates Australia and Eurasia. However, Opak Fault strike-slip strain tend to be obscured due to draping by young active Volcanic Merapi sediments. In this place is hard to encountering outcrop of quasi-continuous fault segment at approximately 30 km of length that is capable to produce M. 6.3 as such earthquake occurring on May 27, 2006. Since this event, Based on conclusions from the experts, fault-s position and dipping role has being disputed; either fault dipping towards Southwest or Northwest, and fault zone along a ruptures are located toward the East in the vicinity of Gunung Kidul 5 or 10 km from Opak River. On the other hand, indicating from sediments typically accommodate within strike-slip fault system show strands where is suggested to traverse from Parangtritis Bantul Regency towards South Merapi Mountain slope. This Merapi sediments basin fill beneath Bantul regency, is considered to evaluate and drawing of important active fault lines in order to present seismic risk of all faults map in this area. Further, the convenient method was resorted to taking comprehensive features for understanding principle of slope surface motions. It may also is located in the vicinity of Bantul basin fill towards Merapi. This study has identified en echelon areas of curving slope shape by using slope propagation shifting analysis from satellite imagery. The aim of this paper is intended to present result of research in which delineates corridor of Opak Fault zone, where could be bounded by confinements within both of sidewall faults and cross-basin faults system identified. After in the last first stage study of the a comparative Opak Fault review presented before, this is second stage result from total four stages of the entire over all studies, which is important in order to get area for much more focus in highlighting any fractures in between its boundaries of Opak Fault system, where underlying and traverse the thick young Merapi sediments beneath Bantul region in Southwest, striking toward Merapi volcano in Northeast. The research will be continuing into other next 2 stages presented later of morphotectonic properties identification and field mapping to get much more comprehensive overview in the ultimate result of research. The indication keys of strike slip fault properties were identified during this second stage by the following: (1) South

Keywords
Opak fault delineations, fault damage zones, Bantul basin fill, Side wall faults and Merapi slope shifted.

Topic
Geology

Link: https://ifory.id/abstract/aKfDuZwXTmjE

Corresponding Author
Joko Soesilo

Institutions
Faculty of Mineral Technology, UPN Veteran Yogyakarta

Abstract
The sub aerial geological cross section of Jurassic magmatic rocks starts from the eastern slope of the Meratus Mountains near Batu Licin Town, through Laut island to the east towards Sebuku Island showing fragmented ophiolite set. Deformed basalt, diabase dyke and plagiogranite with, in some localities chert and red claystone tightened in the sepentinized basalt, some of which still show remnant of the pillows lava such as cropped out north of Batu Licin Town and in the western shoreline of Laut Island are indicative to upper part of Ophiolite. While in the eastern Sebuku Island may be found cromite layer in dunite, layer cromite and bulk.

Keywords
Jurassic magmatic rock, Eastern Meratus, ophiolite

Topic
Geology

Link: https://ifory.id/abstract/QuEDXGqvTJAw

Corresponding Author
Rakhmat Fakhruddin

Institutions
Centre for Geological Survey, Geological Agency, Ministry of Energy and Mineral Resources, Jl. Diponegoro No. 57 Bandung, Jawa Barat, Indonesia

Abstract
Relatively few Pre-Tertiary outcrop examples have been described in the literature. Pre-Tertiary rocks outcrop at these islands is hardly found due to high levels of weathering and dense vegetation. This area needs a further geological works because this is one of the few area near offshore of Arafura sea where we can get Pre-Tertiary rocks outcrop analog for subsurface interpretation. The main objective of this paper is to recognize the stratigraphic successions of the Pre-Tertiary sedimentary rocks exposed in the study area based on their lithological characteristic and palynological ages. The methods used are geological fieldwork and palynological analysis for samples obtained. Four lithostratigraphic units are recognized from the outcrops: 1) Upper Triassic (Rhaetian to Carnian) limestone, sandstones, and claystone of Wotar Formation with depositional environment ranging from marginal marine to deep water environment, 2) Lower Jurassic (Toarcian to Hettangian) sandstones and claystone of Selu Formation, the unit was deposited at shallow marine with tide influenced environment, 3) Upper Jurassic (Tithonian) to Lower Cretaceous (Barrimian) red and brown claystone and siltstone of Arumit Formation, which was deposited in tidal environment, and 4) Lower Cretaceous (Aptian) to Upper Cretaceous (Maastrichtian) sandstone of Ungar Formation, which was deposited in foreshore, shoreface to marine offshore environment. Middle to Upper Jurassic rock unit was not found at the studied area. This time interval is probably represented by the clay dominated matrix of mud volcano (Bubuan Mud Complex).

Keywords
Pre-Tertiary, Tanimbar, Wotar, Selu, Arumit, Ungar, Bubuan Mud

Topic
Geology

Link: https://ifory.id/abstract/4cMUCydY3DhG

Corresponding Author
Nurul Magfirah

Institutions
(a) Master Student of Mining Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung
Jalan Ganesha 10, Bandung 40132, Indonesia
*nurulmage17[at]yahoo.com
(b) Earth Resources Exploration Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung
Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract
This paper reviews our study aimed at identifying hydrothermal alterations to surface minerals as a result of volcanic activity at the Wayang Windu geothermal field, which is in a southern volcanic complex on the island of Java. The characteristics of hydrothermal alterations in Wayang Windu are related to surface manifestations. The geologic conditions are that it lies within andesitic, volcanic highlands formed by a concentration of volcanic centers in this part of the Sunda Arc. The geothermal manifestations are related to faults that are affected by volcanic activity, and the geothermal area is characterized by zones of intensive surface alteration at fumaroles and hot springs. There were 17 soil samples collected during a field survey and then analyzed in the laboratory using primarily X-ray diffraction (XRD). The results show that the alteration mineral assemblages observed are strongly associated with surface manifestation intensity. The presence of silica, kaolinite, halloysite, and alunite minerals identified the location as part of an advanced argillic alteration zone in the surface area.

Keywords
Surface alteration, geothermal, manifestations

Topic
Geology

Link: https://ifory.id/abstract/wY2JqvQeV6Pj

Corresponding Author
Denny Suwanda Djohor

Institutions
1, 4 Fakultas Teknologi Kebumian dan Energi, Universitas TrisaktiJakarta (11440)
denny_sd[at]trisakti.ac.id, agus_g[at]trisakti.ac.id
2,3 Fakultas Ilmu Teknologi Kebumian, Institut Teknologi Bandung (40132)
bsapiie[at]gc.itb.ac.id,emmy[at]gc.itb.ac.id,

Abstract
Detailed studies of shale characteristics as reservoirs in shale hydrocarbon unconventional systems using surface data to illustrate lithofacial and geomechanical models, have not been widely used in Indonesia. Therefore, the potential for shale as a reservoir in shale hydrocarbon systems is not well known, due to the lack of surface data and subsurface data, especially core rock data. Research on the characteristics of lithofacies shale from lower Baong Formation and the integration with the geomechanical characteristics (brittleness index), can be an initial method identifying zones that have potential as reservoirs in shale hydrocarbon systems. This research is expected to be useful for the future of oil and gas exploration in Indonesia, especially in mature sedimentary basins, thus encouraging the discovery of new reserves in Indonesia. The stages of research consists of several: collecting data from field observations, processing data and laboratory analyses, followed by analyzing data on the patterns resulting from data processing; presented in the form of track stratigraphic columns and lithofacies characteristics integrated with geomechanical data. The results of the study are as follows: a) The results of the compressive test (Sch. Hammer Test) show that the lithology found in the field shows different stress values, for siltstone and claystone showing the highest value (slightly strong rock) compared to claystone carbonate sand silt (slightly soft rock); b) Based on the results of laboratory analysis conducted, it was concluded that the characteristics of the lower Baong Formation lithology can be divided into 11 Litofasies, namely: Calc. Mud-Shale, Calc. Sandy Mudstone, Calc. Claystone and Sandy Claystone (NN5), Calc. Mudstone, Claystone and Calc. Silty Claystone (NN6) and Mud-Shale, Calc. Siltstone, Sandy Mudstone and Calc. Clay-Shale (NN7); c) The results of calculation of Brittleness Index (BI) obtained by litofasies which have the highest BI value are Sandy Claystone and Sandy Mudstone, while for litofasies that have low BI values are Claystone; d) Litofacation of Sandy Claystone and Sandy Mudstone with the highest BI value, is a zone that has the potential as a reservoir in the shale hydrocarbon system; e) this research shows that the lower Baong Formation in detail have varied lithological and geomechanical characteristics.

Keywords
reservoir, unconventional, shale hydrocarbons, lithofasies, geomechanics, Lower Baong Formation

Topic
Geology

Link: https://ifory.id/abstract/LqJjrbWd3FkP

Corresponding Author
Muhammad Nurjati Setiawan

Institutions
Geology Departement, Faculty of Mineral and Technology University Pembangunan National Yogyakarta
PT. Dewi Sri Sejati, Jalan Perumnas Mundu Saren, Ruko Baverly R1-R2, Caturtunggal, Sleman, Yogyakarta

Abstract
Pandawa Hil is Located in Jering Sleman Yogyakarta. It is one of Hill who formed by Diorite Intrusion (Miocene) and Intruded Claystone of Nanggulan Formation ages Eocene. In this Area will be Build a Simple Housing and That opens some of western site of Pandawa Hill. So that Expose some of Lithology in Pandawa Hill, Jering, Godean, Sleman. The Beauty of rare Outcrop in the Pandawa Hill, Jering, Godean, Sleman and Then the Authors propose that some of the Area is preserve to become Geoheritage. In this Area will be planned the Construction of Simple Housing are Integrated with Geological Turism Object. For the Supporting of the Development of Simple Housing in this area, So we arrange the Slope Stability Analysis of All the Area who cut of Slope.

Keywords
Pandawa Hill, Simple Housing, Geoheritage, Slope Stability

Topic
Geology

Link: https://ifory.id/abstract/YDpZJhXj84dR

Corresponding Author
Muhammad Gazali Rachman

Institutions
(*) Geological Engineering Department, UPN "Veteran" Yogyakarta

Abstract
Pacitan Regency is the easternmost district of the province of East Java which is directly adjacent with the Wonogiri Regency (Central Java) to the west. Pacitan can be reached in about 4 hours from Yogyakarta by land transportation via the southern route of Java. The morphology of the pacitan district is very unique. Pacitan city is a semicircular valley flanked by high hills in the east, north, and west. The hills are dominated by rocks of ancient Oligo-Miocene volcanic products commonly called the Old Andesite Formation. Pacitan stratigraphy according to Samodra, et al (1992) from the oldest to the youngest are Oligocene Volcanic (Mandalika Formation, Watupatok Formation, and Arjosari Formation), Early Miocene Carbonate (Campurdarat Formation, Jaten Formation), Middle Miocene Volcanic (Wuni Formation), Late-pliocene miocene carbonate (Nampol Formation, Oyo Formation, Wonosari Formation), and holocene alluvial deposits (kalipucang Formation). Pacitan district is not an oil and gas producing district like other districts in North East Java because the presence of dominant volcanic rocks is not considered to be a prospect petroleum play. For this reason, we need to study the potential of the petroleum system of southern mountainous sub-volcanic deposits. This study started from Pacitan district. Jaten Formation and the Nampol Formation are interesting formations in terms of petroleum systems because they are composed of sandstone, shale, and coal intercalations that are very rich in carbon materials. In the other hand they also have the potential to be a reservoir because their physical properties such good porosity and permeability. This study uses surface data with detailed stratigraphic cross section measurements, Rock Eval Pyrolysis (REP), Reflectance of Vitrinite and Kerogen Type of selected samples to analyze the potential of Jaten and Nampol formations to become a source rock. In addition, porosity and permeability analysis was also performed using petrographic thin section analysis and lab tests.

Keywords
Pacitan, Petroleum, Reservoar, Source Rock, Jaten

Topic
Geology

Link: https://ifory.id/abstract/Y6ephVT4xzbu

Corresponding Author
Diah Rini Ratnaningsih

Institutions
Universitas Pembangunan Nasional Veteran Yogyakarta

Abstract
The governments policy in the food sector is to achieve food self-sufficiency in the context of national food security, whose priority is in the form of partiality to farmers to improve welfare. This policy cannot be felt yet by the farmers who live in Tayuban village, Panjatan Subdistrict, Kulonprogo Regency, because there are still obstacles in its implementation. The problem faced by farmers in this village in increasing crop production is the lack of availability of water sources for irrigating secondary crops, especially in the dry season. The lack of water availability causes plant productivity to be low, so that farmers income is low. To overcome the problem of water shortages, a surface geological survey was carried out as a preliminary study to find out the watershed (DAS) and identify the hydrogeological system of the study area. Based on watershed and hydrogeological systems data, in turn engineering can be carried out to meet water supply for irrigated agricultural land.

Keywords
Surface Geological Survey, Hydrogeological

Topic
Geology

Link: https://ifory.id/abstract/dKYFxPDp8wec

Corresponding Author
Aris Buntoro

Institutions
Petroleum Engineering Department, Geological Engineering Department, Faculty of Mineral Technology, UPN "Veteran" Yogyakarta, UTC Pertamina

Abstract
At present, Indonesia has a very large shale hydrocarbon potential, where the Central Sumatra Basin is the biggest potential in Indonesia, especially from the Brown Shale Formation of the Pematang Group. However, the development of shale hydrocarbon in Indonesia is still little studied and poorly understood. Thus, research related to non-conventional hydrocarbon resources is very important in order to improve sustainable national energy security. But further research must be carried out using analog outcrop data, because there is no data core from the Brown Shale Formation of the Pematang Group. Fortunately, there are currently very good analog outcrop at the PT. Karbindo in Kiliran Jao, West Sumatra. In this paper the sweetspot fracable window is determined by using a geomechanical analysis approach from core / analog outcrop samples, so that the prospect formation interval model with a high fraction can be created, which correlates with fracture resistance, and can be applied to determine the location and planning interval for hydraulic fracking. From the sweetspot fracable window of shale hydrocarbon, it is expected to increase success in producing shale hydrocarbons which have very low permeability by determining the exact location and hydraulic fracking interval, so that natural cracks can be opened, and the fracture is connected to maximize hydrocarbon flow.

Keywords
fracable

Topic
Geology

Link: https://ifory.id/abstract/9m7tzQWMLYuh

Corresponding Author
Sugeng Raharjo

Institutions
1. Student of Doctoral Programe of Geological Engineering UPN "Veteran" Yogyakarta
2. Geological Engineering UPN "Veteran" Yogyakarta

Abstract
Tanjung Formation is an Eocene - Oligocene coal carrier formation. This formation is stratigraphically situated above the bedrock of Pratersier age. The location of this formation is in Binuang area, South Kalimantan approximately 20 km northwest of Banjarbaru city. The method of research by taking the Channel sampling from the bottom seam to the top. Laboratory analysis is done in the form of coal petrography analysis and adsorption test. Coal seam of Tanjung Formation is found with thickness 50 to 350 cm. Megascopy, this coal seam is black, bright (bright-bright banded), black scratch, concoidal shards, and lightweight. Based on facies interpretation with the Tissue Preservation Index (TPI) - Gelification Index (GI) method, seam B coal depositional environment in fen stage and seam C coal is in the depositional environment at the stage of wet forest swamp. Coal facies analysis based on the Ground Water Index (GWI) - Vegetation Index (VI) type of peat on coal seam B and C shows in the bog-ombrotrophic zone. Based on the analysis of gas adsorption shows from the lower coal seam to upper with the range 426 - 502 SCF / Ton. The upper coal seam B of the small gas adsorption while at the lower of coal seam C is large gas adsorption. This change in gas adsorption is caused because the upper coal seam B has a depositional environment (facies) at fen stadium conditions , While the coal seam at the bottom (seam C) of the depositional environment (facies) at the stage of wet forest swamp. The difference in depositional environment affects the absorption of coal methane gas.

Keywords
TPI, GI, GWI,VI, adsorption, coal facies, Tanjung Formation

Topic
Geology

Link: https://ifory.id/abstract/3parPcnJNb8y

Corresponding Author
Aton Patonah

Institutions
(a) Faculty of Geological Engineering, Padjadjaran University, Jl. Raya Bandung – Sumedang KM 21. Jatinangor, 45363, West Java, Indonesia

(b) Research Center for Geotechnology LIPI, Jl. Sangkuriang, Bandung 40135, West Java, Indonesia

Abstract
The mineral chemistry data of three gabbro samples of Ciletuh Mélange Complex (CMC), West Java, Indonesia was determined by JEOL Super probe 733 method. The rock shows phaneritic, intersertal to poikilitic texture, 2 to 8 mm mineral size, have been deformed and auto metamorphism experienced. The gabbro constitutes pyroxene and plagioclase, and least of amphibole (hornblende, actinolite, tremolite) replacing pyroxene, while epidote, chlorite sericite and carbonate replacing plagioclase. The Mg

Keywords
Ciletuh Mélange Complex, gabbro, mineral chemistry, Island Arc

Topic
Geology

Link: https://ifory.id/abstract/AfqkayhnrjDR

Corresponding Author
Akhmad Zamroni

Institutions
(a)(b) Department of Geological Engineering, Institut Teknologi Nasional Yogyakarta
Jl Babarsari, Caturtunggal, Depok, Sleman, Yogyakarta, Indonesia
(c)(e)(f) Department of Mining Engineering, Institut Teknologi Nasional Yogyakarta
Jl Babarsari, Caturtunggal, Depok, Sleman, Yogyakarta, Indonesia
*akhmadzamroni[at]itny.ac.id
(d)Department of Mining Engineering, Institut Teknologi Adhi Tama Surabaya
Jl Arief Rachman Hakim No 100 Surabaya, Indonesia

Abstract
Indonesia is a country that has many coal deposits, especially in Sumatra Island and Kalimantan Island. In both Islands have many coal formations. 8 samples in this study are from three formations, they were Warukin Formation in East Kalimantan, Pengasih Formation in Jambi, and Muara Enim Formation in South Sumatra. The main factor to determine coal qualities is the coal rank. The coal rank from the lowest to the highest are lignite, sub-bituminous, bituminous, and anthracite. The factors that influencing of coal ranks are calorific value, volatile matter, moisture (inherent water), and fixed carbon. One of the influencing factors is geologic history. Geologic history is the key to understanding the story of rocks in the past. The purpose of this study is to review the relationship between coal samples qualities and their geologic histories. The differences in coal ranks of those samples have difference geologic histories. Those factors that influencing of coal ranks are rocks age, depositional environment, temperature, pressure, and recent geologic events.

Keywords
coal, formation, quality, geologic history

Topic
Geology

Link: https://ifory.id/abstract/4mCkFdRtjuga

Corresponding Author
Muchamad Ocky Bayu Nugroho

Institutions
UPN Veteran Yogyakarta

Abstract
The Prambanan and its surrounding area is rich in the ancient relics of Buddhist and Hindu culture, in the form of temples or other forms of heritage. When was observed the distribution of the ancient buildings in this area form a specified pattern, which tends to round or close to the Boko Hills and usually were built on the riverbank. Based on the geological idea, it can be interpreted that the spread of these buildings is influenced by the procurement of source material for its. The Boko Hills composed of polimict breccias; lapilli breccias; pebbly sandstones; tuffaceous sandstones and siltstones, is the nearest location where the materials of the temple was taken, in addition to the rivers that supply the igneous andesite as a product of Merapi-s volcanism. Tuffaceous sandstones; pebbly sandstones and lapilli breccias of the Boko Hill are used for stuffing materials, such as flooring, wall around the temple and small statues. Andesite is used for the main temple building materials, such as walls, walkways and large statues. Key words : Boko Hill, source materials, ancient Hindu and Budha temples

Keywords
Boko Hill, source materials, ancient Hindu and Budha temples

Topic
Geology

Link: https://ifory.id/abstract/buLgFeDzYHMa