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Indonesian Journal on Geoscience

IJOG
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Published by Institut Teknologi Nasional Yogyakarta

ISSN : 23559314 EISSN : 23559306 DOI : http://ijog.bgl.esdm.go.id/index.php/IJOG/article/

Core Subject : Science, Engineering,

Earth & Planetary Sciences Engineering

The spirit to improve the journal to be more credible is increasing, and in 2012 it invited earth scientists in East and Southeast Asia as well as some western countries to join the journal for the editor positions in the Indonesia Journal of Geology. This is also to realize our present goal to internationalize the journal, The Indonesian Journal on Geoscience, which is open for papers of geology, geophysics, geochemistry, geodetics, geography, and soil science. This new born journal is expected to be published three times a year. As an international publication, of course it must all be written in an international language, in this case English. This adds difficulties to the effort to obtain good papers in English to publish although the credit points that an author will get are much higher. This Journal publishes 3 numbers per year at least 15 articles. It is a challenge for the management of the journal to remain survive and at the same time continuously maintain its quality and credibility in spite of those various constraints. Fortunately, this effort is strongly supported by the Geological Agency of Indonesia, as the publisher and which financially bear the journal. Last but not least the journal is also managed by senior geologist of various subdisciplines from various countries who are responsible for its quality.

Arjuna Subject : Ilmu Bumi dan Planet (semua kategori) - Geologi

Articles 324 Documents

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Sedimentological and Micropaleontological Characteristics of the Black Clay Deposit of the Baturetno Formation, Wonogiri, Central Java Putra, Purna Sulastya; Yulianto, Eko
Indonesian Journal on Geoscience Vol 3, No 3 (2016)
Publisher : Geological Agency

DOI:10.17014/ijog.3.3.163-171A previous research on black clay of the Baturetno Formation identified that this clay was a palaeolake deposit. In this study, the black clay deposit was characterized by using sedimentological and micropaleontological approaches to reveal its origin. The black clay of the Baturetno Formation has a low organic matter (mostly less than 8%) and almost no pollen content. These characteristics are not representative of a lake deposit. This black clay was suggested a mud flow deposit. This conclusion is supported by the occurrence of dispersed rock fragments in the clay deposit. In addition, the previous research has identified that the formation of a palaeolake was related to the Late Pliocene tilting in South Java. The carbon dating indicates that the deposition of this clay has no relationship to the Late Pliocene tilting in South Java as the age of this clay was determined to be much younger (around 7000 BP; early Holocene).

Sabang Submarine Volcano Aceh, Indonesia: Review of Some Trace and Rare Earth Elements Abundances Produced by Seafloor Fumarole Activities kurnio, Hananto; Syafri, Ildrem; Sudradjat, Adjat; Rosana, Mega Fatimah
Indonesian Journal on Geoscience Vol 3, No 3 (2016)
Publisher : Geological Agency

DOI:10.17014/ijog.3.3.173-182Geochemical analyses of selected coastal and seafloor samples from Sabang Area revealed abundances of trace and rare earth elements. The selected samples of element abundances were mostly taken from seafloor in the vicinities of active fumaroles either by grab sampler operated from survey boat above fumarole point or by diver directly took the samples on the seafloor especially at Serui - Sabang Bay. Results show that samples closed to seafloor fumaroles demonstrate plenty of trace and rare earth elements. The trace and rare earth elements mean values (n=10) are: Nb (4.33 ppm), La (16.52 ppm), Ce (38.82 ppm), Nd (19.15 ppm), Ce (38.82 ppm), Pr (4.907 ppm), Nd (19.15 ppm), Sm (4.04 ppm), Gd (3.95 ppm), Dy (3.38 ppm), Th (6.432 ppm), and U (4.335 ppm). Negatively, statistical correlations between Fe, Zn, and Ni as the main sulphide elements with sulphur is interpreted that sulphide minerals do not form in the Sabang Sea. Sea water influence in the mineralization process was shown by the good correlations between Fe, Zn, Pb, Ni, and Ba.

Nutrient Level Change Based on Calcareous Nannofossil Assemblages During Late Miocene in Banyumas Subbasin Hendrizan, Marfasran
Indonesian Journal on Geoscience Vol 3, No 3 (2016)
Publisher : Geological Agency

DOI:10.17014/ijog.3.3.183-194Hydrographic situation on surface waters is more challenging to be understood, related to global and regional climate change in tropical regions. In addition, records from these tropical areas are limited compared to other areas of subtropical and polar regions. The aim of this study is to reconstruct Cenozoic paleoceanography, in particular nutrient level, using outcrop samples from Kali Pasir, Banyumas, Indonesia. This study is focused on the relationships of the relative abundance of Discoaster, coccolith size of Reticulofenestra, and lithofacies characteristics. Nutrient level is reconstructed using quantitative analysis of calcareous nannofossil by counting calcareous nannofossils on 400 fields of View (FOV) for each sample. The abundance of Discoaster and the large Reticulofenestra represent a deep thermocline and nutricline, which is a typical of oligotrophic condition. This condition also associated with the muddy facies in the early stages of Late Miocene (NN8-NN10a). Conversely, decreasing Discoaster abundance and the abundance of small Reticulofenestra indicate a shallow thermocline and nutricline, resulting strong eutrophication of surface waters in the later stage of Late Miocene (NN10b-NN11). A high nutrient content in this stage is related to classical turbidite deposits. A change in a sea surface resulted in strong eutrophication, which is in this section similar to the eastern Indian Ocean micropaleontology records during the Late Miocene (NN10). This finding shows that strong eutrophication in Kali Pasir section is probably driven by nutrient-rich terrestrial material related to the onset of Indian monsoon during the Late Miocene.

Geochemical Signatures of Potassic to Sodic Adang Volcanics, Western Sulawesi: Implications for Their Tectonic Setting and Origin Shaban, Godang; Fadlin, Fadlin; Priadi, Bambang
Indonesian Journal on Geoscience Vol 3, No 3 (2016)
Publisher : Geological Agency

DOI:10.17014/ijog.3.3.195-214The Adang Volcanics represent a series of (ultra) potassic to sodic lavas and tuffaceous rocks of predominantly trachytic composition, which forms the part of a sequence of Late Cenozoic high-K volcanic and associated intrusive rocks occurring extensively throughout Western Sulawesi. The tectonic setting and origin of these high-K rocks have been the subject of considerable debates. The Adang Volcanics have mafic to mafitic-intermediate characteristics (SiO2: 46 - 56 wt%) and a wide range of high alkaline contents (K2O: 0.80 - 9.08 %; Na2O: 0.90 - 7.21 %) with the Total Alkali of 6.67 - 12.60 %. Al2O3 values are relatively low (10.63 - 13.21 %) and TiO2 values relatively high (1.27 - 1.91 %). Zr and REE concentrations are also relatively high (Zr: 1154 - 2340 ppm; Total REE (TREY = TRE): 899.20 - 1256.50 ppm; TRExOy: 1079.76 - 1507.97 ppm), with an average Zr/TRE ratio of ~ 1.39. The major rock forming minerals are leucite/pseudoleucite, diopside/aegirine, and high temperature phlogopite. Geochemical plots (major oxides and trace elements) using various diagrams suggest the Adang Volcanics formed in a postsubduction, within-plate continental extension/initial rift tectonic setting. It is further suggested magma was generated by minor (< 0.1 %) partial melting of depleted MORB mantle material (garnet-lherzolite) with the silicate melt having undergone strong metasomatism. Melt enrichment is reflected in the alkaline nature of the rocks and geochemical signatures such as Nb/Zr > 0.0627 and (Hf/Sm)PM > 1.23. A comparison with the Vulsini ultrapotassic volcanics from the Roman Province in Italy shows both similarities (spidergram pattern indicating affinity with Group III ultrapotassics volcanics) and differences (nature of mantle metasomatism).

Stable Isotopes and Hydrochemistry Approach for Determining the Salinization Pattern of Shallow Groundwater in Alluvium Deposit Semarang, Central Java Satrio, Satrio; Prasetio, Rasi; Hadian, Muhamad Sapari Dwi; Syafri, Ildrem
Indonesian Journal on Geoscience Vol 4, No 1 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.1.1-10A groundwater study has been conducted in the Semarang City in August 2014, aiming to determine the source of shallow groundwater salinization using stable isotopes (18O, 2H) and water chemistry approach, and supported by local hydrogeological data. A number of shallow groundwater samples were taken at several locations with a depth of 0 - 35 m. Based on geological data, shallow groundwater of Semarang alluvium is dominated by insertion of sand-gravel and sandy-clay with average porosity of around 56.0 %. This layer is thinning towards the south and then increasingly thickening to the north and north-east of the studied area. The results of the analyses show that the characteristics of shallow groundwater, i.e. approximately 51% of groundwater, still have the original composition as meteoric water and the remaining approximately 49% obtained a shift in the isotopic composition as caused by interaction with seawater and the little influence of evaporation. The results of chemical analysis of water indicates that in dry seasons, shallow groundwater aquifers in the Semarang City is dominated by chloride (Cl-) with NaCl of water type. While the parameters of bicarbonate, chloride, and Na/Cl ratio, shallow groundwater can be classified into two groups, namely unintruded groundwater around 51% spread from the foot hills to the south towards the hills with elevations of 9 - 142 m above sea level and intruded groundwater around 49% spread from the coastline to the urban direction.

Lateral Facies and Permeability Changes in Upper Shoreface Sandstones, Berakas Syncline, Brunei Darussalam Ovinda, Ovinda; Lambiase, Joseph J
Indonesian Journal on Geoscience Vol 4, No 1 (2017)
Publisher : Geological Agency

DOI:Â 10.17014/ijog.4.1.11-20Several outcrops were studied to identify sedimentary facies and to analyze permeability distribution, through which an outcrop analogue for upper shoreface reservoirs can be established. Four facies were identified: upper shoreface, lower shoreface, offshore transition, and tidal ones. Stratigraphic correlation of eleven outcrops indicates that the upper shoreface sandstone is generally clean, well sorted, parallel, and planar cross laminated. The sand becomes thinner and pinches out to the northwest where the mud proportion increases within the sand. Muddier sand was deposited in a relatively low energy upper shoreface setting. The thickness of the upper shoreface reservoir sand generally is 5 m. It decreases to zero over approximately 1.3 km as the sand pinches out to the northwest. To the northeast, the thickness also decreases to 4 m over approximately 4 km. Permeability values are more variable laterally than vertically. The permeability distribution has an obvious relationship to the sedimentary facies and is mainly controlled by the proportion of mud and bioturbation. As the sand pinches out in the northwest, permeability decreases from 590 md to 97 md over 1 km. To the northeast, permeability also decreases to 152 md over approximately 4 km where the sand becomes highly bioturbated. These values indicate that the sands are of good to very good reservoir quality. It appears that there are no major barriers to the lateral flow of fluid within the upper shoreface sandstone.

Geochemistry of Late Triassic weak Peraluminous A-Type Karimun Granite, Karimun Regency, Riau Islands Province Irzon, Ronaldo
Indonesian Journal on Geoscience Vol 4, No 1 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.1.21-37Karimun is an island with various geological deposits: tin, granite, sand, and others. The tin deposit in Karimun is related to the granitoid tin belt which extends from Myanmar to western Indonesia. Late Triassic Karimun Granite is composed of quartz, K-feldspar, plagioclase, biotite, and/or muscovite with small amounts of accessory minerals. The granitoid unit is different with other felsic intrusive rocks in Malay Peninsular because of its A-type affinity although it is classified as part of the Tin Islands. All eight samples can be classified as altered rocks since the occurrence of secondary chlorite was identifed both macroscopically and microscopically. Petrography was used to describe the minerals that form the samples, whereas XRF and ICP-MS were used to study Karimun Granite from the geochemical point of view. Harker diagrams confirm that the granites show similarity to other granite units in Malaysia except for CaO. Whalen diagrams indicate the granite as A-type as well as the SiO2, REE, and LILE amounts. REE content in the weak peraluminous granitoid ranges from 183 to 3,296 ppm with Eu and Ce show negative anomalies in the REE spider diagram. Negative anomalies of Eu, Ba, Sr, P, and Ti in normalized spider plot also conclude that the studied granitoid indicates A-type.

Audio-Magnetotelluric Modeling of Cimandiri Fault Zone at Cibeber, Cianjur Handayani, Lina; Maryati, Maryati; Kamtono, Kamtono; Mukti, M. Maâ€™ruf; Sudrajat, Yayat
Indonesian Journal on Geoscience Vol 4, No 1 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.1.39-47The characteristic of Cimandiri Fault Zone has not been completely defined despite plenty of studies had already been accomplished. Therefore, an audio-magnetotelluric modeling was carried out. An audiomagnetotelluric survey was conducted at two parallel lines (N166oE) that intersected Cimandiri Fault Zone in Cibeber area, Cianjur. The distance between those two lines was 4.5 km and each line consisted of twenty-one stations with the distance between stations was 500 m. From the acquired forty-two apparent resistivity curves, inversion was executed to obtain two models. The models indicate layers with resistivity value of > 1000 ohm.m at about 500 m depth at both lines, which are associated to the basement layer. Columns of low resistivity zones in about the middle of each model represent fault zones as the weak zones of the area, and both models displayed them slightly dip southward as thrust faults.

Landslide Vulnerability Assessment (LVAs): A Case Study from Kota Kinabalu, Sabah, Malaysia Roslee, Rodeano; Jamaludin, Tajul Anuar; Simon, Norbert
Indonesian Journal on Geoscience Vol 4, No 1 (2017)
Publisher : Geological Agency

DOI: 10.17014/ijog.4.1.49-59The topic on Landslide Vulnerability Assessment (LVAs) in Malaysia is relatively new and received little attention from geoscientists and engineers. This research paper tries to formulate the concept of LVAs by taking into account the science and socio-economic aspects. A new approach in vulnerability concept is also introduced herein. To achieve this goal, a framework was designed for assessing the LVAs. The framework was formulated semiquantitatively through the development of database for the risk elements (human and properties) based on information from secondary data (technical reports), extensive review of literature, and field observations. The vulnerability parameters included in assessing LVAs are 1) physical implication (building structures, internal materials, property damage, infrastructural facilities, and stabilization actions), 2) social status (injury, fatalities, safety, loss of accommodation, and public awareness), and 3) interference on environment (affected period, daily operation, and diversity). Each considered parameter in the vulnerability assessment is allocated with a certain index value ranges from 0 (0 % damage/victims/period), 0.25 (1 - 25% damage/victims/period), 0.50 (26 - 50% damage/victims/period), 0.75 (51 - 75% damage/victims/period), and 1.00 (75 - 100% damage/victims/period). All of these parameters are compiled and analyzed with â€œLandslide Distribution Mapâ€ (LDM) to generate a â€œLandslide Vulnerability Degree map (LVD)â€. The LDM was produced based on field studies and satellite image interpretations in order to locate the landslide locations in the studied area. Finally, three types of physical, human, and environment vulnerabilities were then classified into five classes of vulnerabilities, namely: Class 1 (< 0.20): Very Low Vulnerability; Class 2 (0.21 - 0.40): Low Vulnerability; Class 3 (0.41 - 0.60): Medium Vulnerability; Class 4 (0.61 - 0.80): High Vulnerability); and Class 5 (> 0.81): Very High Vulnerability. Results from this study indicate that a further study is needed to the areas of high to very high vulnerability only. This LVAs approach is suitable as a guideline for preliminary development planning, controlling, and managing the landslide hazard /risk in the studied area and potentially to be extended with different background environments.

Geochemistry of Natural Gas Seepages in Boto Area, Bancak, Semarang, Central Java Amijaya, Hendra; Pameco, Pracoyo Adi
Indonesian Journal on Geoscience Vol 4, No 2 (2017)
Publisher : Geological Agency

DOI:Â 10.17014/ijog.4.2.61-70Three seepage gas samples collected from Boto Area, Bancak, Semarang, Central Java, were studied to determine their chemical characteristics using GC and GC-IRMS methods. They are composed 53 - 85% of methane predominantly. However, gas seep Site 3 sample has the highest N2 compound and the lesser extent to the samples Site 2 and Site 1 respectively. The two hydrocarbon gas seeps (Site 1, 2, and Site 3 samples) that are characterized by Î´13C methane of -35.61â€° and -27.97â€°, and values of Î´D methane of -112â€° and -109â€° respectively, are each isotopically distinct from all others suggesting, at least, they are derived from different maturity level. The Site 3 gas sample is suggested to be more mature than the others.

Page 22 of 33 | Total Record : 324

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bernadeta subandini astuti

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Home Page

OAI Link

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Contact Name bernadeta subandini astuti

Contact Email bernadeta.palguno@gmail.com

Phone +6222-7213793

Journal Mail Official ijog@bgl.esdm.go.id

Editorial Address Jl. Diponegoro No. 57 Bandung, Indonesia

Location Kab. sleman, Daerah istimewa yogyakarta INDONESIA

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Contact Name
bernadeta subandini astuti

Contact Email
bernadeta.palguno@gmail.com

Phone
+6222-7213793

Journal Mail Official
ijog@bgl.esdm.go.id

Editorial Address
Jl. Diponegoro No. 57 Bandung, Indonesia

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA