Garuda - Garba Rujukan Digital

Article Per Year (5 Year)

All

IJOG : Indonesian Journal on Geoscience

IJOG
Website

Published by Geological Agency of Indonesia

ISSN : 23559314 EISSN : 23559306 DOI : -

Core Subject : Science,

Earth & Planetary Sciences

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.

Arjuna Subject : -

Articles 631 Documents

2 3 4 5 6

Kemungkinan keterdapatan hidrokarbon di Cekungan Bengkulu Heryanto, Rachmat
Indonesian Journal on Geoscience Vol 2, No 3 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no3.20071The Bengkulu Basin is known as a typical fore-arc basin, situated in the southwest of Sumatera Island. The basin was occupied by the Eo-Oligocene equivalent Lahat Formation that is unconformably overlain by the Oligocene-Miocene volcanic rock of Hulusimpang Formation. It is then succeeded by siliciclastics and few carbonates of Early-Middle Miocene Seblat Formation. Unconformably overlies the Seblat Formation is siliciclastics of the Middle-Late Miocene Lemau Formation, followed by the Late Miocene-Pliocene Simpangaur Formation. The deposition was ended by a typical volcanic rock of the Bintunan/Ranau Formation. The results of sedimentary rock and organic petrographic, scanning electron microscopic and geochemistry (TOC & rock-eval and gas chromatography) analyses conducted on several selected surface outcrop samples and some oil seepage samples collected during the field work, indicate that hydrocarbon is possibly present in the Bengkulu Basin. A source rock possibly occurs in fine-grained carbonaceous sediments of the Seblat and Lemau Formations. The reservoir rock is possibly the sandstone bed of the Lemau Formation and the sandstone and limestone beds of the Seblat Formation. The caprock is a claystone bed present within the Seblat Formation as well as in the Lemau Formation. The hydrocarbon trap probably occurs as stratigraphic and structural types. Â

Interpretasi Mineralisasi Epitermal Berdasarkan Studi Ubahan Hidrotermal dan Tekstur Urat Kuarsa di Kawasan Hutan Lindung Taliwang, Nusa Tenggara Barat Herman, Danny Zulkifli
Indonesian Journal on Geoscience Vol 2, No 3 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no3.20072Taliwang conservation forest, West Nusa Tenggara, is particularly covered by volcanic rocks consisting of alternated breccia and tuff. The breccia is composed of andesitic â dioritic clasts and matrix of fine-grained to lapilli tuff which had partially been hidrothermally altered and invaded by gold bearing quartz veins. Outcrops of quartz veins are commonly limonitized, trending nearly east-west and north-south with respectively dip of 70o and 85o. Identification of quartz veins originated from people miningâs waste leads to a prediction that there are quartz stockworks beneath the earth surface (50 â 100 m depth) in the conservation forest area, from which quartz veins penetrated the illite-paragonite-calcite-siderite- nacrite altered country rock. Textures of quartz veins were identified such as comb with some coarse- grained euhedral crystals, sugary/saccharoidal/fine grained crystalline quartz and ghost-bladed. Veins and host rocks generally contain disseminated and spotted pyrites. Evaluation of quartz textures, altered rocks analysis (PIMA method), fluid inclusion studies and chemical analysis (AAS method) of selective altered rocks/quartz vein samples exhibits that the alteration and mineralization processes might occur in an epithermal system, connecting with a change of hydrothermal fluids from near neutral into acid conditions at a temperature ranging from 231 to 185oC. Alteration of illite-paragonite-kalsit-siderite is suggested as a result of reaction between host rock and a near neutral fluid, whilst nacrite (kaolin group) or argillic is a result of reaction between host rock and an acid fluid, within a mixing zone of meteoric fluid and condensed acid gas released during boiling process of hydrothermal fluid in the depth. On the basis of salinity ranging from 0.9 to 2.2 equivalent wt.% NaCl of fluid inclusion, it is predicted that the deposition of gold bearing quartz and associated ore minerals takes place in a depth ranging from 293 to 120 m beneath paleosurface. Â

Asal-usul Pembentukan Gunung Batur di daerah Wediombo, Gunungkidul, Yogyakarta Hartono, Gendoet; Bronto, Sutikno
Indonesian Journal on Geoscience Vol 2, No 3 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no3.20073Physiographically, the Gunung Sewu Subzone is predominantly composed of limestone of the Wonosari Formation, but in Wediombo area volcanic rocks of the Wuni Formation is exposed. The Wediombo volcanic rocks contain lava flows and volcanic breccias associated with Batur intrusive rock, in which all the rocks have andesitic composition. The problem is whether the Wedi- ombo volcanic rocks originated from far distance area which then was intruded by local magma after its deposition, or it is an association of the Wediombo volcanic and the Batur intrusive rocks which both are the remnants of a paleovolcano in the area. To identify the central facies of the paleovolcano, the geological principle that âthe present is the key the pastâ is used as a geological approach.Wediombo area forms a high landscape showing an elevation of about 280 m above sea level with dips of the outer slopes 20 - 40%. The drainage pattern developing in the area fol- lows the existing circular structure to form subradial - radial patterns. The high landscape shows a circular structure with a diameter of less than 2 km and it opens to the Indian Ocean. Besides the Mount Batur intrusive rock, there are some other dikes which have been already hidrothermally altered, with some mineralization in the circular structure. Meanwhile, the outer slopes are composed of alternating lava flows and fragmental volcanic rocks of 22 - 25o in dip forming a concentric pattern. Petrologically, the Batur intrusive rock is light to dark grey in color, hypocrystalline porphyritic texture, with phenocryst ranges from 1.2 - 2.2 mm in size, subhedral-euhedral crystals, fine vesicular structures. The rock comprises plagioclase, pyroxene, hornblende and opaque minerals. Geochemically, the rock indicates an island arc tholeitic magma (SiO = 60.38 â 64.53 wt%, K O = 0.63 â 0.85 wt%). Those data indicate that the circular structure was the central facies and the outer slope was the proximal facies of the Wediombo paleovolcano in Gunungkidul Yogyakarta. Â

Evaluasi awal kerentanan pelulukan/likuefaksi daerah Kendal dan sekitarnya, Jawa Tengah Lumbanbatu, Ungkap M.; Hidayat, Suyatman
Indonesian Journal on Geoscience Vol 2, No 3 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no3.20074The investigated area is a region prone to liquefaction hazards since it consists of loose, saturated Quaternary deposits. The Quaternary deposits were deposited in several sediment environments such as swamp, estuary, near shore, off shore, and fluvial (flood plain, flood basin and paleo channel). Among those Quaternary deposits, the paleo channel and estuary deposits which mainly consist of fine - to medium - sand have high susceptibility to liquefaction. An earthquake-source zone which is able to trigger earthquake and to cause liquefaction hazards is known to be thrust fault and subduction zones. Earthquakes produced by thrust fault activities are classified as shallow earthquakes while earthquakes produced by a subduction zone are deep earthquakes. The investigated area is divided into low liquefaction susceptibility, moderate susceptibility and high liquefaction susceptibility zones. This division has been made based on physical characteristic of the sand deposits, grain size, thickness of sand and its position to groundwater level as well as the physical character of overburden layer. Â

Gerakan struktur dan kaitannya dengan faktor kendali tektonik, berdasarkan analisis stratigrafi; Studi kasus geologi kuarter terhadap fase perkembangan Danau Tondano purba sepanjang Remboken - Kakas, Kec. Remboken dan Kec. Kakas, Kab. Tomohon, Sulawesi Ut Moechtar, Herman; Pratomo, Indyo; Mulyana, Herman; Poedjoprajitno, Soemantri
Indonesian Journal on Geoscience Vol 2, No 3 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no3.20075Studies of stratigraphy on Quaternary deposits in the southwest region of Lake Tondano, Tomohon Regency, South Sulawesi, revealed six facies of deposition environments. These facies consist of Tondano tuff, young volcanic eruption, lake, sand lake, tidal lake, and swamp deposits. Based on the correlation of the lateral and vertical variation of the Quaternary deposits, three unit of the depositional facies were recognized (UFP I-III). Each of the depositional facies unit is characterized by variation of the depositional environment changes which were controlled by tectonics, and was followed by the activity of Sonder main fault. The Sonder main fault activity, which controlled the depositional environment changes was recorded as an UFP. Probably, the character of this stratigraphy could be called as cyclo-tectonostratigraphy. The study was based on analyses of sedimentology and stratigraphy of six borehole information obtained along the E-NW traverse which is approximately parallel to the shorelines of the southwestern part of Lake Tondano. The penetration of the borehead varied from 1.20 to 8.7 m. Â

Berau coal in East Kalimantan; Its petrographics characteristics and depositional environment Suwarna, Nana; Hermanto, Bambang
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no4.20071To asses the characteristics of the Early to Middle Miocene Berau coal in the Berau Basin, leading to interpretation of coal depositional environments, some fresh outcrop and subcrop samples and also drill cores of the coals have been analyzed microscopically. Coal petrographic analysis was performed on twenty four coal samples from the Middle Miocene Lati Formation. Vitrinite, present in a high value, and ranging between 66.2 - 96.2%, is dominated by vitrinite B. On the other hand, inertinite and exinite, showing a similar value, exist in a low to moderate amount. Vitrinite reflectance, present in a low value, varies from 0.40 - 0.58%. Low mineral matter content is dominated by clay minerals (0.4 - 6.6%) with minor pyrite. Transitions from wet and very wet forested swamps to drier conditions with lower tree density are indicated by the higher content of vitrinite B, whilst a reverse trend is indicated by the lower content of vitrinite A. Petrographic indices obtained from facies diagnostic macerals show that an accumulation of the ancient peats under prevailing relatively wet limited influx clastic marsh to very wet forest swamps or moors is considered. The composition of the coal samples supports the interpretation of a system of fluvial to meandering streams in an upper delta plain environment. The original peat-forming vegetation was composed mainly of cellulose rich, shrub-like plants, tree ferns, herbaceous plant communities, with minor amount of trees. Thereby, the organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for depositional environment interpretation. Â

Genesis endapan aluvium Dataran Purworejo Jawa Tengah; Implikasinya terhadap sumber daya geologi Bronto, Sutikno
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no4.20072Purworejo is part of the Southern Central Jawa alluvial plain that is bordered by the South Sera- yu Mountains and Sumbing Volcano in the north, West Progo Mountains in the east, Indian Ocean in the south, and Kebumen-Banyumas plain in the west. This Purworejo plain comprises reworked allu- vial deposits, particularly from Tertiary volcanic rocks of the South Serayu and West Progo Mount- ains, and the Sumbing Quaternary Volcano. In the northern part older reworked material has formed Purworejo alluvial fan in the east and Kutoarjo alluvial fan in the west. Those alluvial fans developed from northeast side of studied area. The central part of Purworejo plain consists of older coastal alluvial deposits which have been covered by recent fluvial deposits that transported by Wawar River in the west, Jali River in the middle, and Bogowonto River in the east. The southern part of Purworejo plain, starting from the Lereng River until present coastal line is composed of younger alluvial coast- al deposits. It is suggested that groundwater resources are abundant under the Purworejo plain, and the young alluvial coastal deposits contain highly potential iron sand and associated minerals. Â

Multi-geohazards of Ende city area Sutawidjaja, Igan Supriatman; Sugalang, Sugalang
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no4.20073The Ende City is a steep mountainous area, of which the height of their peaks are above 1500 m asl. It has the limited extent of plain places, without coastal plains. Due to this condition, large parts of the area are vulnerable to mass-movements mainly debris flows, rock-falls and shallow translational and rotational landslides. On the other hand, Flores Island is a segment of the Banda Arc that contains eleven very active volcanoes and numerous inactive volcanic cones. Two of them, Mount Iya and Mount Kelimutu are included to Ende Regency. The northern foot of Mount Iya is only about 1 km away from the southern outskirts of Ende city. But the presence of Mount Meja and Mount Roja as the barrier, and the orientation of the active crater (K2), the highly explosive eruption of Iya Volcano may not directly endanger the city of Ende. Most pyroclastic flows of previous eruptions and other eruptive material emplaced into the sea, but due to a short horizontal distance between Mount Iya and Ende City, the ejected rock fragments can endanger the city of Ende especially its southern parts. A crack has developed around the active crater (K2) of Iya Volcano. It seems that the crack indicates a major weakness within the volcano, which could result in a giant landslide, entering the sea in future eruptions of Iya Volcano. The kinetic energy which is transmitted through the water may probably generate a tsunami. The Ende City also experienced significant damages in the 1992 earthquake. Luckily this city is located on a solid rock instead of alluvial sediments which can potentially undergo liquefaction. Â

Characteristics of volcanic gas correlated to the eruption activity; Case study in the Merapi Volcano, periods of 1990-1994 Priatna, Priatna; Kadarsetia, Eka
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no4.20074Volcanic gases, collected from Gendol and Woro solfatara fields, the summit of Merapi Volcano during 1990-1994, show an increase in chemical composition of H , CO, CO , SO , and HCl prior to the volcanic events, on the contrary to the drastic decreasing water vapour. The carbon/sulfur ratio of the volcanic gases lies between 1.5 and 5.7 which means that they were derived from the fresh magma. The Apparent Equilibrium Temperature (AET) which is calculated from chemical compositions of volcanic gases using reaction of SO +3H = H S+2H O showed an increasing value prior to the volcanic events. The Merapi activities lasted during August 1990 to November 1994 showed a significant increase in ratio SO /H S prior to the November 1994 pyroclastic flow. The isotopic composition of volcanic gas condensates indicates that water vapour in Gendol is directly derived from the fresh magma. On the other hand, the contamination and cooling by the subsurface water occurred around the Woro field at a shallow part.Â

Karakteristik batubara di Cekungan Bengkulu Heryanto, Rachmat; Suyoko, Suyoko
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

http://dx.doi.org/10.17014/ijog.vol2no4.20075Bengkulu Basin is known as a fore arc basin, which located in the southwestern part of Sumatera Island. Bengkulu Basin is occupied by Oligo-Miocene siliciclastic, coal, and carbonate sediments. Coal, one of alternative energies which can substitute hydrocarbon, is found within the sedimentary rocks of the Middle to Upper Miocene Lemau Formation as observed in Ketaun, Bengkulu, and Seluma areas. The thickness of the coal seams in the Ketaun area ranges from 100 to 200 cm, whereas in the Bengkulu area it varies between 100 to 350 cm, and in Seluma area up to 450 cm. Megascopically, coal seams in the Ketaun area are black in colour, dull to dull banded, with brownish black in streak, whereas in the Bengkulu and Seluma areas show a black colour, bright banded, and black streak. The mean of vitrinite reflectant value (Rv) of coal seam in the Ketaun area ranges from 0.41 to 0.49%, whereas in the Bengkulu and Seluma area it varies from 0.44 to 1.12%. The higher vitrinite reflectance of the Bengkulu and Seluma coals is probably due to the influence of andesitic sill intrusion. In general, the coal in the Ketaun area was deposited in an environment of relatively more to marine direction or limited influx clastic marsh or lower delta plain, where the tree density decreased. However, the coal in the Bengkulu and Seluma areas occurred in an environment which was relatively more to land direction or telmatic, or upper delta plain or wet forest swamp, where the tree density increased. Â

Page 4 of 64 | Total Record : 631

2 3 4 5 6

Filter by Year

2006 2023

Filter By Issues

All Issue Vol 10, No 2 (2023): in-press Vol 10, No 1 (2023) Vol 9, No 3 (2022) Vol 9, No 2 (2022) Vol 9, No 1 (2022) Vol 8, No 3 (2021) Vol 8, No 2 (2021) Vol 8, No 1 (2021) Vol 7, No 3 (2020) Vol 7, No 2 (2020) Vol 7, No 1 (2020) Vol 6, No 3 (2019) Vol 6, No 3 (2019): in-press Vol 6, No 2 (2019) Vol 6, No 2 (2019) Vol 6, No 1 (2019) Vol 6, No 1 (2019) Vol 5, No 3 (2018) Vol 5, No 3 (2018) Vol 5, No 2 (2018) Vol 5, No 2 (2018) Vol 5, No 1 (2018) Vol 5, No 1 (2018) Vol 4, No 3 (2017) Vol 4, No 3 (2017) Vol 4, No 2 (2017) Vol 4, No 2 (2017) Vol 4, No 1 (2017) Vol 4, No 1 (2017) Vol 3, No 3 (2016) Vol 3, No 3 (2016) Vol 3, No 2 (2016) Vol 3, No 2 (2016) Vol 3, No 1 (2016): in-press Vol 3, No 1 (2016) Vol 2, No 3 (2015) Vol 2, No 3 (2015) Vol 2, No 2 (2015) Vol 2, No 2 (2015) Vol 2, No 1 (2015) Vol 2, No 1 (2015) Vol 1, No 3 (2014) Vol 1, No 3 (2014) Vol 1, No 2 (2014) Vol 1, No 2 (2014) Vol 1, No 1 (2014) Vol 1, No 1 (2014) Vol 8, No 4 (2013) Vol 8, No 4 (2013) Vol 8, No 3 (2013) Vol 8, No 3 (2013) Vol 8, No 2 (2013) Vol 8, No 2 (2013) Vol 8, No 1 (2013) Vol 8, No 1 (2013) Vol 7, No 4 (2012) Vol 7, No 4 (2012) Vol 7, No 3 (2012) Vol 7, No 3 (2012) Vol 7, No 2 (2012) Vol 7, No 2 (2012) Vol 7, No 1 (2012) Vol 7, No 1 (2012) Vol 6, No 4 (2011) Vol 6, No 4 (2011) Vol 6, No 3 (2011) Vol 6, No 3 (2011) Vol 6, No 2 (2011) Vol 6, No 2 (2011) Vol 6, No 1 (2011) Vol 6, No 1 (2011) Vol 5, No 4 (2010) Vol 5, No 4 (2010) Vol 5, No 3 (2010) Vol 5, No 3 (2010) Vol 5, No 2 (2010) Vol 5, No 2 (2010) Vol 5, No 1 (2010) Vol 5, No 1 (2010) Vol 4, No 4 (2009) Vol 4, No 4 (2009) Vol 4, No 3 (2009) Vol 4, No 3 (2009) Vol 4, No 2 (2009) Vol 4, No 2 (2009) Vol 4, No 1 (2009) Vol 4, No 1 (2009) Vol 3, No 4 (2008) Vol 3, No 4 (2008) Vol 3, No 3 (2008) Vol 3, No 3 (2008) Vol 3, No 2 (2008) Vol 3, No 2 (2008) Vol 3, No 1 (2008) Vol 3, No 1 (2008) Vol 2, No 4 (2007) Vol 2, No 4 (2007) Vol 2, No 3 (2007) Vol 2, No 3 (2007) Vol 2, No 2 (2007) Vol 2, No 2 (2007) Vol 2, No 1 (2007) Vol 2, No 1 (2007) Vol 1, No 4 (2006) Vol 1, No 4 (2006) Vol 1, No 3 (2006) Vol 1, No 3 (2006) Vol 1, No 2 (2006) Vol 1, No 2 (2006) Vol 1, No 1 (2006) Vol 1, No 1 (2006) More Issue

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name
Ivan Ferdian

Contact Email
ivan.ijgbg@gmail.com

Phone
-

Journal Mail Official
ivan.ijgbg@gmail.com

Editorial Address
-

Location
Kota bandung,

Jawa barat

INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name Ivan Ferdian

Contact Email ivan.ijgbg@gmail.com

Phone -

Journal Mail Official ivan.ijgbg@gmail.com

Editorial Address -

Location Kota bandung, Jawa barat INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
Ivan Ferdian

Contact Email
ivan.ijgbg@gmail.com

Phone
-

Journal Mail Official
ivan.ijgbg@gmail.com

Editorial Address
-

Location
Kota bandung,

Jawa barat

INDONESIA