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Journal : Indonesian Journal on Geoscience

The Evolution of Gajahmungkur Paleovolcano, Wonogiri, Central Java, as A Reference to Revize the Terminology of “Old Andesite Formation” Syafri, Ildrem; Sudradjat, A.; Sulaksana, Nana; Hartono, G.
Indonesian Journal on Geoscience Vol 5, No 4 (2010)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.5.4.263-268

Abstract

DOI: 10.17014/ijog.v5i4.109Gajahmungkur is a Tertiary paleovolcano located in Wonogiri Regency, Central Java. The volcanic product of this volcano are widely distributed and composed of important elements of the stratigraphic sequence in the Southern Mountain area. The volcanic products so far have been simply classified as “Old Andesite Formation” which apparently is not in line with the stratigraphic code and the Indonesian Stratigraphic Code. The description of paleovolcano therefore might contribute to the revision of the “Old Andesite Formation”. The evolution of Gajahmungkur paleovolcano commenced with the formation of a submarine volcano, and then at the second phase a composite volcano emerged above sea level forming a volcano island. The third phase was the self destruction resulting in a formation of a caldera. Pumiceous components dominated the products. At the fourth phase, the activities began to decline producing more basaltic rocks. The statistical analysis of the interrelation between various physical properties of the clastic rocks leads to the identification of volcanic facies and the location of the paleovolcano vent.
Morphotectonics of Mount Rendingan Area Related To the Appearances of Geothermal Surface Manifestations Gentana, Dewi; Sulaksana, Nana; Sukiyah, Emi; Yuningsih, Euis Tintin
Indonesian Journal on Geoscience Vol 6, No 3 (2019)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.6.3.291-309

Abstract

DOI: 10.17014/ijog.6.3.291-309The researched area is situated at Mount Rendingan and its surrounding area, Lampung Province, the southern part of Sumatra Island. It has a big potential of geothermal resource in line with a unique graben like bowl landform and geothermal surface manifestations. This research was carried out using remote sensing and field observation methods. The remote sensing method used topography and Shuttle Radar Topography Mission -Digital Elevation Model (SRTM-DEM) maps to analyze morphotectonic attributes, and the result was validated by morphotectonic data analysis from field observation. The purpose of this research is to evaluate the relation between morphotectonic and the appearances of geothermal surface manifestations. The interpretation of SRTM-DEM and topographic maps are supported by morphotectonic analyses,which indicate that the geothermal surface manifestations in this area are controlled by tectonic activity. It has various levels of lift which are shown by the values of valley height weight ratio (Vf) from 0.16 to 3.31 and the values of mountain front sinuosity (Smf) from 1.05 to 2.09. The morphotectonic characteristics can describe the geological structure activity levels which are reflected in the landform and its rock. The volcanic areas consist of igneous rocks which have small primary permeabilities. However, the development of geological structure can cause fractures in the rock that step in as a medium for passing geothermal fluid from depth to surface. They are found on the fault intersection zone system trending NE-SW and NW-SE, NNE-SSW and NNW-SSE, and WE system directions that indicate the fault system is correlated with the appearances of geothermal manifestations.
The Determination of Volcanic Characteristics Based on Deuterium and Oxygen-18 Isotope Compositions: A Case Study at Dieng Plateau, Central Java Priatna, Priatna; Sulaksana, Nana; Hutabarat, Johanes; Haryanto, Iyan
Indonesian Journal on Geoscience Vol 7, No 2 (2020)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.7.2.201-213

Abstract

DOI:10.17014/ijog.7.2.201-213To find out volcanic characteristics, a geochemical approach can be used, one of which is through the measurement of deuterium and oxygen-18 isotopes from condensate and crater water samples. In this study, Dieng Plateau in Central Java was chosen, because it has a wide spread of fumarole fields and crater water. In addition, research in the Dieng Plateau is very useful in the management of geological-based tourism and geopark development in the future. Results of isotope analysis in Candradimuka Crater show the average number of isotope deuterium is δD – 500/00 and isotope oxygen-18 is δ18O –30/00 which produce the value of the mixing fraction of f 18O = 47.11%. This figure is the highest isotope number compared to other craters on the Dieng Plateau. The high value of the isotope-18 mixing fraction is supported by a strong plume from three vents in Candradimuka. Meanwhile, the results of crater water isotope tests obtained the highest results in Sikidang Crater with the value of the deuterium isotope is δD = – 10.300/00 and the isotope oxygen-18 is δ18O = 6.570/00 which are in the metamorphic water area from the mixing of magmatic processes with surface meteoric water. Based on the deuterium isotope approach with oxygen-18 crater water and fumarole condensate supported by subsurface temperature data, most of the Dieng Plateau has magmatic-hydrothermal characteristics, except Candradimuka Crater which belongs to the magmatic group. 
Co-Authors A. Asseggaf A. Sudradjat A. Sudradjat ACHMAD RIFAI Achmad Sjafrudin, Achmad Adjat Sudrajat Adjat Sudrajat Agoes Loeqman Agus W Oscar Aliyuddin Jamil Andi Makawaru Yasin, Andi Makawaru Andis Priswantoro Ando, Ferry Anggito Saputra Anggoro Tri Mursito Arini Dian Asep Nursalim, Asep Bombom Rachmat Suganda, Bombom Rachmat Boy Yoseph Cahya Sunan Sakti Syah Alam Brilian, Ciria Humanis Budi Muljana Burhanidunnur, Muhammad Cahya Patria Cipta Endayana Cipta Endyana Dadan Wildan, Dadan Daliman, Shaparas Binti Denny Lumban Raja Dewandra Bagus Eka Putra Dewandra Bagus Eka Putra, Dewandra Bagus Eka Dewi Gentana Dicky Muslim Djapani, Yuspian Dudi Nasrudin Usman Dwi Putranto Waloeyo Dyah Ayu Setyorini Emi Sukiyah Euis Tintin Yuningsih Fachrur Reza Assegaff Febri Hirnawan Febri Hirnawan Febri Hirnawan Fikri Abdulah, Fikri G. Hartono G. Hartono Hanik Humaida Hartono, G. Helman Hamdani Hendarmawan Hendarmawan HS, Karyono Ildrem Syafri Imam Santosa Indrakususma, Riko Ardiansyah Indrakususma, Riko Ardiansyah Inu Zaini Yasir -, Inu Zaini Yasir Isandarsyah, Teuku Yan Waliana Muda Iskandarsyah, Teuku Y. M. W. Iwan Nursahan Iyan Haryanto Jamal Jamal Jamal Jamal Johanes Hutabarat Johanes Hutabarat Kamaruddin, Hashari Kamaruddin, Hashari Karyono HS Khoirullah, Nur M. Nursiyam Barkah, M. Nursiyam Mamay Surmayadi Mega Fatimah Rosana Mochamad Aufar Muttaqin Mohamad Sapari Hadian Mudiarsono Mudiarsono Muhammad Agil Prasetyo Muhammad Burhannudinnur Muhammad Kurniawan Alfadli Muhammad Lutfi Muhammad Tobibi Pratama Pohan Murni Sulastri Murni Sulastri Murni Sulastri Murni Sulastri Murni Sulastri Muttaqin, Mochamad Aufar Novi Triany Nurasa , Heru Nurohim, Dede Nursahan, Iwan Nursahan, Iwan Oscar, Agus W Oscar, Agus W P Paramarta Raditya Rendra Persulessy, Janeth Angel Pradnya P. Raditya, Pradnya P. Pradnya Paramarta Raditya Rendra Pradnya Raditya Rendra, Pradnya Raditya Priatna Priatna Priatna, Priatna Priatna, Priatna Princessca, Channia Priswantoro, Andis Andis Puguh Setiyanto, Puguh Rendra, P Paramarta Raditya Rita Yulianti, Rita Rizki Satria Rachman Salsabila, Unik Hanifah Saputra, Adang Setyorini, Dyah Ayu Sipahutar, Sumahang R. Sofyan Rachman Idris Sri Wahyuni Sudradjat, A. Suherman Dwi Nuryana Suherman Dwi Nuryana Sulastri, Murni Syamsul Irham, Syamsul T Yan Waliana T Yan Waliana, T Yan Teuku Yan Waliana Muda Iskandarsyah Tri Mursito, Anggoro Anggoro Trisnadiansyah, Mochamad Ridfan Vijaya Isnaniawardhani Waliana, Teuku Yan Wening Sulistri Winantris Winantris Yoga Andriana Sendjaja Yudhi Listiawan Yuniarti Yuskar Yuniarti Yuskar, Yuniarti Zakia Lukman Zufialdi Zakaria