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All Journal International Journal of Renewable Energy Development TEKNIK Geological Engineering E-Journal Journal of Geoscience, Engineering, Environment, and Technology Jurnal Geosains dan Teknologi
Yoga Aribowo
Departemen Teknik Geologi, Fakultas Teknik, Universitas Diponegoro
Chemistry Earth & Planetary Sciences Energy Engineering Environmental Science Physics

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STUDI PENDAHULUAN DAERAH PROSPEK PANASBUMI BERDASARKAN DATA MANIFESTASI PANASBUMI, GEOKIMIA DAN ISOTOP FLUIDA PANASBUMI KOMPLEK GUNUNG TELOMOYO, KABUPATEN SEMARANG, JAWA TENGAH Rizki Trisna Hutami; Yoga Aribowo; Dian Agus Widiarso
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Telomoyo Mountain (area) is one of geothermal prospect area in Indonesia which is shown by many geothermal manifestations around the mountain. Telomoyo Mountain (area) is located in two regencies, Semarang and Magelang, Central Java. The purpose of this study is to get vision about geothermal model system in Telomoyo Mountain based on geothermal manifestation data, geothermal fluid geochemistry, and geothermal fluid isotope.Based on manifestation mapping there are two kinds of manifestation, warm spring and alteration. Warm springs are spread in Candi Dukuh and Candi Umbul with neutral pH characteristic and 36oC water temperature. Based on fluid geochemistry analysis the type of fluid is chloride-bicarbonate water, and based on Na-K-Mg comparison the fluid is immature water. Based on isotope 18O and 2H analysis, warm spring has mixed with meteoric water. Altered rocks are found in Desa Dangkel, Desa keningar, Desa Sepakung, and Desa Kendal Duwur with the type of alteration is argillic – advanced argillic. Based on petrography analysis, lithology in this area are andesitic lava, tuff breccia, and pyroclastic breccia. Based on XRD analysis, altered minerals in rock which is argillic type are smectite, halloysite, kaolinite, and jarosite. In rock which has advanced argilic type, there are dickite, phyrophillite, alunite, diaspora, cristobalite, and pyrite. Dickite and alunite mineral are typical mineral for physicochemical environment with acid in pH and 230 – 260 oC in temperature. Candi Umbul and Candi Dukuh warm spring shows the lateral outflow zone of the geothermal system, while advanced argillic alteration shows the upflow zone of geothermal system.
GEOLOGI, KARAKTERISTIK DAN GENESA ENDAPAN LATERIT BAUKSIT PT. ANTAM (Persero) Tbk, UNIT GEOMIN, DAERAH KENCO, KABUPATEN LANDAK, PROVINSI KALIMANTAN BARAT Fachrul Rozi Ramadhan; Yoga Aribowo; Dian Agus Widiarso; Betraz A
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Bauxite mining is one of the business units that started to increase mine in Indonesia because it has considerable economic value in the scale of quantity and quality. One of the prospective locations are in areas Kenco, Landak District, West Kalimantan Province. Kenco is an area that addressed the rest of the development of Cretaceous volcanism consisting of the island of Borneo Volcanic Formations Mensibau with unit members Granodiorite, quartz diorite and diorite, and the Formation of the Kingdom Volcanic Andesite-trachite units and Formations of alluvium and swamp sediment quarter. Bedrock types that tend to be acid-intemediet bauxite will produce certain characteristics that are different from the dominant rock properties of acids or bases. Rock intensively weathered have the potential to form a precipitate lateritic bauxite. Conducted a detailed mapping is the next steps of regional mapping to narrow the area of bauxite mineral mining resource prospects.         Geological aspects and lateritic bauxite deposit genesis process on the site is a very interesting research material. Based on field mapping, Gibsite is the bauxite formed with frame type is the result of weatherin sediment residue on the soil catena. The study area consists of rocks that form lateritisation overburden, soil laterite, iron cap /gossan, saprolite and bedrock layers. Lateritic bauxite deposit formation is largely controlled by bedrock type, time, climate (rainfall), morphology, changes the face of groundwater, and vegetation destruction process involving a series of rocks, minerals leaching, transport and deposition of mineral elements of chemical residues.         Lateritic bauxite sludge characteristics according to the analysis of X-Ray Diffraction (XRD) on a layer of overburden to ore (saprolite layer) shows the mineral composition Nacrite, Kaolinite, Gibsite, Goethite, Quartz, Nordstandite, Hematite, and Dickite. The average mineral formed at neutral pH tends to be acidic by 5-7 and temperatures below 150oC. The analysis of X-Ray Fluorescence (XRF) shows the rock has certain characteristics which, if averaged Aluminum trihydrate (Al2O3) as much as ±33%, Iron (II) trihydrate (Fe2O3) of about ±8.5%, Silicate oxide (SiO2) approximately ± 43%, Titanium oxide (TiO2) approximately ≤1% and total silicate (R-SiO2) approximately ≤7%. Saprolite layer showed a thickening layer on the hillside at an angle of 20 - 25o, while the section near the top of the hill or valley will be thinned. The results showed that the value of XRF levels bedrock formation of bauxite have economic value to the content of Al and Fe but less to a total content of Si and Si.
PENENTUAN TIPE ALTERASI BERDASARKAN ANALISIS PETROGRAFI, MINERAGRAFI, DAN GEOKIMIA PADA DAERAH KASIMBAR, KABUPATEN PARIGI MOUTONG, PROVINSI SULAWESI TENGAH Ainul Fatayatis Salamah; Yoga Aribowo; Dian Agus Widiarso; Rinal Khaidar Ali
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Hydrothermal alteration is a complex process, because it involves a change in mineralogy, chemistry and texture resulting from the interaction of hydrothermal solutions with rocks in its path on certain physico-chemical conditions (Pirajno, 1992). Hydrothermal processes in certain circumstances will result a collection of certain minerals known as the set of mineral or mineral assemblage (Guilbert and Park, 1986). One evidence of hydrothermal alteration is the appearance of veins that had level of metal minerals and it is also a change on the rock side, as found in Kasimbar District, Moutong Parigi Regency, Central Sulawesi province. In the area discovered the existence of gold in the alluvium sediments that are the result of weathering schist and quartz veining. Gold is found in alluvium sediments are secondary gold or placer gold. From the research that has been done, found gold in quartz veins trapped on phyllite rocks. This study was conducted to determine the lithology of the region, the study based on petrographic analysis, knowing the characteristics of the rock alteration found in the study area based on petrographic analysis mineragraphy, knowing the type of alteration that develops in the area of research, knowing mineralization contained in the study area. Research in Kasimbar District, Parigi Moutong Regency, Central Sulawesi Province was conducted by analyzing rock samples taken from the area. Analysis is conducted with the petrographic analysis, mineragraphy, lithology and geochemistry of the units located in the area.Based on the results of petrographic thin section analysis of rock samples, lithology contained in Kasimbar District, Parigi Moutong Regency, Central Sulawesi Province is phyllite, granite and gneiss. Alteration characteristics of the study area is known of the characteristics quartz veins, alteration minerals characteristics and  metal minerals characteristics. Quartz veins in the study area was divided into two, namely quartz veins in granite and quartz veins in metamorphic rocks (parallel and cut foliation). Characteristic alteration minerals contained in the study area is chlorite, sericite, biotite, epidote and quartz. Mineralization characteristics of the region, is study of sulphide minerals such as pyrite, bornite, and enargite; iron oxide minerals such as magnetite and hematite and the mineral element in the form of native gold (Au). Type of alteration is developed in the research area of prophylitic alteration, potassic alteration, silicification alteration, and carbonization alteration. Type of mineral deposits research areas is high sulfidation epithermal deposits.
PENENTUAN ZONA PROSPEK HIDROKARBON PADA FRACTURED BASEMENT BERDASARKAN DATA WELL LOG DAN SEISMIK 3D PADA LAPANGAN MALAWAPATI SUB-CEKUNGAN JAMBI, CEKUNGAN SUMATERA SELATAN Rahman Wahyudianto; Hadi Nugroho; Yoga Aribowo; Robet Wahyu Widodo
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Hydrocarbon discovery in the basement of several exploration wells in South Sumatra Basin, giving new challenges for geologists to find hydrocarbon reserves with the concept of new thinking, the best one on the concept of the geology and oil exploration in fractured basement.Research object is on the basement high, which dominant lithology is schist. This research is located at Malawapati and includes part of the Sub-Basin of Jambi, South Sumatra Basin. Based on Drill Stem Test (DST), hydrocarbon potential of fractured basement on Prabu X1 is around 0.2-1 MMSCFGPD (Million Standard Cubic Feet Gas Per Day) and on Dharma X3 is around traces-1 MMSCFGPD, then it needs a good study to determine hydrocarbon potential in the fractured basement.The purpose of this research is obtaining a description of the basement characteristic and vertical fracture intensity in the basement by using well log and master log, obtaining horizontal fracture distribution in the basement by using 3D seismic and seismic attributes, obtaining a description of the basement geometry by analyzing geological structures in the basement, determining correlation of the two data are intensity and distribution of fracture to determine the location of the most prospect as a hydrocarbon zone.The research method is using descriptive and analytical methods. There are 3 wells in Malawapati field. There are 2 wells which reaching the basement, which are Prabu X1 and Dharma X3 and also a well not reaching the basement, which is Dharma X3. Well log and master log is used to determine basement characteristics and vertical fracture intensity with Fuzzy Inference System (FIS), it is used for reference in retraction the target zone on seismic attribute by type variance cube, which the suitable are 70 ms below the horizon of Prabu X1 and 25 ms below the horizon of the well Dharma X3. 3D seismic data is used to determine basement geometry and horizontal fracture distribution with seismic attribute by type variance cube.Based on the correlation analysis of well log, master log and seismic attribute by type variance cube, is known that hydrocarbon prospect zone in vertical is weathered basement zone and high intensity zone. Hydrocarbon prospect zone in horizontal is zone A which is the top of basement high zone and also not affected by zone fault so it has low fracture intensity. Zone B is edge of the basement high zone and also affected by zone fault so it has high fracture intensity
ANALISIS SIKUEN STRATIGRAFI DAN PEMODELAN FASIES FORMASI TANJUNG BERDASARKAN DATA LOG SUMUR DAN DATA INTI BATUAN PADA LAPANGAN MIR CEKUNGAN BARITO, KALIMANTAN SELATAN Muhammad Ilham Ridwan; Hadi Nugroho; Yoga Aribowo; Mill Sartika Indah; Perdana Rakhmana Putra
Geological Engineering E-Journal Vol 6, No 2 (2014): Wisuda Periode Juli - Oktober 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Increased consumption of energy resources of oil and gas, exploration and exploitation process results performed optimally. Interpretation of subsurface using well log data combined with geological disciplines becomes very important in increasing exploration. Location of the study lies in one of the field located in the Barito basin of South Kalimantan province owned by Pertamina UTC. This research was done in the implementation of the final project addressed the subject of mapping subsurface using sequence stratigraphic approachs.The purpose of this research is to determine the type of lithology, facies and depositional environment, sequence stratigraphy, distribution of sedimentation and facies modelling Tanjung Formation in the MIR field. This research is using descriptive method and analytical methods. Descriptive method is a method that does some literature review. While the analysis method is using qualitative analysis to determine the type of lithology, stratigraphy and facies modeling sequence. This analysis uses software petrel 2009 in an analysis of well logs in the distribution of lithology, stratigraphic marker horizon correlation, subsurface mapping and facies modelling.Based on the results of the data analysis and discussion, it can be interpreted that the Tanjung Formation in the MIR field has a type silisiklastik sandstone lithology (sandstone), shale (shale) and coal (coal) with depositional environment in estuarine area. The results of the analysis of stratigraphic marker is 2 MRS (Maximum Surface Regression), 5 FS (Flooding Surface), 2 MFS (Maximum Flooding Surface) and 1 SB (Sequence Boundary) with sequence stratigraphic unit 2 Lowstand System Track (LST), 2 Transgressive System Track (TST) and Highstand System Track 1 (HST). Direction of sedimentation cycles in Tanjung Formation sequence stratigraphy approach leads to Northwest – South east (NNW - SSE). Facies models are divided into two zones: the ZR1 zone and ZR2 zone, where the zone was conducted to calibrate the rock core data. Based on core analysis Estuary facies rocks have Chanel and Tidal flat on Keywell. According to core data support and electrofasies in the study site, there are 3 facies deposition environmental: Chanel Estuary , Tidal flat and Tidal Bars.
Integrasi Log Sumur dan Seismik 2D Untuk Analisis Karakteristik Reservoir dan Menghitung Potensi Hidrokarbon Pada Formasi Tualang, Lapangan “SHANDORA”, Cekungan Sumatera Tengah Ibnu Dwi Bandono Wahyudi; Hadi Nugroho; Yoga Aribowo; Radig Wisnu Yuwono
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Minyak dan gasbumi masih menjadi kebutuhan energi primer meskipun saat ini mulai banyak pengembangan energi alternatif. Produksi minyak bumi yang semakin menurun namun produksi gas semakin meningkat setiap tahunnya karena lapangan migas di Indonesia lebih banyak menyimpan gas. Daerah penelitian terletak pada Lapangan “SHANDORA”, Cekungan Sumatera Tengah dengan target reservoir adalah Formasi Tualang.Metode penelitian yang digunakan adalah metode deskriptif, dan metode analisis. Dari metode tersebut, kemudian dilakukan tahap analisis dan interpretasi dengan data penunjang yaitu data seismik 2D dan data log sumur. Kegiatan yang dilakukan antara lain menganalisis dan menginterpretasi litologi, mengkorelasi antar sumur, menganalisis fasies dan lingkungan pengendapan, menghitung parameter petrofisika, menginterpretasi seismik, memetakan kondisi bawah permukaan, dan menghitung cadangan hidrokarbon. Perangkat lunak yang digunakan untuk menunjang studi Tugas Akhir ini adalah Petrel, GSv5.1, dan SMT Kingdom.Dari hasil analisis data yang telah dilakukan, dapat diinterpretasikan bahwa Formasi Tualang merupakan kumpulan seri serpih, batupasir dan lapisan tipis batugamping. Analisis elektrofasies pada Formasi Tualang menunjukkan bahwa Formasi ini terendapkan di lingkungan Shoreface (Regressive to Transgressive) – Shelf. Target batuan reservoir pada Formasi Tualang adalah lapisan batupasir TS-2 dan TS-5. Lapisan batupasir TS-2 dan TS-5 merupakan lapisan batupasir dengan karakteristik volume serpih berkisar 8,44% - 24,67%, porositas berkisar 15% - 25%, saturasi air berkisar 26,93% - 37,24%, dan permeabilitas berkisar 2,1 mD – 46 mD. Berdasarkan hasil perhitungan cadangan volumetrik pada lapangan “SHANDORA” didapat cadangan gas mencapai 17,90 BCF dan gas yang dapat diproduksi mencapai 10,74 BCF dengan nilai recovery factor 60%. Keberadaan hidrokarbon di Formasi Tualang tidak lepas dari pengaruh tektonik yang terjadi di Cekungan Sumatera Tengah yang menghasilkan pola struktur geologi berarah baratlaut – tenggara. Pada daerah penelitian, hidrokarbon terakumulasi di perangkap reverse-faulted anticline dan flank pinchout.
GEOLOGI, ALTERASI HIDROTERMAL DAN MINERALISASI DAERAH CIURUG DAN SEKITARNYA, KECAMATAN NANGGUNG, KABUPATEN BOGOR, PROVINSI JAWA BARAT Mohammad Tommy Agus Binsar; Yoga Aribowo; Dian Agus Widiarso
Geological Engineering E-Journal Vol 6, No 2 (2014): Wisuda Periode Juli - Oktober 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

The existence of metallic minerals in nature is closely related to geological conditions and hydrothermal alteration. hydrothermal alteration and mineralization occur due to hydrothermal solutions that change the physical and chemical properties of rocks and carrying metal elements which will be deposited on rock porosity and permeability have. hydrothermal alteration will make a special characteristic as an altered mineral association. Study of this alteration zone and mineralization will help us to make a plan for metal resources exploration. The purpose of this study was to determine the geological conditions study area include the morphology , lithology , structural geology , hydrothermal alteration zones , mineralization and determine the relationship between geology , hydrothermal alteration , and mineralization.Methods of research is using survey and analysis methods. Survey conducted by the method of data that collected in the field in the form of surface geological   mapping.   The   analysis   method     was     analysis    of    petrology, petrography, X-ray (XRD), and geological structure.Regional geomorphology of Ciurug Area classification based on Van Zuidam (1983) is divided into two units , namely units steep hilly volcanic landforms and volcanic landform units is very steep mountains. Lithology of the study area consists of older to younger andesite breccia , andesite lava, lapilli tuff , tuff , and andesite intrusion . Geological structure of the study area has a north-south direction . Hydrothermal alteration zones are present in the study area is the zone of argillic ( Illit - Kaolin ) , propylitic zone ( Smectite - Chlorite ) , and silicified zones ( Silica - Quartz ) . Mineralization in the area of research in the form of quartz veins and disseminated pyrite and chalcopyrite mineralization as ore deposits . Type of sediment deposition area of research   is  a   low   sulfidation epithermal type.
ANALISIS LITOLOGI DAN STRUKTUR GEOLOGI BERDASARKAN CITRA LANDSAT PADA AREA PROSPEK PANASBUMI GUNUNG TELOMOYO DAN SEKITARNYA, KABUPATEN MAGELANG, PROVINSI JAWA TENGAH Zendi Agista; Prakosa Rachwibowo; Yoga Aribowo
Geological Engineering E-Journal Vol 6, No 1 (2014): Volume 6, Nomor 1, Tahun 2014
Publisher : Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro

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Abstract

Komplek Gunung Telomoyo merupakan salah satu daerah prospek panasbumi di Indonesia ditandai dengan munculnya manifestasi panasbumi di sekitarnya. Komplek Gunung Telomoyo terletak di Kabupaten Semarang dan Kabupaten Magelang. Secara fisiografis terletak pada Zona Solo. Penelitian ini bertujuan untuk mendapatkan gambaran tentang model sistem panasbumi komplek Gunung Telomoyo berdasarkan data litologi, struktur geologi dari kenampakan citra satelite. Metode penelitian meliputi interpretasi citra, pengamatan lapangan yang dilanjutkan dengan metode analisis.Dari hasil interpretasi citra satelite, didapatkan interpretasi litologi, geomorfologi dan pola kelurusan (lineament). Citra landsat yang digunakan yaitu citra komposit saluran 4R, 5G, 7B. Proses interpretasi citra ini menggunakan unsur – unsur dasar interpretasi citra seperti warna, bentuk, tekstur, rona, pola dan bayangan ditambah dengan interpretasi geologi yang meliputi relief atau morfologi. Interpretasi litologi didapatkan litologi lava, piroklastik dan alluvium. Struktur geologi hasil interpretasi citra  satelit meliputi, struktur sesar, struktur runtuhan (collapse) dan kelurusan (lineament). Struktur permukaan dianalisis melalui kerapatan lineament di permukaan dengan metode FFD (Fault Fracture Density). Berdasarkan peta FFD, diketahui bahwa daerah prospek panasbumi berada di daerah Candiumbul, Kendal Duwur, Keningar, Gunung Telomoyo, Candidukuh, dan baratlaut daerah penelitian. Analisis struktur geologi dari lineament menggunakan diagram roset diketahui arah umumnya yaitu barat – laut, timurlaut-baratdaya. Berdasarkan analisis petrografi, litologi penyusun berupa lava andesit dan piroklastik.Berdasarkan survey lapangan, sistem panasbumi Gunung Telomoyo yang menjadi heat source berasal dari magma andesit – basaltik, lalu reservoir area panasbumi Gunung Telomoyo terdapat pada batuan piroklastik, dan cap rock nya yaitu lava andesit. 
Geologi dan Mineralisasi Logam Daerah Sangon, Kokap, Kulon Progo, Daerah Istimewa Yogyakarta Dyatmico Pambudi; Tri Winarno; Yoga Aribowo
Jurnal Geosains dan Teknologi Vol 1, No 2 (2018): Juli 2018
Publisher : Universitas Diponegoro

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Abstract

Daerah Sangon, Kokap, Kulon Progo, Daerah Istimewa Yogyakarta tersusun dari Formasi Andesit Tua. Vulkanisme tersier pegunungan Kulon Progo telah mengendapkan mineral logam, salah satunya di daerah Sangon. Penelitian bertujuan untuk mengetahui tipe alterasi, tipe mineralisasi, serta hubungan pola sebaran urat kuarsa dengan tipe alterasi dan tipe mineralisasi.Penelitian dilakukan pada kavling seluas 2 x 2 km2 dengan melakukan pemetaan geologi dan analisis laboratorium. Observasi lapangan mencakup pengambilan data struktur dan batuan. Analisis laboratorium yang dilakukan antara lain analisis petrografi, mineragrafi, dan XRD untuk mengetahui mineral primer, sekunder, dan logam.Hasil analisis menunjukkan bahwa stratigrafi daerah penelitian termasuk ke dalam Formasi Andesit Tua berupa batuan lava andesit dan andesit porfir. Struktur geologi yang berkembang berupa sesar geser cabang yang mempengaruhi mineralisasi logam. Kavling bagian utara mempunyai dimensi urat relatif kecil, tipe alterasi advance argilik dan inner propilitik, mineral logam emas, pirit, kalkopirit, arsenopirit, sfalerit dengan suhu yang rendah 50oC - 120oC. Kavling bagian tengah mempunyai dimensi urat relatif besar, tipe alterasi propilitik, mineral logam pirit, kalkopirit dengan suhu yang rendah 200oC - 340oC. Kavling bagian selatan mempunyai dimensi urat relatif kecil, tipe alterasi filik, mineral logam pirit, kalkopirit dengan suhu yang rendah 280oC - 400oC. Dengan demikian, dapat disimpulkan bahwa Daerah Sangon adalah lokasi endapan epitermal sulfida rendah.
Petrogenesis Batuan Beku dan Karakteristik Kekar Tiang di Bukit Pajangan, Desa Sidomulyo, Kecamatan Purworejo, Kabupaten Purworejo, Jawa Tengah Mohammad Bagus Pranata; Jenian Marin; Yoga Aribowo
Jurnal Geosains dan Teknologi Vol 1, No 2 (2018): Juli 2018
Publisher : Universitas Diponegoro

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Abstract

Kekar tiang di Bukit Pajangan, Desa Sidomulyo, Kabupaten Purworejo, yang dikenal sebagai Situs Pajangan, termasuk dalam Formasi Kebobutak di Pegunungan Kulon Progo. Studi kekar tiang di Situs Pajangan yang baru tersingkap pada tahun 2016 masih memerlukan penelitian lanjut yang bertujuan untuk mengetahui petrogenesis hasil magmatisme serta karakteristik kekar tiang Bukit Pajangan.Penelitian ini mencakup survey observasi lapangan, analisis petrografi, dan analisis karakteristik kekar tiang. Observasi lapangan meliputi pemetaan geologi Situs Pajangan dan sekitarnya, pengambilan orientasi kekar tiang, kemiringan kekar tiang, dan pengambilan sampel batuan. Analisis petrografi dilakukan untuk mengetahui tekstur dan persentase mineral. Analisis karakteristik kekar tiang dapat mengetahui geometri kekar tiang, orientasi kekar tiang, dan arah pendinginan magma saat membentuk Bukit Pajangan.Litologi penyusun daerah penelitian dari tua ke muda yaitu, intrusi basalt, lava andesit, breksi andesit, dan endapan aluvial. Seluruh sampel batuan di Bukit Pajangan ditentukan sebagai Andesit Basaltik. Orientasi kekar di daerah penelitian membentuk derajat kemiringan sebesar 0o-45o, diasumsikan sebagai kemiringan magma saat mengintrusi. Magmatisme pada saat pembentukan andesit basaltik secara umum dikontrol oleh fraksinasi kristal dan pencampuran magma, sedangkan komposisi mineralnya mengindikasikan hasil aktivitas Gunung Gajah yang memiliki tipe magma menengah-basa. Karakteristik kekar tiang pada Situs Pajangan adalah tipe subdivisi kekar tiang lower colonnade dan hasil aktivitas intrusi dangkal.
Co-Authors Agnis Triahadini, Agnis Agus Setyawan Ahmad Syauqi Hidayatillah Ainul Fatayatis Salamah Ainul Fatayatis Salamah Ajidityo Putro Fadhlillah Al Ghifari, Syahronidayi Alif Febriansyah Andi Kurniawan Andi Kurniawan Betraz A Betraz A Dalimunte, Hasnan Luthfi Danny Irawan Dina Kusumawardani Dyatmico Pambudi Fachrul Rozi Ramadhan Fachrul Rozi Ramadhan Fahri Usmani fahrudin Febry Irfansyah Ferdy Gregorius Agung Chrishartantyo Gregorius Agung Chrishartantyo Hadi Nugroho Hadi Nugroho Hadi Nugroho Hendry Tri Pradipta Putra Heri Nurohman Ibnu Dwi Bandono Wahyudi Ibnu Dwi Bandono Wahyudi Jenian Marin Kurniasih, Anis Marcelina Ramadhani Michael Silaen Mill Sartika Indah Mill Sartika Indah Mohammad Bagus Pranata Mohammad Tommy Agus Binsar Mohammad Tommy Agus Binsar Muhammad Ilham Ridwan Muhammad Ilham Ridwan Najib Panuju Panuju Perdana Rakhmana Putra Perdana Rakhmana Putra Prakosa Rachwibowo Prakosa Rachwibowo Qadaryati, Nurakhmi Radig Wisnu Yuwono Radig Wisnu Yuwono Rahman Wahyudianto Rahman Wahyudianto Reddy Setyawan Rinal Khaidar Ali Rinal Khaidar Ali Ringga, Anita Galih Rizal Dwi Febriyana Rizki Ramadhan Rizki Trisna Hutami Rizki Trisna Hutami Robet Wahyu Widodo Robet Wahyu Widodo Setyawan, Reddy Tri Winarno Wahyu Budhi Khorniawan Widiarso Dian Agus Wijaya, Ennur Kusuma Yayan Yuliananto Yohanes Brahmo Emianto Zendi Agista Zendi Agista