Faisal Helmi
Departemen Geologi Sain, Fakultas Teknik Geologi, Universitas Padjadjaran

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VALIDASI REKAHAN SEBAGAI INDIKATOR BATUAN TERUBAH DENGAN METODE KELURUSAN DAN PETROGRAFI DI DAERAH BUNGBULANG, KABUPATEN GARUT, PROVINSI JAWA BARAT Khaerani, Puspa; Taufiq, Andra; Muslim, Dicky; Helmi, Faisal; Putri, Yunitha R.I.
Buletin Sumber Daya Geologi Vol 11, No 3 (2016): Buletin Sumber Daya Geologi
Publisher : Buletin Sumber Daya Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16048.034 KB)

Abstract

Garut Selatan menyimpan potensi sumber daya mineral berupa emas, krisopras, dan kalsedon. Di beberapa lokasi di Bungbulang ditemukan adanya batuan terubah dan tambang kalsedon tradisional yang sudah tidak beroperasi lagi yaitu di Sungai Citanggeuleuk. Batuan terubah ini memiliki ciri fisik litologi yang berbeda dengan batuan di sekitarnya seperti berwarna hitam, mengandung mineral muskovit, klorit, dan mineral lempung. Lokasi singkapan batuan terubah diperkirakan berada pada jalur rekahan sesar minor di daerah tersebut. Tujuan penelitian ini untuk mengungkap adanya rekahan yang diperkuat dengan adanya batuan terubah sebagai jalur fluida hidrotermal. Metode yang digunakan dalam penelitian ini yaitu kelurusan dan petrografi. Metode kelurusan yang digunakan berupa analisis kelurusan segmen sungai sebagai analisis dasar kelurusan yang mengindikasikan adanya anomali kelurusan pada lokasi penelitian. Metode petrografi dilakukan untuk mengidentifikasi mineral pada batuan yang menunjukkan adanya pengaruh ubahan karena rekahan. Dari kegiatan pemetaan geologi di daerah penelitian terdapat indikasi batuan terubah di beberapa tempat pada litologi batupasir dan tuf yang mengandung mineral mika putih yang melimpah, klorit, dan mineral lempung. Dari hasil analisis morfometri sungai di daerah ini, diinterpetasikan rekahan yang mempengaruhi pembentukan batuan terubah ini berarah barat-timur yang memanjang dari Sungai Citanggeuleuk sampai Sungai Cianda. Maka rekahan merupakan indikator adanya batuan terubah pada daerah Bungbulang, Garut.
FAULT SEGMENTATION OF SOUTHERN SUMATRA (SIANOK SEGMENT-SEMANGKO SEGMENT) BASED ON ACTIVE FAULT MAPPING THROUGH DIGITAL ELEVATION MODEL (DEM) AND SEISMICITY FALAH, MUHAMMAD FAZRUL; Mukti, Muhammad Ma'ruf; Ismawan, Ismawan; Helmi, Faisal
Journal of Geological Sciences and Applied Geology Vol 7, No 2 (2023): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v7i2.50380

Abstract

Subduction with oblique dimensions causes the formation of structures in the Sumatra area, one of which is the formation of the Sumatran Fault System with dextral fault movements. Strike-slip Fault are segmented in varying geometries and sizes. The Sumatran Fault has been extensively segmented through geometric and structural analysis on the surface and seismic analysis using seismic clusters. This research was conducted to update fault segmentation using surface structure analysis and earthquake data distribution. Surface mapping was carried out through DEM imagery and association with earthquakes and their focal mechanisms, as well as geological factors such as lithology and volcanoes related to the Sumatra Fault. There were 14 segments based on geological and structural identification such as step over, bend, and discontinuity (gap). All the active fault in the region can produce >Mw 6.6 earthquake.
Lithofacies And Depositional Environment Of Halang Formation On Part Of Cihikeu River Section, Majalengka, North Java Wijaya, Eric; Abdurrokhim, .; Helmi, Faisal; Ilmi, Nisa Nurul; Sunardi, Edy
Journal of Geological Sciences and Applied Geology Vol 2, No 1 (2017): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v2i1.13423

Abstract

AbstractThis study about lithofacies and depositional environment is located at Cihikeu River, Village Area of Mekarwangi Village, Bantarujeg District, Majalengka, West Java. Geographically, the research area is located at 60 56’ 11,7” latitude and 60 57’ 09,3” latitude and 1080 11’ 22,3” BT until 1080 12’ 20,3” BT. Based on Arjawinangun Geological Map (Djuri, 1995), the research area is located at Upper Parts of Halang Formation. This research show that the lithology that dominantly occur in the research area is sandstones, mudstones, and breccia.The methods that been used in this research are stratigraphics cross section measurements, lithofacies analysis, and based on secondary data which is paleontology analysis, it can be concluded that there are 8 lithofacies refers to the submarine facies classification by Stow, 1985 that occur in research area, which are facies A1-1, facies A1-3, facies B1-1, facies C2-2, facies C2-3, facies E1-1, facies E2-1, and facies F2-2. Based on the secondary data, the age of research area can be concluded into middle miocene to late miocene.Based on the lithofacies analysis, the lithofacies association concluded into 3 lithofacies association, which are FA-1, FA-2, and FA-3. From those lithofacies associaton characteristics, thereafter the depositional environment can be interpretated into 4 sub-depositional environments which are lower slope, upper fan, middle fan, and lower fan that refers to submarine depositional environments classification by Walker, 1984. Keywords : Lithofacies, Lithofacies association, Depositional environments, Submarine fan
Brief Communication: Rapid Assessment of landslide events based on UAV photogrametry: The 9 January 2021 Cimanggung Landslide, Sumedang, Indonesia Abdurrahman, Ali; Budipraja, Muhammad Ariq; Khoirullah, Nur; Helmi, Faisal; Sophian, Raden Irvan
Journal of Geological Sciences and Applied Geology Vol 4, No 2 (2021): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v4i2.32063

Abstract

The landslide incident in Cisarua Village, Cimanggung District on January 9, 2021, is one of the natural disasters which is quite concerning to see the victims. This short mapping is focused on seeing changes in the shape of the affected area and slope faces before the landslide and after the incident. The brief mapping uses the DJI Mavic Pro model UAV that flies at an altitude of 50 meters and 150 meters above the ground with an overlap of 80% and covers an area of 3 ha. Aerial photo processing will produce output in the form of orthophoto images and digital elevation models (DEM) of landslide affected areas. The result of geometric observation showed that the land surface was covered with an area of 3,789 m2. The measured flat length ranges from 120 meters and 32 meters wide. There is also a slope angle after and before the landslide of 2.8 degrees. Analysis of the causes of landslides in terms of geomorphological aspects shows the landslide affected areas that are right in the hilly valleys coupled with buildings that cover the surface water flow from high rainfall. In addition, the analysis of the causes of technical geological analysis shows that landslides can occur due to differences in soil types with different physical properties so that the two soils are not bound by cohesion forces between soils.
PRELIMINARY STUDY OF ROCK GEOCHEMISTRY FOR GOLD MINERALIZATION IN AREA-“X”, CENTRAL KALIMANTAN Sunarie, Cecep Yandri; Fachrudin, Kurnia Arfiansyah; Barkah, M. Nursiyam; Hadian, M Sapari D.; Suganda, Bombom Rachmat; Helmi, Faisal
Journal of Geological Sciences and Applied Geology Vol 5, No 3 (2021): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v5i3.38348

Abstract

Area-“X” is located in the Central Kalimantan Province of Indonesia, one of several places in the Central Kalimantan region with a high potential for gold deposits. During the investigation, selected mineralized rock samples were collected, resulting in two rock outcrop samples and four rock float samples. All samples were analyzed for Au content at the local laboratorium using the Aqua Regia AAS method.  The lithology of the investigation area can be classified into two different rock units: The sedimentary rock unit and the igneous rock unit. The rock outcrop samples assay return with gold (Au) content from 0.21 ppm to 1.43 ppm. At the same time, the rock floated Au content from 0.79 ppm, Au, to 3.86 ppm. One rock outcrop sample named “Outcrop-001” identified as Quartz Vein up to 40cm width with N500E/850 strike and dip. The other two rock outcrop samples designated “Outcrop-002” and “Outcrop-003” are the parallel quartz veinlet up to 8cm width with strike N350E and unidentified dip. Based on field observation and assay results, this area-“X” has potential for gold mineralization as vein type.
DISTRIBUTION PATTERN DIFFERENCES OF KALIWANGU FORMATION IN UJUNGJAYA AND PASIR MALATI, SUMEDANG, WEST JAVA Ilmi, Nisa Nurul; Haryanto, Iyan; Abdurrokhim, Abdurrokhim; Adhiperdhana, Billy Gumelar; Helmi, Faisal; Hutabarat, Johanes; Sunardi, Edy
Journal of Geological Sciences and Applied Geology Vol 3, No 3 (2019): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v3i3.26225

Abstract

The distribution of Kaliwangu Formation sediment in West Java generally follows the structure of Java fold thrust belt, which directed west-east. The Java fold thurst belt was efectively formed during Pleio-Pleistocene tectonics events, in which all of the Cenozoic sediment were deformed by compression stress in north-south direction. In Ujungjaya area, Kaliwangu Formation has northwest-southeast direction, while in Pasir Malati, the formation was arced relatively in north-south direction. Kaliwangu Formation distribution in Ujungjaya was influenced by the massive compression tectonics occurred in Java. This tectonic event were occurred during Pleio-Pleistocene which resulted in Java thrust fold structure pattern including Baribis Faults. Unlike in Ujungjaya, the distribution of Kaliwangu Formation in Pasir Malati was arced in north-south direction which caused by its fold structure. There is no indication of regional fault in Pasir Malati area although a lot of fault structure was found as a part of regional structure.
GEOTECHNICAL ENGINEERING DESIGN FOR SETTLEMENT MITIGATION IN THE DEEP FOUNDATION CONSTRUCTION AREA, NORTH SUMATRA PROVINCE, INDONESIA Malik Muhammad, Kemal; Sophian, Raden Irvan; Helmi, Faisal; Prasetyo, Rahmat Dwi; Damanhuri, Hilman
Bulletin of Scientific Contribution Vol 22, No 3 (2024): Bulletin of Scientific Contribution : GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/bsc.v22i3.59032

Abstract

The construction project in area Y, North Sumatra will be installed with piles as the preliminary foundation for a multi-story building. The installation of these piles resulted in settlement at several boreholes points analyzed using Rocscience Settle3. The settlement ranged from 65 mm - 95 mm at over 11 boreholes over the construction area. This settlement has the potential to cause structural damage to the building, therefore geotechnical engineering is needed as a solution to prevent it. Ground improvement as geotechnical engineering can be done to support the design of safer foundations by increasing soil consistency in shallow to deep layers. Vibro compaction geotechnical engineering reduces the total settlement of the research area from 90 mm to 68 mm in BH-01, BH-04, and BH-06. In boreholes with low bearing capacity and medium settlement values such as BH-1, monitoring using a settlement gauge is required to provide efficient prevention in safe foundation planning without neglecting cost effective concern.
BASEMENT KOMPLEK BAYAH, KABUPATEN LEBAK, PROPINSI BANTEN Patonah, Aton; Helmi, Faisal; Prakoso, Jodi; Widiaputra, Taufiq
Bulletin of Scientific Contribution Vol 13, No 3 (2015): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1254.822 KB) | DOI: 10.24198/bsc.v13i3.8405

Abstract

Researching metamorphic rocks in Bayah and in its surrounding area has slight data so it has not been clear yet how the stratigraphic position, the age and the metamorphic rocks characteristic is in the study area. By using geological mapping and petrographic method, it showed that the metamorphic rock is believed to be the basement of Bayah complex which accreted because of reverse fault in the northwest so that the rock appeared together with the relatively younger rocks in the south (Bayah Formation and Granodiorite Cihara). These rocks showed that there are foliation, boudinage and crenulation structure consisting of various types of metamorphic rocks which are different in degrees of metamorphism (low grade – high grade metamorphism) and in protoliths as well, so these interpret as a result of orogenic processes of intermediate pressure metamorphism.
POLA STRUKTUR REGIONAL JAWA BARAT Helmi, Faisal; Haryanto, Iyan
Bulletin of Scientific Contribution Vol 6, No 1 (2008): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (559.015 KB) | DOI: 10.24198/bsc.v6i1.8160

Abstract

Regional structure of West Java influenced by interaction of subduction between India-Australia plate with Eurasia plate. Effect of this subduction, in West Java expand some fault structure which devide to 4 faults, that is north-south faults, northwest-southeast faults, and northeast-southwest faults.Fault of North-South which devide into Sunda Pattern, is representing oldest fault and forming of Paleogen Basin in West Java. Stress system of Sunda Pattern is influenced by transtensional tectonic and as a whole form structure pattern of negative structure flower.Change of tectonics in West Java take place at Plio-Plistosen period. At that moment system of stress influenced by tectonic compression yielding fold structure of wast-east thrust-fault (Java Pattern). At same tectonic period, formed a number of northwest-southwest strike-slip fault (Sumatera Pattern) and northeast-southwest strike-slip fault (Meratus Pattern).
GENESIS AMFIBOL PADA DIORIT PASIR CUPU, KECAMATAN PLERED, KABUPATEN PURWAKARTA, JAWA BARAT Arfiansyah, Kurnia; Helmi, Faisal
Bulletin of Scientific Contribution Vol 16, No 3 (2018): Bulletin of Scientific Contribution GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1422.696 KB) | DOI: 10.24198/bsc.v16i3.18458

Abstract

Pasir Cupu secara administratif terletak pada Kecamatan Plered, Kabupaten Purwakarta, Propinsi Jawa Barat. Batas geografisnya terletak pada garis Bujur Timur 107o 26’ 25,2” – 107o 27’ 16,8” dan garis Lintang Selatan 6o 37’ 22,8” – 6o 37’ 03”.Batuan beku Pasir Cupu adalah batuan intrusi berbentuk bos, yang berjenis diorit (Streckeisen, 1978 dalam Gillespic and Styles, 1999). Dalam batuan ini terdapat amfibol, baik sebagai fenokris, dan masadasar. Jenisnya klinoamfibol (horenblenda dan lamprobolit) ; berbentuk euhedral dan anhedral ; memiliki pleokroisme lemah sampai kuat ; berkembar sederhana, jamak, dan penetrasi ; pemadaman bergelombang ; serta bertekstur zona, korona, dan koroded. Pembentukan amfibol ini melalui dua fasa kristalisasi, yaitu amfibol fenokris, dan inklusi pada fasa pertama, dan amfibol masadasar pada fasa ke dua.Kata kunci : Amfibol, diorit, pasir cupu, purwakarta.