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Journal : Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources)

Perubahan Iklim Danau Bandung Purba Berdasarkan Analisis Palinologi, Daerah Cihideung, Lembang, Jawa Barat Rizki Satria Rachman; Winantris Winantris; Budi Muljana; Nana Sulaksana
Jurnal Geologi dan Sumberdaya Mineral Vol. 21 No. 1 (2020): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v21i1.404

Abstract

IClimate is the prevailing weather condition of an area throughout the year. Climate affects the vegetation in a region. The research aimed to study the climate and humidity change during the Holocene in Bandung Paleo-Lake based on palynomorph analysis. The twenty-four samples were taken using hand drill in 172.5 - 52.5 cm depth, continued with preparation and determination. In this study, descriptive analysis and comparison between pollen, spores and their sediments to show the climate and humidity change in Bandung Paleo-Lake. The results show that the samples which were taken on peat deposits showing four times climate changes in five zones, which characterized by montane forest pollens, i.e. Podocarpaceae and Pinaceae, lowland forest pollen i.e. Commelinaceae, Moraceae, spores from the Family Polypodiaceae, Pteridaceae and Dennstaedtiaceae, and Gramineae at the study area.Keywords: Climate, palaeo, analysis, palinology, Bandung Lake.
Optimization of Limestone Production Based on Geological Structure Conditions for Blasting Geometry Design Fachrur Reza Assegaff; Cipta Endayana; Nana Sulaksana; Dwi Putranto Waloeyo
Jurnal Geologi dan Sumberdaya Mineral Vol. 21 No. 2 (2020): JURNAL GEOLOGI DAN SUMBERDAYA MINERAL
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v21i2.483

Abstract

The research location is in Sumber Arum, a village in Kerek District, Tuban Regency, East Java. The object of this study includes the state of the geological structure around the mining site and its effect on blasting activities. The purpose of this study is to obtain a blasting geometry design that is suitable for the geological structure conditions at the mining site so that the resulting blasting fragmentation has a uniform size to increase the amount of company production. The method used in this study is to combine data from measurements and observations in the field with blasting design theory. From these data, further analysis and trial blasting activities are conducted and the results obtained from the actual blasting plan with the proposed blasting plan are compared. The calculation results of the blasting geometry design obtained the proposed blasting geometry values, including the burden of 2.5 meters, the spacing of 3 meters, the stemming of 1.75 meters, the subdrilling of 0.5 meters, the shot hole depth of 6.5 meters, and the direction of the explosion of 6.5 meters that is located at point N37ºE. Based on the application, the blasting fragmentation with a size of ≤ 80 cm is evenly distributed, with a percentage of 99.44% of the total fragmentation resulting from blasting. The amount of limestone produced in one year is 20.138.946 tons.Keywords: blasting geometry, production, limestone, geological structure
Karakteristik Morfotektonik Terhadap Kemunculan Manifestasi Panas Bumi di Daerah Gunung Seulawah Agam, Kabupaten Aceh Besar, Provinsi Aceh Zakia Lukman; Nana Sulaksana; Dewi Gentana; Murni Sulastri
Jurnal Geologi dan Sumberdaya Mineral Vol. 23 No. 2 (2022): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v23i2.593

Abstract

Subduksi antara Lempeng Samudra Indo-Australia dan Lempeng Benua Eurasia membentuk Indonesia berada di wilayah cincin api yang memiliki potensi panas bumi yang besar. Gunung Seulawah Agam dan sekitarnya, Kabupaten Aceh Besar, Provinsi Aceh, dipilih sebagai daerah studi dikarenakan memiliki manifestasi panas bumi di permukaan, mengindikasikan daerah tersebut memiliki potensi panas bumi. Metode yang digunakan dalam penelitian ini yaitu analisis pengindraan jauh dan perhitungan variabel morfotektonik dengan menggunakan peta Rupa Bumi Indonesia (RBI) dan citra Digital Elevation Model Nasional (DEMNAS). Tujuan penelitian untuk mengetahui pola utama kelurusan geologi dan tingkat aktivitas tektonik yang menggambarkan karakteristik morfotektonik dan hubungannya terhadap kemunculan manifestasi panas bumi di daerah studi. Karakteristik morfotektonik di daerah ini menunjukkan daerah yang mengalami tingkat pengangkatan rendah hingga tinggi (nilai Vf ; 0,47 – 1,24), terdeformasi dan tidak terdeformasi (nilai Rb ; 2,98 – 6,27), memiliki tingkat aktivitas tektonik sedang hingga aktif (nilai Smf ; 1,07 – 2,07) dan kerapatan kelurusan rendah hingga tinggi (Ld ; 0 – 1,51 km-1). Kemunculan manifestasi panas bumi permukaan terdapat pada tepi dan perpotongan kelurusan-kelurusan struktur geologi (patahan) yang memiliki pola utama berarah baratlaut - tenggara. Daerah tersebut merupakan daerah yang memiliki kerapatan kelurusan sedang hingga tinggi dan tingkat aktivitas tektonik sedang hingga aktif. Katakunci: Morfotektonik, manifestasi panas bumi permukaan, pola kelurusan geologi