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All Journal IJOG : Indonesian Journal on Geoscience
Sudradjat, Adjat
Padjadjaran University
Earth & Planetary Sciences

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Sabang Submarine Volcano Aceh, Indonesia: Review of Some Trace and Rare Earth Elements Abundances Produced by Seafloor Fumarole Activities kurnio, Hananto; Syafri, Ildrem; Sudradjat, Adjat; Rosana, Mega Fatimah
Indonesian Journal on Geoscience Vol 3, No 3 (2016)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.3.3.173-182

Abstract

DOI:10.17014/ijog.3.3.173-182Geochemical analyses of selected coastal and seafloor samples from Sabang Area revealed abundances of trace and rare earth elements. The selected samples of element abundances were mostly taken from seafloor in the vicinities of active fumaroles either by grab sampler operated from survey boat above fumarole point or by diver directly took the samples on the seafloor especially at Serui - Sabang Bay. Results show that samples closed to seafloor fumaroles demonstrate plenty of trace and rare earth elements. The trace and rare earth elements mean values (n=10) are: Nb (4.33 ppm), La (16.52 ppm), Ce (38.82 ppm), Nd (19.15 ppm), Ce (38.82 ppm), Pr (4.907 ppm), Nd (19.15 ppm), Sm (4.04 ppm), Gd (3.95 ppm), Dy (3.38 ppm), Th (6.432 ppm), and U (4.335 ppm). Negatively, statistical correlations between Fe, Zn, and Ni as the main sulphide elements with sulphur is interpreted that sulphide minerals do not form in the Sabang Sea. Sea water influence in the mineralization process was shown by the good correlations between Fe, Zn, Pb, Ni, and Ba.
Geomorphic Analysis in Determining Tectonic Activity Affected by Sumatra Fault in Liwa Region and Its Surrounding Area, Lampung, Indonesia Yudhicara, Yudhicara; Muslim, Dicky; Sudradjat, Adjat
Indonesian Journal on Geoscience Vol 4, No 3 (2017)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.4.3.193-208

Abstract

DOI: 10.17014/ijog.4.3.193-208The study discusses about characteristics of Sumatra Fault and its tectonic activity in Liwa and the adjacent area. The research uses quantitative methods of verification hypothetical deduction, which starts from the general approach, then it pursues into more specialized and focused ones. While the research work includes field measurements, remote sensing with GIS, and geomorphologic analysis using morphometry, such as: sinousity of mountain front (Smf), percentage of facets, ratio of the width and height of the valley (Vf), bifurcation ratios of the river (Rb), drainage density (Dd), shape of the watershed basin area (Bs), hypsometric curves (HI), and gradient index of stream length (SL). Basically, two blocks separated by the Sumatra Fault do not have a significant difference in tectonic activity, but the tectonic activity change can be seen when the studied area is divided into three blocks (northwest, middle, and southeast), then the change in each part can clearly be seen. Apparently, the tectonic activity in the studied area starts from the southeast continues toward the northwest. It is proved by this research, that geomorphological parameters which are associated with mountain fronts and watershed systems demonstrate the value of the activity increases towards the northwest. Hypsometric curves and a river analysis show that the tectonic activity in the northwest is relatively in a young stage, while towards the southeast it is getting in a mature stage.
Co-Authors Dicky Muslim Ildrem Syafri kurnio, Hananto Rosana, Mega Fatimah Yudhicara, Yudhicara