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Nannoplankton Biostratigraphy from Banggai-Sula Basin, Central Sulawesi Nurhidayah, Efrilia Mahdilah; Akmaluddin, Akmaluddin; Barianto, Didit Hadi; Husein, Salahuddin; Saripudin, Asep
Journal of Tropical Biodiversity and Biotechnology Vol 9, No 1 (2024): March
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jtbb.85308

Abstract

The nannoplankton research was conducted in the MH-2 well, Banggai-Sula Basin, Central Sulawesi. Thirty-four ditch-cutting samples were utilized to observe the Minahaki, Kintom, and Biak Formations. Age determination was carried out using biostratigraphy method and standard procedure for first and last occurrence of nannoplankton biodatum and had an absolute age, widely known as a zone indicator.  This study aims to determine the age and nannoplankton biozonation of each geological formation in Banggai-Sula Basin. Based on the biostratigraphic analysis, 39 species from 14 genera with abundance frequencies ranging from rare to abundant were found in the MH-2 well. In this study, new results of the age of Banggai-Sula Basin areMiddle Miocene – Early Middle Pliocene (13,706 – 3,727 Ma), and can identify into six calcareous nannoplankton zones that are more detailed than previous researchers, Discoaster signus zone (NN5), Discoaster exilis zone (NN6-NN7), Discoaster berggrenii zone (NN11), Ceratolithus acustus zone (NN12), Helicosphaera sellii zone (NN13-NN15), and the Discoaster tamalis zone (NN16). Biostratigraphic data also shows new information for the first time, the absence of three zones from zone NN8 to zone NN10. This result indicates an unconformity in the Late Miocene age (10.606–8.20 Ma). 
The Application of Amino Acid Racemization Geochronology of Tubipora sp. in Marine Terraces of Manokwari Region, West Papua, Indonesia Hidayat, Rahmadi; Saputra, Sukahar Eka Adi; Husein, Salahuddin
Journal of Tropical Biodiversity and Biotechnology Vol 9, No 4 (2024): December
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jtbb.87657

Abstract

The active neotectonics of northern West Papuan coastlines allow the formation of emergent marine terraces associated with Quaternary sea-level high stands. These terraces contain fossils from the coral assemblage, which are useful for geochronological assessments and further estimating uplift rates. Here, we report the applicability of amino acid racemization (AAR) of Tubipora sp. to discriminate different ages associated with stages of sea-level high stand, constrained by previous uranium-thorium (U/Th) series dating. The results from amino acid dating of three samples reveal two distinct extents of racemization corresponding to terraces developed during Marine Isotope Stage (MIS) 5 sensu lato and 1. However, AAR analysis could not further discriminate interstadial MIS 5a and 5c as determined by published radiometric dating. This indicates the low resolving power of amino acid dating to distinguish sub-sequences beyond the interglacial period. Nevertheless, the cost-effective and rapid analysis of AAR dating of Tubipora sp. can be used as preliminary results related to marine terraces formed in different interglacial events.
Planktonic Foraminifera Biostratigraphy of the Pliocene Kintom and Bongka Formation, Central Sulawesi, Indonesia Novian, Moch. Indra; Barianto, Didit Hadi; Husein, Salahuddin; Surjono, Sugeng Sapto
Journal of Tropical Biodiversity and Biotechnology Vol 9, No 4 (2024): December
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jtbb.94685

Abstract

The Pliocene sediments exposed in the eastern arm of southern Sulawesi consist of Kintom and Bongka Formations, thought to be the result of collisions in the Middle Miocene. The research area is located along the Matindok – OndoOndolu road, Banggai Regency, Central Sulawesi Province. The aims of the research is to determine the rock units that developed in the Kintom – Bongka Formation and determine the chronological time frame based on planktonic foraminifera biostratigraphy. This research used stratigraphic measurement on a scale of 1:100 and Plio-Pleistocene planktonic foraminifera biostratigraphy. A lithological column along 315 meters divided into three rock units. The marl unit and calcareous sandstone unit show characteristics similar to flysch deposits from the collision and are part of the Kintom Formation. Intergrade conglomerate gravelly sandstone deposited unconformably on top of the previous unit is part of the Bongka Formation. This last unit shows characteristics similar to molasse deposits. In total of 46 rock samples were analyzed for foraminifera biostratigraphy. Seven foraminifera biozones showing the age of rock deposition from the Early Pliocene to the Late Pleistocene.The order of the foraminifera biozone is Globorotalia tumida Brady LOZ (PL1a; 5.59 - 4.45 Ma), Globoturborotalita nepenthes Todd CRZ (PL1b; 4.45 - 4.39 Ma), Globotalia acostaensis Blow PRZ (PL2a; 4.39 – 4.31 Ma), Globotalia margaritae Bolli HOZ (PL2b; 4.31 - 3.85 Ma), Sphaeroidinellopsis seminulina Schwager HOZ (PL 3-4; 3.85 – 3.20 Ma), Globorotalia (M) miocenica Palmer/Globorotalia miocenica Palmer HOZ (PL5–6; 3.20 – 2.30 Ma), and Pulleniatina praecursor Banner & Blow HOZ (PL6–PT1a; 2.30 – 2.26 Ma).
Excavation Method of Rock Masses at the Matenggeng Dam, Indonesia Afandi, Valentino Ilham; Indrawan, I Gde Budi; Husein, Salahuddin
Journal of Applied Geology Vol 10, No 1 (2025)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jag.103735

Abstract

This paper presents the results of engineering geological investigations and determination of rock mass excavation methods in the main dam area of Matenggeng Dam. The study was carried out through engineering geological mapping, core drill evaluation and supported by laboratory test data. Classifications of rock masses were carried out based on the Geological Strength Index (GSI) and Rock Mass Rating (RMR) to analyze the excavation method. The results showed research area consisted of lithology in the form of andesite, intercalation sandstone - gravelly sandstone unit, intercalation sandstone - siltstone unit, and alluvium deposits. However, at the main dam area consists of lithology in the form of intercalation sandstone-siltstone unit and intercalation sandstone-gravelly sandstone unit. The rock masses at the main dam excavation line have a weathering degree from moderately to complately weathered. Intact rocks have Uniaxial Compressive Strength (UCS) values ranging from 1-50 Mpa and are a category of extremly weak to moderate rocks. The rock mass of intercalation sandstone-siltstone with very poor to poor quality (GSI (0 - 58), RMR (8 - 45)), and intercalation sandstone-gravelly sandstone with poor to fair quality (GSI (20 - 59), RMR (20 - 68)). The recommended rock excavation method based on the EXCASS System is diggir, easy ripper, and hard ripper.