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All Journal ILMU KELAUTAN: Indonesian Journal of Marine Sciences Journal of Tropical Biodiversity and Biotechnology BULLETIN OF THE MARINE GEOLOGY Journal of Applied Geology
Rahmadi Hidayat
Department Of Geological Engineering, Faculty Of Engineering, Universitas Gadjah Mada
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Energy Engineering Environmental Science Immunology & microbiology

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Regional Depositional Model Of South Makassar Basin Depocenter, Makassar Strait, Based On Seismic Facies Rahmadi Hidayat; Salahuddin Husein; Sugeng Sapto Surjono
Journal of Applied Geology Vol 4, No 1 (2012)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (5294.118 KB) | DOI: 10.22146/jag.7196

Abstract

South Makassar Basin Depocenter (SMBD) is located in Southern Makassar Strait which has petroleum potential by the presence of oil and gas indications within the area based on Airborne Laser Fluorescence survey. However, detail studies within this area are not developed well. One of the studies which can be utilized for further discoveries of oil and gas field in SMBD is a study of depositional model using seismic facies method to maximize limited seismic and well data. Interpretation of depositional model in Eocene (syn-rift phase) was varied from alluvial plain and alluvial fan complex, continued gradually to platform. In Oligocene time (post-rift phase), massive transgression caused a major deepening in entire SMBD where the depositional environment changed to basinal plain. In early Miocene – recent interval (syn-orogenic phase), SMBD was relatively in stable condition at basinal plain environment. Lower Tanjung Sequence will be the most prolific petroleum play in SMBD due to its adequate source rock, reservoir rock and seal rock as well. Keywords: South Makassar basin, depositional model, seismic facies
Comparison of Grain-Size Profile and Depositional Process in Mandeh and Nyalo Bar, Mandeh Bay, West Sumatera, Indonesia Rahmadi Hidayat; Muhammad Fadli Rozamuri
Journal of Applied Geology Vol 1, No 1 (2016)
Publisher : Geological Engineering Department Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (5294.836 KB) | DOI: 10.22146/jag.26958

Abstract

Shipwreck of MV Boelongan Nederland situated in offshore of Mandeh Bay of West Sumatera is announced as potential area for tourism destination. Many studies were produced in term of its archeological and historical side but there is no significant work in sedimentological aspect. It is critical to understand depositional process of study area regarding the design of construction to minimize the impact of dynamic activity of waves within the area. Moreover, some areas along Mandeh Bay are covered by Cubadak Island as a protection for wave action derived from Indian Ocean that can produce more complexity in depositional process and will reflect to its characteristic of grain-size profiles. Utilizing thirteen sediment samples in two areas that correspond to inside (Mandeh Bar) and outside (Nyalo Bar) coverage of Cubadak Island, this study attempted to compare and contrast both grain-size profiles as well as interpretation of depositional process based on well-known analysis such as bivariate scatter plots, Linear Discriminant Function plot (LDF), Log probability curves and C-M diagram. Result of this study can be integrated by other researches to gain better policy in maintaining the shipwreck conservation. High energy of Indian Ocean wave supported by strong current clearly dominated depositional process in Nyalo Bar with coarser grain-size; good sortation, lower Y2 of LDF plot; extremely high population of traction materials and lower range of C-M. By contrast, presence of Cubadak Island disrupted the wave effectively and created lower and fluctuated energy in Mandeh Bar. This phenomenon was clearly depicted in its characteristic of finer grain-size with higher Y2 value; high abundance of saltation materials and greater ratio of C-M value.
THE APPLICATION OF SEM-EDS FOR THE SURFACE TEXTURE OF FORAMINIFERA: IDENTIFICATION OF EARLY DIAGENESIS OF REWORKED L. DIMIDIATUS WITHIN MODERN COASTAL DEPOSITS Rahmadi Hidayat; Sarju Winardi; Akmaluddin Akmaluddin
BULLETIN OF THE MARINE GEOLOGY Vol 38, No 2 (2023)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32693/bomg.38.2.2023.831

Abstract

Sediment recycling has been known to occur within Quaternary coastal barriers of the greater Coorong Coastal Plain, southern Australia. A high degree of reworking of skeletal carbonates from Late Pleistocene deposits (Robe Range) is evident based on the novel application of amino acid dating of the single-foraminifera species Lamellodiscorbis dimidiatus. More importantly, some apparently transparent, well-preserved tests indicate anomalously high extents of amino acid racemization, implying that reworked fossils could not be easily distinguished based on taphonomic signatures such as corrosion. Here, we examine the surface microtexture of this species, constrained with well-preserved specimens, on a modern beach of Canunda, southern Australia, using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The aim is to identify surface features of foraminifera in more detail, capturing signs of early diagenesis associated with weakly consolidated Late Pleistocene coastal barriers. The results reveal that some well-preserved tests show localized blocky calcite cementation, most notably within intraseptal spaces or impact sites. The EDS spectra of cement indicate lower Mg content than unaltered foraminifera surface. This suggests low-Mg calcite precipitation due to meteoric diagenesis experienced by the onshore Late Pleistocene coastal barrier. It implies that these foraminifera shells are reworked fossils originated from older successions and were subsequently redeposited within the present-day beach. SEM-EDS used in this study demonstrates its capability in examining small-scale carbonate diagenesis products beyond the traditional binocular microscope. Thus, this tool is recommended to aid amino acid dating in detecting reworked fossils.
Heating Experiments on Benthic Foraminifera Ammonia sp. to Assess the Suitability of Amino Acid-Based Dating Hidayat, Rahmadi; Barianto, Didit Hadi; Surjono, Sugeng Sapto; Ali, Che Aziz
ILMU KELAUTAN: Indonesian Journal of Marine Sciences Vol 29, No 3 (2024): Ilmu Kelautan
Publisher : Marine Science Department Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ik.ijms.29.3.293-300

Abstract

Sub-milligram fossil biominerals, mainly benthic foraminifera, have been recently used to estimate the age of sediments determined from amino acid dating due to the minimum sample size requirement for reverse-phase high-performance liquid chromatography (RP-HPLC). This includes the collection of Ammonia sp., known as a key species occupying restricted lagoonal environments. However, an experiment has not been conducted to understand the racemization kinetics in order to examine the reliability of this species for amino acid racemization (AAR) geochronology. This research aims to determine the trend of the extent of racemization and the amino acid concentration, leading to the recommendation of Ammonia sp. shells as a dating specimen. The results exhibit a predictable pattern, demonstrating a consistently increasing extent of racemization after oven heating for up to 168 h without any indication of reversal pattern. The racemization rate differs from four selected amino acids reported in this study, where aspartic acid is the fastest, followed by glutamic acid, valine and isoleucine epimerization. Moreover, the consistent proportion of total amino acid and the decline of amino acid concentrations can be clearly observed following exponential decay. Therefore, this foraminifer can be used as an alternative specimen to establish amino acid-based geochronology, particularly in the depositional environment lacking other microfossils. Due to its confined habitat, amino acid-based dating of Ammonia sp. is considered applicable to understand the small environmental changes related to marginal marine successions.
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.
Co-Authors Akmaluddin Akmaluddin Ali, Che Aziz Didit Hadi Barianto Husein, Salahuddin Muhammad Fadli Rozamuri Rozamuri, Muhammad Fadli Salahuddin Husein Saputra, Sukahar Eka Adi Sarju Winardi Sugeng Sapto Surjono