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GRANULOMETRIC ANALYSIS OF PALEOTSUNAMI DEPOSITS CANDIDATE IN TERNATE ISLAND, NORTH MALUKU
Get PDFTernate Island is a volcanic island located in the Maluku Sea. Tsunami ever hit Ternate before 1900 or occurred before the age of the people living in this island. The paleotsunami suspect have been found in the western coast of Ternate Island. The outcrop has 50 m length and 1 m width, was discovered beneath the Gamalama eruption product which occurred in 1907. The paleotsunami candidate consists of at least five layers originating from different tsunami events. The granulometric analysis was carried out for each layer. The results obtained were that paleotsunami sediments had poorly sorted which indicated that the grain sizes were mixed, this was due to the energy of tsunami wave varied in time when transporting and depositing the sediments. Skewness varies from very fine to very coarse, indicating a change in the energy of the tsunami wave that occurs from very high when rising inland to decreasing as it returns to sea. Kurtosis varies from leptokurtic, platykurtic, and mesokurtic. Variations in mean, sorting, skewness and kurtosis values indicate a change in tsunami wave energy which causes a change in grain size. The granulometric analysis shows that the deposition of the youngest paleotsunami deposits candidate was initiated by a very strong current with the greatest energy, thus depositing very coarse sand to gravel, followed by a gradual decrease in energy and the tsunami wave process began to reverse towards the sea, then receded with the lowest energy and deposited finer grains. The sediment sources come from two different places, this shows that the sources come from the sea and the coast around the deposited paleotsunami candidates
PROVENANCE AND DISTRIBUTION OF MIDDLE BAONG SAND IN THE MALACCA STRAIT AND ITS SURROUNDING
Get PDFThe Middle Baong Sand Formation has long been ascribed to the Malay Peninsula. However, this contradicts the results of chronostratigraphic correlation and rare earth element (REE) analysis, which indicate another source from the south. This research was conducted in North Sumatra, especially in Pertamina's onshore and offshore work areas. The comparison area is located in Kutacane-Karo and the Malay Peninsula. The objective of the study is to understand the provenance of the Middle Baong Sand Formation in North Sumatra. Data from four wells and 32 outcrops are used to evaluate the provenance and distribution of Middle Baong Sand in the study area. Besides that, secondary data from three outcrops are also used to support the analysis. The methods used in this study are chronostratigraphic correlation and REE analysis. The results showed that the provenance of the Middle Baong Sand onshore is estimated to originate from southwest Sumatra, contrary to general assumptions. Validation was carried out by comparing Malay Peninsula data with Kutacane research data and wells using REE analysis. The analysis results showed that the Middle Baong Sand Formation in the onshore area has a different provenance from the Middle Baong Sand Formation in the offshore area, which contradicts other research conducted so far. Based on this study, it is concluded that the paleogeography of the North Sumatra basin undergoes deepening symmetrically in the central basin since 10.46 million years ago (Mya)
KLASIFIKASI MORFOLOGI DASAR LAUT PERAIRAN PULAU KEMUJAN, KEPULAUAN KARIMUNJAWA
Get PDFPengetahuan morfologi dasar laut berkaitan dengan bidang oseanografi, biologi, geologi kelautan, kerusakan habitat dan sumberdaya laut. Penelitian ini bertujuan untuk mengklasifikasikan morfologi dasar laut perairan Pulau Kemujan, Kepulauan Karimunjawa. Data yang digunakan dalam penelitian ini adalah data batimetri dan citra Sentinel-2A yang diproses menggunakan perangkat lunak Benthic Terrain Modeler yang terintegrasi pada perangkat lunak ArcGIS. Hasil klasifikasi terdiri dari tujuh kelas morfologi dasar laut, yaitu: crest, valley bottom, flat, rough, valley flank, break shelf dan depression. Rough, relif positif dengan sudut curam 0,21° sampai 0,81°, dengan luas 429,36 ha (65,56%) merupakan kelas dengan area paling luas di lokasi penelitian. Kondisi tersebut menunjukan bahwa morfologi dasar perairan Pulau Kemujan cukup landai dan cenderung datar
STUDY OF POTENTIAL INSTALLATION OF OCEAN THERMAL ENERGY CONVERSION (OTEC) IN THE NORTH WATERS OF LEMBATA, NTT
No full textOcean thermal energy conversion is an attempt to convert potential energy in the variances heat content of seawater into other energy by utilizing the temperature change between the sea surface and deep sea at least 20°C. The Lembata waters is near to the equator, sea surface temperature tends to be warm and stable. This research was conducted to estimate the potential energy generated from a closed cycle OTEC system in North Lembata Waters. This study used temperature data from Global Ocean Physics Reanalysis from Copernicus Marine Environment Monitoring Service (CMEMS) for 9 years (2012-2020) in 6 stations. Validation was performed using the primary CTD Lembata OTEC Team of the Marine Geological Institute (MGI). Temperature data validation results on the MSE (Mean Square Error), RMSE (Root Mean Square Error), and MAPE (Mean Absolute Percentage Error) methods are considered to represent field temperature conditions. The variability value shows the station point in the North Lembata Waters has a temperature with slight differences. The vertical temperature change (ΔT) shows between 20.98°C to 23.44°C. Potential electric power resulting from the OTEC system using the technical estimation formula. The average net power generated from those temperature gradients ranges from 5.65 MW-7.56 MW, respectively. The Lembata waters have temperature conditions suitable for OTEC installations. Station C-4 has a power potential of 6.84 MW with a depth of 763 m and the distance of 1.86 km from the coastline. Station C-4 in the Omesuri sub-district is the best point for OTEC installation in North Lembata Waters
THE APPLICATION OF SEM-EDS FOR THE SURFACE TEXTURE OF FORAMINIFERA: IDENTIFICATION OF EARLY DIAGENESIS OF REWORKED L. DIMIDIATUS WITHIN MODERN COASTAL DEPOSITS
Get PDFSediment 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
PENENTUAN LOKASI TURBIN PEMBANGKIT LISTRIK TENAGA ARUS LAUT SKALA KECIL DI PERAIRAN SELAT LEMBEH, BITUNG SULAWESI UTARA
Get PDFSelat Lembeh terletak di antara Kota Bitung dan Pulau Lembeh, Sulawesi Utara. Penelitianpotensienergiaruslauttelahdilakukandilokasiini,untukmengkajikemungkinandikembangkannya Pembangkit Listrik Tenaga Arus Laut (PLTAL) skala kecil (2 kW)denganmodelturbinsumbuvertikal.SalahsatutahapandalamimplementasiPLTALskala kecil adalah untuk mendapatkan rapat daya arus dan penentuan lokasi penempatanturbin. Beberapa kriteria teknis yang dipersyaratkan harus dipenuhi pada tahapan ini.Untuk maksud tersebut dilakukan kajian awal dengan melakukan analisis data kedalamanlaut,SubBottom Profiling (SBP), arusbergerak,arus insitudan pasangsurut. Data tersebut direpresentasikan dalam data kecepatan arus laut, morfologi dasar laut,kedalamanlaut,durasiwaktukecepatanaruskuat,jarakterhadapgarispantai. Berdasarkanhasilanalisisdatatersebutdiperolehhanyasatulokasiyangpalingrepresentatif untuk penempatan turbin yaitu pada lokasi Stasiun 1. Kedalaman laut padalokasiinisekitar20mdengan kecepatanarusmaksimum antara1,4 m/det –2m/det. Selat Lembeh terletak di antara Kota Bitung dan Pulau Lembeh, Sulawesi Utara. Penelitianpotensienergiaruslauttelahdilakukandilokasiini,untukmengkajikemungkinandikembangkannya Pembangkit Listrik Tenaga Arus Laut (PLTAL) skala kecil (2 kW)denganmodelturbinsumbuvertikal.SalahsatutahapandalamimplementasiPLTALskala kecil adalah untuk mendapatkan rapat daya arus dan penentuan lokasi penempatanturbin. Beberapa kriteria teknis yang dipersyaratkan harus dipenuhi pada tahapan ini.Untuk maksud tersebut dilakukan kajian awal dengan melakukan analisis data kedalamanlaut,SubBottom Profiling (SBP), arusbergerak,arus insitudan pasangsurut. Data tersebut direpresentasikan dalam data kecepatan arus laut, morfologi dasar laut,kedalamanlaut,durasiwaktukecepatanaruskuat,jarakterhadapgarispantai. Berdasarkanhasilanalisisdatatersebutdiperolehhanyasatulokasiyangpalingrepresentatif untuk penempatan turbin yaitu pada lokasi Stasiun 1. Kedalaman laut padalokasiinisekitar20mdengan kecepatanarusmaksimum antara1,4 m/det –2m/det
GAS BIOGENIK DI TELUK LADA KABUPATEN PANDEGLANG PROVINSI BANTEN ( MENGGUNAKAN METODE SEISMIK PANTUL DANGKAL)
Get PDFPenelitian keberadaan gas biogenik di Teluk Lada Kabupaten Pandeglang Provinsi Banten dilakukan dengan metode seismik pantul dangkal saluran tunggal resolusi tinggi. Tujuan penelitian adalah untuk mengetahui potensi gas biogenik. Stratigrafi seismik diinterpretasikan menjadi satuan Tersier yaitu sub-satuan A1 dan A2, satuan Kuarter yaitu sub-satuan B1 dan B2. Berdasarkan hasil interpretasi data seismik, gas biogenik terdapat pada sub-satuan B2 yaitu satuan batuan sedimen berumur Pleistosen Akhir hingga Holosen. Struktur yang berkembang adalah lipatan dan sesar normal yang kemungkinan merupakan representasi kondisi tarikan (tensional regime) di Selat Sunda
ANALISIS PERUBAHAN GARIS PANTAI MENGGUNAKAN CITRA SATELIT LANDSAT 8 OLI-TIRS (STUDI KASUS : PANTAI JOLANGKUNG KABUPATEN MALANG)
Get PDFMencairnya es di kutub utara memberikan kontribusi penambahan pada volume air laut, sehingga memberikan dampak lingkungan pesisir laut seperti abrasi pantai, perubahan garis pantai dan banjir rob. Penelitian ini bertujuan untuk mengetahui besar perubahan garis pantai sebab dari kenaikan muka airlaut di Pantai Jolangkung, Kabupaten Malang antara tahun 2011-2021 menggunakan citra Landsat-7 ETM+ dan penyelidikan lapangan. Metode yang digunakan yaitu ekstraksi garis pantai dan tumpang susun (overlay)data citra, sehingga diperoleh data garis pantai dan besar selisih dari perubahan garis pantai. Dari penelitian ini dapat diketahui besar perubahan garis pantai sebesar 9.723,9 m2
Biostratigrafi Dan Sedimentologi Plio-Pleistosen Daerah Bumiayu - Tonjong, Jawa Tengah
Get PDFBatuan sedimen Plio-Pleistosen yang termasuk kedalam unit stratigrafi Formasi Kalibiuk, Formasi Kaliglagah, Formasi Mengger, dan Formasi Gintung. Batuan sedimen pada formasi – formasi tersebut tersebar pada Daerah Bumiayu - Tonjong. Penelitian formasi – formasi tersebut masih sedikit, khususnya yang membahas biostratigrafi dan paleogeografi. Tujuan penelitian ini untuk interpretasi biostratigrafi dan sedimentologi formasi – formasi tersebut. Metode yang digunakan dalam penelitian adalah analisis biostratigrafi untuk penentuan umur relatif, analisis arus purba, dan pengukuran penampang stratigrafi pada keempat formasi yang dapat menjadi penentu interpretasi lingkungan pengendapan berdasarkan pendekatan analisis litofasies dan asosiasi fasies. Hasil penelitian menunjukkan adanya 9 litofasies, yaitu: Litofasies Batulempung (Fm); Litofasies Batupasir Laminasi (Sh); Litofasies Batupasir Swaley (Ssc); Litofasies Batupasir Planar Cross Bed (Sp); Litofasies Batupasir Through Cross Bed (St); Litofasies Batupasir Low Angle Bed (Sl); Litofasies Batupasir Scours (Ss); Litofasies Konglomerat Clastic Supported (Gcs); Litofasies Konglomerat Planar Cross Bed (Gp). Analisis biostatigrafi dan analisis litofasies menunjukkan bahwa Formasi Kalibiuk berumur Pliosen Tengan yang terendapkan pada lingkungan laut dangkal tepatnya pada offshore, Formasi Kaliglagah berumur Pliosen Akhir yang terendapkan pada lingkungan laut dangkal tepatnya pada shoreface, Formasi Mengger berumur Pleistosen Awal yang terendapkan pada lingkungan transisi tepatnya pada beach, dan Formasi Gintung berumur Pleistosen Akhir yang terendapkan pada lingkungan darat tepatnya pada braided channel fluvial. Analisis arus purba menunjukkan bahwa arah orientasi pengendapan sedimen pada formasi – formasi tersebut ke arah timur – tenggara