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BULLETIN OF THE MARINE GEOLOGY
ISSN : 14106175     EISSN : 25278843     DOI : -
Core Subject : Science,
Bulletin of the Marine Geology is a scientific journal of Marine geoscience that is published periodically, twice a year (June and December). The publication identification could be recognized on the ISSN 1410-6175 (print) and e-ISSN: 2527-8843 (on-line) twice a year (June & December) and it has been accredited by Lembaga Ilmu Pengetahuan Indonesia (Indonesian Institute of Sciences) by Decree Number: 818/E/2015. As an open access journal, thus all content are freely available without any charge to the user. Users are allowed to download, and distribute the full texts of the articles without permission from the publisher.
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Articles 5 Documents
Search results for , issue "Vol 29, No 1 (2014)" : 5 Documents clear
LATE NEOGENE SEISMIC STRUCTURES OF THE SOUTH BATANTA BASIN, WEST PAPUA Dida Kusnida; Tommy Naibaho
BULLETIN OF THE MARINE GEOLOGY Vol 29, No 1 (2014)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1188.063 KB) | DOI: 10.32693/bomg.29.1.2014.61

Abstract

Study on multi-channel seismic records from South Batanta Basin, West Papua acquired during RV Geomarin III cruise in 2013 were aimed to invent and map geological aspects and for geo-tectonic and geological history studies. Seismic data indicate that sediment sequences which can be observed from our seismic system in the study area are characterized by pre-extension sediments (Lower Early Miocene-Upper Early Pliocene), syn-extension sediments (Lower Middle Pliocene-Upper Late Pliocene), post-extension sediments (Early Pleistocene), and syn-inversion sediments (Late Pleistocene-Recent) typical of the West Papua tectonic system. In the study area, sediment sequences are possibly characterized by clastical sedimentary cover such as slumps, debrites and turbidites. Key words: South Batanta Basin, seismic sequence, tectonic, faults, clastical sediments. Studi rekaman seismik multi kanal dari Cekungan Batanta Selatan, Papua Barat yang diperoleh selama pelayaran KR Geomarin III pada tahun 2013 bertujuan untuk menginventarisir dan memetakan aspek-aspek geologi serta untuk studi geo-tektonik dan sejarah geologi. Data seismik menunjukkan bahwa urutan sedimen yang dapat diamati dari sistem seismik di daerah studi ditandai oleh sedimen pra-ekstensi (Miosen Awal Bagian Bawah-Pliosen Awal Bagian Atas), sedimen syn-ekstensi (Pliosen Tengah Bagian Bawah-Pliosen Akhir Bagian Atas), sedimen post-ekstensi (Plestosen Awal), dan sedimen syn-inversi (Pleistosen Akhir-Resen) tipikal sistem tektonik Papua Barat. Di daerah studi, urutan sedimen dicirikan oleh sedimen penutup klastika kemungkinan berupa slump, debrit dan turbidit. Kata kunci: Cekungan Batanta Selatan, sekuen seismik, tektonik, sesar, sedimen klastika.
ANALYSES OF FORAMINIFERS MICROFAUNA AS ENVIRONMENTAL BIOINDICATORS IN KOTOK BESAR, KOTOK KECIL AND KARANG BONGKOK ISLANDS, KEPULAUAN SERIBU, DKI JAKARTA PROVINCE Nazar Nurdin; Luli Gustiantini
BULLETIN OF THE MARINE GEOLOGY Vol 29, No 1 (2014)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2515.269 KB) | DOI: 10.32693/bomg.29.1.2014.62

Abstract

Kepulauan Seribu is a well-known destination of marine tourism in Indonesia. Inevitably, the place has been affected by human activities. Hence it is important to preserve and conserve the area so as it is still suitable for reef community to grow and develop. One of the methods to evaluate the feasibility for reef environment is calculated by FoRAM Index (FI) values. Benthic foraminifera as a tool for environmental bioindicators were collected from 15 marine surface sediment samples in the vicinity areas of Kotok Besar, Kotok Kecil and Karang Bongkok islands in Kepulauan Seribu to assess the FI values. Approximately 20 genera of benthic foraminifera were found in the study area. The genera are dominated by Amphistegina and Calcarina along with Operculina, Quinqueloculina, Peneroplis, and Discorbis. The finding signifies reef flat environment as the dominant morphology, although the presence of fore slope is also observed particularly at the western part of Kotok Besar island. The assemblages of Operculina and Quinqueloculina suggest that the abundance of benthic foraminifera is influenced not only by the morphology of seafloor, but also by tidal current and terrestrial influence. The FI formula using foraminifers found in the study area results values above 4, thus the area can be reviewed as a decent environment for reef growth and development. Keywords: benthic foraminifera; bioindicator; FoRAM Index; coral community; seafloor morphology Kepulauan Seribu terkenal sebagai tujuan wisata laut di Indonesia, sehingga dapat dipastikan tempat ini dipengaruhi oleh aktifitas manusia. Oleh sebab itu sangat penting untuk menjaga dan melindungi kelestarian lingkungannya sehingga tetap cocok bagi komunitas karang untuk hidup dan berkembang. Salah satu metode untuk mengevaluasi kelayakan lingkungan terumbu adalah dengan menghitung nilai FoRAM Index (FI). Untuk analisis ini, foraminifera bentik dikoleksi dari 15 sampel sedimen permukaan laut dari daerah sekitar Pulau Kotok Besar, Kotok Kecil dan Pulau Karang Bongkok di Kepulauan Seribu. Hasil penelitian menunjukkan sekitar 20 genera foraminifera bentik yang ditemukan di daerah penelitian. Foraminifera didominasi oleh Amphistegina dan Calcarina, sedangkan jenis lain yang juga cukup berlimpah adalah Operculina, Quinqueloculina, Peneroplis, dan Discorbis. Hal ini menunjukkan lokasi penelitian memiliki jenis morfologi rataan karang sebagai morfologi dominan, walaupun kehadiran lereng karang (fore slope) juga teramati terutama pada bagian barat pulau Kotok Besar. Distribusi kelimpahan Operculina dan Quinqueloculina menunjukkan bahwa kelimpahan foraminifera bentik selain dipengaruhi oleh morfologi dasar laut juga dipengaruhi oleh pasang surut dan pengaruh terestrial. Hasil perhitungan FI berdasarkan foraminifera di wilayah penelitian menunjukkan nilai FI > 4 sehingga daerah ini dapat ditinjau sebagai lingkungan yang layak untuk pertumbuhan karang dan perkembangannya. Kata kunci: foraminifera bentik; bioindikator; FoRAM Index; komunitas koral; morfologi dasar laut
THE INFLUENCE OF COASTAL CONDITIONS TO TSUNAMI INUNDATION OF BIMA BAY, WEST NUSA TENGGARA Yudhicara Yudhicara; Rahayu Robiana
BULLETIN OF THE MARINE GEOLOGY Vol 29, No 1 (2014)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3944.628 KB) | DOI: 10.32693/bomg.29.1.2014.63

Abstract

Area along the coast that includes the territorial waters of the Bima Bay, West Nusa Tenggara, is prone to tsunamis, evidenced by the historical tsunamis record in 1815 due to the volcanic eruption of Tambora, 1818, 1836 and 1992 caused by earthquakes associated with tectonic system in the north of the island of Sumbawa, and 1892 were sourced from a distant source. Based on the coastal characteristics, the research area was divided into four types of beaches, namely: Steep rocky beach; Coastal walled plain; Flat coastal mangroves; and Flat sandy beaches. According to the lateral measurement, houses were built in the plains with a minimum height difference of 0.04 m at Rababuntu beach and a maximum of 22.63 m in New Asakota area. The settlement closest distance to the coastline is 10.3 m in Rababuntu, while the farthest extent is at Kawananta 194.58 m from the shoreline. The local bathymetry range between 1 and 42.5 m, where the inside of the very shallow waters of the Bay of Bima, gradually steeper at the mouth of the bay to the open sea. This conditions will influence the wave when entering the bay. It will come with large enough speed at the mouth of the bay, spread along the coastal waters of the eastern and continue spreading to all parts with the diminishing velocity, but the height increasing when it reaches shallow water, especially in the waters of the western Gulf of Bima. Several factors can affect the amount of risk that would be caused by the tsunami, in the research area include are: (1) The research area is located in an enclosed bay; (2) The local sea floor depths around the bay is relatively shallow waters; (3) Coastal characteristics of the research area is dominated by a gently sloping beach morphology with low relief, especially in the area of ??Bajo, Rababuntu and Bontokape and other beaches in the city of Bima; (4) Residential location very close to the shoreline; (5) Minimal vegetation cover; and (6) The presence of the artificial protective are inadequate. Based on tsunami modeling using the 1992 Flores earthquake parameter which is placed perpendicular to the research area obtain the maximum tsunami height around 4-5 m at Sowa and Kolo, near to the mouth of Bima Bay, while the minimum is at Kalaki, about 0,2 m which is at the inner bay. Keywords: Tsunami, coastal characteristics, bathymetry, factors influenced to tsunami inundation. Lokasi di sepanjang pantai yang mencakup wilayah Perairan Teluk Bima, Nusa Tenggara Barat, rentan terhadap tsunami, dibuktikan oleh catatan sejarah tsunami tahun 1815 karena letusan gunung berapi Tambora, 1818, 1836 dan 1992 disebabkan oleh gempa bumi yang terkait dengan tektonik sistem di bagian utara pulau Sumbawa, dan 1892 yang bersumber dari sumber yang jauh. Berdasarkan karakteristik pantai, daerah penelitian dibagi menjadi empat jenis pantai, yaitu: Pantai terjal berbatu; Pantai datar berdinding; Pantai datar berbakau; dan Pantai datar berpasir. Berdasarkan hasil pengukuran kemiringan pantai secara lateral, rumah dibangun di dataran pantai dengan perbedaan ketinggian minimal 0,04 m di Rababuntu dan maksimal 22,63 m di daerah Asakota Baru. Jarak terdekat bangunan terhadap garis pantai adalah 10.3 m di Rababuntu, sedangkan jarak terjauh adalah di Kawananta 194,58 m dari garis pantai. Rentang batimetri di perairan Teluk Bima berkisar antara 1 dan 42,5 m. Bagian dalam Perairan Teluk Bima sangat dangkal, secara bertahap makin alam dan curam di mulut teluk hingga ke laut terbuka. Kondisi ini akan mempengaruhi gelombang ketika memasuki Teluk. Gelombang akan datang dengan kecepatan yang cukup besar di mulut teluk, tersebar di sepanjang perairan pantai timur dan terus menyebar ke seluruh bagian dengan kecepatan berkurang, namun ketinggian meningkat saat mencapai perairan dangkal, terutama di perairan barat Teluk Bima. Beberapa faktor yang dapat mempengaruhi jumlah risiko yang akan disebabkan oleh tsunami, di daerah penelitian meliputi: (1) Daerah penelitian terletak di teluk tertutup; (2) Kedalaman dasar laut di sekitar Teluk adalah perairan yang relatif dangkal; (3) Karakteristik Pantai daerah penelitian didominasi oleh pantai morfologi landai dengan relief rendah, terutama di daerah Bajo, Rababuntu dan Bontokape dan pantai-pantai lainnya di Kota Bima; (4) Lokasi perumahan sangat dekat dengan garis pantai; (5) Minimalnya vegetasi penutup; dan (6) Keberadaan pelindung buatan tidak memadai. Kata Kunci: Tsunami, karakteristik pantai, batimetri, faktor yang mempengaruhi landaan gelombang tsunami.
COASTAL CHARACTERISTICS OF SOUTH SINGKEP AREA, RIAU ISLANDS PROVINCE Noor C.D. Aryanto; Setyanto C.D. Pranoto
BULLETIN OF THE MARINE GEOLOGY Vol 29, No 1 (2014)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3820.131 KB) | DOI: 10.32693/bomg.29.1.2014.64

Abstract

Observations of coastal characteristics, such as coastal constituent lithology, oceanographic processes and the influence of human activities along the coastal area, are the factors that affect the coastal typology. The typology of coastal area can be divided into 3 types namely: (1) Sandy beaches, dominated by medium size quartz sand, gravelly sand and silt of alluvium deposits ; (2) Rocky beaches that belong to the Tanjung Buku Granite lithologic units and Persing metamorphic complex, its beach slope between 5° and 15°, and a fault structure encountered. The steep beach slopes (45°-50°) trends to offshore with the maximum depth of 28 meters below the sea level at the distance of 3.5 km from the its shore line. At the depth of 20 m, there are a foot slope of 1.5 km width interpreted as the fault plane; (3) Muddy beaches is characterized by mangroves, gentle beach slopes until flats. Those sandy and muddy beaches are alluvial deposits of Quarternary sediments. Keywords: Coastal characteristics, relief, oceanographic processes and South Singkep Pengamatan karakteristik pantai, seperti litologi penyusun tubuh pantai, proses-proses oseanografi serta pengaruh aktivitas manusia di sepanjang pantai merupakan faktor-faktor yang mempengaruhi tipologi pantai. Tipe pantai di daerah penelitian, dapat dibagi menjadi 3 jenis pantai, yaitu: (1) Pantai berpasir, disusun oleh dominasi pasir kuarsa, berukuran menengah, pasir kerikilan dan lanau dari alluvium, serta kemiringan pantai rendah; (2) Pantai berbatu merupakan bagian dari satuan batuan Granit Tanjung Buku dan Kompleks metamorfik Persing, kemiringan pantai antara 5° hingga 15° serta dijumpai sesar. Kearah laut kemiringan lerengnya makin besar (45°-50°) dengan bagian terdalam mencapai 28 meter pada jarak 3,5 km dari garis pantai. Pada kedalaman laut 20 m, terdapat kaki lereng ( foot of slope) dengan lebar 1,5 km yang diperkirakan sebagai bidang sesar; (3) Pantai berlumpur yang dicirikan oleh tanaman bakau memiliki kemiringan pantai yang relatif datar.Pantai berpasir dan pantai berlumpur merupakan endapan aluvium yang berumur Kuarter. Kata kunci: Karakteristik pantai, relief, proses oseanografi dan Singkep Selatan
OSTRACODA FROM SUBSURFACE SEDIMENTS OF KARIMATA STRAIT AS INDICATOR OF ENVIRONMENTAL CHANGES Kresna Tri Dewi; Riza Rahardiawan
BULLETIN OF THE MARINE GEOLOGY Vol 29, No 1 (2014)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1768.258 KB) | DOI: 10.32693/bomg.29.1.2014.60

Abstract

Karimata Strait is a part of Sunda Shelf connected South China Sea with Malacca Strait, Indian Ocean and Java Sea. This shelf was a large Sunda Land that has been detected by many evidences as records of various paleo-environments. The purpose of this study is to recognize the characteristic community of ostracoda related to the environmental history of this shelf. Three selected cores sediments represented east (A), middle (B) and west (C) parts of Karimata Strait were used for Ostracoda based on standard method on micropaleontology. Additional method was applied of SEM-EDX analysis to abnormal specimens. The result shows that there are 43 species of ostracoda belonging to 34 genera identified in the study area. The highest number of ostracoda is found in Core B, in the middle part of the strait, and the lowest value belongs to the Core A that close to the land of Kalimantan. Several genera of Ostracoda were documented in all cores: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere and Xestoleberis. Vertically, ostracoda are mostly found in the upper part of the cores and decrease or disappear in the lower part of Cores A and C where dominated by black organic materials. It may relate to a wide swampy area before the last sea level rise as part of the history of the SundaShelf about 15,000 years ago. Some major elements (C, CaO, Al2O4, FeO, SiO2, MgOdan SO3 covered or filled abnormal specimens that can provide additional information about environmental changes in the study area, such as Carbon may relate to charcoal from land of Kalimatan and Sumatera Keywords: Ostracoda, subsurface sediment, EDX, environmental changes, Karimata Strait Selat Karimata merupakan bagian dari Paparan Sunda menghubungkan Laut China Selatan dengan Selat Malaka, Samudera Hindia, dan Laut Jawa. Paparan ini merupakan sebuah Dataran Sunda yang luas yang terdeteksi dari bukti-bukti sebagai rekaman berbagai lingkungan purba.Tujuan dari studi ini adalah untuk mengetahui karakteristik komunitas ostracoda berkaitan dengan sejarah lingkungan paparan ini. Terpilih tiga sedimen pemercontoh inti mewakili bagian timur (A), tengah (B) dan barat (C) Selat Karimata digunakan untuk studi Ostracoda berdasarkan metoda standar pada mikropaleontologi. Metoda tambahan adalah aplikasi SEM-EDX terhadap spesimen abnormal. Hasil menunjukkan bahwa di daerah penelitian teridentifikasi 43 spesies ostracoda termasuk dalam 34 genera. Jumlah ostracoda tertinggi ditemukan di Core B dari bagian tengah selat dan terendah di Core A yang berdekatan dengan daratan Kalimantan. Beberapa genera ostracoda ditemukan di semua sampel: Actinocythereis, Cytherella, Cytherelloidea, Keijia, Keijella, Hemicytheridea, Hemikrithe, Neocytheretta, Neomonoceratina, Loxoconcha, Pistocythereis, Stigmatocythere dan Xestoleberis. Secara vertikal, ostracoda umumnya ditemukan di bagian atas dari core dan menurun atau menghilang di bagian bawah Core A dan C yang di dominasi oleh material organik berwarna hitam. Hal ini kemungkinan berkaitan dengan daerah rawa yang luas dan sebelum muka laut naik terakhir pada sejarah Paparan Sunda sekitar 15.000 tahun yang lalu. Beberapa zat kimia (C, CaO, Al2O3, FeO, SiO2, MgO dan SO3) menutupi atau mengisi spesimen abnormal dapat memberi informasi tambahan tentang perubahan lingkungan di daerah penelitian, seperti karbon mungkin berkaitan dengan arang dari daratan Kalimantan dan Sumatera. Kata kunci: Ostracoda, sedimen bawah dasar laut, EDX, perubahan lingkungan, Selat Karimat

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