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BULLETIN OF THE MARINE GEOLOGY
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.
Articles
160
Articles
Structural complexity in the boundary of forearc basin – accretionary wedge in the northwesternmost Sunda active margin

Mukti, Maruf M.

BULLETIN OF THE MARINE GEOLOGY Vol 33, No 1 (2018)
Publisher : Marine Geological Institute of Indonesia

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Abstract

The area from Andaman to northern Sumatran margin is a region where major faults collided that complicates the structural configuration. The origin of structures in the boundary between the accretionary wedge and forearc basin in the northwesternmost segment of the Sunda margin has been a subject of debates. This article reviews several published works on the Andaman – north Sumatran margin to characterize the boundary between forearc basin and accretionary wedge. Complex strain partitioning in this margin is characterized by sliver faults that crossing boundaries between the backarc basin, volcanic arc, forearc basin, and accretionary wedge. The fault zone can be divided into two segments: The West Andaman Fault (WAF) in the north and Simeulue Fault (SiF) in the southern part. A restraining step-over formed in between WAF and SiF. The SiF may extent onshore Simeulue to a strike-slip fault onshore. Strain-partitioning in such an oblique convergent margin appears to have formed a new deformation zone rather than reactivated the major rheological boundary in between the accretionary wedge and forearc basin. The eastern margin of the Andaman-north Sumatra accretionary wedge appears to have form as landward-vergent backthrusts of Diligent Fault (DF) and Nicobar Aceh Fault (NAF) rather than strike-slip faults. This characteristic appears to have formed in the similar way with the compressional structures dominated the eastern margin accretionary wedge of the central and south Sumatra forearc. Keywords: Andaman, North Sumatra, forearc, structure, accretionary wedge, strain partitioningDaerah Andaman - Sumatera bagian utara adalah wilayah di mana patahan-patahan besar saling bertemu dan membuat konfigurasi struktur menjadi rumit. Asal-usul struktur di batas antara prisma akresi dan cekungan busur muka di bagian paling baratlaut dari tepian Sunda telah menjadi topik perdebatan. Artikel ini mengulas beberapa studi yang telah diterbitkan sebelumnya mengenai tepian Andaman - Sumatra bagian utara untuk mengkarakterisasikan batas antara cekungan muka dan prisma akresi. Pemisahan regangan yang kompleks di tepian ini dicirikan oleh sliver fault yang melintasi batas antara cekungan busur belakang, busur vulkanik, cekungan busur muka, dan prisma akresi. Zona sesar tersebut dapat dibagi menjadi dua segmen, yaitu Sesar Andaman Barat (WAF) di utara dan Simeulue Fault (SiF) di bagian selatan. Sebuah restraining step-over terbentuk di antara WAF dan SiF. SiF kemungkinan menerus sampai ke Pulau Simeulue dan menyatu dengan sesar geser. Pemisahan regangan di tepian konvergen yang miring seperti itu tampaknya telah membentuk zona deformasi baru daripada mengaktifkan kembali batas reologi utama di antara prisma akresi dan cekungan busur muka. Batas bagian timur dari prisma akresi di Andaman – Sumatera bagian utara memiliki bentuk sebagai backthrusts berarah darat yaitu Sesar Diligent (DF) dan Sesar Nicobar Aceh (NAF) dan bukan merupakan sesar geser. Karakteristik ini tampaknya terbentuk dengan proses yang mirip dengan struktur-struktur kompresional yang mendominasi bagian timur prisma akresi di daerah Sumatra bagian tengah dan selatan.Kata kunci: Andaman, Sumatera bagian, busur muka, struktur, prisma akresi, pemisahan regangan 

Concentrations of PAHs (Polycyclicaromatic Hydrocarbons) Pollutant in Sediment of The Banten Bay

Munawir, Khozanah, Yogaswara, Deny

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

Banten Bay is end of stream for a few rivers from Banten mainland where many manufactures and petrochemical industries are built. This may give environmental pressure of water quality of the bay due to pollutant input, such as Polycyclic Aromatic Hydrocarbons (PAHs). This study is to identify those pollutants and determine their total concentration and distribution in sediments. Surface sediment samples were collected in four zones: inner coastline within the bay, middle bay, coastline off the bay and outer of the Bay in April 2016. PAH components were extracted and measured using a gas chromatography-mass spectrometry. Levels of total PAHs in sediments in inner coastline within the bay ranged between 0.381-2.654 ppm with an average of 1.288 ppm, middle of the bay ranged between 0.747-1.762 ppm with an average of 1.198 ppm, outer of the bay ranged between 0.192-1.394 ppm with an average of 0.921 ppm, and east coast of the bay ranged between 0.191-1.394 ppm and an average of 0.778 ppm. The levels of total PAH contamination is apparently lower than those of PAH threshold in sediments (i.e. 4.5 ppm).Keywords: PAHs (Polycyclic Aromatic Hydrocarbons), Banten Bay Teluk Banten merupakan muara dari beberapa sungai di daratan utama Banten yang sebagian besar berupa kawasan industri dan kegiatan lain sekitar laut. Kondisi ini berpotensi memberikan tekanan terhadap kualitas perairan Teluk Banten karena masukan bahan pencemar diantaranya senyawa Polisiklik Aromatik Hidrokarbon (PAH). Penelitian ini bertujuan mengidentifikasi PAH dan menentukan konsentrasi total dan distribusinya di sedimen. Pengambilan sampel sedimen permukaan pada April 2016 diempat zona: zona pantai bagian dalam teluk, bagian tengah teluk, pantai bagian luar teluk, dan bagian luar teluk. Konsentrasi PAH diukur menggunakan alat kromatografi gas spektrometer massa (GCMS). Konsentrasi total PAH dalam sedimen pantai bagian dalam berkisar antara 0,381-2,654 ppm dengan rata-rata sebesar 1,288 ppm. Bagian tengah teluk berkisar antara 0,747-1,762 ppm dengan rata-rata sebesar 1,198 ppm, bagian luar teluk antara 0,192-1,394 ppm dengan rata-rata sebesar 0,921 ppm dan pantai bagian timur teluk antara 0,191-1,394 ppm dengan rata-rata sebesar 0,778 ppm. Level pencemaran total PAH di perairan Teluk Banten dalam sedimen mengindikasikan masih lebih rendah dari standar bakumutu PAH dalam sedimen yaitu 4,5 ppm.Kata kunci: PAH (Polisiklik Aromatik Hidrokarbon), Teluk Banten

Back Cover

Sutisna, Sutisna

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

Sediment Characteristics of Mergui Basin, Andaman Sea based on Multi-proxy Analyses

Zuraida, Rina, Troa, Rainer Arief, Hendrizan, Marfasran, Gustiantini, Luli, Triarso, Eko

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

This paper presents the characteristics of sediment from core BS-36 (6°55.85’ S and 96°7.48’ E, 1147.1 m water depth) that was acquired in the Mergui Basin, Andaman Sea. The analyses involved megascopic description, core scanning by multi-sensor core logger, and carbonate content measurement. The purpose of this study is to determine the physical and chemical characteristics of sediment to infer the depositional environment. The results show that this core can be divided into 5 lithologic units that represent various environmental conditions. The sedimentation of the bottom part, Units V and IV were inferred to be deposited in suboxic to anoxic bottom condition combined with high productivity and low precipitation. Unit III was deposited during high precipitation and oxic condition due to ocean ventilation. In the upper part, Units II and I occurred during higher precipitation, higher carbonate production and suboxic to anoxic condition.Keywords: sediment characteristics, Mergui Basin, Andaman Sea, suboxic, anoxic, oxic, carbonate content Makalah ini menyajikan karakteristik sedimen contoh inti BS-36 (6°55,85’ LS dan 96°7,48’ BT, kedalaman 1147,1 m) yang diambil di Cekungan Mergui, Laut Andaman. Metode analisis meliputi pemerian megaskopis contoh inti, pemindaian contoh inti dengan menggunakan multi-sensor core logger, dan pengukuran kandungan karbonat. Tujuan penelitian adalah untuk mengetahui karakteristik fisik dan kimiawi sedimen untuk menafsirkan kondisi lingkungan pengendapan. Hasil penelitian menunjukkan bahwa contoh inti ini dapat dibagi menjadi 5 unit litologi yang mewakili kondisi lingkungan yang berbeda. Pada bagian bawah sedimen, Unit V dan IV ditafsirkan sebagai hasil endapan pada kondisi suboksik hingga anoksik pada saat produktivitas tinggi dan curah hujan rendah. Unit III diendapkan pada saat curah hujan tinggi dan kondisi oksik yang diperkirakan berkaitan dengan ventilasi samudera. Pada bagian atas, Unit II dan I diendapkan pada saat curah hujan cukup tinggi dengan produksi karbonat yang cukup besar dan kondisi dasar laut suboksik hingga anoksik. Kata kunci: karakteristik sedimen, Cekungan Mergui, Laut Andaman, suboksik, anoksik, oksik, kandungan karbonat 

Elemental Analysis on Marine Sediments Related to Depositional Environment of Bangka Strait

Sampurno, Pungky, Zuraida, Rina, Nurdin, Nazar, Gustiantini, Luli, Aryanto, Noor Cahyo Dwi

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

Study of elemental composition in sediment has been proven useful in interpreting the depositional environmental changes. Multi Sensor Core Logger (MSCL) is a non-destructive analysis that measures several parameters in sediment core including magnetic susceptibility and elemental composition. Magnetic susceptibility and elemental analysis were measured in four selected marine sediment cores from western part of Bangka Strait (MBB-67. MBB-119, MBB-120 and MBB-173) by using magnetic susceptibility and X-ray Fluorescence (XRF) sensors attached to the MSCL. The data was collected within 2 cm interval. Scatter plots of Y/Zr and Zr/Ti show singular trend demonstrated by sediments from MBB-173 and two groups that composed of MBB-67 (Group 1) and MBB-119 + MBB-120 (Group 2). MBB-67 that is located adjacent to Klabat Granite shows upward changes in mineralogy, slight increase of grain size and negligible change in Y concentration. Cores MBB-119 and MBB-120 are inferred to be deposited during regression that resulted in the accummulation of Y-bearing zircon in MBB-119 before the mineral could reach MBB-120. Core MBB-173 is interpreted to be the product of plagioclase weathering that is submerged by rising sea level. This core contains a horizon of rich Y-bearing zircon at 60 cm.Keywords: Multi Sensor Core Logger, X-Ray Fluorescence, magnetic susceptibility, depositional environment, Bangka Island Studi tentang komposisi unsur kimia dalam sedimen telah terbukti bermanfaat dalam interpretasi perubahan lingkungan pengendapan. Multi Sensor Core Logger (MSCL) adalah sebuah analisis yang non-destructive, untuk mengukur beberapa parameter dalam bor sedimen termasuk suseptibilitas magnetik dan kandungan unsur. Suseptibilitas magnetik dan kandungan unsur diukur dari 4 bor sedimen laut yang terpilih di bagian barat Selat Bangka (MBB-67. MBB-119, MBB-120 and MBB-173) dengan menggunakan sensor suseptibilitas magnetik (MS) dan X-ray Fluorescence (XRF) yang terpasang pada MSCL. Pengukuran dilaksanakan dengan interval 2 cm. Plot Y/Zr dan Zr/Ti menunjukkan satu trend yang diperlihatkan oleh sedimen bor MBB-173 dan dua grup yang terdiri atas MBB-67 (Grup 1) dan MBB-119 + MBB-120 (Grup 2). Bor MBB-173 ditafsirkan sebagai hasil pelapukan plagioklas yang kemudian terendam air laut. Bor ini memperlihatkan horizon yang kaya akan zirkon pembawa yttrium pada kedalaman 60 cm.Kata kunci : Multi Sensor Core Logger, X-Ray Fluorescence, suseptibilitas magnetik, lingkungan pengendapan, Pulau Bangka

Estimation of Sea Current Energy Potential by Using Calculation Models of Horizontal Axis Current Turbine in Toyapakeh Strait, Nusa Penida, Bali

Rachmat, Beben, Ilahude, Delyuzar

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

Toyapakeh Strait has a fairly strong ocean current velocity with a velocity between 0.5 m/s – 3.2 m/s. The duration of the strong current (V> 0.5 m/s) ranges from 13-22 hours per day. The location of the strong current occurrence is located to the east of Nusa Lembongan Island, precisely at the stationary current measurement location. Vertical distribution of the direction and velocity currents at this location are not uniform from the top to the bottom, especially in the water column depths of 2 m, 4 m and 6 m, whereas at the water column depths of 8 m to 16 m are relatively uniform. Calculation results of potential electrical power by using the horizontal axis turbine model with a capacity of 35.9 kW (Rite Verdan), 100 kW (Tocardo DD702HT) and 250 kW (Tocardo DD1001HT) show that all of the values have the optimal electric powers, especially during the spring tide, whereas during the neap tide only the turbine with a capacity of 35.9 kW can retrieved an optimal electrical power. Calculation result of the electric power potential by using the method of calculation performed by the Electric Power Research Institute Inc. at the point of measurement, indicated that the total amount of energy 42.5 MWh per month for the turbine model Tocardo DD1001HT, 17.27 MWh per month for turbine model DD702HT Tocardo, and 9.08 MWh per month for the turbine model Rite Verdan.Keywords: Toyapakeh Strait, current velocity, time duration, electric power, depth of the water column Perairan Selat Toyapakeh mempunyai kecepatan arus laut yang cukup kuat dengan kecepatan berkisar antara 0,5 m/det – 3,2 m/det. Durasi terjadinya arus kuat (V>0,5 m/det) berkisar 13 – 22 jam per hari. Lokasi tempat terjadinya arus kuat terletak di sebelah timur Pulau Nusa Lembongan, tepatnya di lokasi tempat pengukuran arus stasioner. Secara vertikal distribusi arah dan kecepatan arus di lokasi ini tidak seragam dari atas ke bawah, terutama pada kedalaman kolom air 2 m, 4 m dan 6 m, sedangkan untuk kedalaman kolom air 8 m sampai 16 m relatif seragam. Hasil perhitungan potensi daya listrik dengan menggunakan model turbin sumbu horisontal dengan kapasitas 35,9 kW (Rite Verdan), 100 kW (Tocardo DD702HT) dan 250 kW (Tocardo DD1001HT) diperoleh daya listrik yang cukup optimal terutama saat spring tide, sedangkan saat neap tide hanya turbin dengan kapasitas 35,9 kW yang masih menghasilkan daya listrik secara optimal. Hasil perhitungan potensi daya listrik dengan menggunakan metode perhitungan yang digunakan oleh Electric Power Research Institute Inc. di titik pengukuran diperoleh total energi yang dihasilkan dari model turbin Tocardo DD1001HT adalah sebesar 42,5 MWh per bulan, model turbin Tocardo DD702HT adalah sebesar 17,27 MWh per bulan, dan model turbin Rite Verdan adalah sebesar 9,08 MWh per bulan.Kata Kunci : Selat Toyapakeh, kecepatan arus, durasi waktu, daya listrik, kedalaman kolom air

Front Cover

Sutisna, Sutisna

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 2 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

The Identification of Land Subsidance by Levelling Measurement and GPR Data at Tanjung Emas Harbour, Semarang

Raharjo, Purnomo, Yosi, Mira

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

Recently, the main problem in Semarang City is flood. This area has low relief that consists of coastal alluvial deposits, swamp and marine sediments. The coastline is characterized by muddy, sandy, and rocky coasts, and mangrove coast. Ground Penetrating Radar (GPR) records, show that subsurface geological condition of northern part of Semarang is coastal alluvial deposit and in the south is volcanic rocks. The aims of this this research is to determine land subsidence by levelling measurement in 2005 in Tanjung Emas Harbour area built on 1995. During ten years, there are various land subsidance in this area: in Coaster Street (21 – 41 cm), container wharf (62 – 94 cm), north breakwater (64 – 79 cm), west breakwater (74 – 140 cm), east groin (76 – 89 cm), and stacking area ( 77 – 109 cm). According to this research, it is concluded that one reason causes of flooding in this area is land subsidence.Keywords : flood, land subsidence, levelling, Tanjung Emas Harbour, Semarang Permasalahan yang berkembang di Kota Semarang saat ini adalah terjadinya banjir. Kawasan ini berelief rendah yang disusun oleh endapan aluvial pantai, rawa dan sedimen laut. Karakteristik garis pantai dicirikan oleh pantai berlumpur, berpasir dan berbatuan, serta pantai berbakau. Rekaman Ground Penetrating Radar (GPR) menunjukkan kondisi geologi bawah permukaan utara kota Semarang merupakan endapan aluvial pantai dan bagian selatan disusun oleh batuan vulkanik. Tujuan penelitian ini adalah untuk mengetahui kondisi penurunan tanah melalui pengukuran sifatdatar yang dilakukan pada tahun 2005, di kawasan Pelabuhan Tanjung Emas yang dibangun pada tahun 1995. Dalam kurun waktu 10 tahun, diketahui bahwa terdapat variasi penurunan tanah di kawasan ini: ruas jalan Coaster (21-41 cm), di kawasan dermaga peti kemas (62-94 cm), pemecah gelombang sebelah utara (64-79 cm), pemecah gelombang sebelah barat (74-140 cm), penahan gelombang sebelah timur (76-89 cm), dan pelataran peti kemas (77-109 cm). Berdasarkan penelitian ini, maka dapat disimpulkan bahwa salahsatu penyebab banjir di kawasan ini adalah akibat penurunan tanah.Kata Kunci : banjir, penurunan tanah, sipatdatar, Pelabuhan Tanjung Emas, Semarang

The Occurences of Heavy Mineral Placer at Kendawangan and Its Surrounding, West Kalimantan Province

Setyanto, Agus, Surachman, Maman

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

The main objective of this study is to identify and to determine the variation and content of heavy mineral placer of Kendawangan coastal, offshore and its surrounding area. Sediment samples were taken from 18 locations, such as 12 samples from offshore and 6 samples from coastal area. For this analysis the heavy metals were identified and analyzed using isodynamic separator and binocular microscopic. The result indicates that heavy minerals consist of zircon, cassiterite, rutile, ilmenite, topaz, chalcopyrite, epidote, pyrite, hematite, hornblende and magnetite. Cassiterite and zircon are also found in sediment samples in all locations and potentially to be further developed. Keywords: Heavy minerals placer, Zircon, Cassiterite, Kendawangan, West Kalimantan Tujuan penelitian ini adalah untuk mengidentifikasi dan menentukan variasi kandungan mineral berat plaser pada sedimen pantai dan lepas pantai Kendawangan dan sekitarnya. Sampel sedimen diambil dari 18 lokasi yang terdiri atas 12 sampel sedimen lepas pantai dan 6 sampel sedimen pantai. Analisis dilakukan dengan menggunakan isodinamik separator dan mikroskop binokular. Hasil analisis menunjukkan bahwa mineral berat terdiri atas zircon, kasiterit, rutil, ilmenit, topas, kalkopirit, epidot, pirit, hematit, hornblende, dan magnetit. Kasiterit dan zircon juga dijumpai pada sampel sedimen di semua lokasi yang dianalisis dan berpotensi untuk dikembangkan lebih lanjut. Kata kunci: Mineral berat plaser, Zirkon, Kasiterit, Kendawangan, Kalimantan Barat

Seismic Facies of Pleistocene–Holocene Channel-fill Deposits in Bawean Island and Adjacent Waters, Southeast Java Sea

Albab, Ali, Aryanto, Noor Cahyo Dwi

BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

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Abstract

The late Pleistocene-Holocene stratigraphic architecture of the Bawean Island and surrounding waters, southeast Java Sea has been analyzed by using sparker seismic profiles. Geological interpretation of these seismic profiles revealed the widespread distribution of paleochannels with different shape and size in the present-day Java Sea. Two channel types can be distinguished based on its morphology: U-shaped channels in the western part and V-shaped channels in the eastern part. The stratigraphic successions were grouped into two major seismic units separated by different seismic boundaries. Characters of marine and fluvial deposits were determined based on seismic boundaries and internal reflectors. Three seismic facies can be identified within late Pleistocene – Holocene incised channel fills associated with SB2. The internal structure of incised-channels consist of chaotic reflector at the bottom, covered by parallel–sub parallel and almost reflection-free indicating the homogenous sediment deposited during the succession.Keywords : Pleistocene-Holocene channel fills, sparker seismic profiles, seismic boundaries, incised–channel, Java Sea. Rekaman seismik sparker digunakan untuk menganalisis endapan stratigrafi berumur Plistosen Akhir–Holosen di Perairan Pulau Bawean dan sekitarnya. Berdasarkan interpretasi geologi dari rekaman seismik tersebut teridentifikasi sebaran alur purba yang berbeda bentuk dan ukuran dengan kondisi Laut Jawa sekarang. Berdasarkan morfologinya, dua tipe alur purba yang terdentifikasi adalah alur purba berbentuk U di bagian barat dan berbentuk V yang terbentuk di bagian timur daerah penelitian. Suksesi stratigrafi kemudian dibedakan menjadi dua grup unit seismik utama yang dibatasi oleh perbedaan batas seismik, yaitu endapan asal darat dan laut yang ditentukan berdasarkan batas sikuen dan reflektor internal. Pada unit Pleistosen–Holosen teridentifikasi tiga tipe fasies seismik yang berkorelasi pada batas sikuen SB2. Struktur internal alur purba yang tertoreh terdiri dari reflektor kaotik yang di bagian bawah, kemudian ditutupi oleh reflektor paralel - sub paralel sampai hampir bebas refleksi yang mengindikasikan terendapkannya sedimen homogen selama suksesi tersebut.Kata kunci : Pengisi alur Plistosen - Holosen, penampang seismik sparker, batas seismik, alur tertoreh, Laut Jawa.