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INDONESIA
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 32, No 1 (2017)" : 5 Documents clear
The Occurences of Heavy Mineral Placer at Kendawangan and Its Surrounding, West Kalimantan Province Agus Setyanto; Maman Surachman
BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1166.995 KB) | DOI: 10.32693/bomg.32.1.2017.319

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
The Identification of Land Subsidance by Levelling Measurement and GPR Data at Tanjung Emas Harbour, Semarang Purnomo Raharjo; Mira Yosi
BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3947.682 KB) | DOI: 10.32693/bomg.32.1.2017.351

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
Temporal and Spatial Distribution of Heavy Metal in Sediment of Urban Coastal Waters: A Case Study in Jakarta Bay, Indonesia Fitri Budiyanto; Lestari Lestari
BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1064.612 KB) | DOI: 10.32693/bomg.32.1.2017.364

Abstract

Heavy metals, hazardous chemical substances, increase in marine environment due to anthropogenic discharges. However, due to the hydrodynamic of the marine system these metals could vary both temporal and spatial distribution of metals in Jakarta Bay. This study was to reveal the temporal and spatial distribution of metals in sediment over the bay and to assess the environmental condition. Sediment samples were collected in11 stations of March (transitional season) and June(dry season)2013. The result showed that the concentration of heavy metals varied spatially, in which elevated concentration occurred adjacent terrestrial indicating the enrichment of metal-anthropogenic source, but insignificant temporarily.Keywords: heavy metals, spatial distribution, temporal distribution, anthropogenic activities, Jakarta Bay. Logam berat merupakan bahan berbahaya yang tersebar di lingkungan laut karena pengaruh aktifitas antropogenik. Akan tetapi, logam berat ini dapat terdistribusi secara temporal ataupun spasial di Teluk Jakarta akibat sistem hidrodinamika laut. Tujuan dari penelitian ini adalah untuk mengetahui distribusi spasial dan temporal logam berat dalam sedimen dan untuk menilai kondisi lingkungan teluk. Sedimen diambil dari 11 stasiun pada bulan Maret (musim transisi) dan Juni (musim kering) tahun 2013. Hasil penelitian menunjukkan bahwa distribusi spasial logam berat bervariasi, dimana konsentrasinya meningkat di lokasi dekat daratan yang mengindikasikan tingginya sumber logam-antropogenik namun secara temporal tidak signifikan.Kata kunci: logam berat, distribusi spasial, distribusi temporal, kegiatan antropogenik, Teluk Jakarta.
Practical Implementation of Multiple Attenuation Methods on 2D Deepwater Seismic Data : Seram Sea Case Study Tumpal Bernhard Nainggolan; Deny Setiady
BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6529.918 KB) | DOI: 10.32693/bomg.32.1.2017.365

Abstract

Some deepwater multiple attenuation processing methods have been developed in the past with partial success. The success of surface multiple attenuation relies on good water bottom reflections for most deepwater marine situations. It brings the bigger ability to build an accurate water bottom multiple prediction model. Major challenges on 2D deepwater seismic data processing especially such a geologically complex structure of Seram Sea, West Papua – Indonesia are to attenuate surface related multiple and to preserve the primary data. Many multiple attenuation methods have been developed to remove surface multiple on these seismic data including most common least-squares, prediction-error filtering and more advanced Radon transform.Predictive Deconvolution and Surface Related Multiple Elimination (SRME) method appears to be a proper solution, especially in complex structure where the above methods fail to distinguish interval velocity difference between primaries and multiples. It does not require any subsurface info as long as source signature and surface reflectivity are provided. SRME method consists of 3 major steps: SRME regularization, multiple modeling and least-square adaptive subtraction. Near offset regularization is needed to fill the gaps on near offset due to unrecorded near traces during the acquisition process. Then, isolating primaries from multiples using forward modeling. Inversion method by subtraction of input data with multiple models to a more attenuated multiple seismic section.Results on real 2D deepwater seismic data show that SRME method as the proper solution should be considered as one of the practical implementation steps in geologically complex structure and to give more accurate seismic imaging for the interpretation.Keywords : multiple attenuation, 2D deepwater seismic, Radon transform, Surface Related Multiple Elimination (SRME). Banyak metode atenuasi pengulangan ganda dikembangkan pada pengolahan data seismik dengan tingkat keberhasilan yang rendah pada masa lalu. Keberhasilan dalam atenuasi pengulangan ganda permukaan salah satunya bergantung pada hasil gelombang pantul pada batas dasar laut dan permukaan pada hampir seluruh survei seismik laut. Hal tersebut menentukan keakuratan dalam membuat model prediksi pengulangan ganda dasar laut dan permukaan air. Tantangan utama dalam pemrosesan data seismik 2D laut dalam khususnya struktur geologi kompleks seperti Laut Seram, Papua Barat – Indonesia adalah pada kegiatan menekan pengulangan ganda permukaan sekaligus mempertahankan data primer. Beberapa metode yang dikembangkan untuk menghilangkan pengulangan ganda permukaan pada data seismik seperti least-square, filter prediksi kesalahan dan transformasi Radon.Dekonvolusi Prediktif dan Metode Surface Related Multiple Elimination (SRME) digunakan sebagai solusi yang baik pada struktur kompleks dimana metode-metode lain gagal untuk memisahkan perbedaan kecepatan interval data primer dan pengulangan ganda. Metode tersebut tidak membutuhkan informasi bawah permukaan selain parameter sumber dan reflektivitas permukaan. Metode SRME terdiri dari 3 tahapan utama : regularisasi SRME, pemodelan pengulangan ganda dan pengurangan adaktif least-square. Regularisasi near offset diperlukan untuk mengisi kekosongan pada near offset yang disebabkan oleh adanya sejumlah tras terdekat yang tidak terekam selama akuisisi. Pemodelan maju digunakan untuk memisahkan data primer dan pengulangan ganda kemudian inversi dengan pengurangan input data dengan model multiple.Hasil pada data seismik 2D laut dalam menunjukkan bahwa metode SRME layak diterapkan sebagai salah satu pengembangan metode atenuasi multiple permukaan serta untuk meningkatkan akurasi data seismik terutama untuk struktur geologi kompleks.Kata kunci : peredaman pengulangan ganda (multiple), seismik 2D laut dalam, transformasi Radon, Surface Related Multiple Attenuation (SRME).
Seismic Facies of Pleistocene–Holocene Channel-fill Deposits in Bawean Island and Adjacent Waters, Southeast Java Sea Ali Albab; Noor Cahyo Dwi Aryanto
BULLETIN OF THE MARINE GEOLOGY Vol 32, No 1 (2017)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6608.835 KB) | DOI: 10.32693/bomg.32.1.2017.373

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.

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