Kurnio, Hananto
Marine Geological Institute of Indonesia

Published : 24 Documents
Articles

Found 24 Documents
Search

Geochemical Characteristics of Sunda Volcanic Arc in Sumatra and Andaman Kurnio, Hananto
Indonesian Journal on Geoscience Vol 6, No 1 (2019)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.6.1.1-16

Abstract

DOI: 10.17014/ijog.6.1.1-16Geochemical characteristics of Sunda volcanic belt are recognized from each characteristic of Weh Island, Tabuan Island in Semangko Bay, South Sumatra, and Andaman Islands. Trace and rare earth elements (REE) are produced by fumaroles in a marine environment of submarine volcano of Weh Island characterized by barium (Ba) as an indicator of sea water influence in the mineralization process, while sulphide minerals do not occur in this area. REE pattern compared to Mid Oceanic Ridge Basalt (MORB) shows a characteristic of subduction tectonics and is distributed in shallow coastal water of high energy. Based on comparison of REE contents in all samples, it reveals that volcanism process causes REE enrichments either in the past or in recent. Geochemical characteristics of Tabuan Island in Semangko Bay reveal the occurrence of hydrothermal mineralization followed by pervasive occurrences of sulphide minerals in vein-type disseminations enriched in Au, Ag, Zn, Pb, Cu, As, Sb, Ba, and Mn. Geochemical characteristics of Andaman Islands reveal imprint of substantial subduction component in the form of sediment fluid and melt and fluid-induced subduction component derived from altered oceanic crust.
Characteristics of Boleng Strait Sediments, East Nusa Tenggara, and its Relationship with Current Velocity Kurnio, Hananto; Yuningsih, Ai; Zuraida, Rina
BULLETIN OF THE MARINE GEOLOGY Vol 33, No 1 (2018)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32693/bomg.33.1.2018.387

Abstract

Islands of Nusa Tenggara are separated by narrow and deep straits resulted from complex tectonic activties. One of the strait is Boleng Strait where tidal current as high as 310 cm/s occurred which might be suitable for an ocean current power plant. Utilization of such resources would need various information of the area, one of them is sediment textures that characterized the seafloor and coastal area and their relationship to current velocity. Grain size analyses were conducted on 12 seafloor sediment samples and 26 coastal sediment samples to identify sediment texture. An additonal 14 seafloor sediment samples with limited volume were observed to determine their sediment types. The result of analysis yielded six types of seafloor sediments: Sand, Gravelly Sand, Sandy Gravel, Silty Sand and Sandy Silt. The sediment grain size is equally influenced by current velocity (r = 0.57) and water depth (r = 0.52) which is reflected by sediment distribution: coarse–grain sediments cover the area near Boleng Strait which has stronger current and fine–grain sediments cover the inner part of the Lewoleba Bay. Plot of six sets of mean grain size and current velocity on Hjulström diagram shows that most of seafloor sediments are on the move and one (SBL. 14) is being eroded. This condition might affect the turbine and thus needs to be taken into consideration when designing the turbine. Grain size analyses on coastal sediment samples show that the mean grain size of coastal sediments ranges between 0.19 mm and 0.62 mm with average value of 0.33 mm that is classified as medium sand. Sand fraction in coastal sediments composes 57% to 100% of the sediments. Observation on mineralogy of the sediments shows abundance of magnetite that concentrates in the fine and medium sand fractions. The presence of magnetite indicate that current–related selective entrainment occurs in the study area. This condition suggests that the coastal area is also strongly affected by ocean current.Key words: current velocity, sediment grain size, Boleng Strait.Aktivitas tektonik di Nusa Tenggara Timur menyebabkan terbentuknya batimetri yang kompleks di sekitar kepulauan tersebut yang dicirikan oleh adanya selat sempit dan dalam yang memisahkan pulau–pulau. Salah satu selat tersebut adalah Selat Boleng yang memiliki kecepatan arus terukur maksimum sebesar 310 cm/s yang dapat digunakan sebagai pembangkit energi listrik. Desain turbin arus akan membutuhkan banyak informasi, salah satunya adalah sedimen dasar laut dan pantai serta hubungannya dengan kecepatan arus. Analisis besar butir dilakukan pada 12 sampel sedimen dasar laut dan 26 sampel sedime pantai untuk menentukan jenis sediment. Sebanyak 14 sampel sedimen dasar laut dengan volume terbatas diamati untuk mengetahui jenis sedimen. Hasil analisis menunjukkan bahwa sedimen dasar laut terdiri atas enam jenis: Pasir, Pasir Kerikilan, Kerikil pasiran, Pasir Lanauan dan Lanau Pasiran. Ukuran butir sedimen dipengaruhi oleh kecepatan arus (r = 0.57) dan kedalaman laut (r = 0.52) yang tercermin pada distribusi sedimen: sedimen berukuran kasar menutupi dasar laut di dekat Selat Boleng yang berarus lebih kuat, dan sedimen berukuran halus menutupi dasar laut di bagian dalam Teluk Lewoleba. Plot enam set ukuran butir rata–rata dan kecepatan arus pada diagram Hjulström menunjukkan bahwa hampir seluruh sampel berada dalam kondisi bergerak dan bahkan satu (SBL. 14) sedang mengalami erosi. Kondisi ini akan mempengaruhi turbin sehingga perlu dijadikan pertimbangan saat mendesain turbin. Hasil analisis besar butir pada sedimen pantai menunjukkan bahwa ukuran butir rata–rata sedimen pantau berkisar 0.19 mm dan 0.62 mm dengan nilai rata–rata 0.33 mm yang termasuk dalam fraksi pasir sedang. Fraksi pasir dalam sedimen pantai menyusun 57%–100% sedimen. Pengamatan mineralogi menunjukkan melimpahnya magnetit yang terkonsentrasi pada fraksi pasir halus–sedang. Keberadaan magnetit menunjukkan adanya proses pemisahan yang berkaitan dengan arus laut. Kondisi ini menunjukkan bahwa daerah pantai Selat Boleng juga dipengaruhi oleh arus laut. Kata Kunci: kecepatan arus, ukuran butir sedimen, Selat Boleng.
Rare Earth Elements Vapor Transport By Fumaroles in the Post Caldera Complex of Weh Island Submarine Volcano, Aceh Province Northern Sumatra Kurnio, Hananto; Usman, Ediar
BULLETIN OF THE MARINE GEOLOGY Vol 31, No 2 (2016)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Research found out that fumaroles and solfataras are rare earth element (REE) vapor transport agents in Weh Island submarine volcano – Aceh. Shallow high resolution single channel seismic was used to map the distribution of seafloor fumaroles surrounding the submarine volcano. Samples of REE depositions were taken from Jaboi geothermal field, and mineralization zone at Pria Laot coast; as well as seafloor surrounding active fumaroles by divers.  Rare earth elements (REE) were analysed using ICP – MS (inductively coupled plasma – mass spectrometry) with detection limits ranged from 0.05 to 0.1 ppm (part per million).The central part of Weh submarine volcano is the most active REE deposition. This area is build by normal faults and grabens oriented north – south of open character which acted as channel for hydrothermal fluids reaching seafloor surface.Some REE abundances such as La, Ce, Pr, and Nd due to its location in the central of hydrothermal activity. This proximity explains such abundances of this andesitic component sample of agglomerate.  Keywords: REE, vapor transport, fumaroles, Weh Island, Aceh.Penelitian mendapatkan bahwa fumarole dan solfatara adalah sebagai agen transportasi uap Logam Tanah Jarang (LTJ) di gunungapi bawah laut Pulau Weh – Aceh, Provinsi Nanggroe Aceh Darussalam (NAD). Seismik saluran tunggal dangkal resolusi tinggi digunakan untuk memetakan fumarole dasarlaut di sekitar gunungapi bawah laut tersebut.Bagian tengah gunungapi bawah laut Pulau Weh merupakan area paling aktif pengendapan LTJ. Bagian ini dibangun oleh sesar-sesar normal dan graben berorientasi utara – selatan dengan karakter terbuka sebagai saluran untuk fluida hidrotermal mencapai permukaan dasar laut.Kelimpahan unsur tanah jarang La, Ce, Pr dan Nd dikarenakan posisinya pada pusat aktivitas hidrotermal. Kedekatan dengan pusat hidrotermal ini menjelaskan kelimpahan REE dari contoh komponen andesitic yang diambil dari aglomerat ini.Kata kunci: UTJ (Unsur Tanah Jarang), transportasi uap, fumarol, PulauWeh, Aceh.
STRUCTURAL GEOLOGICAL CONTROL ON THE MINERALIZATION ON TABUAN ISLAND,SEMANGKO BAY, SOUTH SUMATERA, INDONESIA Kurnio, Hananto; Schampera, Ulrich Schwarz
BULLETIN OF THE MARINE GEOLOGY Vol 23, No 1 (2008)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (273.147 KB) | DOI: 10.32693/bomg.23.1.2008.7

Abstract

Mineralization have been discovered on Tabuan Island, Semangko Bay, South Sumatera, Indonesia. Tabuan Island belongs to the Neogene Sunda-Banda magmatic arc system. Tabuan Island is a tectonic horst structure which belongs to the subduction-related, magmatically active Barisan zone along the active continental margin of western Sumatera. Basaltic-andesitic volcanics of the late Oligocene to earliest Miocene Hulusimpang Formation are distributed in a broad zone along and subparallel to the regional Semangko Fault and are hosts for several epithermal-style auriferous deposits. The occurrence of hydrothermal mineralization was first suggested from seismic identification of small intrusive bodies which form elongated northwest-southeast ridges passing through the island. Surface sampling campaigns on the island revealed significant hydrothermal alteration and mineralization with pervasive occurrences of sulphide minerals. Detailed mineralogical and geochemical studies at the Federal Institute for Geoscience and Natural Resources show pronounced disseminations and vein-type mineralization. Mineralization shows moderate enrichments in Au, Ag, Zn, Pb, Cu, As, Sb, Ba, and Mn. The association of subaerial island arc volcanism and subvolcanic intrusive bodies, the regional extensional and strike-slip structural regime, and the occurrence of epithermal-style alteration and mineralization in the same volcanic sequence along the coastal zone of Semangko Bay and on Tabuan Island reveal the great potential of this region for epithermal type Au-Ag and base metal deposits. On Tabuan Island, delineation of structural blocks and fault systems suggests that normal faults and margins of grabens may have acted as fluid channelling structures. Key words: structural geology, mineralization, Tabuan Island, Semangko Bay
THE RELATIONSHIP OF SEAFLOOR SURFACIAL SEDIMENT WITH SEABOTTOM MORPHOLOGY OF LEMKUTAN ISLAND WATER, WEST KALIMANTAN Kurnio, Hananto; Aryanto, Noor C.D.
BULLETIN OF THE MARINE GEOLOGY Vol 28, No 2 (2013)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1286.057 KB) | DOI: 10.32693/bomg.28.2.2013.56

Abstract

Sea floor sediment surrounding Lemukutan Island, West Kalimantan is distributed on rather steep sea bottom morphology. The steep bottom seems a continuation of rugged morphology of the island, especially at the northeast and southeast parts. This paper discusses the relation between sediment grain sizes and the steepness of sea bottom morphology. Grain size analyses of sediment shows various sediment types such as slightly gravelly muddy sand, gravel mostly composed of coral and lithic, and gravelly sand. Results show that steepness of sea bottom slope control deposited sediment types, coarse fraction sediments tend to settle on the area of high slope angle as at the northeastern and southeastern of the island. On the other hand, high energy marine environment, such as at the sea in front of north headland of Lemukutan Island, tends to accumulate coarse sediments. High percentages of organism shells in marine sediments obviously are deposited at those two domains. Keywords: sea bottom morphology, sediment, Lemukutan Island, West Kalimantan. Sedimen dasar laut sekitar Pulau Lemukutan, Kalimantan Barat tersebar pada morfologi yang agak curam. Permukaan dasar laut yang curam tampaknya merupakan kelanjutan morfologi kasar pulau tersebut, terutama pada bagian timur laut dan tenggara. Makalah ini membahas hubungan antara besar butir sedimen dan kecuraman morfologi dasar laut. Analisis besar butir sedimen memperlihatkan jenis sedimen yang bervariasi, seperti pasir lumpuran sedikit krikilan, kerikil umumnya terdiri koral dan fragmen batuan, dan pasir krikilan. Hasil kajian menunjukkan bahwa kecuraman lereng dasar laut mengontrol tipe sedimen yang diendapkan, sedimen fraksi kasar cenderung mengendap pada daerah dengan sudut lereng tinggi seperti di bagian timur laut dan tenggara Pulau Lemukutan. Di samping itu, lingkungan laut enerji tinggi, seperti di bagian utara pulau, cenderung mengakumulasikan sedimen kasar. Prosentase tinggi dari cangkang organisma dalam sedimen laut tampak nyata diendapkan pada kedua lingkungan tersebut. Kata kunci: morfologi dasar laut, sedimen, Pulau Lemukutan, Kalimantan Barat.
THE INFLUENCE OF SEA-LEVEL CHANGES ON SEA-BOTTOM MORPHOLOGY OF SINGKAWANG WATERS WEST KALIMANTAN BASED ON ANALYSES OF BATHYMETRIC AND SEISMIC DATA Kurnio, Hananto; Aryanto, Noor C.D.
BULLETIN OF THE MARINE GEOLOGY Vol 26, No 2 (2011)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1418.792 KB) | DOI: 10.32693/bomg.26.2.2011.35

Abstract

In the history of Quaternary geology, global climate changes influenced worldwide sea-level variations. On this study, these phenomena are tried to be assessed through sea-bottom morphology changes using bathymetric and seismic strata box data obtained during field survey in Singkawang Waters, West Kalimantan. Sea-level changes in this area are referred to global variations that had been studied by many researchers. Maximal depth attained during bathymetry mapping was -52 meters which take place as a depression between Lemukutan and Penata Besar Islands. General depths are - 30 m; thus, morphology reconstruction was done for sea-level positions - 10 m, - 20 m, and - 30 m from mean sea level. At the study area, sea-level dropped more than -30 m was only occurred in sea bottom morphology of isolated depressions. These isolated depressions are assumed as paleo-lakes which occurred throughout Sunda Land by some authors. The study also shows that sea-level history in Singkawang’s area span from approximately 10,000 years ago or Holocene time to Recent. During low sea-levels, the sea-bottom morphology was characterized by more extension of Singkawang land, formations of narrow straits between islands and developments of paleo-lakes assumed as fresh water lakes in the past. These events, based on Voris’s Diagram, occurred about 10,200 up to 8,300 years ago. On the other hand, marine clays appeared on coastal area of Singkawang. These might be evidence of sea-level rise in this area. About + 5m sea-level rise flooded this area approximately 4,200 years ago. Influences of sea-level changes to subbottom geological conditions were also assessed. The assessment was carried out by analyzing shallow seismic reflection records by using strata box. The records demonstrated that subsurface geology were characterized by truncation reflector configurations interpreted as fluvial environments. Keywords : sea-level changes, sea-bottom morphology, bathymetry, strata box, Singkawang Waters, West Kalimantan. Dalam sejarah geologi Kuarter, perubahan iklim global mempengaruhi variasi permukaan laut di seluruh dunia. Pada kajian ini fenomena tersebut dicoba dipelajari melalui perubahan morfologi dasar laut menggunakan data batimetri dan seismik pantul dangkal yang diperoleh selama survei lapangan di Perairan Singkawang, Kalimantan Barat. Perubahan muka laut di daerah ini mengacu pada variasi global yang telah dikaji oleh beberapa peneliti. Kedalaman tertinggi yang diperoleh selama pemetaan batimetri adalah 52 meter, yaitu berupa suatu daerah depresi antara Pulau Lemukutan dan Penata Besar. Umumnya kedalaman adalah -30 m; sehingga, rekonstruksi morfologi dilakukan pada posisi muka laut - 10 m, - 20 m, dan -30 m dari muka laut rata-rata. Di daerah kajian, muka laut turun lebih dari - 30 m hanya terjadi dalam morfologi dasar laut yang berupa daerah-daerah depresi yang terisolasi. Morfologi depresi terisolasi ini diduga sebagai danau purba oleh beberapa penulis yang terdapat pada Daratan Sunda. Kajian ini juga menunjukkan bahwa sejarah muka laut di daerah Singkawang mulai dari sekitar 10.000 tahun lalu (Holosen) hingga saat ini (Resen). Selama turunnya muka laut, morfologi dasar laut dicirikan oleh semakin meluasnya daratan Singkawang, terbentuknya beberapa selat sempit dan berkembangnya danau-danau purba yang diduga sebagai danau air tawar di masa lalu. Peristiwa tersebut, berdasarkan diagram umur terhadap muka laut Voris, terjadi sekitar 10.200 hingga 8.300 tahun lalu. Sementara itu, keterdapatan lempung endapan laut dari data pemboran pantai di Singkawang merupakan bukti naiknya muka laut di daerah ini. Kenaikan muka laut sekitar + 5 m telah menggenangi daerah ini kira-kira 4.200 tahun lalu. Tulisan ini juga membahas tentang pengaruh perubahan muka laut terhadap kondisi geologi bawah dasar laut. Kajian dilaksanakan dengan menganalisa rekaman seismik pantul dangkal. Rekaman menunjukkan bahwa geologi bawah dasar laut dicirikan oleh konfigurasi reflektor ’toreh dan isi’ atau truncation yang ditafsirkan sebagai lingkungan fluvial. Kata kunci : perubahan muka laut, morfologi dasar laut, batimetri, strata box, Perairan Singkawang, Kalimantan Barat.
PALEO-CHANNELS OF SINGKAWANG WATERS WEST KALIMANTAN AND ITS RELATION TO THE OCCURRENCES OF SUB-SEABOTTOM GOLD PLACERS BASED ON STRATA BOX SEISMIC RECORD ANALYSES Kurnio, Hananto; Aryanto, Noor C.D.
BULLETIN OF THE MARINE GEOLOGY Vol 25, No 2 (2010)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (912.18 KB) | DOI: 10.32693/bomg.25.2.2010.26

Abstract

Strata box seismic records were used to analyze sub-seabottom paleochannels in Singkawang Waters, West Kalimantan. Based on the analyses, it can be identified the distribution and patterns of paleochannels. Paleo channel at northern part of study area interpreted as a continuation of Recent coastal rivers; and at the southern part, the pattern radiates surround the cone-shaped morphology of islands, especially Kabung and Lemukutan Islands. Paleochannels of the study area belong to northwest Sunda Shelf systems that terminated to the South China Sea. A study on sequence stratigraphy was carried out to better understanding sedimentary sequences in the paleochannels. This study is also capable of identifying placer deposits within the channels. Based on criterias of gold placer occurrence such as existence of primary gold sources, intense chemical and physical weathering to liberate gold grains from their source rocks of Sintang Intrusive. Gravity transportation that involved water media, stable bed rock and surface conditions, caused offshore area of Singkawang fulfill requirements for gold placer accumulations. Chemical and physical whethering proccesses from Oligocene to Recent, approximately 36 million, might be found accumulation of gold placer on the seafloor. Based on grain size analyses, the study area consisted of sand 43.4%, silt 54.3% and clay 2.3%. Petrographic examination of the sample shows gold grains about 0.2%. Keywords: paleochannels, strata box seismic records, gold placer. Rekaman seismik strata box digunakan untuk menganalisa sungai purba bawah permukaan di Perairan Singkawang, Kalimantan Barat. Berdasarkan hasil analisis data strata box dapat diidentifikasi sebaran dan pola sungai purba. Sungai purba di bagian utara daerah penelitian ditafsirkan sebagai kelanjutan sungai sekarang, dan di selatan sungainya berpola memancar yang berasal dari pulau-pulau bermorfologi kerucut, seperti Pulau Kabung dan Lemukutan. Sungai purba daerah penelitian termasuk pada sistem sungai purba Paparan Sunda barat laut berakhir di Laut Cina Selatan. Suatu kajian sekuen stratigrafi dilaksanakan untuk lebih memahami sekuen-sekuen sedimen dalam sungai purba. Kajian ini juga mampu mengidentifikasi endapan-endapan plaser dalam alur tersebut. Berdasarkan kriteria pembentukan emas plaser atau letakan, seperti terdapatnya sumber emas primer, pelapukan kimia dan fisika yang sangat intensif untuk membebaskan butiran-butiran emas dari batuan induknya yaitu Batuan Terobosan Sintang. Transportasi gaya berat yang melibatkan media air, kondisi batuan dasar dan permukaan yang stabil, membuat daerah lepas pantai Singkawang memenuhi kriteria untuk akumulasi emas letakan. Proses pelapukan kimia dan fisika mulai dari Oligosen hingga Resen, sekitar 36 juta tahun memungkinkan dijumpainya akumulasi emas letakan di dasar laut. Berdasarkan hasil analisa besar butir daerah penelitian terdiri dari pasir 43,4%, lanau 54,3% dan lempung 2,3 %. Uji petrogafi menunjukan kandungan emas sekitar 0,2%. Kata kunci: sungai purba, rekaman seismik strata box, emas letakan.
REVIEW OF COASTAL CHARACTERISTICS OF IRON SAND DEPOSITS IN CILACAP CENTRAL JAVA Kurnio, Hananto
BULLETIN OF THE MARINE GEOLOGY Vol 22, No 1 (2007)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32693/bomg.22.1.2007.4

Abstract

Mineable iron sand deposits in Cilacap – southern coastal area of Central Java have certain coastal characteristics that need to be studied in order to understand its depositional environment. With the knowledge of such environment, it can be applied to look for other places prospective of iron sand deposits that have the same characteristics especially recently when Cilacap’s deposits were almost depleted. Coastal characteristics of iron sand deposit in Cilacap is shown by successive sandy beach ridges separated by marshy valleys typical of prograded coasts and by dunes of sand elongated parallel to the shore line with elevation varies from 0 m to 15 m above sea level. The iron sand deposit was derived from denudation of andesite and “Old Andesite Formation” enriched in magnetite and ilmenite minerals in the steep elevated and deeply weathered rock hinterlands of Cilacap. High sediment loads of Serayu Basin in the hinterland (3,500-4,500 ton/km2/year; Citarum River basin only 800-1,200 ton/km2/year) was causing extensive deposition of iron sand in the coastal zone. Key words: coast, characteristic, iron sand, Cilacap Endapan pasir besi yang dapat ditambang di Cilacap – pesisir selatan Jawa Tengah memiliki karakteristik pantai tertentu yang perlu dikaji agar dapat dipahami lingkungan pengendapannya. Dengan pengetahuan tentang lingkungan pengendapan tersebut, dapat diterapkan untuk mencari daerah-daerah lain prospek endapan pasir besi yang memiliki karakteristik yang sama terutama pada akhir-akhir ini ketika endapan Cilacap akan habis. Karakteristik pantai endapan pasir besi di Cilacap dicirikan oleh urutan pematang pantai berpasir yang dipisahkan oleh lembah-lembah berawa khas pantai maju dan oleh gumuk-gumuk pasir memanjang sejajar dengan garis pantai dengan ketinggian bervariasi dari 0 m hingga 15 m dari muka laut. Endapan pasir besi di daerah ini berasal dari proses denudasi andesit dan “Formasi Andesit Tua” yang kaya akan mineral magnetit dan ilmenit pada pedalaman Cilacap dengan kondisi elevasi curam dan batuan sangat terlapukkan. Muatan sedimen yang tinggi dari Cekungan Serayu di pedalaman tersebut (3.500-4.500 ton/km2/tahun; cekungan Sungai Citarum hanya 800-1.200 ton/km2/tahun) menyebabkan pengendapan yang sangat luas pasir besi di wilayah pantai. Kata kunci: pantai, karakteristik, pasir besi, Cilacap
SEAFLOOR FAULTING AND ITS RELATION TO SUBMARINE VOLCANIC ACTIVITIES BASED ON SUB BOTTOM PROFILING (SBP) ANALYSES IN WEH ISLAND WATERS AND ITS SURROUNDING, NANGROE ACEH DARUSSALAM PROVINCE Kurnio, Hananto; Syafri, Ildrem; Sudradjat, Adjat; Rosana, Mega Fatimah; Muslim, Dicky
BULLETIN OF THE MARINE GEOLOGY Vol 30, No 1 (2015)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1240.409 KB) | DOI: 10.32693/bomg.30.1.2015.70

Abstract

Sub bottom Profiling survey using strata box, a specially designed low penetration sub bottom Profiling (< 80 m) for coastal waters exploration, found out evidence of submarine volcanic activities in northern coastal waters of Weh Island, NanggroeAceh Darussalam Province. Gas bubbling could be observed at water columns of the digital sub bottom Profiling records as acoustic turbidity. There are at least 33 spots of volcanic gas bursts observed from the sub bottom Profiling. Examination of gas bursts at coastal area which show fumaroles and solfatara indicate reduce volcanic activity either at submarine or terrestrial. Identification of seafloor gas burst by diving team found out that center of such burst is occurred at a north - south opened lineation assumed as normal fault. It seems that the seafloor normal fault is the continuation of terrestrial fault of the same direction as observed from terrain earth google of Weh Island.Keywords: seafloor faulting, submarine volcanic activities, shallow sub bottom Profiling data, Weh Island Aceh Survei penampang bawah dasar laut (SBP) menggunakan strata box, suatu alat SBP penetrasi rendah yang didisain untuk eksplorasi perairan pantai, mendapatkan bukti-bukti aktivitas gunungapi bawah laut di perairan sebelah utara Pulau Weh, Provinsi Nanggroe Aceh Darussalam. Gelembung-gelembung gas dapat diamati pada kolom air rekaman digital penampang bawah dasar laut sebagai turbiditas akustik. Sedikitnya dijumpai 33 titik semburan gas volkanik yang teramati dari penampang bawah dasar laut tersebut. Pemeriksaan semburan-semburan gas pada wilayah pantai sebagai fumarola dan solfataramenunjukkan telah berkurangnya aktivitas volkanik apakah pada dasar laut maupun darat. Identifikasi semburan gas dasar laut oleh tim selam mendapatkan bahwa pusat semburan berada pada kelurusan berarah utara - selatan yang diduga sebagai sesar normal. Tampaknya adalah bahwa sesar normal dasar laut tersebut merupakan kelanjutan sesar darat yang berorientasi sama seperti teramati dari citra earthgoogle terrain Pulau Weh. Kata kunci: pensesaran dasar laut, aktivitas gunungapi bawah laut, data penampang bawah dasar laut, Pulau Weh Aceh
BIOGENIC GAS IN DELTAIC DEPOSITION ENVIRONMENT IN KAPUAS RIVER, WEST KALIMANTAN AND ITS UTILIZATIONS FOR LOCAL COMMUNITY Kurnio, Hananto; Darlan, Yudi
BULLETIN OF THE MARINE GEOLOGY Vol 24, No 2 (2009)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32693/bomg.24.2.2009.15

Abstract

Biogenic gas within a deltaic deposition environment in the Kapuas rivermouth of West Kalimantan occurred in fine to very fine quartz sand reservoir of shallow boreholes of having the depth of 1-12 m below ground surface. This reservoir is covered by peaty layers of semi-impermeable property. During high tide, gas bubbling took place in the water column above the ground of these semi-impermeable layers. Utilizations of biogenic gas had been done succesfully. These works were carried out through drilling, piping, gas storage and installations for gas stove and gas electricity generator of 500 watt capacity at chief village house as an example before widely used to the local community. Keywords: Biogenic Gas; Deltaic Deposition Environment; Kapuas River; west Kalimantan, Utilization. Gas biogenik dalam suatu lingkungan pengendapan delta di muara Sungai Kapuas Kalimantan Barat terdapat dalam reservoar pasir kuarsa berukuran halus hingga sangat halus pada kedalaman bor dangkal 1-12 m di bawah permukaan tanah. Reservoar ini ditutupi oleh lapisan gambut semiimpermeabel. Selama pasang naik, gelembung gas teramati dalam kolom air di atas permukaan lapisan semi-impermeabel ini. Pemanfaatan gas biogenik telah dilaksanakan dengan sukses. Pemanfaatan ini dilakukan melalui pemboran, pipanisasi, penampungan gas dan instalasi untuk kompor gas dan generator listrik berbahan bakar gas kapasitas 500 watt di rumah Kepala Desa sebagai contoh sebelum dimanfaatkan secara luas oleh masyarakat setempat. Kata kunci: Gas Biogenik, Lingkungan Pengendapan Delta, Sungai Kapuas, Kalimantan Barat, Pemanfaatan