Ediar Usman
Pusat Penelitian dan Pengembangan Geologi Kelautan, Jln. Dr. Junjunan No. 236 Bandung - 40174

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Sediment Distribution related to Gold and Silver Placer Deposits in Offshore of Sambas Besar Estuary, Sambas Regency, West Kalimantan Usman, Ediar; Lugra, I. W.
Indonesian Journal on Geoscience Vol 6, No 1 (2011)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1601.086 KB) | DOI: 10.17014/ijog.v6i1.113

Abstract

DOI: 10.17014/ijog.v6i1.113Result of grain size analysis of the sea floor sediments from the study area indicates four sediment types, those are silt, sandy silt, silty sand, and sand. The silt unit has the widest distribution that is around 127.2 km2, sandy silt 12.65 km2, sand 1.176 km2, and silty sand 0.44 km2. Result of gold and silver content analysis from some selected samples indicates that the highest gold and silver amount are at PMK-08 location in northern part of the study area with gold content of 0.21 ppm and silver 13.36 ppm; both are silt sediment types. The highest gold and silver content occur within medium - coarse sediments containing subrounded grains of quartz and pyrite, at northern part of the study area. The presence of silver and gold is suggested to be controlled by a north-south longshore current pattern. The source of sediments from Sambas Besar River follows the longshore current, e.g. in northern estuary from south to north, and at southern estuary from north to south direction.
HUBUNGAN KANDUNGAN MINERAL KUARSA DAN MINERAL LAINNYA DENGAN SEDIMEN DASAR LAUT DI KEPULAUAN ARUAH PROVINSI RIAU Setiady, Deny; Usman, Ediar
Buletin Sumber Daya Geologi Vol 8, No 2 (2013): Buletin Sumber Daya Geologi
Publisher : Buletin Sumber Daya Geologi

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Abstract

Secara geologi perairan Selat Malaka, termasuk dalam kawasan granit Sumatera bagian barat sebagai satu rangkaian pulau-pulau timah yang membujur dari daratan Thailand – Malaysia hingga Bangka – Belitung. Berdasarkan hal tersebut maka perairan tersebut kemungkinan kayadengan potensi mineral-mineral letakan yang bernilai ekonomis. Tujuan penulisan paper ini adalah mengetahui hubungan kandungan mineral dengan sedimen dasar laut yang ada di daerah penelitian.Berdasarkan analisis besar butir, sedimen yang terdapat di dasar laut daerah perairan Kepulauan Aruah adalah: pasir lanauan (zS) Pasir lempungan (cS), lanau pasiran (sZ), Lanau Lempungan (cZ), lempung lanauan (zC) serta lempung (C).Berdasarkan analisis mineral,  mineral di daerah penelitian terdiri dari kuarsa dengan kandungan antara 60 – 80%. Mineral lainnya adalah zirkon, cassiterite, hematit, magnetit, limonit, biotit dan dolomit.Endapan letakan pada sedimen permukaan dasar laut secara mekanik umumnya terkonsentrasi oleh sungai dan  proses laut.  Mineral kuarsa dan mineral berat adalah mineral yang merupakan endapan letakan yang berasal dari pelapukan batuan dan tertransport
PENENTUAN LOKASI SARANA PENGHUBUNG JAWA - BALI (SELAT BALI) SESUAI DENGAN KONDISI OPTIMAL GEOLOGI KELAUTAN Usman, Ediar
Jurnal Geologi dan Sumberdaya Mineral Vol 17, No 4 (2007): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Abstract

To decide the preferable location of a bridge or tunnel site connecting Jawa - Bali, marine geological survey on the sea floor of Bali Strait encompassing morphology and geology should be taken into consideration. Depression of 140 meters deep as a result of bathymetrical data recording can be observed. Besides this, the result of reflection seismic record gave a clear interpretation about materials constructing the sea floor, which consists of unconsolidated sediments of coral fragments and sands (such as mounded and slump type). The basement rocks were also found in a narrow basin with cliffs of about 100 to 140 metres deep going north - south direction.  Keywords: marine geology, bathimetry, seismic interpretation, bridge location, Jawa – Bali
PENYEBARAN BATUAN GRANIT DAN SEDIMEN KUARTER BERDASARKAN INTERPRETASI DATA SEISMIK DI PERAIRAN BATAM UTARA Usman, Ediar
Jurnal Geologi dan Sumberdaya Mineral Vol 17, No 1 (2007): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Abstract

Results of mappings and publications concerning the distribution  of granite and Quaternary sediments in territorial waters of Batam Island and its surroundings are still limited.  It is caused by the distribution of the granite which emerges to sea bottom in territorial waters in the  part of the North  Batam  and its surroundings  is also limited.  Results of seismic interpretation show the existence of some reflector characteristics of the granite and the Quaternary sediments. Based on the interpretation model at bedrock and the Quaternary sediment, distribution area of the bedrock is in part of west and north of Batam Island and also in the part of the north of Bintan Island. While the Quaternary sediment, based on reflector seismic characters, is coarse fluvial deposits at the bottom as the channel fill between some domes of granite body and recent marine deposits at the top. If the bedrock is correlated with regional geology in territorial water of the Batam Island and its surroundings,the bedrock is granite. Keywords: granite, bedrock, Quatenary sedimen,seismic interpretation ,North Batam
PENYEBARAN SEDIMEN MENGANDUNG MINERAL BERAT DI PANTAI DAN PERAIRAN BAGIAN SELATAN BANYUWANGI Usman, Ediar
Jurnal Geologi dan Sumberdaya Mineral Vol 17, No 5 (2007): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Abstract

Territorial waters of southern part of Banyuwangi  are located in the southern  slope of Southern  Mountains of Jawa, included  in fore arc basin which is very rich in heavy minerals.   The heavy minerals are the result of volcanic activity along the Southern Mountains of Jawa.  Its products have been transported and deposited along the south coast and sea floor of the Southern Waters of Jawa.Results of analysis of sediments  collected from the coastal area and sea floor in the southtern part of Banyuwangi, indicate high content of heavy mineral especially magnetite.  The heavy minerals which are present within sands are dominated by fine to coarse fractions, i.e.  Sand (S), silty sand (zS), sandy silt (sZ) and gravelly sand (gS).  They are distributed from coastal plain to offshore area. Some samples show that the content of heavy minerals range from 80 to 100% in weight. Rate of Fe content  within magnetite along the sooth part of Banyuwangi  ranges between  6,8 and 30, 6%, whereas that on the sea between 3,3- 27,4%. Result of seismic record interpretation shows that thickness of the sediment containing the heavy minerals is approximately 20 meters from sea floor. Keywords: sea floor sediment, heavy mineral, magnetite, southern part of waters, Banyuwangi
PROSES SEDIMENTASI DASAR LAUT DI TELUK KUMAI, KALIMANTAN TENGAH, DAN HUBUNGANNYA DENGAN CEBAKAN EMAS DAN PERAK Usman, Ediar; R.Silalahi, Imelda
Jurnal Geologi dan Sumberdaya Mineral Vol 19, No 4 (2009): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Abstract

Results of analysis of gold and silver contents within the sea floor sediments in the Kumai Bay show that the highest contents are at the location of TPL-43, TPL-44, TPL-54, TPL-74 and TPL-75 locations with ranging from 0,09 to 0,19 ppm for gold and 1,6 to 3,75 ppm for silver. A curve showing the relationship between grain size and percentage of grain cumulative of gold and silver bearing sediments indicates that the deposition process is a combination pattern between saltation and suspension. The saltation pattern happened at the grain size between -1,5 to 2 phi and suspension pattern 2 - 4 phi. Based on relation curve of the grain size and frequency percentage of the grains indicate the present of a certain grain dominated the depositional process. The most influenced grain size on depositional process are between 0,5 - 2,5 phi that are a medium sand to very fine sand of about 10 - 28%. The depositional pattern of the sediment in the survey area is influenced by the regime of bay current as a combination of the sea and river currents to form the coastal sand sediments. Result of the analysis can become a guidence in gold and silver mining activities in the study area in order to obtain optimal results, that is on sediments with size ranging from medium - very fine sand around the coastline area. Keywords: sediment, gold and silver, depositional process, grain size, Kumai Bay
SEDIMENTASI SEBAGAI DILEMA PENGEMBANGAN PELABUHAN NUSANTARA DI PERAIRAN LASEM JAWA TENGAH Ilhaude, Delyuzar; Usman, Ediar
Jurnal Geologi dan Sumberdaya Mineral Vol 17, No 3 (2007): Jurnal Sumber Daya Geologi
Publisher : Pusat Survei Geologi

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Abstract

The studied area is geographically located on the northern coast of Jawa, which is an open beach influenced by wave action from the northwest and northeast direction. The erosion process occurs relatively in the northeastern coastline of the Lasem area. Sediment supply from the northeastern of Lasem tends to be deposited in the central and the southwestern part of the studied area. The thickness of sediment of subsequence B4 on line L-1 in the southwestern part of the studied area is thicker compared with subsequense B4 on the line L-17 of the northeastern part of the studied area. The eastern part of Lasem can be developed as a harbor area. Keywords : bearing capacity, sediment supply
STUDI POLA SEDIMENTASI DAERAH LEMBAH DAN SUNGAI PURBA (PALEO-CHANNEL) BERDASARKAN ANALISIS DATA SEISMIK DI PERAIRAN SELAT BANGKA Primananda, Mohamad Iqbal; Widada, Sugeng; Usman, Ediar
Journal of Oceanography Vol 4, No 1 (2015)
Publisher : Program Studi Oseanografi, Jurusan Ilmu Kelautan, Universitas Diponegoro

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Abstract

Secara geologi Pulau Bangka merupakan bagian dari peneplain Sunda sehingga dimungkinkan terdapat sungai purba sebagaimedia terjadinya penyebaran sedimen di masa lampau. Sedimen akan mengalami proses transportasi dari darat ke laut melalui sungai-sungai purbadan menyebar dalam bentuk limpahan secara lateral dan vertikal (progadation) ke cekungan-cekungan di laut yang tertutup oleh sedimen resen yang lebih muda. Penelitiandilakukan dengan metode seismik yaitu suatu metode dalam geofisika yang digunakan untuk mempelajari struktur dan strata bawah permukaan bumi.Penelitian bertujuan untuk mengetahui pola pergerakan sedimen melalui pendekatan keberadaan sungai purba dan lembah purba beserta percabangannya serta mendapatkan pola rendahan (lembah atau sungai purba) sebagai wadah akumulasi sedimen. Hasil interpretasi seismik berupa perhitungan kedalaman dasar laut (batimetri) antara 16,2-30,9 meter, ketebalan sedimen (isopach) 3,7-45,6 meter dan kedalaman batuan dasar (basement) antara 30,9-75 meter,yang dimodelkan dalam bentuk 2D dan 3D yang kemudian dibagi menjadi daerah tinggian/punggungan, lereng dan daerah lembah/sungai purba. Berdasarkan pembagian daerah tersebut dapat diketahui pola aliran sedimen di daerah penelitian yang bergerak dari daerah tinggian ke daerah yang lebih rendah melalui daerah lereng.Hasil penelitian juga dapat menentukan bentuk pola penyebaran sedimen sungai purba dan sungai modern (recent) beserta percabangannya.