Deny Setiady
Marine Geological Institute of Indonesia, Jl. DR. Junjunan No. 236, Telp. 022 603 2020, 603 2201, Faksimile 022 601 7887, Bandung

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CHARACTERISTIC OF RARE EARTH ELEMENT IN SEDIMENT AT COASTAL AND OFFSHORE AREA OF KUNDUR ISLAND, RIAU PROVINCE Deny Setiady; I Wayan Lugra
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 (1373.426 KB) | DOI: 10.32693/bomg.28.2.2013.57

Abstract

The study area is located at coastal and offshore Kundur and Adjacent Area, geographically located at coordinates of 0º 39'00 "0º 50'00" N and 103º 10'00 "103º 25 '00" S. Rare earth elements are found in seven seafloor surfacial sediment and 3 core samples are Cerium (15.41 to 16.88 ppm), Lanthanum (5.40 to 6.80 ppm), Ytrium (5.18 to 5, 58 ppm), Zirconium (5.05 to 5.95 ppm) and Neodymium 20.25 to 20.95 ppm). The minerals that containing of rare earth elements at the study area are apatite, zircon, monazite, and pyrochlore and xenotime. Seafloor surfacial sediment at Kundur are composed by silt (Z), sandy silt (sZ), sandy gravel, mud and sand. Silt unit covering nearly 55% of the study area and followed by sandy gravel, sand, silt and sandy silt. Seafloor morphology varies those are flat morphology with gradually depth changes and a regularly shaped identation curves and holes likely a result of sand mining. Coastal characteristics consists of: sandy and muddy beach. Sandy beach has medium relief (5° - 8°), composed by medium to coarse sand, brownish yellow. The muddy beach has low relief (1° - 5°) where the edges of the beach is mangroves planted by the local peoples. Key words : rare earth elements, seabed sediments, sea floor morphology, and Kundur Island Daerah penelitian terletak di kawasan pantai dan lepas pantai perairan Pulau Kundur dan Sekitarnya. Secara geografis terletak pada koordinat 0º 39’00” - 0º 50'00” LU dan 103º 10'00”- 103º 35' 00”BT. Mineral di daerah penelitian yang mengandung unsur tanah jarang adalah mineral apatit, zirkon, monazit, dan mineral pyrochlore. Unsur tanah jarang yang dijumpai pada tujuh contoh sedimen permukaan dasar laut dan 3 contoh bor inti adalah Cerium (15,41 – 16,88 ppm), Lanthanum (5,40 – 6,80 ppm), Ytrium (5,18-5,58 ppm), Zirkonium ( 5,05-5,95 ppm) dan Neodimium 20,25 – 20,95 ppm). Sedimen permukaan dasar laut di perairan Kundur tersusun oleh lanau (Z), lanau pasiran (sZ), kerikil pasiran, lumpur dan pasir. Satuan lanau menutupi hampir 55% dari seluruh daerah penelitian diikuti oleh krikil pasiran , pasir, lumpur dan lanau pasiran. Morfologi permukaan dasar laut sangat bervariasi ada yang landai dengan perubahan kedalaman yang teratur ada juga yang berbentuk lekukan lekukan dan lubang lubang besar kemungkinan akibat dari penambangan pasir. Karakteristik pantainya terdiri dari : pantai berpasir dan pantai berlumpur.   Pantai berpasir, berelief sedang (5° - 8°), tersusun oleh pasir ukuran butir sedang sampai kasar, berwarna kuning kecoklatan. Pantai berlumpur berelief rendah berkisar antara  (1° - 5°) dimana pada bagian tepinya ditanami bakau oleh penduduk setempat. Kata kunci: unsur tanah jarang, sedimen permukaan dasar laut, morfologi permukaan dasar laut, dan Pulau Kundur
HEAVY MINERALS IN PLACER DEPOSIT IN SINGKAWANG WATERS, WEST Kalimantan, RELATED TO FELSIC SOURCE ROCK OF ITS COASTAL AREA Deny Setiady; Noor C.D. Aryanto
BULLETIN OF THE MARINE GEOLOGY Vol 25, No 1 (2010)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (474.457 KB) | DOI: 10.32693/bomg.25.1.2010.21

Abstract

Placer deposits are physically accumulated by fluvial and marine processes in coastal area. Thirty six samples were selected from seventy seven samples of seafloor sediment of Singkawang waters. Those samples have been analyzed microscopically for heavy mineral contents. Based on this analysis, the heavy minerals can be divided into four groups: oxyde and hydroxyde, silicate, sulphide, and carbonate. The source of most heavy minerals in the study area is commonly formed by Felsic igneous rock and finally deposited on the seafloor sediments. Keywords: heavy minerals, placer deposit, felsic igneous rock, Singkawang Endapan letakan secara fisik umumnya terakumulasi oleh proses sungai dan laut. Sebanyak 36 contoh dipilih dari 77 contoh sedimen permukaan dasar laut di Perairan Singkawang. Contoh tersebut telah dilakukan analisis kandungan mineral berat secara mikroskopis. Berdasarkan hasil analisis mineral berat ini dapat dibedakan menjadi empat kelompok yaitu oksida dan hidroksida, silikat, sulfida, dan karbonat. Sebagian besar sumber mineral berat di daerah penelitian pada umumnya berasal dari batuan beku felsik yang akhirnya diendapkan di permukaan dasar laut. Kata kunci: mineral berat, endapan letakan, batuan beku felsik, Singkawang.
NEW LAND ACCRETION FROM 2000-2003 AT SEGARA ANAKAN LAGOON, SOUTH COAST OF WEST AND CENTRAL JAVA I Wayan Lugra; Deny Setiady
BULLETIN OF THE MARINE GEOLOGY Vol 27, No 2 (2012)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3078.468 KB) | DOI: 10.32693/bomg.27.2.2012.49

Abstract

Segara Anakan Lagoon is an unique lagoon , where a lot of rivers enter into the lagoon such as Citanduy, Cibeureum, Cijolang, Cikawung and Ciseel Rivers. These rivers bring the sediment materials from upstream to the lagoon areas and resisted by Nusa Kambangan Island. The rate of sediment transportation every year occurred continuously and significantly. Its caused the creation of new land at eastern part of Segara Anakan Lagoon was about 376.69 hectares which is located at Cilacap District, while in the western part is about 15,78 hectares which is located at Ciamis District. Since 1999 to 2003 land accretion at Segara Anakan Lagoon was about 392.47 hectares with the rate of accretion around 78.50 hectares/year. In 1999 the area of the Segara Anakan Lagoon approximately 1,595 hectares. Based on the averages of rate land accretion, its predicted that in the middle of the 2019 whole of Segara Anakan will be land. The study had been done in 2003 by using hand drilling up to 2 meters depth, grab sampler and GPS Garmin 250 Map. The hand drilling result at accretion area, show that at eastern part of study area is composed of silt and cly, while at Nusawere Bay and Solok Jero is characterized by fine to coarse sand. Keywords : sediment materials, accretion area, and Segara Anakan Segara Anakan merupakan sebuah laguna yang unik dimana banyak sungai yang bermuara di perairan tersebut seperti Citanduy, Cibeureum Cimuntur, Cijolang, Cikawung, dan Ciseel. Sungai-sungi tersebut membawa material sedimen dari daerah aliran hulu ke kawasan laguna yang tertahan oleh Pulau Nusa Kambangan. Transportasi sedimen berlangsung terus menerus dengan laju pertambahan dari tahun ke tahun cenderung meningkat secara signifikan. Akibatnya terjadi pertambahan daratan di perairan Segara Anakan bagian timur sekitar 376,69 hektar yang termasuk wilayah Kabupaten Cilacap dan di bagian barat sekitar 15,78 hektar yang terletak di wilayah Kabupaten Ciamis. Sejak 1999 – 2003, total luas pertambahan daratan di perairan Segara Anakan sekitar 392,47 hektar dengan perkiraan laju pertambahan daratan sekitar 78,50 hektar/tahun. Tahun 1999 luas Perairan Segara Anakan kurang lebih 1.595 hektar. Berdasarkan laju pertambahan daratan rata-rata tersebut, maka diperkirakan pada pertengahan tahun 2019 Perairan Segara Anakan seluruhnya menjadi daratan. Pada tahun 2003, telah dilakukan penelitian dengan menggunakan bor tangan sampai kedalaman 2 meter, pemercontoh comot dan GPS Garmin 250 Map. Hasil pemboran di lokasi pertambahan daratan tersebut menunjukkan di bagian timur tersusun dari lanau dan lempung, sedangkan di Teluk Nusawere dan Solok Jero disusun oleh pasir berbutir halus sampai sangat kasar. Kata kunci : material sedimen, pertambahan daratan, dan Segara Anakan