The Mechanism of Sediment Depositional Environment of Core Drilling of Gilimanuk Coast, Bali and Ketapang, East Java, Based on Sediment Textures

The analysis result of grains frequency curve and relation between grains size to cumulative have shown medium grains at Gilimanuk (Core drilling-1) and coarse grains at Ketapang (Core drilling-2). In general both of them are showed by pattern uniformity, which is represented by the similar of curve pattern. On the grain size of -2 phi as medium gravel with percentage between 6.47 to 35.88%, while core drilling -2 on the size of -2 phi between 6.86 to 61.11%.The average grains size of core drilling -1 are gravel about 21.3%, sand 60.2%, silt 5% and clay about 0.4% while core drilling-2 are characterized by 44.3%, sand 26.8%, silt 24.6% and clay about 0.6%. These result shows that at location of Core drilling -1 is dominated by sand where as at location of Core drilling -2 is dominated by gravel. These situation can be interpreted that the sediment at core drilling -2 location have influenced by strong marine current which can transport the large amount of gravel size compare to the location of Core drilling-1 which is dominated by sand. Based on the relation shape of grains size curve versus cumulative frequency shows that the sediment of Core drilling-1is interpreted as a beach sand deposits and only one sample which shows as a river sand deposits which was found at depth 0 – 3 m depth. In general, the sample of Core drilling –2 shows that the pattern of sediment tend as a beach sand deposits and only one sample which shows the combination between coastal deposits and river deposits ( 4 – 5 m depth). From this sample, the coarse to fine grains is deposited by coastal media and fine grains material (about 10%) is deposited by river media. The sample of river deposits is found as lamination because the only one which is created from combination between coastal and river depos its from all sample of core drilling-2.Keywords: core drilling, grain sediments, media transport, environmental deposition Hasil analisis menggunakan kurva frekuensi butiran serta hubungan antara besar butir terhadap kumulatif menunjukkan dominasi ukuran butiran sedang di daerah Gilimanuk (Bor-1) dan kasar di daerah Ketapang (Bor-2). Pada kedua daerah tersebut, secara umum memperlihatkan pola keseragaman, yang ditunjukkan oleh pola kurva yang sama. Pada ukuran butir -2 phi (kerikil sedang) pada Bor-1 berjumlah antara 6,47 – 35,88%, sedangkan pada Bor-2 pada ukuran -2 phi berjumlah antara 6,86 – 61,11%.Kandungan rata-rata butiran pada Bor-1 adalah: kerikil 21,3%, pasir 60,2%, lanau 5% dan lempung 0,4%, sedangkan Bor-2 adalah: kerikil 44,3%, pasir 26,8%, lanau 24,6% dan lempung 0,6%. Hasil ini menunjukkan bahwa pada Bor-1 didominasi oleh pasir dan pada Bor-2 didominasi oleh kerikil. Hasil ini dapat memberi gambaran bahwa pada Bor-2 berarus lebih kuat karena mampu menstranspor butiran kerikil dalam jumlah yang lebih besar dibandingkan dengan Bor-1 yang didominasi oleh pasir. Berdasarkan beberapa kurva hubungan antara besar butir vs frekuensi komulatif pada Bor-1 menunjukkan endapan pantai (beach sand), hanya satu contoh menunjukkan endapan sungai (river sand), yaitu contoh B1 (0 – 3m). Pada Bor-2, secara umum menunjukkan pola yang lebih mendekati endapan pantai (beach sand), hanya satu contoh menunjukkan kombinasi endapan pantai dan endapan sungai (river sand), yaitu contoh B2 (4 – 5 m). Pada contoh ini, butiran berukuran kasar sampai halus diendapkan oleh media pantai dan ukuran halus dengan persentase sekitar 10% merupakan endapan sungai. Contoh endapan sungai adalah pada B2 (4 – 5 m) ini merupakan endapan sisipan karena satu-satu terbentuk dari kombinasi pantai dan sungai dari seluruh contoh pada Bor-2

Kandungan Mineral pada Sedimen Pantai dan Laut, Hubungannya dengan Batuan Sumber di Pesisir Kabupaten Rembang, Jawa Tengah

Sedimen di sepanjang pantai Kabupaten Rembang terdiri atas sedimen muda (aluvial) dan sedimen tua (breksi dan batugamping). Sedimen muda merupakan sedimen lepas dan terdapat di daerah sedimentasi. Sedimen tua berupa sedimen kompak yang secara fisik mempunyai resisitensi tinggi terhadap abrasi Batuan yang terdapat di kawasan pesisir adalah: pasir kuarsa, andesit, tras kaolin, batugamping, batubara dan lempung. Peta sebaran sedimen dasar laut perairan Kabupaten Rembang, menunjukkan dominasi endapan pasir, lanau (pasir halus) dan lanau pasiran (pasir halus - kasar). Kandungan mineral yang terdapat di perairan Kabupaten Rembang terdiri dari: magnetit, pirit, hematit, zirkon, ilmenit diopsid, augit, hornblende, kuarsa, biotit, muskovit dan dolomit Kata Kunci: sedimen, mineral, Rembang The coastal sediment along the coastal of Rembang District consists of young sediment (alluvium) and old sediment (breccias and limestones). Young sediment is placer sediment that occupies the sedimentation area. Old sediment is massive sediment that has a high resistance to abrasion Rocks content in the coastal zone area consist of quarzt sand, andesite, caoline, limestone, trass, coal and clay. Seafloor surficial sediments map of the Rembang water area shows the domination of sand deposits, silt (fine sand) and sandy silt (fine to medium sand). Mineral content in Rembang waters area consists of magnetites, pyrites, hematites, zircons, ilmenite diopsides, augitse, hornblendas, quartzs, biotitse, muskovites and dolomites. Keywords: sediment, mineral, Remban

Pendekatan secara Empirik terhadap Gejala Perubahan Garis Pantai Daerah Indramayu dan Sekitarnya

Lokasi daerah studi Indramayu secara geografis terletak di pesisir utara Pulau Jawa dan termasuk pantai terbuka terhadap pengaruh energi gelombang dari arah barat laut, utara dan timur laut. Tujuan dari penelitian ini yaitu menganalisis Perubahan garis pantai dari analisis parameter oseanografi yang dibangkitkan oleh komponen angin permukaan. Pendekatan secara empirik terhadap Perubahan garis pantai dari parameter oseanografi, menunjukkan telah terjadi proses erosi dan sedimentasi di pantai Indramayu dan sekitarnya. Daerah abrasi meliputi kawasan bagian tenggara dan barat laut pantai Indramayu. Pergerakan arus sepanjang pantainya disertai oleh pengendapan sedimen (Q) berarah barat laut. Nilai Q pada zona Z-3 lebih besar dari pada di zona Z-1 dan Z-2 dengan jumlah nisbi pasokan sedimen cenderung bergerak ke arah barat laut. Daerah pesisir kawasan Delta Cimanuk diperkirakan akan menjadi zona akumulasi sedimen sepanjang tahun. Sementara proses erosi di bagian tenggara Indramayu tetap berkembang dan berlangsung secara musiman. Kata kunci : Erosi , Indramayu, pasokan sedimen The study area Indramayu, is geographically located at the northern coast of Jawa, which is an open beach that influenced by wave action from the northwest, north and northeast directions. The purpose of this study is to analyze the shift of the shore line based on oceanographic parametric analysis made by surface wind component. An empiric approach to the coastal line change conduct oceanographic parameters shows that erosion and sedimentation have occured along the coastal area of Indramayu and its surounding. The eroded area encompasses the northeastern and northwestern coasts of Indramayu. Its longshore current is follow by sediment (Q) supplies that tend to be deposited in the northwest area. The value of Q in the Z-3 zone is larger than Z-1 and Z-2 zones, as relative amount of sediment supplies tend to move northwest. The coastal area of Delta Cimanuk is estimated to be zone of sediment accumulation along the year, while the erosion process in southeast part of Indramayu spreads and occurs seasonally. Keywords : Erosion, Indramayu, sediment suppl

Mineral Content of Surficial Sediment of the Rangsang Island and Its Surrounding Area, Meranti Regency, Archipelago Riau Province

According to the regulation No 4 of 2009 of Mineral and Coal Mining Management stated that the requirement of an inventory for mineral resources data was created to support the establishment of mining area. This study is intended to obtain mineral resources content and surficial sediment data, Geographically the study area belongs to Meranti Archipelago Regency, Riau Province. it is located between 102o00'00" - 103o 15'00" E and 00o35'00" - 01o28'00" N. Grain size analyses result show that surficial sediment in the study area consists of silt, silty sand and sand which is dominated by silt. Based on the mineral identification, some of the minerals such as quartz, cassiterite, magnetite, hematite, dolonite, biotite and zircon have been found. Silt distribution is very wide started from estuarine southeast part northen part of Rangsang Island toward southeast of rangsang island. Sandy silt only found at the southeast of Rangsang Island, while sand sediment is found at the south and southeast of Rangsang Island. The presence of silt and sand grains is influenced by moderate to strong currents and wave patterns, so that the silt and sand grains sediment was transported along coastal to offsore area, while the fine grained (clay - silt) are deposited in the valley at the western part of Rangsang Island.Keywords: mineral, surficial sediment, Rangsang Island Berdasarkan Undang Undang Nomor 4 tahun 2009 tentang Pengelolaan Pertambangan Mineral dan Batubara, disebutkan bahwa inventarisasi data sumber daya mineral diperlukan dalam rangka mendukung penetapan Wilayah Pertambangan (WP). Penelitian ini dimaksudkan untuk memperoleh data kandungan sumber daya mineral dan sedimen dasar laut. Daerah penelitian, secara geografis termasuk dalam Kabupaten Kepulauan Meranti, Provinsi Riau, dan terletak pada koordinat antara 102o00'00" - 103o15'00" BT dan 00o35'00" - 01o28'00" LU. Hasil analisis besar butir menunjukkan sedimen permukaan dasar laut di daerah penelitian terdiri atas lanau, lanau pasiran dan pasir yang didominasi oleh lanau. Berdasarkan identifikasi mineral pada sedimen permukaan dasar lautnya menunjukkan kehadiran mineral kasiterit, magnetit, hematit, dolomit, biotit, zirkon dan kuarsa. Penyebaran lanau sangat luas dimulai dari daerah estuari barat laut dan bagian utara Pulau Rangsang, hingga ke sebelah tenggara Pulau Rangsang. Lanau pasiran hanya terdapat di tenggara Pulau rangsang, sedangkan pasir hanya terdapat di daerah di bagian selatan - tenggara Pulau Rangsang. Adanya butiran lanau - pasir dipengaruhi oleh pola arus dan gelombang yang sedang sampai kuat, sehingga butiran berukuran lanau - pasir dapat terangkut ke arah lepas pantai, sedangkan butiran halus (lempung) mengendap di daerah lembah di bagian barat Pulau Rangsang