scholarly journals PROSES SEDIMENTASI SUNGAI KALIJAGA, DAN SUNGAI SUKALILA PERAIRAN CIREBON

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Deny Setiady ◽  
Asep Permana
Keyword(s):  
Grain Size ◽  
Size Range ◽  
River Mouth ◽  
Fine Sand ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Medium Size ◽  
Sandy Silt ◽  
Bathymetric Map

Berdasarkan hasil analisis besar butir sebanyak 36 percontoh sedimen permukaan dasar laut di Perairan Cirebon, didapatkan 4 jenis sedimen: lanau, lanau pasiran, pasir lanauan dan pasir. Sedimen lanau, lanau pasiran, dan pasir, tersebar di lepas pantai Cirebon dan muara Sungai Kalijaga, sedangkan pasir lanauan di muara sungai Sukalila. Dari Peta Batimetri terlihat daerah dangkal di sekitar muara Sungai Kalijaga. Sedimen paling tebal terdapat di sekitar muara Sungai Kalijaga dan Sungai Sukalila. Sedimen tersebut tersebar ke arah lepas pantai dan ke daerah rencana lokasi pelabuhan. Di muara Sungai Kalijaga sedimennya berupa pasir. Berdasarkan plot pada grafik antara ukuran besar butir terhadap persen frekuensi, didapatkan hasil sedimen dengan persen frekuensi yang tinggi antara 2.25 phi - 2.75 phi atau pasir sedang sampai pasir halus. Berdasarkan grafik frekuensi kumulatif terhadap besar butir terdapat 2 cara transpor yaitu traksi untuk butiran pasir sedang dan saltasi untuk kisaran butiran lanau sampai pasir halus. Kata Kunci : S. Kalijaga, S. Sukalila, Cirebon, besar butir, sedimen Based on grain size analysis of 36 seafloor surficial sediment samples from Cirebon Water; there are 4 types of sediments silt, sandy silt, silty sand and sand. Silt, sandy silt and sand are distributed offshore of Cirebon and in the river mouth of Kalijaga, while silty sand is in the river mouth of Sukalila. From the bathymetric map the shallow water can be observed in Kalijaga river mouth. The thicker sediments are found in Kalijaga mouth and Sukalila river. These sediments have been transported to the offshore and to the proposed Harbour location. Sediment in Kalijaga river mouth is sand. Based on graphic presentation between grain size and percent frequencies, it indicates that the percentage of higher frequencies ranges between 2.25 TO 2.75 phi. Based on the cumulative frequency to grain size graphic, there are two transport modes: traction for medium size sand and saltation for grain size range silt to fine sand. Keywords : Kalijaga River, Sukalila River, Cirebon, grain size, sediment

scholarly journals SEBARAN PASIR LAUT SEBAGAI BAHAN GALIAN DI LEPAS PANTAI SELAT RIAU

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Deny Setiady ◽  
Udaya Kamiludin ◽  
Ildrem Syafri
Keyword(s):  
Grain Size ◽  
Silty Sand ◽  
Coastal Sediments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sand Beach ◽  
Sediment Grain Size ◽  
Offshore Area ◽  
Sandy Gravel ◽  
Sandy Silt

Daerah penelitian terletak di perairan antara Pulau Batam dan Pulau Bintan (Selat Riau), termasuk ke dalam wilayah Kotamadya Batam dan Kabupaten Bintan, Provinsi Kepulauan Riau. Metode penelitian yang dilakukan adalah pengambilan posisi (navigasi), pengukuran kedalaman dasar laut, pengamatan dan pengambilan contoh sedimen pantai, pengambilan contoh sedimen dasar laut, serta analisis laboratorium. Tujuan penelitian adalah untuk mengetahui sebaran pasir pasir laut, serta ketebalannya berdasarkan karakteristik ukuran butirannya, agar potensi bahan galian tersebut dapat diketahui. Berdasarkan analisis ukuran butir sedimen di pantai Pulau Batam dan Pulau Bintan diketahui berukuran pasir, kerikil pasiran, pasir kerikilan dan lanau pasiran, sedangkan sebaran sedimen dasar laut terdiri dari: kerikil pasiran, pasir kerikilan, pasir, pasir lanauan dan lanau pasiran. Kedalaman sedimen pasir di pantai Pulau Batam antara 1 meter sampai 2,6 meter, sedangkan ketebalan sedimen pasir di Pulau Bintan antara 0,6 meter sampai 2 meter. Kata Kunci: sedimen, ukuran butir, pasir, bahan galian, Selat RiauThe study area is located in offshore area between Batam and Bintan Islands (Riau Strait), including of Batam and Bintan regency, Kepulauan Riau Province. The research methods carried out were position taking (navigation), depth of seabed measurement (bathymetry), observation and coastal sediments sampling, seabed sediments sampling, and laboratory analysis. The objectives of the study is to know the sand beach and sea sand distribution and its thickness based on characteristics of grain size, as well as to know those construction materials. Based on sediment grain size analysis on the Batam and Bintan islands, sand beach consists of: sand, sandy gravel, gravelly sand and sandy silt, while seafloor surficial sediments distribution consist of sandy gravel, gravelly sand, sand, silty sand and sandy silt. The depth of sand sediment on Batam beach is between 1 to 2.6 meters, while the depth of sand sediment in Bintan Island coastal is between 0.6 meters to 2 meters. Keywords: sediment, grain size, sands, substrate material, Riau Strait

scholarly journals JENIS DAN SEBARAN SEDIMEN DI PERAIRAN PAPELA DAN SEKITARNYA, ROTE-NDAO, NUSA TENGGARA TIMUR

2016 ◽  
Vol 13 (3) ◽  
pp. 153
Author(s):  
Deny Setiady ◽  
Udaya Kamiludin ◽  
Nienu Yayu Gerhaneu
Keyword(s):  
Grain Size ◽  
Water Area ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Sediment Distribution ◽  
The North ◽  
Sandy Silt ◽  
Seafloor Sediments

Daerah Penelitian terletak di perairan Papela dan sekitarnya yang merupakan bagian dari Selat Rote yang secara administratif merupakan wilayah dari Kabupaten Rote-Ndao, Provinsi Nusa Tenggara Timur. Di daerah penelitian pada 40 lokasi telah dilakukan pengambilan sedimen dasar laut dengan pemercontoh comot, deskripsi megaskopis dan analisis besar butir. Penelitian bertujuan untuk mengetahui jenis sedimen, sebaran sedimen dan lingkungan pengendapannya. Berdasarkan hasil analisis besar butir nomenklatur sedimen di daerah penelitian dijumpai 4 jenis sedimen yaitu: kerikil, pasir, pasir lanauan, lanau pasiran dan lanau. Sebaran kerikil terdapat di dua tempat, yaitu di utara dan selatan tepian daerah penelitian.Sebaran pasir mencapai kurang lebih 30 % dari luas perairan penelitian, pasir lanauan menutupi kurang 5 % dari luas perairan penelitian, lanau pasiran mempunyai sebaran kurang lebih 30 % dari luas perairan daerah penelitian dan sebaran lanau terdapat di muka muara sungai bagian dalam Teluk Papela dengan tutupan kurang lebih 5 % dari luas perairan penelitian.Kata kunci Sedimen permukaan dasar laut, analisis besar butir, sebaran sedimen, perairan Papela The study area is located in Papela waters area and that is part of the Rote Strait, administratively is a region of Rote-Ndao regency, East Nusa Tenggara Province. The method of research conducted is sampling seafloor sediments, megaskopis description and analysis of the grain size. The study area is located in Papela waters area and that is part of the Rote Strait, administratively is a region of Rote-Ndao regency, East Nusa Tenggara Province. The method of research conducted is sampling seafloor sediments, megaskopis description and analysis of the grain size. The purpose of research is the grain size analysis of seabed surface sediment to determine the type of sediment, sediment distribution and depositional environment. Based on nomenklature sediment grain size analysis result in the study area was found four types of sediments , there are: gravelly, sand, silty sand, sandy silt and silt Distribution of gravel found in two places, namely on the north and south banks of the study area. Distribution of sand reaches approximately 30% of the water area of research, silty sand covering approximately 5% of the water area of research, sandy silt has spread approximately 30% of the total water area of research and distribution of silt contained in the inner face of the Gulf estuaries Papela with cover approximately 5% of the water area of research. Keywords: Surficial sediment, grain size analysis, sediment distribution, Papela Waters

scholarly journals Preliminary Study of Heavy Metal (Zn, Pb, Cr, As, Cu, Cd) Contaminations on Different Soil Level from Post-Mining Bauxite Production for Aquaculture

2018 ◽  
Vol 47 ◽  
pp. 02008
Author(s):  
Risandi Dwirama Putra ◽  
Tri Apriadi ◽  
Ani Suryanti ◽  
Henky Irawan ◽  
Tengku Said Raja'I ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Grain Size ◽  
Negative Impact ◽  
Fine Sand ◽  
Mining Area ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The Mean ◽  
Soil Level

Bauxite production and exploration give negative impact environmental modification and increasing concern pollution of heavy metals. One of an alternative to reduce the negative impact of bauxite post-mining production is by re-utilizing the abandoned bauxite land and necessary exploratory study to obtain the current environmental conditions primarily related to heavy metals in bauxite mining area. Soil and water quality samples from 5 (five) sites based on post-mining activities were used to determine concentration heavy metals of As, Cd, Pb, Zn, Cr, Cu from different soil level. They were also collected for grain size analysis including those of sand and mud percentages along with the mean, and sorting analysis. The mean grain size post-mining bauxite ranged between very fine sand to medium sand and had heterogeneous texture. The coarse grain size percentage increased towards the bottom of the soil. Total heavy metal contents for post-mining bauxite soils are 0,081 ppm, 0,245 to 0,471 ppm and 0,007 ppm for As, Pb and Cd respectively. Heavy metals for Cd, uniformly at every depth from soil level. On the other hand, Pb showed significance pattern, it was indicated every depth from soil level, the concentration of Pb was different.

scholarly journals Pengolahan Sedimen Layang dan Sedimen Terendap Survei Hidro-Oseanografi Banjarmasin 2015

2016 ◽  
Vol 2 (1) ◽  
pp. 71-88
Author(s):  
Ngavif Ardani ◽  
Saroso Saroso ◽  
Kamija Kamija ◽  
Khoirol Imam Fatoni
Keyword(s):  
Grain Size ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Size Analysis

Keselamatan pelayaran adalah suatu keadaan terpenuhinya persyaratan keselamatan dan keamanan yang menyangkut aktivitas angkutan pada alur pelayaran dan di pelabuhan. Salah satu kendala yang dihadapi untuk mendukung terlaksananya kegiatan di pelabuhan dengan aman adalah terjadinya pendangkalan kolam. Laju sedimentasi yang cepat merupakan kendala bagi kelancaran operasional pelabuhan Banjarmasin dan alur pelayarannya. Penting dilakukan kajian untuk mengetahui karakteristik proses sedimentasi yang terjadi. Karakter sedimen laut dapat diidentifikasi dengan ukuran butir sedimen, komposisi sedimen, mekanisme transportasi, dan lingkungan pengendapan. Ukuran butir adalah sifat-sifat yang sangat fundamental dari partikel sedimen, mempengaruhi pengangkatan (entrainment), transport dan pengendapan sedimen. Analisa ukuran butir sedimen memberikan kunci penting bagi asal-usul sedimen, sejarah transportasi, dan kondisi pengendapan. Analisa ukuran butir sedimen memberikan gambaran tentang sifat-sifat fisik sedimen yang berkaitan dengan kemungkinan pemanfaatannya untuk berbagai keperluan. Adapun untuk pengolahan sedimen layang dapat dilakukan dengan metode penyaringan (filtering) dan sedimen terendap dengan metode kering sampai dengan mendapatkan hasil jenis sedimen dan analisis ukuran butir (Grain Size Analysis). Hasil pengolahan sedimen tersebut didapatkan nilai rata-rata kandungan sedimen layang pada daerah survei adalah 0,0309 gram/liter dan berdasarkan ukuran rata-rata dari ukuran partikel sedimen yang mendominasi adalah fraksi pasir dengan jenis Silty Sand. Berdasarkan nilai Sortasi, terlihat bahwa partikel sedimen pada umumnya terpisah dengan buruk dengan klasifikasi Poorly Sorted. Dilihat dari nilai kurtosisnya didominasi jenis leptokurtic. Selanjutnya dari nilai Skewness dominan bernilai negatif, hal ini dapat menggambarkan bahwa kecendrungan partikel kasar.

scholarly journals SEDIMENTOLOGICAL PROPERTIES OF THE 2010 MENTAWAI TSUNAMI DEPOSIT

2016 ◽  
Vol 27 (2) ◽  
pp. 55
Author(s):  
Yudhicara Yudhicara ◽  
Andrian Ibrahim
Keyword(s):  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Transport Processes ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Tsunami Deposit ◽  
Tsunami Deposits ◽  
Sponge Spicule ◽  
Run Up

Post tsunami survey of the October 25, 2010, Mentawai tsunami, has been carried out by a collaboration team of Indonesian-German scientists from 20 to 28 November 2010. One activity of the researches were investigation on tsunami deposits along the coast following the event that devastated the islands of Sipora, North Pagai and South Pagai. Sedimentological properties of Mentawai tsunami deposit were explained by this study, from both megascopic and laboratory result. In general, beaches along the study area are underlying by a stretch of reef limestone, sediments mostly composed of white sand while grey sand was found only at Malakopa. Tsunami sediments were taken from 20 locations, start from Betumonga at Sipora Island until Sibaru-baru Island at the southern tip of the study area. The thickness of tsunami deposits are ranged between 1.5 and 22 cm, which are generally composed of fine to coarse sand in irregular boundaries with the underlying soil. Based on grain size analysis, variation of sedimentological properties of tsunami deposits range between phi=-0,5793 and phi=3,3180 or very coarse to very fine sand. Tsunami deposits mostly have multiple layers which described their transport processes, run up at the bottom and back wash at the top. Structural sediments such as graded bedding of fining upward, parallel lamination and soil clast were found. The grain size distribution curves show two types of mode peak, unimodal and multimodal which are indication of different sorting condition representing the source materials. While segment grain size accumulative plot generally shows domination of dilatation and traction transport mechanism rather than suspension. In general, very rare fossils were found from Mentawai tsunami deposit, but those findings gave information on how depth tsunami start to scour the seafloor and transport it landward, such as an abundance of Sponge spicule was found which indicate shallow water environments (20-100 m seafloor depth). Keywords: 2010 Mentawai tsunami, tsunami deposit, grain size analysis, fossils identification. Survei pasca-tsunami Mentawai 25 Oktober 2010, telah dilakukan oleh Tim gabungan Indonesia-Jerman pada tanggal 20 - 28 November 2010. Salah satunya adalah melakukan identifikasi endapan tsunami yang ditemukan di sepanjang pantai yang terlanda tsunami di Pulau Sipora, Pagai Utara dan Pagai Selatan. Berdasarkan hasil penelitian baik megaskopik maupun analisis laboratorium, dalam tulisan ini dapat dijelaskan mengenai sifat-sifat sedimentologi dari endapan tsunami Mentawai. Secara umum litologi penyusun pantai di daerah penelitian disusun oleh hamparan batugamping terumbu, sebagian disusun oleh pasir berwarna putih, sedangkan di Malakopa tersusun oleh endapan pasir pantai berwarna abu-abu. Berdasarkan hasil analisis laboratorium, diperoleh variasi sifat sedimentologi, seperti kisaran ukuran butir endapan tsunami antara -0,5793 phi dan 3,3180 phi, yaitu pasir sangat kasar hingga sangat halus. Endapan tsunami umumnya memiliki beberapa lapis yang menunjukkan adanya proses transportasi, seperti saat air naik (run up) di lapisan bagian bawah dan surut di bagian atas, yang ditunjukkan dengan adanya perbedaan ukuran butir. Struktur sedimen ditemukan seperti adanya perubahan besar butir secara berangsur menghalus ke bagian atas, perlapisan sejajar dan fragmen tanah yang terperangkap dalam sedimen. Kurva distribusi ukuran butir memperlihatkan dua jenis model puncak, yaitu unimodal dan multimodal yang memperlihatkan kondisi pemilahan yang berbeda yang menunjukkan kondisi sumber material endapan tsunami, sedangkan grafik akumulasi ukuran butir umumnya memperlihatkan dominasi mekanisme transportasi dilatasi dan traksi daripada suspensi. Secara umum fosil yang terkandung dalam endapan tsunami Mentawai sangat jarang, namun sedikit banyak telah memberikan informasi seberapa dalam gelombang tsunami mulai menggerus lantai samudera dan memindahkannya ke darat, misalnya dengan ditemukannya fosil bentonik Sponge spicule yang melimpah, menunjukkan asal lingkungan laut dangkal dengan kedalaman laut 20-100 m. Kata kunci: Tsunami Mentawai 2010, endapan tsunami, analisis besar butir, identifikasi fosil.

scholarly journals GEOMORPHOLOGY, SEDIMENTOLOGY AND GEOCHEMISTRY IN THE MARINE AREA BETWEEN SIFNOS AND KIMOLOS ISLANDS, GREECE

2017 ◽  
Vol 50 (1) ◽  
pp. 334 ◽  
Author(s):  
A.P. Karageorgis ◽  
Chr. Ioakim ◽  
G. Rousakis ◽  
D. Sakellariou ◽  
G. Vougioukalakis ◽  
...  
Keyword(s):  
Grain Size ◽  
Surface Sediment ◽  
Aegean Sea ◽  
Mineralogical Composition ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Sediment Provenance ◽  
Size Analysis ◽  
Sediment Distribution ◽  
Marine Area

An extensive oceanographic survey was conducted in the marine area between Kimolos and Sifnos Islands, a rather poorly-studied sector of the Aegean Sea, in order to gain better understanding of submarine geomorphological features and associated sediment provenance. Multi-beam bathymetry and surface sediment sampling with a box corer were carried out on board R/V Aegaeo, followed by grain-size analysis, XRD and XRF measurements. A large circular depression was identified north of Kimolos reaching a water depth of 743 m, filled with fine grained sediments. Surface sediment distribution is characterized by gradual decrease in grain-size from silty sand to silt in a S-N direction. The mineralogical composition comprises calcite, Mgcalcite, aragonite, dolomite, quartz, K feldspars, plagioclase, amphiboles and clay minerals. Major sediment provinces identified were: (i) the shallow sector proximal to Kimolos, characterized by higher contents in Si, Al, K, Rb and Ba; (ii) the deep area west of Sifnos, including the large depression, characterized by higher contents in Fe, Ti, Na, Mg, S, Cr, Cu, Ni, V, Zn; and (iii) the south passage between Kimolos and Sifnos, which exhibits higher Ca, S, and Sr contents. Manganese enrichment was observed in and around the bathymetric depression, where Mn oxides act efficiently as scavengers of a suite of metals.

scholarly journals CARACTERÍSTICAS SEDIMENTOLÓGICAS DA PLATAFORMA CONTINENTAL INTERNA RASA NA PORÇÃO CENTRAL DO LITORAL PARANAENSE

2004 ◽  
Vol 55 ◽  
Author(s):  
Fernando Alvim VEIGA ◽  
Rodolfo José ANGULO ◽  
Eduardo MARONE ◽  
Frederico Pereira BRANDINI
Keyword(s):  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Bathymetric Data ◽  
Mean Grain Size ◽  
Inner Continental Shelf ◽  
Water Depths ◽  
Sand Sediments

O objetivo deste trabalho é caracterizar os sedimentos da plataforma continental interna paranaense entre as profundidades de 5 a 15 m entre os estuários de Guaratuba, ao sul e Paranaguá, ao norte da área de estudo. Informações batimétricas, análises granulométricas e determinação de teores de carbonato e matéria orgânica de amostras de sedimentos de fundo permitiram a geração dos mapas temáticos. Observou-se uma grande predominância de areia fina, porém a média granulométrica dos sedimentos varia do silte grosso até a areia grossa. Foram identificados cinco padrões distintos de sedimentos na área estudada: i) as areias fina e muito fina do delta de maré vazante associado à desembocadura sul do Complexo Estuarino de Paranaguá; ii) as areias muito finas bimodais, com teores de finos entre 10 e 40 %, localizadas próximas à costa, iii) as areias média e grossa unimodais; iv) as areias finas na faixa dos 10 a 15 m de profundidade, unimodais menos selecionadas que as areias finas do delta de maré vazante; v) as areias finas a muito finas das barras do início da zona de arrebentação. SHOREFACE SEDIMENTOLOGY AT PARANÁ MIDDLE COAST Abstract The aim of this work aims at knowing the shallow inner continental shelf between 5 and 15 m water depths of the State of Paraná between the Guaratuba (south) and Paranaguá (north) estuaries. Bathymetric data, grain size analysis and carbonate and organic matter rates of bottom sediments samples allowed to make thematic charts of this deposicional environment. The predominance of fine sand is quite large; despite the mean grain size of the samples varies (coarse silt to coarse sand). It was identified five different sediment patterns at the study area: i) fine and very fine sands of the Paranaguá Estuarine Complex south mouth tide delta; ii) bimodal very fine sand with 10 to 40% rates of silt and clay that occurs near the coastline between 5 and 10 m water depths; iii) unimodal medium and coarse sand sediments; iv) fine sand sediments between 10 and 15 m water depths, unimodal but different from the delta fine sands because the distributions in more Ø intervals; v) fine and very fine sands of the beach braking bars zone.

scholarly journals Morfologia e Sedimentação em Praias Oceânicas da Amazônia Oriental durante a Variação Anual de Chuvas

2020 ◽  
Vol 13 (5) ◽  
pp. 2086
Author(s):  
LEILANHE ALMEIDA RANIERI ◽  
Maâmar El-Robrini
Keyword(s):  
Grain Size ◽  
Fine Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Dynamic Effects ◽  
Statistical Parameters ◽  
Western Sector ◽  
Sediment Sampling ◽  
Wave Heights ◽  
The Mean

Este artigo buscou analisar os efeitos dinâmicos da sazonalidade climática sobre a morfologia e sedimentação de praias oceânicas da Amazônia durante as estações chuvosa e menos chuvosa. A importância deste estudo foi demonstrar um comportamento deposicional de sedimentos nestas praias de uma estação climática à outra. A metodologia consistiu em perfilagem topográfica nas praias dos setores: oeste (Corvina e Maçarico), central (Farol Velho) e leste (Atalaia) de Salinópolis (PA), amostragem de sedimentos, análise granulométrica com aplicação de parâmetros estatísticos e medições de altura e período de ondas. O diâmetro médio dos sedimentos consistiu predominantemente de areia fina (2,6 a 2,8 phi), muito bem a bem selecionada (0,2 a 0,5). A assimetria variou, principalmente, entre positiva (0,10 a 0,30) e aproximadamente simétrica (-0,10 a 0,10). O grau de curtose entre muito platicúrtica (<0,67) a muito leptocúrtica (1,50 a 3,00). As alturas de ondas foram mais elevadas no setor leste (máximo de 1,05 m) e períodos de ondas foram mais curtos (< 4,5 s) no setor oeste. As praias apresentaram declives suaves (< 1,5°) e grandes variações na largura entre as estações do ano (9,6 a 88,4 m). Predominou o estado morfodinâmico dissipativo (Ω>5,5), mas com ocorrência do estado de banco e calha longitudinais (4,7<Ω<5,5) no setor oeste. Foi observada acreção sedimentar da estação chuvosa a menos chuvosa em todas as praias. O transporte transversal de sedimentos foi elevado, especialmente no sentido onshore (máximo: 11x10-3 kg/s/m, setor leste). No setor central foi baixo (mínimo: 0,72x10-3 kg/s/m), favorecendo tendências erosivas neste local. Morphology and Sedimentation in Ocean Beaches in the Eastern Amazon during the Annual Rain Variation A B S T R A C TThis paper aimed to analyze the dynamic effects of climatic seasonality on the morphology and sedimentation of oceanic beaches in the Amazon during the rainy and less rainy seasons. The importance of this study was to demonstrate a depositional behavior of sediments on these beaches from one climatic season to another. The methodology consisted of topographic profiling on the beaches of the sectors: west (Corvina and Maçarico), central (Farol Velho) and east (Atalaia) of Salinópolis (PA), sediment sampling, grain-size analysis with application of statistical parameters and measurements of height and wave period. The mean diameter of the sediments consisted predominantly of fine sand (2.6 to 2.8 phi), well sorted and very well sorted (0.2 to 0.5). The asymmetry varied, mainly, between positive (0.10 to 0.30) and nearly symmetrical (-0.10 to 0.10). The degree of kurtosis between very platykurtic (<0.67) to very leptokurtic (1.50 to 3.00). The wave heights were higher on the eastern sector (maximum 1.05 m) and wave periods were shorter (<4.5 s) on the western sector. The beaches presented smooth slopes (<1.5°) and great variations in width between the seasons (9.6 to 88.4 m). The dissipative morphodynamic state (Ω > 5.5) predominated, but with the occurrence of the longshore bar and trough (4.7 < Ω <5.5) in the western sector. Sedimentary accretion from the rainy to less rainy season was observed on all beaches. Cross-shore sediment transport was high, especially in the onshore (maximum: 11x10-3 kg.s-1.m-1, east sector). In the central sector it was low (minimum: 0.72x10-3 kg.s-1.m-1), favoring erosive trends in this location.Keywords: Beach, Morphodynamic, Grain-Size, Amazon.

scholarly journals Environments of upper miocene sediments in the Hanoi depression interpreted from grain-size parameters

2019 ◽  
Vol 41 (2) ◽  
pp. 182-199
Author(s):  
Mai Thanh Tan ◽  
Dinh Van Thuan ◽  
Nguyen Dich Dy ◽  
Nguyen Van Tao ◽  
Le Duc Luong ◽  
...  
Keyword(s):  
Grain Size ◽  
River Mouth ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Discriminant Functions ◽  
Linear Discriminant ◽  
Upper Miocene ◽  
Grain Size Distributions ◽  
Sand Sheet

The grain-size analysis is carried out for 49 samples of Upper Miocene sediments taken from three boreholes in the Hanoi depression. The statistic parameters of the grain size distributions such as percentiles, median, graphic mean, sorting or inclusive graphic standard deviation, inclusive graphic skewness, and graphic kurtosis are used to decipher the depositional environments and transportation mechanisms of sediments. Bivariate plotting of these parameters, the discriminant functions with four basic parameters of graphics mean, sorting, inclusive graphic skewness and graphic kurtosis, and the CM pattern with the one percentile (C) and median (M) diameters are applied for this determination. The plots of graphics mean versus sorting suggest 14% of samples being the sand sheet, 46% related to rivers and 40% of the estuarine environment. The sorting - inclusive graphic skewness plot shows a river-related environment for all samples. Linear discriminant functions show the sandstone of upper Miocene in Hanoi depression are deltaic sediments formed in unstably transporting and depositional environment, impacted by turbidity current in the coastal river-mouth. The CM pattern shows sediment transportation for most of the samples in three modes: rolling, suspension and rolling, and uniform suspension. The environmental dynamics are relatively complex and change over time.

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