Identification of suspected paleotsunami deposits study from Karapyak Beach, Pangandaran area, West Jawa, Indonesia

2021 ◽  
Vol 36 (2) ◽  
Author(s):  
Aswan Aswan ◽  
Yan Rizal
Keyword(s):  
Thin Layer ◽  
Energy Flow ◽  
Fine Sand ◽  
High Energy ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Tsunami Deposit ◽  
Tsunami Deposits ◽  
Rock Fragments ◽  
Coarse Grains

Identifying and constraining palaeotsunami deposits can be a vital tool for establishing the periodicity of earthquakes and their associated tsunami events beyond the historical records. However, the deposits can be difficult to establish and date. In this study we used the characteristics of the 2006 Pangandaran tsunami deposit as a reference for identification of paleotsunami deposits in Karapyak Beach, Pangandaran area, West Java, Indonesia. Similar to the 2006 Pangandaran tsunami deposit, the Karapyak Beach paleotsunami deposit is characterized by light brown loose sand materials overlying a dark brown paleosoil layer with erosional contact. A thin layer that varies in thickness is locally found right above the erosional contact, with non-laminated coarser grain in the lower part that gradually change into medium to fine sand-sized in upper part. The base of the lower part is rich with broken mollusc shells and corals, and the mid-top of the lower part may contain several intact molusc shells and corals, rock fragments and anthropogenic products (rooftile). Those types of fragments are absent in the upper part of the thin layer. Grain size analysis shows a mixture of fine and coarse grains in the lower part of 2006 tsunami deposits as well as in the suspected paleotsunami deposits, suggesting uprush high energy flow during sedimentation. Fining upward sequence above mixed grain layers reflects waning flow or pre-backwash deposition. Foraminifera analysis also shows a mixture of shallow and deep marine foraminifera in the two deposits. Based on the characteristics of the 2006 tsunami deposits, there are at least four identified paleotsunami deposits at Karapyak Beach, Pangandaran area.

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 Compositional and industrial assessment of Isua-Akoko, Akure, Ayadi and Lafe (Ode Aye) clay deposits of Ondo state, Nigeria

1970 ◽  
Vol 21 (1) ◽  
pp. 41-49
Author(s):  
O Adegbuyi ◽  
GP Ojo ◽  
AJ Adeola ◽  
MT Alebiosu
Keyword(s):  
Chemical Properties ◽  
Fine Sand ◽  
Coarse Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Medium Sand ◽  
Southwestern Nigeria ◽  
Firing Test ◽  
Clay Deposits ◽  
Ondo State

The physical and chemical properties of clay deposits around Isua-Akoko, Akure, Lafe and Ayadi in Ondo State southwestern Nigeria have been examined. The results have shown that Isua-Akoko, Akure and Lafe Clays are plastic fire clays while Ayadi clay is kaolinite. Grain size analysis reveals that Isua Akoko Clay contains 45% of clay, 18% silt, 12% fine sand,14% medium sand and 11% coarse sand and no gravel; Akure clay contains 42% clay, 14% silt, 13% fine sand, 20% medium sand and 8% coarse sand with 1% gravel. Lafe Clay contains 21% clay, 8% silt, 25% fine sand, 37% medium sand and 8% coarse sand with 1% gravel while Ayadi clay contains 83% clay and 17% silt. The liquid limits of these clay samples range from 41% to 73%% and plastic limits range from 18% to 26% respectively. The chemical analysis reveals that the most abundant mineral is silica (60.97%) and aluminum was next in abundance (23.69%) while other oxides are low. The results show that Isua-Akoko and Akure are residual while Lafe and Ayadi are sedimentary and transported Clays. The firing test, PH, and bleaching tests of the clays are also discussed. The chemical and physical characteristics of the clay deposits are strongly indicative of their industrial importance in the production of ceramics, refractories, paving bricks, paint and pharmaceutical products.KEYWORDS: Kaolinite, fire clay, gravel, ceramics and alumina.

Metagenomics of tsunami deposits: developments, challenges and recommendations from a case study on the Shetland Islands (UK)

2020 ◽  
Author(s):  
Max Engel ◽  
Tasnim Patel ◽  
Sue Dawson ◽  
Anna Pint ◽  
Isa Schön ◽  
...  
Keyword(s):  
Dna Amplification ◽  
Ct Scanning ◽  
Extraction Methods ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Metagenomic Sequencing ◽  
Extreme Wave ◽  
Tsunami Deposits ◽  
Shetland Islands ◽  
Dna Primers

<p>Onshore tsunami deposits provide crucial information on tsunami recurrence patterns in flood-prone areas. Their composition is mainly a function of the site-specific coastal sediment system, bathymetry, and onshore topography and flow conditions. Microfossils (e.g. foraminifera, ostracods, diatoms) are often utilised to recognize tsunami deposits and differentiate them from other deposits. Foraminifera found within tsunami deposits mostly comprise allochthonous associations dominated by benthic intertidal to inner shelf taxa. Specimens may also originate from outer shelf to bathyal depths; even planktonic forms may occur. Furthermore, changes in test numbers, taphonomy, size or adult/juvenile ratios compared to background sedimentation are common. However, post-depositional degradation (e.g. dissolution) of carbonate tests often prevents identification, thereby reducing their value as a proxy.</p><p>The project “GEN-EX - Metagenomics of Extreme Wave Events” aims at developing high-throughput, metagenomic sequencing techniques to identify foraminifera assemblages and to unravel their cryptic diversities in onshore extreme wave deposits from their environmental DNA (eDNA) signature. The project has sampled tsunami deposits from coastal peat sections at three sites on the Shetland Islands, UK, dated to approximately 1.5, 5.5 and 8 ka BP, respectively. Tsunami deposits were identified by utilising integrative high-resolution grain-size analysis, CT scanning, multi-sensor core logging and geochemical analyses. When applying classical micropalaeontological techniques, no foraminiferal tests were found in any of the tsunami deposits analysed to date, whilst inter- to subtidal offshore source deposits show moderate to high foraminiferal concentrations, indicating possible severe post-depositional dissolution of foraminifera in the onshore tsunami deposits, which are bracketed in between massive dystrophic peats.</p><p>Several different extraction methods, polymerase chain reaction (PCR) protocols (to amplify target regions of the foraminifera DNA) and primers were tested. So far, the S14 F3 and S14 F1 primers were able to amplify the DNA of specific foraminiferal taxa from modern offshore samples, but this approach was less successful for the palaeo-samples. Current tests are focusing on targeting the amplification of another region of the foraminiferal DNA (V9), with the best available protist specific universal DNA primers at present. Possible reasons for the challenges in amplifying foraminifera DNA in the palaeotsunami samples may be due to the high age of the deposits and time-associated DNA degradation; transportation and storage of samples at ~-20 °C may also be key. However, it is possible that the foraminifera DNA is altogether absent from the sediment collected, even though this is considered unlikely given the number of tests recorded and identified in the potential subtidal source sediments. Thus, at present, a “shotgun sequencing” approach is being applied to these samples to obtain the eDNA signal in its entirety from the remains of all taxa within the sediment.</p><p>Finally, our tests so far have further revealed that the extraction method and DNA amplification protocols must be modified individually for each of the different sample types, i.e. modern offshore, modern intertidal and palaeotsunami samples, posing an added challenge to this metagenomics research. A comprehensive summary of all recommendations will be made available in the near future.</p>

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 Stratigraphic Investigations into the Late Miocene-Early Pliocene of the Northern Aorangi Range, Wairarapa

2021 ◽  
Author(s):  
◽  
Tamsin Lesley Beatrice Bertaud-Gandar
Keyword(s):  
Cross Sections ◽  
Late Miocene ◽  
High Energy ◽  
Depositional Environments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Geological History ◽  
Early Pliocene ◽  
Lithostratigraphic Units ◽  
Uplift And Erosion

<p>The late Miocene-early Pliocene geology of the Makara and Ruakokoputuna Valleys in the northern Aorangi Range, south-east Wairarapa, is described in detail. In this area, a succession of Neogene sedimentary units laps onto basement rocks of Cretaceous age, and late Miocene-early Pliocene stratigraphy varies markedly, from bathyal mudstone to high energy coastal environments, over distances of only a few kilometres. Sections were measured at four key locations, which provided reference sites for stratigraphic changes across the study area. Additional detailed field mapping was carried out around Te Ahitaitai Ridge. Depositional environments were interpreted using grain size analysis, macrofossil and foraminiferal assemblages, and palynology. Foraminiferal biostratigraphy was used to constrain the ages of samples. Data obtained by these methods were combined with previous authors’ work to produce a synthesis map, unit correlations, and geological cross-sections of the Makara and Ruakokoputuna Valleys. Late Miocene-early Pliocene geological history is interpreted, and a depositional model is proposed to explain the presence of giant cross-beds in the Clay Creek Limestone.  Despite major differences in lithology, the Clay Creek Limestone and Bells Creek Mudstone are shown to be partially laterally equivalent, while the overlying Makara Greensand is shown to be a diachronous unit which ranges from late Miocene (Kapitean) to early Pliocene (Opoitian) in age. This revised stratigraphy raises questions about the current classification of the Palliser and Onoke Groups, and provides new insights into regional geological history. The late Miocene-early Pliocene stratigraphy records a history of regional subsidence, punctuated by episodes of deformation which caused localised uplift and erosion. Previous seismic imaging studies identified one such episode of accelerated crustal shortening and deformation in the Wairarapa region near the Miocene-Pliocene boundary. The Clay Creek Limestone has proven to be a useful marker horizon for constraining the timing and style of deformation, which is interpreted to have occurred prior to 7.2 Ma. Major differences in stratigraphy between the upthrown and downthrown sides of the Mangaopari Fault indicate that the fault was active during this deformational episode. Lithostratigraphic units from the study area have been correlated with units in other parts of the Wairarapa, and these correlations suggest that late Miocene deformation in the region may have propagated from south to north.</p>

scholarly journals Evolution of sedimentation in the Vistula Lagoon of the Baltic Sea due to anthropogenic impact

2021 ◽  
Vol 12 (33) ◽  
pp. 131-148
Author(s):  
Vladimir A. Chechko
Keyword(s):  
Organic Matter ◽  
Bottom Sediments ◽  
River Runoff ◽  
Fine Sand ◽  
Test Sample ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Vistula Lagoon ◽  
The Baltic ◽  
The Vistula Lagoon

The work pursued basic objectives: to study the structure of the sedimentary strata, identify the sediment units corresponding to specific sedimentation stages of the late Holocene and evaluate the factors that influenced their formation in the Vistula Lagoon. For the achievement of the goals, well-known methods were used. The thickness of the silt deposits was measured by a hand drill. The grain size analysis of bottom sediments was determined by the mass content of particles of various sizes as a percentage of the test sample mass. The content of the total amount of organic matter in the bottom sediments and the mass loss during calcination was determined by the weight method, the determination of the mineral vivianite was carried out by standard methods accepted in geology. The Research results showed that in the lower part of the cores, organic-rich silts of olive shades are common, formed under the influence of river runoff. The sediment composition in the upper part of the cores is sharply different due to an anthropogenic factor – artificial river runoff regulation. Instead of silty sediments, the lagoon accumulated poorly consolidated, dark gray fine sand and siltstone sediments with small organic matter.

scholarly journals Sedimentological Properties of the Sand Dunes and Valley Sediments in Al-Muthanna, Southern Iraq

2021 ◽  
Vol 54 (1F) ◽  
pp. 69-84
Author(s):  
Mohammed L. Hussein
Keyword(s):  
Sand Dunes ◽  
Minor Component ◽  
Alkali Feldspar ◽  
Silty Sand ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rock Fragments ◽  
Southern Iraq

Sedimentological properties of the dunes and valley terrigenous sediments in Al-Muthanna Governorate, southern Iraq were carried out. Ten samples were collected, where five samples from both sand dunes, and valley sediments. Grain size analysis revealed that sand, silt and clay fractions are the constituents of these sediments. Sand fractions predominant in the dunes and the texture is classified as silty sand, whereas clay fractions dominate in the valley sediments, with sandy clay texture. The mineralogy is determined by X-ray diffraction, which revealed that quartz is the main mineral in both study areas, followed by calcite, feldspars in lesser amount and evaporates (gypsum) in minor component of the light minerals. Petrographically, monocrystalline quartz dominates over polycrystalline quartz in both areas. Rock fragments in the valley sediments are higher than in the sand dunes, which are comprised of carbonate, chert, igneous, metamorphic, evaporate, and mudstone rock fragments. Feldspars are approximately similar in the study areas and comprised mainly alkali feldspar (potash feldspar) and plagioclase. Petrogenically, the sand dunes occupy the quartzose-recycled field, while the valley sediments fall in transitional recycled fields represented recycled orogeny.

scholarly journals Grain Size Analysis, Textural Characterisation and Depositional Environment of Turonian Amasiri Sandstone, Southern Benue Trough, Nigeria

2021 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Grain Size ◽  
Depositional Environment ◽  
Function Analysis ◽  
High Energy ◽  
Coarse Grained ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Benue Trough ◽  
Shallow Marine ◽  
Wide Range

Grain size analysis of Turonian Amasiri Sandstone in southern Benue Trough has been undertaken to determine the controversial depositional environment of the formation. The formation was first studied on outcrops and 26 representative samples were collected and subjected to particle size analysis in line with standard procedures for dry sieving. Various methods of environmental interpretation of grain size distribution data were applied to constrain the depositional of the sandstones. The result indicates that the sands are medium and coarse-grained with mean size ranging from 0.15 to 1.87φ and averaging 0.96 φ. The sandstones are moderately to poorly sorted with standard deviation values ranging from 0.72 to 1.38 φ and averaging 1.07 φ. They exhibit a wide range of distribution from strongly coarse skewed to strongly fine skewed with skewness values ranging from -2.31 to 1.52 φ and averaging -0.04 φ but indicate a narrow range of kurtosis from mesokurtic to leptokurtic distribution with values ranging from 0.99 to 3.49 φ and an average of 2.06 φ. The sediments have bimodal with minor polymodal and unimodal distribution with primary modal size of 1.2 φ. The bivariate plots of size statistical parameters indicate fluvial environment of deposition. However, linear discriminant function analysis and the interpretations of log-probability plots indicate deposition in a fluvial, beach, and shallow marine settings, and thus suggesting a possible deposition in high-energy transitional environment. The C-M pattern of the samples indicates that sediments were transported mainly by rolling and suspension with subordinate fractions moved by rolling as well as suspension. Thus, it is deduced that Amasiri Sandstone was deposited in fluvial, beach, and agitated shallow marine environments.

The origin of igneous layering in the Nunarssuit syenite, South Greenland

1998 ◽  
Vol 62 (1) ◽  
pp. 9-27 ◽  
Author(s):  
M. E. Hodson
Keyword(s):  
Alkali Feldspar ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Density Currents ◽  
Coarse Grains ◽  
Size Sorting ◽  
Lateral Extent ◽  
Modal Layering ◽  
Preliminary Application ◽  
Igneous Layering

AbstractThe rhythmic modal layering in the Nunarssuit syenite has a vertical extent of >150 m and a lateral extent of >15 km. Individual layers average 20 cm thick and grade from a relatively melanocratic base into more leucocratic syenite over a distance of up to 5 cm. The major cumulus phases are alkali feldspar, ferro-salite/hedenbergite and fayalite. Two basic stratigraphic cycles have been identified in which faint modal layering becomes more pronounced up section, each cycle terminating in a thick melanocratic zone. Slumps, slump breccias, troughs, micro-rhythmic layering and one occurrence of crossed layers were observed.Qualitative grain size analysis indicates no size sorting in the layers. Preliminary application of crystal size distribution theory to ferro-salite/hedenbergite and fayalite from the bases of individual layers gives results which may be interpreted as indicating a relative lack of coarse grains. If the layers were deposited from density currents it would be expected that the coarsest grains would be deposited close to the source of the currents. There is no evidence in the majority of the syenite that the cumulus pile underwent compaction during crystallization.There was little, or no, primary chemical variation across individual layers. Whole-rock compositions and the ferro-salite/hedenbergite, fayalite, biotite and amphibole present in the syenites show a slight, but statistically significant, increase in the ratio Mg/(Mg+Fetotal), from the base up to the top of the layered succession.A model is suggested in which successive magma layers become more ferroan towards the top of the chamber. Cooling is concentrated at the top of the chamber and layers of magma crystallize sequentially, the uppermost, ferroan layers first. As layers of magma cool and crystallize they sink, as crystal-melt plumes, to the bottom of the chamber where they source density currents from which layers are deposited.

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

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