Effect of Sedimentation on Infaunal Invertebrate Populations of Cobequid Bay, Bay of Fundy

1981 ◽  
Vol 38 (6) ◽  
pp. 642-648 ◽  
Author(s):  
Ted R. Turk ◽  
Michael J. Risk
Keyword(s):  
Grain Size ◽  
Macoma Balthica ◽  
Fine Sand ◽  
Coarse Sand ◽  
Sediment Deposition ◽  
Mya Arenaria ◽  
Bay Of Fundy ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Order Of Magnitude

Construction of a tidal dam in the upper reaches of the Bay of Fundy is expected to result in deposition of sediment. We investigated the effect of sediment deposition on populations of three major benthic species of the upper reaches: Corophium volutator, Macoma balthica, and Mya arenaria. In fences and boxes that induced deposition on intertidal mudflats, accumulation of 1.0–3.5 cm of sediment at rates of 1.9–10.2 cm/mo caused Corophium density to decrease sharply, usually by an order of magnitude. Macoma density was generally unaffected. In fishing weirs, mud that accumulated at 1.5 cm/mo to a mean depth of 5.2 cm supported normal Corophium densities. The effect of sedimentation on Mya depends strongly on grain size: LD50 was 24 cm for coarse sand, 6 cm for fine sand, and 3 cm for mud. Mya is able to burrow upward in accumulating coarse sand. Even moderate rates and depths of sediment deposition, particularly of fine sediment, could have a major adverse effect on existing Corophium and Mya populations.Key words: Bay of Fundy, tidal power, sedimentation, grain size, water content, Corophium volutator, Macoma balthica, Mya arenaria

Intertidal Catastrophes: Effect of Storms and Hurricanes on Intertidal Benthos of the Minas Basin, Bay of Fundy

1979 ◽  
Vol 36 (6) ◽  
pp. 667-669 ◽  
Author(s):  
R. K. Yeo ◽  
M. J. Risk
Keyword(s):  
Key Words ◽  
Surface Sediment ◽  
Macoma Balthica ◽  
Bay Of Fundy ◽  
Lateral Migration ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Secondary Productivity

Hurricane Beulah (July 1975) and a major storm both caused catastrophic mortalities among intertidal benthos of the Minas Basin. In both events, surface sediment was scoured off the flats, resulting in high mortalities in shallow-burrowing organisms. The storm was a more severe catastrophe than the hurricane. The demonstrated high secondary productivity of these flats is difficult to reconcile with these observations; extensive lateral migration of the benthos may aid in recovery from catastrophes. Key words: benthos, intertidal productivity, Bay of Fundy, tidal power, catastrophes, Macoma balthica, Corophium volutator

scholarly journals Marine substrate response from the analysis of seismic attributes in CHIRP sub-bottom profiles

2017 ◽  
Vol 65 (3) ◽  
pp. 332-345 ◽  
Author(s):  
Larissa Felicidade Werkhauser Demarco ◽  
Antonio Henrique da Fontoura Klein ◽  
Jorge Antonio Guimarães de Souza
Keyword(s):  
Grain Size ◽  
Seismic Reflection ◽  
Ground Truth ◽  
Fine Sand ◽  
Seismic Attributes ◽  
Coarse Sand ◽  
Unconsolidated Sediments ◽  
Shallow Gas ◽  
Size Classes ◽  
Seismic Reflection Profiles

Abstract This paper presents an evaluation of the response of seismic reflection attributes in different types of marine substrate (rock, shallow gas, sediments) using seafloor samples for ground-truth statistical comparisons. The data analyzed include seismic reflection profiles collected using two CHIRP subbottom profilers (Edgetech Model 3100 SB-216S), with frequency ranging between 2 and 16 kHz, and a number (38) of sediment samples collected from the seafloor. The statistical method used to discriminate between different substratum responses was the non-parametric Kruskal-Wallis analysis, carried out in two steps: 1) comparison of Seismic Attributes between different marine substrates (unconsolidated sediments, rock and shallow gas); 2) comparison of Seismic Attributes between different sediment classes in seafloors characterized by unconsolidated sediments (subdivided according to sorting). These analyses suggest that amplitude-related attributes were effective in discriminating between sediment and gassy/rocky substratum, but did not differentiate between rocks and shallow gas. On the other hand, the Instantaneous Frequency attribute was effective in differentiating sediments, rocks and shallow gas, with sediment showing higher frequency range, rock an intermediate range, and shallow gas the lowest response. Regarding grain-size classes and sorting, statistical analysis discriminated between two distinct groups of samples, the SVFS (silt and very fine sand) and the SFMC (fine, medium and coarse sand) groups. Using a Spearman coefficient, it was found that the Instantaneous Amplitude was more efficient in distinguishing between the two groups. None of the attributes was able to distinguish between the closest grain size classes such as those of silt and very fine sand.

scholarly journals Relationship between Grain Size Distribution and Radon Content in Surficial Sediments of Wadi Arar, Saudi Arabia

2018 ◽  
Vol 8 (1) ◽  
pp. 2447-2451 ◽  
Author(s):  
M. A. M. Alghamdi
Keyword(s):  
Grain Size ◽  
Saudi Arabia ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Fine Sand ◽  
Coarse Sand ◽  
Negative Slope ◽  
Surficial Sediments ◽  
Fourth Degree ◽  
Radon Content

Surficial sediments with low radon content are desirable materials in construction applications. In this study, the relationship between grain size and radon content was investigated in sediments collected from seven sites in Wadi Arar, Saudi Arabia, with the intent of determining whether grain size analysis could be used for rapidly assessing the suitability of potential construction materials. Thirty-five samples were collected (five per site) and the grain size distribution was determined using sieves. Radon contents were measured on composite samples with a RAD7 radon detector. Among the sediment types (gravel, coarse sand, medium sand, fine sand, and silt and clay), the best linear correlations between grain size and radon contents were found for the coarse sand (negative slope, r=0.82) and fine sand (positive slope, r=0.78). Polynomial relationships were also tested. A fourth-degree polynomial equation effectively described the correlation between grain size and radon content (R2 = 0.933). As shown by this model, the highest correlations with radon contents were detected at grain sizes smaller than 2.0 mm. Thus, grain size may be useful for preliminary site assessment work.

scholarly journals Dust Particle Size and Statistical Parameters

2021 ◽  
pp. 57-93
Author(s):  
Noor Al-Dousari ◽  
Modi Ahmed ◽  
Ali Al-Dousari ◽  
Musaad Al-Daihani ◽  
Murahib Al-Elaj
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Fine Sand ◽  
Coarse Sand ◽  
Optical Methods ◽  
Size Analysis ◽  
Coarse Silt ◽  
Statistical Parameters ◽  
Fine Silt

AbstractGrain ‘size’ can be specified and measured in several different ways. All methods of grain size determination have blemishes, and the choice of the most appropriate method is governed by the nature of the sample and the use to which the data are placed. Four main methods are currently used for size analysis of sands: (a) sieving; (b) settling tube analysis; (c) electro-optical methods, including Coulter Counter analysis and laser granulometry; and (d) computerized image analysis. The classification of the particle size distribution of Kuwait dust was mapped according to the parameters proposed by Folk And Ward (1957) which were widely used for quantitative comparisons between natural grain size distribution and the lognormal distribution that shows better sorted sediments have lower values of σ1. Maps of the distribution of dust in Kuwait were obtained that included: fine sand (F.S.), Coarse sand (C.S), Medium Sand (M.S), Very Fine Sane (V.F.S), Very Coarse Silt (V.C.Silt), Coarse Silt (C.Silt), Medium Silt (M.Silt), Fine Silt (F.Silt), Very Fine Silt (V.F.Silt), in addition to that, the deposition percentage of Clay, Sand, mud (silt plus clay) and silt were provided.

scholarly journals Analysis of the LNAPL Migration Process in the Vadose Zone under Two Different Media Conditions

2021 ◽  
Vol 18 (21) ◽  
pp. 11073
Author(s):  
Rui Zuo ◽  
Xiao Zhao ◽  
Jie Yang ◽  
Minghao Pan ◽  
Zhenkun Xue ◽  
...  
Keyword(s):  
Vadose Zone ◽  
Natural Attenuation ◽  
Fine Sand ◽  
Coarse Sand ◽  
Near Surface ◽  
Attenuation Rate ◽  
Order Of Magnitude ◽  
Medium Particle ◽  
The Media ◽  
Surface Leakage

This study focused on the processes of free infiltration, precipitation displacement, and natural attenuation of the LNAPL under the condition of near-surface leakage. Sandbox experiments were performed to explore the migration characteristics of LNAPL in the vadose zone with two media structures and the influences of the soil interface on the migration of LNAPL. The results indicate that the vertical migration velocity of the LNAPL infiltration front in medium and coarse sand was 1 order of magnitude higher than that in fine sand and that the LNAPL accumulated at the coarse–fine interface, which acted as the capillary barrier. Displacement of precipitation for LNAPL had little relationship with rainfall intensity and was obviously affected by medium particle size, where coarse sand (40.78%) > medium sand (20.5%) > fine sand (10%). The natural attenuation rate of the LNAPL in the vadose zone was related to the water content of the media; the natural attenuation rate of fine sand was higher. This study simulated the process of the LNAPL leakage from the near surface into the layered heterogeneous stratum, improved the understanding of the migration of the LNAPL under different stratum conditions, and can provide support for the treatment of LNAPL leakage events in the actual site.

Sedimentological and Biological Changes in the Windsor Mudflat, an Area of Induced Siltation

1980 ◽  
Vol 37 (9) ◽  
pp. 1387-1397 ◽  
Author(s):  
Ted R. Turk ◽  
Michael J. Risk ◽  
Roy W. M. Hirtle ◽  
Ross K. Yeo
Keyword(s):  
Organic Carbon ◽  
Water Content ◽  
Macoma Balthica ◽  
Biological Characteristics ◽  
High Water Content ◽  
Intertidal Mudflat ◽  
Organic Carbon Content ◽  
Corophium Volutator ◽  
Tidal Power ◽  
Shell Size

The causeway-induced mudflat at Windsor, Nova Scotia, was studied to determine the effect of rapid sedimentation on the sedimentological and biological characteristics of an intertidal mudflat. Compared to typical Minas Basin mudflats, the Windsor flat has high water content, (50% vs. 30% wet wt, approximately) small grain sizes, and elevated organic carbon content (0.82% vs. 0.24% dry wt). The two principal infaunal species of the Windsor flat, the amphipod Corophium volutator and the clam Macoma balthica, are less abundant than in nearby typical flats (~840 vs. ~13 000/m2 and ~640 vs. ~1500/m2, respectively), while the polychaete Heteromastus filiformis is particularly abundant at Windsor. Macoma balthica at Windsor grow faster and have a shorter lifespan (~6 yr vs. ~13 yr) than at other Minas Basin flats. Compared to other Minas Basin Macoma, the weight of Windsor Macoma increases more slowly with increasing shell size, possibly an adaptation to the more fluid Windsor sediments.These sedimentological and biological characteristics exist at Windsor nearly 10 yr after the start of flat development and show little tendency to approach typical mudflat characteristics. Our results indicate, therefore, that secondary productivity of Macoma and Corophium could be reduced by about two-thirds for at least a decade in existing Minas Basin mudflats that are covered by Windsor-type sediments as a result of the construction of a tidal power dam.Key words: Bay of Fundy, tidal power, sedimentation, water content, organic carbon, infauna, Corophium volutator, Macoma balthica, growth, mortality

Fiber Concrete for 3-D Additive Technologies

2019 ◽  
Vol 974 ◽  
pp. 367-372 ◽  
Author(s):  
Sergey V. Klyuev ◽  
Andrey V. Shevchenko ◽  
E.S. Shorstova
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Fine Sand ◽  
Coarse Sand ◽  
Additive Technologies ◽  
Fine Aggregate ◽  
Cement Ratio ◽  
Fine Grained ◽  
Fiber Concrete ◽  
Concrete Placement

Fine-grained fiber concrete used in 3D printing is significantly different from conventional heavy concrete, which is determined by the increased consumption of cement, low water-cement ratio and the absence of large aggregates. The largest grain size of fine aggregate is selected taking into account the thickness of the section, the frequency and type of reinforcement, as well as the method of concrete placement. Despite the fact that the tensile strength of concrete on fine sand is more than 1.5 times higher than the strength of concrete on coarse sand, while there is a decrease in compressive strength. Due to the peculiarities of the technology of concrete manufacturing for layering, the use of coarse sands is impractical, and therefore it was decided to use quartz sand with a particle size module of 1.12 as a filler.

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 Life-cycle analysis of coesite-bearing garnet

2021 ◽  
pp. 1-20
Author(s):  
Jan Schönig ◽  
Hilmar von Eynatten ◽  
Guido Meinhold ◽  
N. Keno Lünsdorf
Keyword(s):  
Grain Size ◽  
Fine Fraction ◽  
Fine Sand ◽  
Inclusion Size ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
Surface Erosion ◽  
Fluid Infiltration ◽  
Size Heterogeneity ◽  
High Degree

Abstract Detrital coesite-bearing garnet is the final product of a complex geological cycle including coesite entrapment at ultra-high-pressure conditions, exhumation to Earth’s surface, erosion and sedimentary transport. In contrast to the usual enrichment of high-grade metamorphic garnet in medium- to coarse-sand fractions, coesite-bearing grains are often enriched in the very-fine-sand fraction. To understand this imbalance, we analyse the role of source-rock lithology, inclusion size, inclusion frequency and fluid infiltration on the grain-size heterogeneity of coesite-bearing garnet based on a dataset of 2100 inclusion-bearing grains, of which 93 contain coesite, from the Saxonian Erzgebirge, Germany. By combining inclusion assemblages and garnet chemistry, we show that (1) mafic garnet contains a low number of coesite inclusions per grain and is enriched in the coarse fraction, and (2) felsic garnet contains variable amounts of coesite inclusions per grain, whereby coesite-poor grains are enriched in the coarse fraction and coesite-rich grains extensively disintegrated into smaller fragments resulting in an enrichment in the fine fraction. Raman images reveal that: small coesite inclusions of dimension < 9 µm are primarily monomineralic, whereas larger inclusions partially transformed to quartz; and garnet fracturing, fluid infiltration and the coesite-to-quartz transformation is a late process during exhumation taking place at c. 330°C. A model for the disintegration of coesite-bearing garnet enables the heterogeneous grain-size distribution to be explained by inclusion frequency. High abundances of coesite inclusions cause a high degree of fracturing and fracture connections to smaller inclusions, allowing fluid infiltration and the transformation to quartz, which in turn further promotes garnet disintegration.

scholarly journals Influence of Grain Sizes on Undrained Strength of Sand Mixtures

2019 ◽  
Vol 8 (9) ◽  
pp. 3154-3159
Keyword(s):  
Grain Size ◽  
Shear Strength ◽  
Land Reclamation ◽  
Fine Sand ◽  
Undrained Shear Strength ◽  
Coarse Sand ◽  
Sand Particle ◽  
Undrained Strength ◽  
Undrained Shear ◽  
Sand Grain Size

Sand is known as the main material in land reclamation works to develop and widen an area. It is important for the Geotechnical Engineer to ensure the sand used can accommodate the burden imposed from the structures to be built on it. Previous researchers have conducted studies on the strength of sand, whether focusing on the sand itself or with the presence of fines. However, the study of sand grain size effects in sand mixtures in affecting sand behavior is extremely limited. The sizes and angularity of the sand particle are believed to contribute to the behavior of sand mixtures soil. Hence, the study to investigate the effect of sand grain size on sand mixtures in term of undrained strength is being carried out. The sand was sieved to coarse sand, medium sand and fine sand then each size was mixed with kaolin at 0 %, 20 % and 40 %. The undrained strength was obtained from triaxial test on undrained condition. As a result, it is found that the maximum deviator stress, qmax increases with the decrease of fines (kaolin) content. On the other hand, at the same fines content, increased of sand size leads to the increased of qmax, which means the increased of undrained shear strength. In addition, the angular shape of sand particle was thought to contribute to the high value of undrained shear strength for the sand mixtures.

Sign in / Sign up

Export Citation Format

Share Document