Physical and chemical depositional processes when volcanoes meet lacustrine environments: the Cretaceous Imjado Volcanics, Jeungdo, southwestern Korea

2021 ◽  
pp. SP520-2021-65
Author(s):  
Yong Sik Gihm
Keyword(s):  
Lake Water ◽  
Microscopic Analysis ◽  
Chemical Precipitation ◽  
Turbidity Currents ◽  
Density Currents ◽  
Depositional Processes ◽  
Hyperpycnal Flows ◽  
Bedded Chert ◽  
Physical And Chemical ◽  
Volcaniclastic Deposits

AbstractA Cretaceous volcano-sedimentary succession (Imjado Volcanics, Jeungdo, SW Korea) was analysed to understand volcanic influences on physical and chemical depositional processes of a shallow alkaline lake during and after explosive eruptions. The succession is composed of primary and resedimented volcaniclastic deposits interbedded with fine-grained sediments and a bedded chert. The primary volcaniclastic deposits are characterized by two end-members: thick (20 m) welded lapilli tuff and thin (0.9 m) planar stratified tuff deposits. The first member deposits were accumulated by steady pyroclastic density currents (PDCs) that displaced the lake water from the shoreline. The second end-member deposits were accumulated by unsteady PDCs rapidly disintegrated at the shoreline and transformed into turbidity currents. Reworked volcaniclastic deposits are constituted of reverse to normally graded volcaniclastic sandstone, accumulated by hyperpycnal flows originating from subaerial discharge. On top of this deposit, a bedded chert is exposed and composed of microcrystalline texture without biogenic remains. The microscopic analysis and stratigraphic relationship suggest that the chert bed is formed by chemical precipitation as a result of changes in hydrochemistry of lake water by inflowing of fresh water (hyperpycnal flows) in the alkaline bottom water of the lake.

scholarly journals Ultrafiltration Process in Disinfection and Advanced Treatment of Tertiary Treated Wastewater

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 221
Author(s):  
Rafał Tytus Bray ◽  
Katarzyna Jankowska ◽  
Eliza Kulbat ◽  
Aneta Łuczkiewicz ◽  
Aleksandra Sokołowska
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Microscopic Analysis ◽  
Fecal Coliforms ◽  
Treated Wastewater ◽  
Chemical Parameters ◽  
Virus Particles ◽  
E Coli ◽  
The One ◽  
Physical And Chemical

The paper presents the results of research on the use of ultrafiltration, using membranes of 200 and 400 kDa separation, for disinfection of municipal treated wastewater. The research was conducted on a fractional technical scale using real municipal treated wastewater from two large wastewater treatment plants treating most of the wastewater over the one-million polycentric Gdańsk agglomeration (1.2 million inhabitants). UF 200 kDa and UF 400 kDa processes enabled further improvement of the physical and chemical parameters of treated wastewater. Total phosphorus (to below 0.2 mg/L–UF 200 kDa, 0.13 mg/L–UF 400 kDa) and turbid substances (to below 0.2 mg/L, both membranes) were removed in the highest degree. COD was reduced efficiently (to below 25.6 mgO2/L–UF 200 kDa, 26.8 mgO2/L–UF 400 kDa), while total nitrogen was removed to a small extent (to 7.12 mg/L–UF 200 kDa and 5.7 mg/L–UF 400 kDa. Based on the reduction of indicator bacteria; fecal coliforms including E. coli (FC) and fecal enterococci (FE) it was found that the ultrafiltration is an effective method of disinfection. Not much indicator bacterial were observed in the permeate after processes (UF 200 kDa; FC—5 CFU/L; FE—1 CFU/L and UF 400 kDa; FC—70 CFU/L; FE—10 CFU/L. However, microscopic analysis of prokaryotic cells and virus particles showed their presence after the application of both membrane types; TCN 3.0 × 102 cells/mL–UF 200 kDa, 5.0 × 103 cells/mL–UF 400 kDa, VP 1.0 × 105/mL. The presence of potentially pathogenic, highly infectious virus particles means that ultrafiltration cannot be considered a sufficient disinfection method for treated wastewater diverted for reuse or discharged from high load wastewater treatment plants to recreational areas. For full microbiological safety it would be advisable to apply an additional disinfection method (e.g., ozonation).

scholarly journals Application of the adjoint approach to optimise the initial conditions of a turbidity current

2016 ◽  
Author(s):  
Samuel D. Parkinson ◽  
Simon W. Funke ◽  
Jon Hill ◽  
Matthew D. Piggott ◽  
Peter A. Allison
Keyword(s):  
Initial Conditions ◽  
Current Model ◽  
Deep Ocean ◽  
Turbidity Current ◽  
Significant Advance ◽  
Turbidity Currents ◽  
General Behaviour ◽  
Depositional Processes ◽  
Sediment Deposits ◽  
Adjoint Approach

Abstract. Turbidity currents are one of the main drivers for sediment transport from the continental shelf to the deep ocean. The resulting sediment deposits can reach hundreds of kilometres into the ocean. Computer models that simulate turbidity currents and the resulting sediment deposit can help to understand their general behaviour. However, in order to recreate real-world scenarios, the challenge is to find the turbidity current parameters that reproduce the observations of sediment deposits. This paper demonstrates a solution to the inverse sediment transportation problem: for a known sedimentary deposit, the developed model reconstructs details about the turbidity current that produced these deposits. The reconstruction is constrained here by a shallow water sediment-laden density current model, which is discretised by the finite element method and an adaptive time-stepping scheme. The model is differentiated using the adjoint approach and an efficient gradient-based optimisation method is applied to identify turbidity parameters which minimise the misfit between modelled and observed field sediment deposits. The capabilities of this approach are demonstrated using measurements taken in the Miocene-age Marnoso Arenacea Formation (Italy). We find that whilst the model cannot match the deposit exactly due to limitations in the physical processes simulated, it provides valuable insights into the depositional processes and represents a significant advance in our toolset for interpreting turbidity current deposits.

Introduction to Leachate Treatment

2015 ◽  
pp. 200-218
Author(s):  
Amin Mojiri ◽  
Siti Fatihah Binti Ramli ◽  
Wan Izatul Saadiah Binti Wan Kamar
Keyword(s):  
Landfill Leachate ◽  
Membrane Filtration ◽  
Chemical Precipitation ◽  
Electrochemical Treatment ◽  
Chemical Oxidation ◽  
Treatment Technique ◽  
Leachate Treatment ◽  
Exchange Adsorption ◽  
Suitable Treatment ◽  
Physical And Chemical

Leachate is created while water penetrates through the waste in a landfill, carrying some forms of pollutants. The goal of this chapter is the introduction to leachate treatment. Biological, physical, and chemical treatments of leachate are the most common methods. The biological techniques in leachate treatment are studied. The physical-chemical ways for landfill leachate treatment like chemical precipitation, chemical oxidation, coagulation–flocculation, membrane filtration, ion exchange, adsorption and electrochemical treatment are studied. The landfill leachate properties, technical applicability and constraints, effluent discharge alternatives, cost-effectiveness, regulatory requirements and environmental impact are important factors for selection of the most suitable treatment technique for landfill leachate treatment.

3-D Simulation of Sedimentation in Turbidity Currents

2007 ◽  
Author(s):  
S. Hormozi ◽  
B. Firoozabadi ◽  
H. Ghasvari Jahromi
Keyword(s):  
Experimental Data ◽  
Local Density ◽  
Three Dimensional ◽  
Tangential Component ◽  
Density Difference ◽  
Turbidity Currents ◽  
Density Currents ◽  
Dispersed Particles ◽  
Sloping Surface ◽  
Concentration Equation

The gravity currents on the inclined boundaries are formed when the inflow fluid has a density difference with the ambient fluid and a tangential component of gravity becomes the driving force. If the density difference arises from the suspended particles, the currents are known as particle-laden density currents, or turbidity currents in which the local density depends on the concentration of particles. A low Reynolds k-ε turbulent model is used to simulate three dimensional turbidity currents. Also some laboratory tests were conducted to study the 3D flow resulting from the release of particle laden density currents on a sloping surface in a channel of freshwater via a sluice gate. Kaolin was used as the suspended material. The height, width, velocity and concentration profiles of turbidity currents were calculated and compared with the experimental data and showed good agreement. Different settling velocity formulas based on, first, solitary particle and, second, considering the effect of dispersed particles thorough the fluid are exerted in the concentration equation and the results compare with each other. Also the sedimentation heights of the turbidity current are simulated which are compatible with the experimental data.

Geology and mineralogy of a sepiolite-palygorskite occurrence from SW Eskişehir (Turkey)

Clay Minerals ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 93-104 ◽  
Author(s):  
M. Yeniyol
Keyword(s):  
Lake Water ◽  
Genetic Relationships ◽  
Field Work ◽  
Chemical Precipitation ◽  
Main Process ◽  
Arid Conditions ◽  
Alkaline Lake ◽  
Thick Part ◽  
Sem Analyses

AbstractThe present occurrence is the only deposit among those found in Eskişehir province containing both sepiolite and palygorskite in economic amounts. To describe the geology, mineralogy and genetic relationships, two representative measured sections were examined by field work and XRD, XRF and SEM analyses. Sepiolite and palygorskite occur in a ∼40 m thick part of Pliocene sequence where saponite is also found. These minerals appear in ascending order as: palygorskite, saponite, saponite + palygorskite, sepiolite and sepiolite + palygorskite, frequently in association with dolomite. Chemical precipitation from the alkaline lake environment under semiarid or arid conditions was the main process resulting in sepiolite, palygorskite and saponite formation. Of these, saponite and palygorskite were formed when the lake water was rich-in Al and Fe. Changes in pH may have controlled whether saponite or palygorskite could be formed. Palygorskite was also developed by transformation from saponite during diagenesis.

EXPERIMENTS ON DENSITY AND TURBIDITY CURRENTS: II. UNIFORM FLOW OF DENSITY CURRENTS

1966 ◽  
Vol 3 (5) ◽  
pp. 627-637 ◽  
Author(s):  
Gerard V. Middleton
Keyword(s):  
Reynolds Number ◽  
Average Velocity ◽  
Large Scale ◽  
Quantitative Estimation ◽  
Uniform Flow ◽  
Turbidity Currents ◽  
Density Current ◽  
Density Currents ◽  
Review Of The Literature ◽  
Fluid Interface

The basic theory for the average velocity of uniform flow of a density current is now well established. The resistance at the bottom may be estimated from reasonable assumptions regarding the roughness of the bottom and the size of the current. The principal problem remaining is quantitative estimation of the resistance of the upper (fluid) interface. A review of the literature suggests that this resistance increases with increase in Froude number and decreases with increase in Reynolds number, and the writer's experiments support this hypothesis.As many turbidity currents are large scale and flow over low slopes of relatively small roughness it seems probable that both the bottom resistance and the resistance at the upper interface are small.

scholarly journals How do tectonics influence the initiation and evolution of submarine canyons A case study from the Otway Basin, SE Australia

2021 ◽  
Author(s):  
Nan Wu ◽  
Harya Nugraha ◽  
Michael Steventon ◽  
Fa Zhong
Keyword(s):  
Late Miocene ◽  
Submarine Canyon ◽  
Turbidity Currents ◽  
Submarine Canyons ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Depositional Processes ◽  
Seabed Topography ◽  
Gravity Driven ◽  
Unconformity Surface

The architecture of canyon-fills can provide a valuable record of the link between tectonics, sedimentation, and depositional processes in submarine settings. We integrate 3D and 2D seismic reflection data to investigate the dominant tectonics and sedimentary processes involved in the formation of two deeply buried (c. 500 m below seafloor), and large (c. 3-6 km wide, >35 km long) Late Miocene submarine canyons. We found the plate tectonic-scale events (i.e. continental breakup and shortening) have a first-order influence on the submarine canyon initiation and evolution. Initially, the Late Cretaceous (c. 65 Ma) separation of Australia and Antarctica resulted in extensional fault systems, which then formed stair-shaped paleo-seabed. This inherited seabed topography allowed gravity-driven processes (i.e. turbidity currents and mass-transport complexes) to occur. Subsequently, the Late Miocene (c. 5 Ma) collision of Australia and Eurasia, and the resulting uplift and exhumation, have resulted in a prominent unconformity surface that coincides with the base of the canyons. We suggest that the Late Miocene intensive tectonics and associated seismicity have resulted in instability in the upper slope that consequently gave rise to emplacement of MTCs, initiating the canyons formation. Therefore, we indicate that regional tectonics play a key role in the initiation and development of submarine canyons.

scholarly journals Fringe or background: Characterizing deep-water mudstones beyond the basin-floor fan sandstone pinchout

2020 ◽  
Vol 90 (12) ◽  
pp. 1678-1705
Author(s):  
Kévin Boulesteix ◽  
Miquel Poyatos-Moré ◽  
David M. Hodgson ◽  
Stephen S. Flint ◽  
Kevin G. Taylor
Keyword(s):  
Deep Water ◽  
Turbidity Currents ◽  
Stratigraphic Correlation ◽  
Low Density ◽  
Karoo Basin ◽  
Depositional Processes ◽  
Stratigraphic Architecture ◽  
Sand Supply ◽  
Stacking Pattern ◽  
Basin Floor

ABSTRACT Mud dominates volumetrically the fraction of sediment delivered and deposited in deep-water environments, and mudstone is a major component of basin-floor successions. However, studies of basin-floor deposits have mainly focused on their proximal sandstone-prone part. A consequent bias therefore remains in the understanding of depositional processes and stratigraphic architecture in mudstone-prone distal settings beyond the sandstone pinchouts of basin-floor fans. This study uses macroscopic and microscopic descriptions of over 500 m of continuous cores from research boreholes from the Permian Skoorsteenberg Formation of the Karoo Basin, South Africa, to document the sedimentology, stratigraphy, and ichnology of a distal mudstone-prone basin-floor succession. Very thin- to thin-bedded mudstones, deposited by low-density turbidity currents, stack to form bedsets bounded by thin packages (< 0.7 m thick) of background mudstones. Genetically related bedsets stack to form bedset packages, which are bounded by thicker (> 0.7 m thick) background mudstones. Stratigraphic correlation between cores suggests that bedsets represent the distal fringes of submarine fan lobe elements and/or lobes, and bedset packages represent the distal fringes of lobe complexes and/or lobe complex sets. The internal stacking pattern of bedsets and bedset packages is highly variable vertically and laterally, which records dominantly autogenic processes (e.g., compensational stacking, avulsion of feeder channels). The background mudstones are characterized by remnant tractional structures and outsize particles, and are interpreted as deposited from low-density turbidity currents and debris flows before intense biogenic reworking. These observations challenge the idea that mud accumulates only from hemipelagic suspension fallout in distal basin-floor environments. Thin background mudstones separating bedsets (< 0.7 m thick) are interpreted to mainly represent autogenically driven lobe abandonment due to up-dip channel avulsion. The thicker background mudstones separating bedset packages (> 0.7 m thick) are interpreted to dominantly mark allogenically driven regional decrease of sand supply to the basin floor. The recognition of sandstone-prone basin-floor fans passing into genetically linked distal fringe mudstones suggests that submarine lobes are at least ∼ 20 km longer than previously estimated. This study provides sedimentological, stratigraphic, and ichnological criteria to differentiate mudstones deposited in different sub-environments in distal deep-water basin-floor settings, with implications for the accurate characterization of basin-floor fan architecture, and their use as archives of paleoenvironmental change.

Comparison of 2-D Turbulent Particle Laden Density Current and Wall Jets

2006 ◽  
Author(s):  
S. Hormozi ◽  
B. Firoozabadi ◽  
H. Ghasvari Jahromi ◽  
H. Afshin
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Suspended Solids ◽  
Turbidity Currents ◽  
Density Current ◽  
Wall Jet ◽  
Density Currents ◽  
Ambient Water ◽  
Wall Jets ◽  
Good Agreement

Dense underflows are continuous currents, which move down the slope due to the fact that, their density are heavier than ambient water. In turbidity currents the density differences arises from suspended solids. Vicinity of the wall make density currents and wall jets similar in some sense but Variation of density cause this flows more complex than wall jets. An improved form of ‘near-wall’ k-ε turbulence model is chosen which preserve all characteristics of both density and wall jet currents and a compression is made between them. Then the outcomes from low Reynolds number k-ε model is compared with v2–f model which show similarity. Also results show good agreement with experimental data.

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