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.

scholarly journals Petrographic Study of Sedimentary Iron Ore in Shendi -Atbara Basin, River Nile State, Sudan.

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Abubaker A. M. A. Abasher ◽  
Sadam H.M.A. Eltayib ◽  
El Sheikh M. Abdelrahman ◽  
Mohammed M.A. Amlas
Keyword(s):  
Chemical Weathering ◽  
Iron Ore ◽  
Field Work ◽  
Chemical Precipitation ◽  
Office Work ◽  
River Nile ◽  
Stratigraphic Sequence ◽  
Thin Sections ◽  
Geological Conditions ◽  
Petrographic Study

This paper presents the results of petrographic study of sedimentary iron ore from surface strata of the Shendi -Atbara Basin, River Nile State, Sudan. The aims of this study are to investigate the geological behavior and geological conditions affecting precipitation of sedimentary iron ore. The methodologies have been used to realize the objectives of this study included; field work, office work and labrotary work include thin sections and polished sections analysis. According to field observation sedimentary iron ore can broadly be considered as occurring in three major classes: Ferribands iron, ferricrete iron and oolitic iron ores. The modes of occurrence of iron ore was described at the outcrops and vertical sedimentary profiles revealed that the iron occurred in study area at different types in stratigraphic sequence such as cap, beded and interbeded conformable with Shendi Formation. Petrographic study of iron ore in collected samples using polarized microscope and ore microscope includes study of the textures and structures of ores to obtain ore history. The main types of textures and structures in studied samples are oolitic, granular, lamellar and bands. According to these results the origin of iron ore is formed by chemical precipitation during chemical weathering of surrounding areas in continental lacustrine environment. The iron ore in study area is potential for future mining works and steals industry.

scholarly journals Authigenic formation of Ca–Mg carbonates in the shallow alkaline Lake Neusiedl, Austria

2020 ◽  
Vol 17 (7) ◽  
pp. 2085-2106
Author(s):  
Dario Fussmann ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Andreas Reimer ◽  
Dominik Schneider ◽  
Hana Babková ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Water Column ◽  
Community Composition ◽  
Pore Water ◽  
Lake Water ◽  
Bacterial Community Composition ◽  
Anoxic Sediment ◽  
Alkaline Lake ◽  
Core Depth ◽  
Dolomite Formation

Abstract. Despite advances regarding the microbial and organic-molecular impact on nucleation, the formation of dolomite in sedimentary environments is still incompletely understood. Since 1960, apparent dolomite formation has been reported from mud sediments of the shallow, oligohaline and alkaline Lake Neusiedl, Austria. To trace potential dolomite formation or diagenetic alteration processes in its deposits, lake water samples and sediment cores were analyzed with respect to sediment composition, hydrochemistry and bacterial community composition. Sediments comprise 20 cm of homogenous mud with 60 wt % carbonate, which overlies dark-laminated consolidated mud containing 50 wt % carbonate and plant debris. Hydrochemical measurements reveal a shift from oxic lake water with pH 9.0 to anoxic sediment pore water with pH 7.5. A decrease in SO42- with a concomitant increase in ΣH2S and NH4+ from 0 to 15 cm core depth indicates anaerobic heterotrophic decomposition, including sulfate reduction. The bacterial community composition reflects the zonation indicated by the pore water chemistry, with a distinct increase in fermentative taxa below 15 cm core depth. The water column is highly supersaturated with respect to (disordered) dolomite and calcite, whereas saturation indices of both minerals rapidly approach zero in the sediment. Notably, the relative proportions of different authigenic carbonate phases and their stoichiometric compositions remain constant with increasing core depth. Hence, evidence for Ca–Mg carbonate formation or ripening to dolomite is lacking within the sediment of Lake Neusiedl. As a consequence, precipitation of high-magnesium calcite (HMC) and protodolomite does not occur in association with anoxic sediment and sulfate-reducing conditions. Instead, analytical data for Lake Neusiedl suggest that authigenic HMC and protodolomite precipitate from the supersaturated, well-mixed aerobic water column. This observation supports an alternative concept to dolomite formation in anoxic sediments, comprising Ca–Mg carbonate precipitation in the water column under aerobic and alkaline conditions.

scholarly journals EFFECTS OF THERMODYNAMICAL PROCESSES ON RADIOCESIUM BEHAVIOR IN LAKE TAPELIAI / TERMODINAMINIŲ PROCESŲ ĮTAKA RADIOCEZIO ELGSENAI TAPELIŲ EŽERE

2012 ◽  
Vol 3 (6) ◽  
pp. 95-100
Author(s):  
Anastasija Moisejenkova ◽  
Aloyzas Girgždys ◽  
Nikolaj Tarasiuk
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Lake Water ◽  
Sediment Surface ◽  
Main Process ◽  
Complex Data ◽  
Data Set ◽  
Activity Concentrations ◽  
Lake Bottom ◽  
Integrated Study

The article presents the results of the integrated study of radiocesium behavior in Lake Tapeliai using not only conventional data on radiocesium activity concentrations in lake water and sediments but also a complex data set on seasonal variations and vertical profiles of standard water variables. Radiocesium activity concentrations in lake water as well as the vertical structure of the water column considerably depend on the inflows of the colored waters from the swampy watershed of the lake enriched in radiocesium. The global fallouts are mainly responsible for radiocesium inventory in lake sediments, which reaches maximum in the upper part of the water column above the ~5.4-m depth. The maximum values of radiocesium inventories in lake sediments are consistent with the respective densities of its deposits in the nearest forest soils. The main process of sediment activation is the direct sorption of radiocesium onto the sediment surface. Sedimentation rates in the lake vary mainly in the range of 3.5–5 mm·a–1. Lake bottom feeding sources located mainly on the southern terrace as well as their related near-bottom flows reduce respective sedimentation and radiocesium inventories in the sediments. Santrauka Straipsnyje nagrinėjama radiocezio elgsena Tapelių ežere, naudojant ne tik radiocezio savitojo ir tūrinio aktyvumų duomenis, bet ir standartinius vertikaliuosius parametrus, tokius kaip temperatūra, elektros laidumai ir oksiduoto sluoksnio storis. Radiocezio aktyvumas ežero vandenyje priklauso nuo spalvoto pelkinio vandens, kuriame yra radiocezio, patekimo į ežerą. Radiocezio apkrova dugno nuosėdose yra didžiausia viršutinėje ežero dalyje, t. y. iki 5,4 m gylio. Sedimentacijos greitis svyruoja 3,5–5 mm·m–1. Ežero priedugniniai vandens šaltiniai daugiausia išsidėstę pietinėje ežero terasoje, jų srovės sumažina sedimentaciją ir radiocezio apkrovą dugno nuosėdose.

scholarly journals Simulations and Laboratory Tests for Assessing Phosphorus Recovery Efficiency from Sewage Sludge

Resources ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 54 ◽  
Author(s):  
Saba Daneshgar ◽  
Armando Buttafava ◽  
Arianna Callegari ◽  
Andrea Capodaglio
Keyword(s):  
Wastewater Treatment Plants ◽  
Human Life ◽  
Chemical Precipitation ◽  
Environmental Pollutant ◽  
Phosphorus Recovery ◽  
Main Process ◽  
Recovery Efficiency ◽  
Case Scenario ◽  
Current Water ◽  
Struvite Precipitation

Phosphorus is a potential environmental pollutant, which could lead to the eutrophication of water bodies. For this reason, wastewater treatment plants worldwide are often designed and operated to eliminate phosphorous from effluents, at substantial cost. At the same time, phosphorus is an essential nutrient for agriculture and, consequently, human life. Data seem to suggest that the world will run out of phosphorus by around 2300, in the best case scenario, although even shorter estimates exist. This situation evokes the need for more efficient phosphorus recovery technologies, in order to meet current water quality requirements and—at the same time—critical future phosphorous needs. Chemical precipitation is the main process for achieving a phosphorus-containing mineral suitable for reuse as a fertilizer, where Struvite is an example of such a product. In this study chemical equilibrium of struvite precipitation was simulated using US Geological Survey (USGS)’ PHREEQC model, and results were compared to laboratory precipitation tests to evaluate struvite recovery efficiency under various conditions. pH had the most significant effect on the results and P recovery of >90% was achieved at pH = 9.5. Simulations indicated that struvite precipitation is affected by the presence of Amorphous Calcium Phosphate (ACP) and calcite in the final product of the process. The model showed great potential for predicting equilibrium conditions, and could be very helpful for future optimization of the process.

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 Reclamation of Disturbed Lands in Glen Canyon National Recreation Area

1990 ◽  
Vol 14 ◽  
pp. 69-72
Author(s):  
Cyrus McKell
Keyword(s):  
Native Species ◽  
Field Work ◽  
Small Water ◽  
Arid Conditions ◽  
Disturbed Areas ◽  
Recreation Area ◽  
Glen Canyon ◽  
Study Sites ◽  
Moisture Conditions ◽  
Mulch Cover

This report covers the first half of a project dealing with establishment of field study plots to guide reclamation of disturbed areas in Glen Canyon National Recreation Area and comparable sites. Unpredictable weather in the current drought cycle has required the rescheduling of field work to coincide with favorable soil moisture conditions. In April, 1990, study sites were established in two locations; near Paige, AZ and Hall's Crossing, UT. The site at Paige was ripped prior to planting, and the site at Hall's Crossing was located on fill over a dump area. At each site, 8 replications of 4 planting treatments involving 10 native species of grasses, forbs and shrubs were set out. Treatments were designed to create optimal conditions for establishment; including seeding with a mulch cover, transplanting of container-grown plants, planting into a small water collecting basin, and planting into a basin plus receiving a slow-release fertilizer pellet and a water retaining soil amendment. Tasks remaining are replanting some plants in March, 1991, gathering plant establishment data in March, and completing a literature review on land revegetation under arid conditions.

scholarly journals Belliella buryatensis sp. nov., isolated from alkaline lake water

2016 ◽  
Vol 66 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Lyudmila Kozyreva ◽  
Darya Egorova ◽  
Lyudmila Anan'ina ◽  
Elena Plotnikova ◽  
Elena Ariskina ◽  
...  
Keyword(s):  
Lake Water ◽  
Alkaline Lake
Sign in / Sign up

Export Citation Format

Share Document