نتایج جستجو برای: sediment geochemistry
تعداد نتایج: 42812 فیلتر نتایج به سال:
We examined the use of dC, TOC and C/N geochemistry of sedimentary organic matter to reconstruct former sea levels and paleoenvironments in the absence of suitable microfossil data. The modern distribution of dC, TOC and C/N of 33 vegetation and 74 surface sediment samples collected from four coastal wetlands in the Thames Estuary and Norfolk, UK are described. The dC, TOC and C/N geochemistry ...
BACKGROUND Seasonal changes in pore water and sediment redox geochemistry have been observed in many near-surface sediments. Such changes have the potential to strongly influence trace metal distribution and thus create seasonal fluctuations in metal mobility and bioavailability. RESULTS Seasonal trends in pore water and sediment geochemistry are assessed in the upper 50 cm of littoral kettle...
The composition of sediment organic matter (OM) exerts a strong control on biogeochemical processes in lakes, such as those involved in the fate of carbon, nutrients and trace metals. While between-lake spatial variability of OM quality is increasingly investigated, we explored in this study how the molecular composition of sediment OM varies spatially within a single lake and related this vari...
Access to drinking water is one of the largest problems modern times, and pollution a growing problem worldwide [...]
Two data sets commonly used for geological resource assessment include bedrock geology and stream-sediment geochemistry. Traditional methods for determining relationships between these data include both qualitative and quantitative techniques. Qualitative interpretation and integration is generally based upon visual observations of spatial coincidence between the data. Quantitative results can ...
The spatial variability of As concentrations in aquifers of the Red River Delta, Vietnam, was studied in the vicinity of Hanoi. Two sites, only 700 m apart but with very different As concentrations in groundwater (site L: <10 lg/L vs. site H: 170–600 lg/L) in the 20–50 m depth range, were characterized with respect to sediment geochemistry and mineralogy as well as hydrochemistry. Sequential ex...
Environmental impact statement: This paper presents advances in a sampling technique that allows the co-analysis of anions of P, V, As, Mo, Sb, W, U and sulphide in sediment. Coanalysis of sediment solutes is particularly valuable as it allows interpretation of geochemical processes based on the behaviour of multiple analytes at the same precise time and locations. This technique has the abilit...
sediments are generally regarded as the sink for dissolved elements carried out to the sea by rivers. in order to study the source and mechanism of metal transport in sea water, 123 surface sediment samples were taken by using grab sampler in the northwest part of the persian gulf in summer. grain size analysis and geochemical analysis by icp-oes were carried out on samples after sample prepara...
The geochemical history of an upper deltaic plain pending tidal wetland restoration was reconstructed to assess remobilization of redox-sensitive constituents in sediment, identify depositional processes promoting geochemical retention, and determine the extent of contamination with Hg, As, Pb, Cu, and Zn. Three 12-14-m sediment cores were analyzed for bulk sediment geochemistry using ICP-AES. ...
The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribut...
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