نتایج جستجو برای: sedimentary cover

تعداد نتایج: 120130  

1999
H. A. Makse

Many sedimentary rocks are formed by migration of sand ripples. Thin layers of coarse and fine sand are present in these rocks, and understanding how layers in sandstone are created has been a longstanding question. Here, we propose a mechanism for the origin of the most common layered sedimentary structures such as inverse graded climbing ripple lamination and cross-stratification patterns. Th...

Journal: :Environmental pollution 2006
Adi Oren Zeev Aizenshtat Benny Chefetz

The Kishon River, the second largest coastal river in Israel, has been severely polluted for several decades. Sediments from upstream and downstream sites of the river were analyzed, lipid-extracted and evaluated for phenanthrene uptake. Total polycyclic aromatic hydrocarbon (PAH) concentration in downstream sediments was 299 microg kg(-1), consisting mostly of petrogenic-derived PAHs. Downstre...

1999
A. C. Fowler Xinshe Yang

Mathematical models of compaction in sedimentary basins typically assume a relationship between effective pressure p• and porosity •, which is of a non-linear type; that is, p• = p•(d). However, at depths greater than a kilometer, pressure solution becomes important and this relationship approaches a viscous one. We derive a mathematical model for viscous compaction in sedimentary basins and sh...

2005
Ye Zhang Mark Person Chris Paola Carl W. Gable Xian-Huan Wen Matthew Davis

[1] A high-resolution stratigraphic image of a flume-generated deposit was scaled up to sedimentary basin dimensions where a natural log hydraulic conductivity (ln(K)) was assigned to each pixel on the basis of gray scale and conductivity end-members. The synthetic ln(K) map has mean, variance, and frequency distributions that are comparable to a natural alluvial fan deposit. A geostatistical a...

2006
Ji-hun Ryu Robert A. Zierenberg Randy A. Dahlgren Suduan Gao

Groundwater and sediment samples (~1 m depth) at sites representative of different groundwater pathways were collected to determine the aqueous speciation of sulfur and the fractionation of sulfur isotopes in aqueous and solid phases. In addition, selected sediment samples at 5 depths (from oxic to anoxic layers) were collected to investigate the processes controlling sulfur biogeochemistry in ...

Journal: :Environmental science & technology 2004
K David Hambright Werner Eckert Peter R Leavitt Claire L Schelske

Current paradigms of reservoir ontogeny suggest that water-level fluctuations may increase sedimentary nutrient release, causing long-term eutrophication of water bodies formed by dryland flooding. Less is known of the changes in nutrient status following conversion of natural lakes into reservoirs. Here, we use historical hydrological and limnological data and paleolimnological records of sedi...

2004
W. R. Martin F. L. Sayles

7.02.3 ORGANIC MATTER DECOMPOSITION IN SEDIMENTS 40 7.02.3.1 Electron Acceptors for Sedimentary Organic Matter Oxidation 43 7.02.3.2 The Stoichiometry of Oxic Sedimentary Organic Matter Decomposition 45 7.02.3.3 The Depth Distribution of Organic Matter Oxidation in the Sediment Column 48 7.02.3.4 The Response Time for Organic Matter Oxidation 51 7.02.3.5 The Burial of Organic Matter in Marine S...

Journal: :Ecotoxicology and environmental safety 2010
Roberto Quiroz Joan O Grimalt Pilar Fernández

Sediment quality guidelines and toxic equivalent factors have been used for assessment of the toxicity of sedimentary long-range atmospherically transported polycyclic aromatic hydrocarbons (PAHs) to the organisms living in high mountain European lakes. This method has provided indices that are consistent with experimental studies evaluating in situ sedimentary estrogenic activity or physiologi...

Journal: :Geologia Croatica 2022

An exceptional exposure of volcaniclastic breccia intercalated with radiolarian cherts and limestones was studied which constitutes a unique block within the Upper Cretaceous Mamonia Mélange in Akamas Peninsula southwestern Cyprus. This breccia, represents lower part sedimentary cover Triassic Phasoula Formation volcanics. The mainly consists clasts metabasalts, diabases, metagabbros, hyaloclas...

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