نتایج جستجو برای: grained sediments from fine
تعداد نتایج: 5676530 فیلتر نتایج به سال:
Natural water bodies mostly contain cations, and the type content of these cations are main factors affecting flocculation fine-grained cohesive sediments floc sedimentation rate at interface between clear turbid water. From microscopic aspect, this study examined changing patterns porosity fractal dimension flocs sediments. Sedimentation experiments under different sediment contents electrolyt...
We analyzed the abundance and distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in grain size fractions of 7 globally distributed river flank sediments and catchment soils in order to determine if and how the initial soil-brGDGT signature is influenced by hydrodynamic sorting upon entering a river and during subsequent transport from land to sea. BrGDGTs are hypothesized ...
Abstract. Alkenone signatures preserved in marine sedimentary records are considered one of the most robust paleothermometers available and often used as a proxy for paleoproductivity. However, important gaps remain regarding provenance fate alkenones, well their impact on derived environmental signals sediments. Here, we analyze abundance, distribution radiocarbon (14C) age alkenones bulk sedi...
Exceptionally preserved fossil biotas of the Burgess Shale and a handful of other similar Cambrian deposits provide rare but critical insights into the early diversification of animals. The extraordinary preservation of labile tissues in these geographically widespread but temporally restricted soft-bodied fossil assemblages has remained enigmatic since Walcott's initial discovery in 1909. Here...
Extended Abstract 1-Introduction Interdisciplinary studies play an important role in answering engineering questions. Identifying the characteristics of alluviums, underground water exploration and minerals, along with geotechnical studies in the construction of heavy structures are just some of these applications. Following the increasing drying of Lake Urmia, various research has been conduc...
The concentration of Fe, Mn, Zn, Cu, Pb, Ni, Cr, Cd, and Ag were determined in the brown alga Fucus vesiculosus and intertidal surface sediments from coastal locations of northeast England. Levels of heavy metals similar to those of polluted areas of the British coastline were detected. There is evidence of contamination (especially with Zn and Pb) in sediments from sites affected by colliery s...
Near-surface seafloor properties affect offshore mining and infrastructure engineering. Shallow sediments experience extremely low effective stress, consequently, these exhibit very in-situ density, shear wave velocity, stiffness. We combined data extracted from the literature with new laboratory field results to develop a comprehensive understanding of shallow sediments. First, we explored sed...
To understand the degradation processes of organic matter related to sulfate reduction by Sulfate Reduction Bacteria (SRB) in the tidal flat sediments of Hwang-do and Sogeun-ri, Tae-an Peninsula in Chungnam-do, biogeochemical characteristics were analyzed and highlighted using specific microbial biomarkers. The organic geochemical parameters (TOC, δCorg, C/N ratio, long-chain-n-alkane) indicate...
Heterogeneity can boost biodiversity, as well as increase the resilience of an ecosystem to changing environmental conditions; therefore, it is important to understand how topographic heterogeneity in ecosystems is formed. Sandy tidal marshes have a repetitive pattern of higher elevated hummocks surrounded by lower elevated depressions, representing topographic heterogeneity at the scale of a f...
North Africa experienced dramatic changes in hydrology and vegetation during the late Quaternary driven by insolation-induced shifts of the tropical rain belt and further modulated by millennial-scale droughts and vegetation-climate feedbacks. While most past proxy and modelling studies concentrated on the temporal and spatial dynamics of the last African humid period, little is known about the...
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