conditions sedimentation redox

Periodic changes in the Cretaceous ocean and …

The Cretaceous Thermal Maximum is marked by high surface and deep-water temperatures 1,2 and rhythmic marine sedimentation with ... Fe-rich conditions develop in a narrow redox …

Frontiers | Response and Potential Indication to …

The correlation analysis shows that the authigenic enrichment of Mo and U in sediment core 3,050–2 is primarily controlled by redox conditions, rather than sediment grain size, adsorption on …

Redox classification and calibration of redox

Redox classification and calibration of redox thresholds in sedimentary systems. Thomas J. Algeo a b c., Chao Li a. Add to Mendeley. …

Timothy LYONS | Distinguished Professor of …

Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space Article Full-text available

The Role of Ice Cover in the Formation of Bottom Sediment …

The average sedimentation rate obtained for the upper part of the section was taken for the deeper horizons. Data on 137 ... In the areas with low productivity and unfavorable redox conditions, the variations of calcium and strontium contents, in addition to biogenic carbonate remains, are partially or completely determined by their contents in ...

(PDF) Geochemical and Hydrographic Evolution of the Late …

Cyclic, coupled changes in sedimentation, redox, and salinity are recorded in environments near the Catskill Delta. Additionally, a pronounced salinity gradient was present from low‐brackish ...

(PDF) Redox conditions in sediments and during …

Redox-sensitive elements in sediments, such as manganese (Mn), vanadium (V), molybdenum (Mo), and uranium (U), are promising …

Distribution of rare earth elements in sediments of the …

The fluctuation of redox conditions could account for this phenomenon due to fact that Ce is readily to be precipitated as insoluble Ce(IV) via oxidative scavenging, and when conditions evolve into reducing, the precipitated Ce will be released into solution by reductive dissolutions (Bau and Koschinsky, 2009; Steinmann and Stille, 2008).

Sea Level Rise Impacts to Coastal Marshes may be …

Sedimentation improved growth conditions at current and moderate increases in sea level by reducing flooding duration, which in-turn, increased soil Eh, and lowered porewater sulfide. ... Redox Potential. Sedimentation increased redox potential 2 cm below the soil surface under current sea levels and when sea level was increased 15 …

Beyond redox: Control of trace-metal enrichment in

Given the nearly identical redox conditions and sedimentation rates at these two sites, the most likely cause of the >2× enrichment of Mo and U at Station 6 relative to Station 7 is differences ...

Spatial variation in sediment fluxes, redox conditions, and

Albeit the conspicuous oxic environmental condition shown by the trace elements, the sedimentation rate in this oxic and shallow marine setting together with the primary productivity, suggest that ...

The Study of Uranium Accumulation in Marine …

Abstract. To evaluate the effect of redox conditions at the sedimentation stage on uranium content and U/TOC ratio in marine source rocks, we analyzed the accumulation of uranium in modern …

Changes in Redox Conditions of Surface Sediments …

First Online: 29 June 2019. 1207 Accesses. 4 Citations. Abstract. Following the blowout of the Macondo well, a sedimentation pulse resulted in significant changes in sedimentary …

A tale of shales: The relative roles of production, decomposition…

The main controlling factors for the enrichment of OM in the TYF and SXF were the sedimentation rate, paleoproductivity, and redox conditions, thus establishing the enrichment models for OM in the ...

Euxinic Environment

Overall, the Fe and Mn gets more soluble under oxygen deficient conditions (anoxic) while Cr despite being enriched under poor oxygen conditions but may be influenced by terrestrial inputs. The trace elements such as U, V, Mo are sensitive towards the redox conditions and gets enriched in the sediment providing a robust cue on redox conditions.

Beyond redox: Control of trace-metal enrichment in

Given the nearly identical redox conditions and sedimentation rates at these two sites, the most likely cause of the >2× enrichment of Mo and U at Station 6 relative to Station 7 is differences in aqueous Mo and U concentrations, which decline steeply through the upper part of the Black Sea water column, demonstrating the influence of ...

What besides redox conditions? Impact of sea-level …

Concentrations of redox-sensitive trace-element (RSTE) in marine shales have long been interpreted simply as redox proxies. However, the impact of other non-redox factors (e.g., sea-level fluctuation and seawater chemistry) on the enrichment of RSTE, especially molybdenum (Mo) and uranium (U), in sediments has been rarely …

Redox conditions in sediments and during …

Redox conditions in sediments and during sedimentation …

Redox-sensitive elements in sediments, such as manganese (Mn), vanadium (V), molybdenum (Mo), and uranium (U), are promising indicators of past redox conditions during sedimentation and early diagenesis. However, in the Ontong Java Plateau, west equatorial Pacific, there are sparse datasets of redox-sensitive elements in sediment …

Redox conditions in sediments and during …

Abstract Redox-sensitive elements in sediments, such as manganese (Mn), vanadium (V), molybdenum (Mo), and uranium (U), are promising indicators of past redox …

Organic matter enrichment of the Chang 7 member in the …

1. Introduction. The preservation of organic matter involves many physicochemical processes and factors, including nutrient availability, volcanism and hydrothermal activities, primary productivity, redox conditions, sedimentation rate, and post-depositional degradation processes (Murphy et al., 2000; Lash and Blood, …

(PDF) Development of a sediment redox potential model for …

The sedimentation of particulate organic matter from the overlying water column is the source of electron donors, and is the driving force of the overall reactions in the model. ... of primary electron acceptors such as oxygen and nitrate from the overlying water into the benthic sediments govern the redox conditions in the vicinity of the ...

Bottom water oxygenation history in southeastern

The concentrations of multiple redox-sensitive elements such as Re, U, Mo, Cd, V, Sb, and Tl were determined in sediments from the southeastern Arabian Sea (9°21′N: 71°59′E) to understand the bottom water oxygenation history throughout the past 140 ka. The enrichment of redox-sensitive elements (Re, U, Cd and Sb) above average crustal …

Geosciences | Free Full-Text | The Study of Uranium …

To evaluate the effect of redox conditions at the sedimentation stage on uranium content and U/TOC ratio in marine source rocks, we analyzed the accumulation of uranium in modern marine bottom sediments formed in different redox conditions. The behavior of uranium from bottom sediments formed in oxidizing and sub-oxidizing settings …

Phosphorus cycling from a coastal upwelling zone in the

Factors such as redox condition, sedimentation rate, grain size and metal (oxy)hydroxides have a significant impact on the dynamics of P. Authigenic P called phosphorites (Cook, 1984) are found to be rich in sediments of upwelling areas like Oman margin (Schenau et al., 2000), the continent margin of Peru (Froelich et al., 1988) and …

Astronomically forced changes in chemical weathering and redox …

Seawater redox conditions were assessed using V/Al, Mo/Al and lithofacies analyses, and these data reveal possibly two putative deoxygenation events during the Anisian. ... This suggests sedimentation rates vary throughout this section. eCOCO analyses of the 0–520.8 m Fe/Al and Zr/Al series of the of the Yongning section indicates …

Trace and rare earth element geochemistry of organic-rich …

The TOC versus redox ratios show negative correlation coefficients proving that oxic conditions are not suitable for organic matter preservation. According to the boron/gallium (B/Ga) ratio, water salinity ranges between 0.2 and 4.15 during sedimentation, indicating a freshwater environment.

Sedimentary redox conditions in continental margin …

Sedimentary redox conditions in continental margin sediments (N.E. Pacific) — Influence on the accumulation of redox-sensitive trace metals - …

Cerium geochemical composition of the upper continental

Understanding Earth's past surface redox conditions is critical for investigating the evolution of Earth's habitability, as well as understanding the causes and consequences of bio-radiation and mass extinction events (e.g., Canfield, 2005, Holland, 2006).Moreover, past surface redox data provide valuable insights into the linkage …

Palaeoclimatic influence on lake palaeoenvironment and

OM accumulation in Stage I was primarily controlled by redox conditions, followed by palaeoproductivity, terrigenous influx, and sedimentation rate. In Stage II, high palaeoproductivity and anoxic bottom water conditions controlled OM accumulation, resulting in the deposition of oil shales with abundant hydrocarbon potential.