Natural radionuclides (232Th, 226Ra, 40K) and 137Cs, coming from atmospheric radioactive fallout, have been measured in sea-bed sediments of the Bay of Cádiz (South Western Spain). In this report, multivariate analysis methods have been employed to study the relationships between the activities of the radionuclides and some sedimentological variables like granulometric facies, organic content and apparent density. The correlation functions found show that it is possible to determine, with a satisfactory degree of approximation, the granulometric facies of the sediments using only radiometric information.
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http://dx.doi.org/10.1016/s0265-931x(00)00213-7 | DOI Listing |
PLoS One
November 2024
Department of Biology, University of Washington, Seattle, Washington, United States of America.
The fossil record of the U.S. Pacific Northwest preserves many Middle Miocene floras with potential for revealing long-term climate-vegetation dynamics during the Miocene Climatic Optimum.
View Article and Find Full Text PDFSci Total Environ
June 2024
Key Laboratory of Groundwater Quality and Health (China University of Geosciences), Ministry of Education, Wuhan 430078, China; School of Environmental Studies, China University of Geosciences, Wuhan 430078, China.
Significant spatial variability of groundwater arsenic (As) concentrations in South/Southeast Asia is closely associated with sedimentogenesis and biogeochemical cycling processes. However, the role of fine-scale differences in biogeochemical processes under similar sedimentological environments in controlling the spatial heterogeneity of groundwater As concentrations is poorly understood. Within the central Yangtze Basin, dissolved organic matter (DOM) and microbial functional communities in the groundwater and solid-phase As-Fe speciation in Jianghan Plain (JHP) and Jiangbei Plain (JBP) were compared to reveal mechanisms related to the spatial heterogeneity of groundwater As concentration.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2024
Ion Beam Physics, Eidgenössische Technische Hochschule Zürich, Zürich 8093, Switzerland.
Today, relatively warm Circumpolar Deep Water is melting Thwaites Glacier at the base of its ice shelf and at the grounding zone, contributing to significant ice retreat. Accelerating ice loss has been observed since the 1970s; however, it is unclear when this phase of significant melting initiated. We analyzed the marine sedimentary record to reconstruct Thwaites Glacier's history from the early Holocene to present.
View Article and Find Full Text PDFJ Environ Radioact
March 2024
Russian Academу of Sciences, Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKhI), Moscow 119991, Russia; Bauman Moscow State Technical University (BMSTU), Moscow 105005, Russia.
The Laptev Sea is remote from the impact of technogenic radionuclides, which makes it a convenient natural testing ground for determining the natural flux of radionuclides to the marine environment and further to sediments. Analysis of the use of different models for dating recent sediments using Pb showed that in conditions of erosion-accumulative (unstable) sedimentation of the shelf, the constant initial concentration (CIC) model is most preferable. This study uses a new age-depth model "RUS2023" to recalculate the excess Pb (Pb) activity into calendar years, which is a variation of the CIC model.
View Article and Find Full Text PDFNatl Sci Rev
January 2024
School of Environmental Sciences, University of Hull, Hull HU6 7RX, UK.
The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos (e.g.
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