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Full-Text Articles in Social and Behavioral Sciences
Reappraisal Of Uranium-Series Isotope Data In Kamchatka Lavas: Implications For Continental Arc Magma Genesis, Anthony Dosseto, Simon Turner
Reappraisal Of Uranium-Series Isotope Data In Kamchatka Lavas: Implications For Continental Arc Magma Genesis, Anthony Dosseto, Simon Turner
Faculty of Science, Medicine and Health - Papers: part A
Uranium-series isotopes can be used to determine constraints on the timescale of slab dehydration and melt production at subduction zones. However, interpretations of U–Th–Ra data suggest very different timescales of slab dehydration. Here, we present new U–Th–Ra data from Kamchatka along with a number of alternative models for production of radioactive disequilibrium. Variations in (226Ra/230Th) and (231Pa/235U) activity ratios are best explained by crystal fractionation with host rock assimilation for a duration of less than c. 6000 years. The association of the largest 226Ra excesses with high Sr/Th in the most primitive lavas suggests that Ra–Th fractionation is controlled by …
Pliocene To Pleistocene Climate And Environmental History Of Lake El'gygytgyn, Far East Russian Arctic, Based On High-Resolution Inorganic Geochemistry Data, V Wennrich, P S. Minyuk, V Borkhodoev, Alexander Francke, B Ritter, Norbert R. Nowaczyk, M A. Sauerbrey, J Brigham-Grette, Martin Melles
Pliocene To Pleistocene Climate And Environmental History Of Lake El'gygytgyn, Far East Russian Arctic, Based On High-Resolution Inorganic Geochemistry Data, V Wennrich, P S. Minyuk, V Borkhodoev, Alexander Francke, B Ritter, Norbert R. Nowaczyk, M A. Sauerbrey, J Brigham-Grette, Martin Melles
Faculty of Science, Medicine and Health - Papers: part A
The 3.6 Ma sediment record of Lake El'gygytgyn/NE Russia, Far East Russian Arctic, represents the longest continuous climate archive of the terrestrial Arctic. Its elemental composition as determined by X-ray fluorescence scanning exhibits significant changes since the mid-Pliocene caused by climate-driven variations in primary production, postdepositional diagenetic processes, and lake circulation as well as weathering processes in its catchment. During the mid- to late Pliocene, warmer and wetter climatic conditions are reflected by elevated Si / Ti ratios, indicating enhanced diatom production in the lake. Prior to 3.3 Ma, this signal is overprinted by intensified detrital input from the catchment, …