Dating Bulk Sediments from Limnic Deposits Using a Grain Size Approach

Bibliographic Data

ID9246205
AuthorsLeo Rothacker
Year2013
Volume55
Issue3–4
Publication date2013-01-01
Open AccessNo
TypeARTICLE
VenueRadiocarbon (JOURNAL)
Journal identifiersISSN: 0033-8222 • E-ISSN: 1945-5755
PublisherCambridge University Press (CUP) (PUBLISHER)
DOI10.2458/azu_js_rc.55.16208
OpenAlexW4251410959
LanguageEN
References cited3

Radiocarbon measurements on bulk subaqueous sediments typically provide ages significantly older than actual time of deposition. This is generally caused by the presence of reworked organic compounds, which are depleted in 14C. To explore this issue of age heterogeneity, we collected 4 organic-rich samples from varying depths in a lake sediment core at the Gemündener Maar (Eifel, Germany), a lake of volcanic origin. We divided each sample into 5 standard grain-size fractions: gravel, sand, silt, clay, and 1 fraction smaller than 0.45 μm. These were cleaned separately using a standard acid-alkali-acid treatment. The highly organic gravel-size fraction provided the youngest 14C ages of all grain-size fractions and seems to be associated most closely with the time of deposition. By contrast, the silt and clay fractions show significantly older ages. If the investigated limnic sediment layer does not contain any identifiable terrestrial macrofossils, extracting and measuring coarser grain-size fractions instead of measuring bulk sediment samples will provide a better approximation of the time of sedimentation

Geochemistry · Geomorphology · Grain size · Holocene · Maar · Macrofossil · Mineralogy · Radiocarbon dating · Sediment · Sedimentation · Silt · Total organic carbon · Volcano · Chemistry · Geochemistry and Geologic Mapping · Geological formations and processes · Hydrocarbon exploration and reservoir analysis · Environmental Chemistry · Geology · Paleontology · Soil Science

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