Podrobnosti záznamu

    Sulfur isotope evidence for changing input of continental and marine aerosols in a 60,000-year sediment core from Lake Tulane, central Florida, USA
    Bůzek, František
    Grimm, Eric
    Jacobson, George
    Jačková, Ivana
    Norton, Stephen
    Novák, Martin
    Štěpánová, Markéta
Typ dokumentu
    článek v periodiku
Zdrojový dokument - seriál
    Chemical Geology
    Roč. 349, č. červen
Výraz tezauru
    lake sediment, sulfur isotopes, pollen, sea level, marine aerosols, climate proxy
Klíčové slovo
Abstrakt (anglicky)
   Variations in sulfur isotope ratios in lacustrine sediments are used here to reveal regional aspects of past environmental change at Lake Tulane, Florida, USA. Earlier studies of this late-Pleistocene/Holocene lake-sediment core provided the framework for assessing some of the underlying mechanisms of change in the paleolimnology of Lake Tulane. Prior research on the lake's history identified seven phases of Pinus-dominated vegetation, interpreted as periods with warm and wet climate; intervening times were relatively cool and dry. We hypothesized that variations in vegetation and climate, along with deepening of the lake, might lead to temporal changes in S cycling and in d34S of sulfur delivered to the sediment. The stratigraphy is characterized by a wide range of d34S values (+7 to +15?V-CDT), and a sequence of four major, extended trends in d34S within the 60,000-year period. Changes in the d34S profile were statistically unrelated to five tested parameters (concentrations of S, or
   ganic matter, Al, and Fe, and local vegetation). Total sulfur concentration was positively correlated with organic matter; pyrite was not detected. The d34S trends were more likely related to changes in the distance to sources of marine aerosols during the late Pleistocene and Holocene. Flux of marine aerosols (with more positive d34S) would have been lowest at the Last Glacial Maximum, about 20-25,000 cal y BP, when sea level was at least 120 m lower than present and the shorelines east and west of Florida were as much as 200 km seaward of the modern position. The d34S lake-sediment profile thus provides insights into past paleogeographic changes that are not evident in other geochemical or palynological data.
    Česká geologická služba
Kód přispěvatele
    ČGS (RIV)
Zdrojový formát
Datum importu
    15. 10. 2014