%0 Journal Article
%A Mayr, C.
%A Lücke, A.
%A Maidana, N. I.
%A Wille, M.
%A Haberzettl, T.
%A Corbella, H.
%A Ohlendorf, C.
%A Schäbitz, F.
%A Fey, M.
%A Jansen, S.
%A Zolitschka, B.
%T Isotopic fingerprints on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina) reflect environmental changes during the last 16,000 years
%J Journal of Paleolimnology
%V 42
%@ 1129-5767
%C Verbania
%I Ist.
%M PreJuSER-6425
%P 81 - 102
%D 2009
%Z We are grateful to H. Wissel for assistance with isotope analyses and to S. Stahl for elemental analyses. The authors thank H. Kling for inspiring discussions about and determination of cyanobacteria. L. Hedena r s is thanked for determining aquatic mosses. Logistic support by C. Kennard, J. Moreteau, and G. Oliva is gratefully acknowledged. The article benefited greatly from the suggestions of P. Meyers and an anonymous reviewer and we thank T. Whitmore for editorial handling. This research was financially supported by the German Federal Ministry of Education and Research in the framework of the German Climate Research Program DEKLIM (Grants 01 LD 0034 and 0035).
%X A combination of carbon-to-nitrogen ratios (TOC/TN), Rock Eval-analyses, and stable isotope values of bulk nitrogen (delta N-15) and organic carbon (delta C-13(org)) was used to characterize bulk organic matter (OM) of a piston core from the Patagonian maar lake Laguna Potrok Aike (Argentina) for the purpose of palaeoenvironmental reconstruction. Sedimentary data were compared with geochemical signatures of potential OM sources from Laguna Potrok Aike and its catchment area to identify the sources of sedimentary OM. Correlation patterns between isotopic data and TOC/TN ratios allowed differentiation of five distinct phases with different OM composition. Before 8470 calibrated C-14 years before present (cal. yrs BP) and after 7400 cal. yrs BP, isotopic and organo-geochemical fingerprints indicate that the sediments of Laguna Potrok Aike consist predominantly of soil and diatom OM with varying admixtures of cyanobacterial and aquatic macrophyte OM. For a short phase of the early Holocene (ca. 8470-7400 cal. yrs BP), however, extremely high input of soil OM is implied by isotopic fingerprints. Previous seismic and geochronological results indicate a severe lake-level drop of 33 m below present-day shortly before 6590 cal. yrs BP. It is suggested that this lake level drop was accompanied by increased erosion of shore banks and channel incision enhancing soil OM deposition in the lake basin. Thus, isotopic data can be linked to hydrological variations at Laguna Potrok Aike and allow a more precise dating of this extremely low lake level. An isotopic mixing model was used including four different sources (soil, cyanobacteria, diatom and aquatic macrophyte OM) to model OM variations and the model results were compared with quantitative microfossil data.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000266911700007
%R 10.1007/s10933-008-9249-8
%U https://juser.fz-juelich.de/record/6425