Bündelantrag PASADO-Support 3: Identification of eolian input at the Laguna Potrok Aike drill site, Patagonia
Final Report Abstract
The goal of the project PASADO-EOLIAN was to identify a proxy for dust input that can be determined in high resolution down-core in sedimentary sequence by scanning or logging techniques (XRF or MS measurements). In particular it should be tested weather magnetic susceptibility (MS), which is successfully applied as a dust tracer in marine sediment cores can be used in the same manner in a terrestrial environment. To achieve this, a set of representative high volume (80 cm3) samples from site 5022-2CP of the ICDP-PASADO deep drilling was taken. The samples were separated into different grain size fractions and geochemical analyses were performed on bulk samples as well as on the different fractions separately. Using statistical analyses in the framework of PASADO-EOLIAN it could be demonstrated that the usability of MS as proxy for changes in the eolian sediment component is limited in the continental record of Laguna Potrok Aike (PTA). This is thus different from marine records where MS is used as a proxy for the input of dust and as such shows a good agreement with ice-core records from Antarctica. An alternative proxy for dust could not be elaborated which probably is due to the interfingering of different transport processes within the region where dust that is detectable in marine and ice-core records is generated. Principal component analyses revealed that lithological variability in the PTA 5022-2CP record is to a large extent represented by the Fe/coh values, which are positively correlated to the clay fraction of the sediments. For the last Glacial (MIS2) an external input of Fe which is probably contained in unweathered phyllosilicates in the lake’s catchment is suggested. The input path – eolian, fluvial or diffuse slope runoff – cannot be reconstructed. In the postglacial part of the record high Fe/coh variability most likely is to a large extent controlled by lake internal redox processes. Because the latter are related to changes in the prevailing climate which largely is controlled by variations in the southern hemisphere westerly winds (SHW), reconstructions of SHW changes are possible only indirectly with the PTA sediment sequence.
Publications
- (2011). New insights into paleoenvironmental changes in Laguna Potrok Aike, southern Patagonia, since the Late Pleistocene: The PASADO multiproxy record. The Holocene 22: 1323-1335
Recasens, C, D. Ariztegui, C. Gebhardt, C. Gogorza, T. Haberzettl, A. Hahn, P. Kliem, A. Lisé-Pronovost, A. Lücke, N. Maidana, C. Mayr, C. Ohlendorf, F. Schäbitz, G. St-Onge, M. Wille, B. Zolitschka and PASADO Science Team
- (2012). A step towards the identification of eolian input in the 51 ka BP sediment record of Laguna Potrok Aike in southeastern Patagonia. Abstract EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria., p.9427
Ohlendorf, C., Gebhardt, C. and the PASADO science team
- (2012). Attempts to identify eolian input in the sediment record of Laguna Potrok Aike (southeastern Patagonia). Terra Nostra 2012(2), 26-27
Ohlendorf, C., Gebhardt, C. and the PASADO science team
- (2012). Identification of eolian input at the Laguna Potrok Aike drill site, Patagonia PASADO-Eolian (Project bundle PASADO-support 3). Abstract IODP/ICDP Kolloquium Kiel 07.09.03.2012,130-131
Ohlendorf, C., Gebhardt, C. and the PASADO science team
- (2012). Seismic evidence of up to 200 m lake-level change in Southern Patagonia since Marine Isotope Stage 4. Sedimentology 59: 1087- 1100
Gebhardt, A.C., C. Ohlendorf, F. Niessen, M. De Batist, F.S. Anselmetti, D. Ariztegui, P. Kliem, S. Wastegård, B. Zolitschka
(See online at https://doi.org/10.1111/j.1365-3091.2011.01296.x) - (2013). Characterizing the eolian sediment component in the lacustrine record of Laguna Potrok Aike (southeastern Patagonia). Abstract PP11B-1820 presented at 2013 Fall Meeting, AGU, San Francisco, Calif., 9-13 Dec.
Ohlendorf, C., Gebhardt, C. and the PASADO science team
- (2013). Environment and climate of the last 51,000 years – new insights from the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). Quaternary Science Reviews 71: 1-12
Zolitschka B., Anselmetti F., Ariztegui D., Corbella H., Francus P., Lücke A., Maidana N.I., Ohlendorf C., Schäbitz F. and Wastegård S.
(See online at https://doi.org/10.1016/j.quascirev.2012.11.024) - (2013). Mechanisms of lake-level change at Laguna Potrok Aike (Argentina) – insights from hydrological balance calculations. Quaternary Science Reviews 71: 27-45
Ohlendorf C., Fey M., Gebhardt C., Haberzettl T., Lücke A., Mayr C., Schäbitz F., Wille M. and Zolitschka B.
(See online at https://doi.org/10.1016/j.quascirev.2012.10.040) - Experiences with XRF-scanning of long sediment records. In: Rothwell G. and Croudace I. (eds). Micro-XRF Studies of Sediment Cores. Developments in Paleoenvironmental Research, Vol. 17. 2015, pp 351-372.
Ohlendorf, C., Wennrich V. and Enters D.
(See online at https://dx.doi.org/10.1007/978-94-017-9849-5_13)
