[Ohlendorf] Bündelantrag PASADO-Support 3: Identification of eolian input at the Laguna Potrok Aike drill site, Patagonia

German Title: Bündelantrag PASADO-Support 3: Identification of eolian input at the Laguna Potrok Aike drill site, Patagonia

Abbreviation: 288

Current Status: completed

Main Applicant:Dr. Christian Ohlendorf

Resources Recipient

Other Persons

Dr. Catalina Gebhardt

Conveyor Begin:
Conveyor End:
Conveyor Duration:
Year: 2011


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.

Related Publications

Recasens Vargas, Cristina (2012). "Diatoms as indicators of hydrologic and climatic changes in Laguna Potrok Aike, Patagonia (PASADO)" Dissertation