End-member modelling as a tool for climate reconstruction-An Eastern Mediterranean case study

PLoS One. 2017 Sep 21;12(9):e0185136. doi: 10.1371/journal.pone.0185136. eCollection 2017.

Abstract

The Eastern Mediterranean Sea is a sink for terrigenous sediments from North Africa, Europe and Asia Minor. Its sediments therefore provide valuable information on the climate dynamics in the source areas and the associated transport processes. We present a high-resolution dataset of sediment core M40/4_SL71, which was collected SW of Crete and spans the last ca. 180 kyr. We analysed the clay mineral composition, the grain size distribution within the silt fraction, and the abundance of major and trace elements. We tested the potential of end-member modelling on these sedimentological datasets as a tool for reconstructing the climate variability in the source regions and the associated detrital input. For each dataset, we modelled three end members. All end members were assigned to a specific provenance and sedimentary process. In total, three end members were related to the Saharan dust input, and five were related to the fluvial sediment input. One end member was strongly associated with the sapropel layers. The Saharan dust end members of the grain size and clay mineral datasets generally suggest enhanced dust export into the Eastern Mediterranean Sea during the dry phases with short-term increases during Heinrich events. During the African Humid Periods, dust export was reduced but may not have completely ceased. The loading patterns of two fluvial end members show a strong relationship with the Northern Hemisphere insolation, and all fluvial end members document enhanced input during the African Humid Periods. The sapropel end member most likely reflects the fixation of redox-sensitive elements within the anoxic sapropel layers. Our results exemplify that end-member modelling is a valuable tool for interpreting extensive and multidisciplinary datasets.

MeSH terms

  • Aluminum Silicates / chemistry
  • Clay
  • Climate*
  • Geologic Sediments / chemistry
  • Mediterranean Sea
  • Models, Statistical*
  • Time Factors

Substances

  • Aluminum Silicates
  • Clay

Grants and funding

We thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) for providing financial support to carry out the project, and also acknowledge the support of the DFG and the University of Leipzig within the programme of Open Access Publishing. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.