Kolling, Henriette and Bauch, Henning A. (2017) A stratigraphical-sedimentological study of the last interglacial period in the central Nordic seas on the basis of XRF core scanning. Polarforschung, 87 (1). pp. 15-22. DOI 10.2312/polarforschung.87.1.15.

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Abstract

The recognition of specific geological time intervals is one of the
major issues when establishing the stratigraphies of marine sediment cores.
The automatic XRF core scanning method provides a fast and non-destructive
method to precisely identify a given time interval and its changeable sedimentation
histories. To test the applicability of XRF core scanning to recognize
such periods, we studied in detail sedimentation processes across the
last interglacial climate cycle (MIS 5e) on unsampled sediment core section
from the central Nordic Seas – an area of high interest for paleoceanographic
reconstructions. To further ground truth the XRF scanning results the core
was sampled and the contents of iceberg-rafted debris (IRD) and shards of
tephra were quantified. On that basis we identified Ti/Ca ratios as a potential
indicator for IRD depositional peaks, and Ca as indicator of high biogenic
carbonate production. Two well-known tephras from MIS 5e, Midt-RHY
and 5e-low/Bas-IV, could be identified based on specific elemental content,
such as Si, Ti, Zr, and Rb. By cross-core correlations using Ca-content and
IRD-counts, the iceberg-free interval with enhanced deposition of biogenic
carbonate lasted for about 9 ky, with a return of significant iceberg presence
around 115 ka, notifying the onset of the last glacial inception. According to
the age model applied we could further define the age of the 5e-Midt-RHY
tephra at ~121.5 ka and of the 5e-low/Bas-IV at ~125.5 ka.

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