Abstract
Abstract. The records of ice-rafted debris (IRD) provenance in the North Atlantic–Barents Sea allow the reconstruction of the spatial and temporal changes of ice-flow drainage patterns during glacial and deglacial periods. In this study a new approach to characterization of the provenance of detrital quartz grains in the fraction > 500 μm of marine sediments offshore of Spitsbergen is introduced, utilizing scanning electron microscope backscattered electron and cathodoluminescence (CL) imaging, combined with laser ablation inductively coupled plasma mass spectrometry. Based on their micro-inclusions, CL and trace element characteristics, the investigated IRD grains can be classified into five distinct populations. Three of the populations are indicative of potential IRD provenance provinces in the Storfjord area including Barentsøya and Edgeøya. The results imply that under modern (interglacial) conditions IRD deposition along the western Spitsbergen margin is mainly governed by the East Spitsbergen Current controlling the ice-drift pattern. The presence of detrital quartz from local provinces, however, indicates that variations in IRD supply from western Spitsbergen may be quantified as well. In this pilot study it is demonstrated that this new approach applied on Arctic continental margin sediments bears a considerable potential for the definition of the sources of IRD and thus of spatial/temporal changes in ice-flow drainage patterns during glacial/interglacial cycles.
Highlights
Provenance studies of ice-rafted debris (IRD) in the North Atlantic–Barents Sea are a remarkable tool for providing insights into the dynamics of large ice sheets and the timing and duration of their disintegration (e.g. Hemming, 2004 for a review)
We focus on detrital quartz grains in the > 500 μm fraction of marine sediments offshore of Spitsbergen considered to be IRD derived from melting icebergs and sea ice
The quartz grains of offshore samples were classified into five major types, A to E, based on mineral micro-inclusions, CL intensity, intra-granular structures visualized by scanning electron microscope cathodoluminescence (SEM-CL) imaging and trace element content (Fig. 4)
Summary
Provenance studies of ice-rafted debris (IRD) in the North Atlantic–Barents Sea are a remarkable tool for providing insights into the dynamics of large ice sheets and the timing and duration of their disintegration (e.g. Hemming, 2004 for a review). The results of all studies have demonstrated their potential to provide insights into both the changing sea ice drift patterns in the Arctic Ocean and the complex Eurasian ice-sheet history during the Quaternary. The application of these provenance proxies is relevant for identifying large-scale geological provinces and circum-North Atlantic/Arctic ice sheet dynamics and sea ice patterns.
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