9:15 AM - 9:30 AM
[BCG06-02] Holocene Antarctic subglacial weathering and ice-sheet history reconstructed using the 10Be/9Be ratios of lake Maruwan Oike sediments
Keywords:Beryllium, Holocene, Antarctica, Weathering, Glacier
Meteoric 10Be is produced in the atmosphere by cosmic rays and delivered to the Earth and ocean surface via dust and precipitation. In Antarctica, these sources of 10Be become locked up in ice sheets and are subsequently released to the continental shelf during periods of melting and freshwater discharge (3), where they adhere to suspended particles in the water column and subsequently accumulate on the basin floor (4, 5). Stable 9Be is present in silicate rocks and is released during subglacial weathering (5), with little simultaneous release of 10Be (4), and transported to the oceans via meltwater outflow. When Be is incorporated into the authigenic phase of marine sediments, the 10Be/9Be reflects that of the overlying water column (6), which in turn reflects the relative dominance of freshwater flux and/or subglacial weathering.
Here, we present authigenic 10Be/9Be ratios for a sedimentary core from Lake Maruwan Oike situated at the head of the Rundvåg glacier in the Lützow-Holm Bay area of East Antarctica. Sedimentary material from L. Maruwan Oike provides an ~6,000 year record of subglacial weathering and nutrient input from the nearby glacier (7). Authigenic 10Be/9Be records reflect variations in freshwater flux and subglacial weathering and indicate several periods of enhanced melting of the Rundvåg glacier. This study provides further constraints on EAIS fluctuations during the Holocene and offers an insight into the behaviour of beryllium in high-latitude subglacial-marine systems.
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