Antarctic Science

Earth Sciences

A geochemical record of late Holocene palaeoenvironmental changes at King George Island (maritime Antarctica)

Patrick Moniena1 c1, Bernhard Schnetgera1, Hans-Jürgen Brumsacka1, H. Christian Hassa2 and Gerhard Kuhna3

a1 Institute for Chemistry and Biology of the Marine Environment (ICBM), PO Box 2503, D-26111 Oldenburg, Germany

a2 Alfred Wegener Institute for Polar and Marine Research, Wadden Sea Research Station, Hafenstrasse 43, D-25992 List, Germany

a3 Alfred Wegener Institute for Polar and Marine Research, Am Alten Hafen 26, D-27568 Bremerhaven, Germany

Abstract

During RV Polarstern cruise ANT-XXIII/4 in 2006, a gravity core (PS 69/335-2) and a giant box core (PS 69/335-1) were retrieved from Maxwell Bay off King George Island (KGI). Comprehensive geochemical (bulk parameters, quantitative XRF, Inductively Coupled Plasma Mass Spectrometry) and radiometric dating analyses (14C, 210Pb) were performed on both cores. A comparison with geochemical data from local bedrock demonstrates a mostly detrital origin for the sediments, but also points to an overprint from changing bioproductivity in the overlying water column in addition to early diagenetic processes. Furthermore, ten tephra layers that were most probably derived from volcanic activity on Deception Island were identified. Variations in the vertical distribution of selected elements in Maxwell Bay sediments further indicate a shift in source rock provenance as a result of changing glacier extents during the past c. 1750 years that may be linked to the Little Ice Age and the Medieval Warm Period. Whereas no evidence for a significant increase in chemical weathering rates was found, 210Pb data revealed that mass accumulation rates in Maxwell Bay have almost tripled since the 1940s (0.66 g cm-2 yr-1 in ad 2006), which is probably linked to rapid glacier retreat in this region due to recent warming.

(Received May 27 2010)

(Accepted November 29 2010)

(Online publication February 01 2011)

Correspondence:

c1 monien@icbm.de

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