An extensive late Holocene glacier advance of Kötlujökull, central south Iceland

Anders Schomacker, Johannes Krüger, Gudrun Larsen

Rannsóknarafurð: Framlag til fræðitímaritsGreinritrýni

18 Tilvitnanir (Scopus)

Útdráttur

This paper presents data on an extensive late Holocene advance of Kötlujökull, a southeastern outlet glacier from the ice cap Mýrdalsjökull, central south Iceland. During the advance, basal till was deposited on top of a volcanic ash layer resting on lava hummocks. Remnants of this landscape are now seen 3.5-5.5 km in front of Kötlujökull as a fragment surrounded by the Mýrdalssandur. Electron microprobe analysis of the volcanic ash shows that it is silicic and originates from the volcano Katla underneath Mýrdalsjökull. A 14C AMS date on a twig fragment sampled in the upper part of the volcanic ash layer provides a maximum age of the till of 1610±40 yr BP, and this is supported by tephrochronological and geochemical analyses of the volcanic ash. It is concluded that Kötlujökull must have advanced more than 5.5 km from its present position after 1.6 kyr BP. This advance is much more extensive than the Little Ice Age (LIA) advance and took place in a relatively cold period also identified in the Greenland ice cores and the diatom record in the seas surrounding Iceland. In the proglacial environment in front of the Icelandic ice caps, the preservation potential of older end-moraines is strongly restricted due to intense glaciofluvial erosion. Therefore, the LIA end-moraines have in many cases been interpreted as marking the outermost Holocene glacier front position. This study as well as other recent results stresses the fact that the "LIA glacial maximum" in Iceland may not be identical to the Holocene glacial maximum, and that far more case studies with well-constrained dating control are needed.

Upprunalegt tungumálEnska
Síður (frá-til)1427-1434
Síðufjöldi8
FræðitímaritQuaternary Science Reviews
Bindi22
Númer tölublaðs14
DOI
ÚtgáfustaðaÚtgefið - jún. 2003

Athugasemd

Funding Information:
For financial support the authors thank the Danish Natural Science Research Council. We are also grateful to the Icelandic National Research Council for allowing us to work at the margin of Mýrdalsjökull. The polished thin sections for the electron microprobe analysis were made at the Geological Institute, University of Copenhagen. Kurt H. Kjær, Lund University, Sweden took part in the fieldwork and discussions and is recognised for invaluable partnership. The paper benefited by comments by Dr. Martin Kirkbride as well as an anonymous reviewer and Editor in Chief, Professor Jim Rose. AS acknowledges Åse H. Bringedal and Birgitte Friestad Nyland, University of Bergen, Norway for encouraging this work.

Fingerprint

Sökktu þér í rannsóknarefni „An extensive late Holocene glacier advance of Kötlujökull, central south Iceland“. Saman myndar þetta einstakt fingrafar.

Vitna í þetta