The Holocene Moraine Record of Scottbreen, Spitsbergen, Svalbard

Abstract:

Scottbreen is a small alpine glacier on the west coast of Spitsbergen, Svalbard

(77°33'1.51"N, 14°21'50.21"E), whose terminal moraine abuts a 64 m a.s.l. high

marine terrace dated to an average (n=4) reservoir corrected radiocarbon age of

11,256 ± 63 14C yr BP at 57 m a.s.l. (Mangerud and Landvik, 2007, Boreas 36, 278-

285). Outboard of the right lateral moraine is an outcrop of glacially polished

quartz-rich metaconglomerate that we dated to 14.8± 0.7 ka at 142 m a.s.l. and

15.3± 0.7 ka at 104 m a.s.l. using 10Be dating. Scottbreen’s terminal moraine

formation is attributed to a serge event that occurred in the 1880’s that was

hypothesized to have overridden all older deposits (Mangerud and Landvik, 2007,

Boreas 36, 278-285). However, new high-resolution aerial photographs obtained

during the Norwegian Polar Institute’s 2012 mapping campaign reveal a series of

distinctive ridge crests on the moraine. Furthermore, field observations of these

crests show substantial variation in the degree of weathering from the most ice

distal to the proximal crests. The multiple crests may represent several cycles of

advance and retreat of the glacier that date to significantly older than the 1880’s

advance. To test this hypothesis we have collected nineteen moraine boulders on

four distinctive ridges of the terminal moraine complex for 10Be dating. The pending

results of this study will aid in bridging the time gap of this glacier’s evolution

during the course of the Holocene. The results will also reveal if Scotbreen’s

terminal moraine represents a single event or multiple advances of the glacier that

may act in or out of phase with known climatic events.