15 Glacial Landscapes as Recorders of Geomorphic Process and Climate Change

Monday, 21 March 2016
1:30 PM - 5:30 PM
Meeting Room 1

RECORDS OF NEOGLACIATION AT SCOTTBREEN AND ON THE TRESKELEN PENINSULA, WESTERN SVALBARD

Paper number: 15-5
Program: Theme Sessions
Time: 2:35 PM – 2:55 PM

Authors

Abstract

On the archipelago of Svalbard, most glaciers reached their maximum Holocene extent during the Little Ice Age (LIA), and thereby destroyed traces of previous re-advances. However, increasing evidence of Neoglacial activity on Svalbard is mounting. We present cosmogenic 10Be exposure dating documenting pre-LIA glacier activity to further constrain the temporal and spatial variability of Holocene glaciation on Western Svalbard. The Treskelen peninsula (77.0073°N, 16.2240°E), in inner Hornsund Fjord, preserves a sequence of lateral moraines deposited by local tidewater glaciers. Nine 10Be ages range between 0.5± 0.2 ka to 6.4± 0.5 ka, and have a bimodal cluster that averages 1.9± 0.3 ka (n=4) and 0.7± 0.2 ka (n=4). Scottbreen (77.5553°N, 14.3857°E) is a small alpine glacier on the west coast of Van Keulenfjorden, whose terminal moraine abuts a raised Bølling-Allerød marine terrace. The terminal moraine has been attributed to a surge event that occurred in the 1880’s that was hypothesized to have overridden all older deposits. However, aerial photographs and field observations reveal a series of distinctive moraine crests with a substantial variation in the degree of weathering from the most ice distal to the ice proximal crests. We dated moraine boulders from the distal moraine crests; these average to 1.5± 0.1 ka (n= 6). To further test this hypothesis we are analyzing seven more moraine boulders on the outer ridges of the terminal moraine complex with 10Be dating. The current and pending results of this study will aid in bridging the time gap of glacier evolution during the course of the Holocene on Western Svalbard. The ~1.9 ka and ~1.5 ka average ages at Treskelen and Scottbreen, suggest there near-Holocene-maximum positions were first reached in the first millennium AD. This is similar to findings elsewhere from the Arctic (e.g., Alaska), potentially revealing an Arctic-wide pattern of a significant glacier advance in the middle of the first millennium AD.

Geological Society of America Abstracts with Programs. Vol. 48, No. 1

doi: 10.1130/abs/2016NE-272764

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