Campus Units

Geological and Atmospheric Sciences

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

10-2016

Journal or Book Title

Boreas

Volume

45

Issue

4

First Page

567

Last Page

583

DOI

10.1111/bor.12195

Abstract

The drumlin field at Múlajökull, Iceland, is considered to be an active field in that partly and fully ice-covered drumlins are being shaped by the current glacier regime. We test the hypothesis that the drumlins form by a combination of erosion and deposition during successive surge cycles. We mapped and measured 143 drumlins and studied their stratigraphy in four exposures. All exposures reveal several till units where the youngest till commonly truncates older tills on the drumlin flanks and proximal slope. Drumlins inside a 1992 moraine are relatively long and narrow whereas drumlins outside the moraine are wider and shorter. A conceptual model suggests that radial crevasses create spatial heterogeneity in normal stress on the bed so that deposition is favoured beneath crevasses and erosion in adjacent areas. Consequently, the crevasse pattern of the glacier controls the location of proto drumlins. A feedback mechanism leads to continued crevassing and increased sedimentation at the location of the proto-drumlins. Drumlin relief and elongation ratio increases as the glacier erodes the sides and drapes a new till over the landform through successive surges. Our observations of this only known active drumlin field may have implications for the formation and morphological evolution of Pleistocene drumlin fields with similar composition, and our model may be tested on modern drumlins that may become exposed upon future ice retreat.

Comments

This is the peer reviewed version of the following article: Benediktsson, Ívar Örn, Sverrir A. Jónsson, Anders Schomacker, Mark D. Johnson, Ólafur Ingólfsson, Lucas Zoet, Neal R. Iverson, and Johann Stötter. "Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence." Boreas 45, no. 4 (2016): 567-583, which has been published in final form at doi: 10.1111/bor.12195. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.

Copyright Owner

Collegium Boreas

Language

en

File Format

application/pdf

Published Version

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