T159 Looking to the Past to Understand the Future: Glacial Chronology and Process (Posters)

Monday, 23 October 2017
9:00 AM - 6:30 PM
Halls 4EF

GEOMORPHIC EVIDENCE FOR A PALEO-ICE STREAM NEAR BÁRÐARDALUR, NORTH ICELAND

Paper number: T159-4
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The properties of streamlined landforms and paleo-flow indicators in the valley of Bárðardalur in north Iceland were quantified using a combination of spatial analyses and fieldwork. Drumlins and mega-scale glacial lineations (MSGL) were identified using satellite imagery from Google Earth, the National Land Survey of Iceland (NLSI) Map Viewer, and from contours on the 5 m mosaic of the Arctic Digital Elevation Model (Arctic DEM). The outlines of the landforms were drawn manually in either Google Earth or using 5 m contours in ArcGIS generated from the Arctic DEM. Quantitative analyses were conducted in ArcGIS using a 20 m DEM of Iceland from the NLSI due to gaps in the Arctic DEM. Landforms were classified as either drumlins or MSGL by their elongation ratio, with drumlins having a ratio of < 10 and MSGL having a ratio of ≥ 10. At least 159 streamlined landforms were identified using Google Earth, with 80 drumlins and 79 MSGL. Comparison of drumlins identified from 5 m contours with those identified on Google Earth is in progress. The distribution of elongation ratios is positively skewed, and the average elongation ratio is 11.5:1. The average density of streamlined landforms is 1.86 landforms per 1 km2 , and packing ranges from 0.0002 - 0.67 landform surface area per km2, with an average value of 0.14 landform surface area per km2. Parallel conformity is 6.02 degrees, indicating uniform ice flow direction. The modal orientation of long axes of streamlined landforms is 318 degrees, demonstrating that ice flowed from Bárðardalur into Skjálfandi. The properties of streamlined landforms in this valley suggest that a paleo-ice stream was present and supplied ice to the margin of the marine-terminating Iceland Ice Sheet during the Last Glacial Maximum. Fieldwork to ground-truth the spatial analyses and preliminary sedimentological investigations are ongoing.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-295477

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