Using GIS and Streamlined Landforms to Interpret Paleo-Ice Flow in Northern Iceland
This presentation was given at the 48th Annual Northeast Geological Society of America Meeting in Bretton Woods, NH, March 18-20, 2013.
It was also presented at the 43rd International Arctic Workshop of the Institute of Arctic and Alpine Research (INSTAAR), University of Colorado at Boulder, March 11-13, 2013.
Climate oscillations since the Last Glacial Maximum (LGM) led to massive glacial retreat in Northern Iceland, exposing streamlined landforms that are used to study past subglacial conditions. Common exposed streamlined landforms include drumlins and mega-scale glacial lineations (MSGL). Drumlins, MSGL, grooves, and striations provide direction of paleo-ice flow and MSGL may indicate fast subglacial ice flow. In this study, Google Earth and ArcGIS are used to quantify characteristics of landforms located south of Húnaflói in the two valleys, Viðidalur and Vatnsdalur. Characteristics quantified include length of the long axis, maximum width perpendicular to long axis, elongation ratio, orientation, parallel conformity, density, and packing. 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. Based on these elongation ratios, 115 of the 117 landforms delineated are classified as drumlins and 2 are classified as MSGL. Initial results include an average elongation ratio of approximately 4.6 for drumlins and 11.5 for MSGL. Parallel conformities are approximately 10.4 and 66.6 decimal degrees for Vatnsdalur and Viðidalur, respectively. The higher parallel conformity for Viðidalur is due to the movement of paleo-ice flow around a mountain peak, which suggests a strong topographical influence on ice flow. Landforms in Vatnsdalur have a higher density than those in Viðidalur, indicating a higher rate of paleo-ice flow in Vatnsdalur than in Viðidalur, primarily due to the smaller valley width of Vatnsdalur (approximately 7.8km) compared to Viðidalur (approximately 12.2km). Packing of landforms is evenly distributed in both valleys. These initial results suggest the presence of two regions of fast paleo-ice flow feeding out into Húnaflói, supplying ice to reach the LGM margin of the Iceland Ice Sheet. Additional analyses are currently in progress.