This grid was then converted to an XYZ data file, the Z-values were sorted in a Surfer worksheet in ascending order, and the exact X and Y locations of the minimum surface movement were easily found. We also found that the movement vectors of the ice are not the same on the glacier surface as they are at depth. Most significantly, the use of Surfer for this project has allowed us to determine, in a cost effective manner, the optimal site for a future ice core drilling project on the Juneau Icefield. And as an added bonus, we have for the first time located the exact point of the beginning of the Yukon River. Upper surface shows the surface topography and movement vectors in the area of the Matthes Glacier-Llewellyn divide.
Arrows indicate the magnitude and direction of the surface movement at each survey flag.
This minimum movement is between flags 29 and 30. Lower surface shows the subglacial valley at the Matthes-Llewellyn divide, with the actual bedrock divide being located between Flags 14 and 18. Subglacial topography was determined by using a combination of seismic and gravimetric methods. The maximum observed ice thickness was 992 meters at Flag 20, while the minimum was 442 meters at Flag 4. Note that the area of minimum surface movement is not coincident with the bedrock divide.