SLIP - Geographical Information Systems



A geographic information system (GIS) is an integral part of our project. We are constructing a database to incoporate mapping data into and compare with our model results.  The GIS uses ArcView software by ESRI.  Patrick Colgan at Northeastern University is directing this part of the project. Our project requires three types of geological data.

Type I data - These are data input into the numerical model as boundary conditions:

         - topographic elevation
         - bedrock lithology
         - unconsolidted sediment thickness
         - unconsolidated sediment type
         - till texture type
        - flow line divergence parameters
         - climate data to drive model

Type II data - These are data  to be used to test or calibrate our numerical model

         - ice margin positions
         - chronology for each lobe
         - ice surface profiles and thicnkess estimates
         - extent of permafrost features

Type III data - These data consists of maps showing the distribution of glacial landforms for which we would like to learn more about bed conditions and ice dynamics from the model output (bed temps, sliding velocitys, water, ice  thickness, etc). These data are not to be used in model input or calibration, only to be compared to model results. In this way we avoid cicularity while providing a way to both interpret glacial landforms and improve and test our numerical models.

         - drumlin distribution
         - esker distribution
         - moraine types
         - distribution of tunnel valleys
         - distribution of till plains
         - distribution of aligned hummocks

Besides compiling existing geologic data to be used in the modelling effort now we are also developing new mapping techniques. We are currently developing mapping techniques using digital elevation models at 30 m resolution to speed up the processes of mapping landforms at a regional scale. Ultimately, we will make available layers of data for the distribution of drumlins, eskers, moraines, tunnel channels, ice-walled lake plains, glacial episodes, and compilations of bedrock geology, sediment thickness, and surface topography. By examining associations between various layers of information, we hope to reveal controlling mechanisms for landform genesis. The basic information collected in the GIS is being used as input to ice-sheet models that run along former flowlines of the southern Laurentide Ice Sheet.

Some examples of these data layers can be found in current work in progress



This page was last updated by P.M. Colgan on June 22, 2000.