Geology datasets of North America for use with ice sheet models

Abstract. The ice-substrate interface is an important boundary condition for ice sheet modelling. The substrate affects the ice sheet by allowing sliding through sediment deformation and accommodating the storage and drainage of subglacial water. We present three datasets with different geological parameters for the region that was covered by the ice sheets in North America, including Greenland and Iceland. The first dataset includes the distribution surficial sediments, which is separated into continuous, discontinuous and predominantly rock categories. The second dataset includes sediment grain size properties, which is divided into three classes: clay, silt and sand, based on the dominant grain size of the glacial sediments. The third dataset is the generalized bedrock geology. We demonstrate the utility of these datasets for governing ice sheet dynamics by using an ice sheet model with a simulation that extends through the last glacial cycle. Changes in ice thickness by up to 40 % relative to a reference simulation happened when the shear friction angle was reduced to account for a weaker substrate. These datasets provide a basis to improve the basal boundary conditions in ice sheet models. Gowan, E. J., Niu, L., Knorr, G., and Lohmann, G., 2018. Geology datasets of North America for use with ice sheet models, link to datafiles. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.895889