Glacial Landforms: Des Moines Drift Sheet, Iowa

Abstract

Cluster analysis of data from county soils reports and from aerial photographs produced three regions with distinctly different assemblages of glacial landforms. The northern region is composed of bogs, kames, terraces, and crossheated to circular feature ice-stagnation moraine. The central region is characterized by level, poorly drained soil and nonpatterned ground moraine. The marginal region consists of heated to cross-lineated ice stagnation features. These clusters are associated with differences in the bedrock topography. The success of this study in defining coherent, logical clusters of counties with similar landforms indicates that the landform data available in county soils reports can be employed in regional analysis even when using county-sized sample cells if the study does not require the establishment of definitive regional boundaries. HE Des Moines drift sheet in north-central

Spatial analysis of Des Moines Lobe washboard moraines using LiDAR data

“…This ice-stagnation mode of retreat has been proposed for southern lobes of the Laurentide Ice Sheet (e.g. Gravenor & Kupsch, 1959;Palmquist & Connor, 1978;Colgan, 1996).…”

Laboratory studies of till deformation with implications for Des Moines Lobe motion and sediment transport

“…The paleo ice-flow direction is determined from aligned hummocks oriented transverse to ice flow (Gwynne, 1942;Ruhe, 1969;Palmquist and Connor, 1978;Stewart et al, 1988) and from tunnel valleys and eskers oriented parallel to flow (Fig. 5) Goebel, 1982, Patterson, 1996).…”