S-23 Geologic Map of Minnesota - Quaternary Geology

Abstract

There are no GIS files associated with this compilation. It was made for printing and visualization. GIS files are available with the detailed digital database D-1 at the MGS Data Portal -- https://mngs-umn.opendata.arcgis.com/ and are not available in this archive. S-23 compiles new and previously published geologic mapping to show the surficial sediments in Minnesota as a printable !:500,000 scale version. In contrast to Hobbs and Goebel (1982), where map colors indicated provenance, on this map unit colors refer to texture: green for diamicton interpreted to be till, red/orange for sand and gravel-dominated sediments, and blue for silt and clay. Glacial sediments were mapped using lithostratigraphic formation names of Johnson and others (2016) and references therein. Post glacial and proglacial sediments were named for their genesis. Peat is shown in Figure 1. Modern lake sediment is not shown here. Refer to Figure 2 for the location of major provenances and the names and extent of ice lobes during the late Wisconsinan glaciation. Unless otherwise noted, the two-letter map-unit abbreviation indicates diamicton interpreted to be till of a particular formation. The addition of a third letter indicates associated sediments.