Geologic Map of Minnesota - Bedrock Geology (MGS Map S-21)

This map is a new construct that incorporates existing geologic maps where prior mappers had adequate ground control, and new interpretations based on drill hole, geophysical, and unpublished data where they did not. The interpretation differs significantly from previous maps to reflect new data and accommodate scale. It portrays our current geologic understanding of the temporal and geographic distribution of units within major Precambrian terranes and of the Phanerozoic strata. The western part of the mapped Precambrian terrane is inferred largely from geophysical maps, anchored locally by drilling. In many places, contacts are drawn between units of the same or similar apparent rock type (and same unit label); these are recognized as geometrically distinct, though geophysically or lithologically similar. Digital files corresponding to this map allow removal of Cretaceous, Paleozoic, and some parts of Mesoproterozoic strata to reveal an interpretation of the underlying Precambrian bedrock.<br/><br/>Note: This publication supersedes the bedrock geologic map elements of MGS Open-File OF10-02. Other components of OF10-02 are still valid, including the state-wide maps of bedrock topography, depth to bedrock, and outcrop locations, and the geochronology shapefiles.