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The map depicts bedrock geologic units exposed and covered by glacial sediment in Renville County. The interpretation relies on previously published and unpublished geologic mapping, augmented with high-resolution geophysical data and field work by the authors. The bedrock ranges in age from Paleoarchean (3600-3200 Ma, or million years old) to Late Cretaceous (~90 Ma), and records a complex history involving multiple igneous, sedimentary, metamorphic, and tectonic events, as well as significant episodes of weathering and erosion. |