The Erhards Grove plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Erhards Grove’s center stands about 1,290 ft above sea level. Within three miles the land runs from 1,270 ft to 1,460 ft, a difference of 190 ft: gently rolling country.
Under the town center the state geologic map shows Gabbro, peridotite, pyroxenite, lamprophyre, and metamorphic equivalents, from the Neoarchean, 2.5 to 2.8 billion years old.
The section below crosses 4 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 44×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granite, granodiorite. Age: Neoarchean, 2.5 to 2.8 billion years old. About 11 mi of the line.
Granitic. Age: Neoarchean, 2.5 to 2.8 billion years old. About 7 mi of the line.
Gabbro, peridotite, pyroxenite. Age: Neoarchean, 2.5 to 2.8 billion years old. About 4 mi of the line.
Metabasalt, greenstone. Age: Neoarchean, 2.5 to 2.8 billion years old. About 3 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Erhards Grove reaches Hudson Bay by way of the Pelican, the Otter Tail, the Red River of the North and the Nelson: about 1,270 river miles. Past the border it runs north through Canada to Hudson Bay.
Lake on the way: Lake Winnipeg.
550 miles of the trip are on the Red River of the North.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Erhards Grove; river miles along the main stem, rounded.