The Idun 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.
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Showers likely
Idun’s center stands about 1,310 ft above sea level. Within three miles the land runs from 1,250 ft to 1,350 ft, a difference of 100 ft: gently rolling country.
Under the town center the state geologic map shows Gray granodiorite to granite intrusions (granodiorite, granite), from the Paleoproterozoic, 1.6 to 1.8 billion years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granodiorite, granite. Age: Paleoproterozoic, 1.6 to 1.8 billion years old. About 12 mi of the line.
Orthogneiss. Age: Neoarchean, 2.5 to 2.8 billion years old. About 7 mi of the line.
Sandstone, siltstone. Age: Mesoproterozoic, 1 to 1.2 billion years old. About 3 mi of the line.
Age: Paleoproterozoic, 1.8 to 2 billion years old. About 0.7 mi of the line.
Sandstone, marble, mica-schist. Age: Paleoproterozoic, 1.8 to 2 billion years old. About 0.5 mi of the line.
Schist, slate. Age: Paleoproterozoic, 1.6 to 2.5 billion years old. About 0.4 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 Idun reaches the Gulf of America by way of Malone Creek, the Rum and the Mississippi: about 2,020 river miles.
Lakes on the way: Mille Lacs Lake and Lake Pepin.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Idun; river miles along the main stem, rounded.
