The Mamre 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.
Mamre’s center stands about 1,200 ft above sea level. Within three miles the land runs from 1,100 ft to 1,220 ft, a difference of 120 ft: gently rolling country. The highest named summit within 15 miles is Mount Tom, about 1,370 ft, 11 miles northeast.
Under the town center the state geologic map shows Leucogranite (leucocratic-granitic), from the Neoarchean, 2.5 to 2.8 billion years old.
The section below crosses 5 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.
Leucocratic-granitic. Age: Neoarchean, 2.5 to 2.8 billion years old. About 10 mi of the line.
Orthogneiss, migmatite. Age: Paleoarchean to Mesoarchean, 2.8 to 3.6 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.
Orthogneiss. Age: Paleoarchean to Mesoarchean, 2.8 to 3.6 billion years old. About 2 mi of the line.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 0.7 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 Mamre reaches the Gulf of America by way of Shakopee Creek, the Chippewa, the Minnesota and the Mississippi: about 2,160 river miles.
Lake on the way: Lake Pepin.
1,750 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mamre; river miles along the main stem, rounded.