Name applied to diverse group of gneissic rocks exposed on both sides of Mississippi River north of St. Cloud in T125N, Rs28 and 29W, Stearns Co, and in Ts36 and 37N, R31W, Benton Co, east-central MN in the Lake Superior region. Name taken from city of Sauk Rapids in Benton Co, near south edge of outcrop area. Rocks here assigned to Sauk rapids Metamorphic Complex are Sartell Gneiss and its mappable enclaves, Watab Amphibolite and St. Wendel Metagabbro (all new). Originally mapped as granite, diorite, and gabbro by Bowles (1918) and as metagranodiorite (Woyski, 1949). Now considered diverse metamorphic sequence having a pronounced gneissic fabric which defines a series of open antiforms and synforms having moderate-dipping limbs and shallow eastward-plunging axes. Episodic deformation indicated. Oldest units shown on geologic map. Is early Precambrian in age.

Source: GNU records (USGS DDS-6; Denver GNULEX).