INTERPRETATION OF TERRACES AND PROFILE OF THE SOUTH TWO RIVER, A TRIBUTARY OF THE MISSISSIPPI

South Two River is a tributary on the west side of the Mississippi River in Minnesota. The stream profile, surficial geologic units, and bedrock geology were examined, and terraces were identified from topographic maps. The order of geologic events was evaluated. South Two River flows to the northeast and is surrounded by quaternary surficial material such as glacial outwash composed of sand, gravelly sand, cobble gravel that is reworked superior lobe till, peat, and Mississippi River alluvium. One terrace is present 1090 ft. to 1080 ft. high where the river drops sharply before it draining into the Mississippi river. This river terrace is most likely a terrace of the Mississippi and not a terrace of South Two River. The presence of one sole terrace at the confluence with the Mississippi contrasts with rivers to the south, some of which display as many as 5 terraces. Depth to bedrock ranges from 30 ft. to 130 ft. based on the Minnesota County Well Index and the Stearns County Geologic Atlas. Bedrock is mostly mottled red, green and brown shale with white sandstones. In another area undivided Gneissic rocks are present that are early to mid-Archean in age. The final bedrock is the Little Falls Formation which is light to dark grey, quartz rich shale, argillite and quartz wacke, green schist to middle amphibolite.