Analyses of 36 trace, minor, and major elements were used to classify the sediments of 46 Minnesota lakes. Q-mode factor analyses grouped Minnesota lake sediments according to clastic-, carbonate-, organic-, and redox-related elements. Carbonate lakes occur in west-central Minnesota; their sediments have relatively high concentrations of CaCO3, Ba, and Sr. Lakes with sediments containing more than 30% organic matter occur in east-central and northeastern Minnesota; these sediments have high concentrations of organic C, N, and H, and slightly elevated concentrations of Pb. Only three lakes have sediments included in the “redox” group, with relatively high concentrations of Fe, Mn, Mo, La, and Zn. High concentrations of redox-sensitive elements appear to be associated with oxidized iron and manganese minerals, but in Elk Lake, one of the three lakes in this group, a significant amount of iron and manganese is contained in iron phosphate, iron sulfide, and manganese carbonate. Clastic lake sediments are not diluted by large amounts of organic matter, carbonate minerals, or iron-manganese minerals, and are of two types: a western group derived largely from Cretaceous shales in the prairie regions, and a northeastern group derived from Precambrian crystalline rocks in the forested arrowhead region. Western clastic lake sediments have higher concentrations of Al, Na, K, B, Ba, V, Mg, and Sr. Most northeastern clastic lake sediments contain higher concentrations of Cu, Y, Be, and Ni, but several are chemically more similar to those of western prairie lakes.
