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Eville Gorham

Publications and source records attributed to Eville Gorham.

3 recordsLinked to original sources
USGS2003

The chemical composition of lakes in the north‐central United States

Lake waters of the north‐central U.S.A. are classified into five groups, based on increasing specific conductivity and changes in ionic composition from east to west, from Wisconsin through Minnesota to North and South Dakota. The most dilute group of waters has specific conductivities <29 µ mhos · cm −1 at 25°C; the most concentrated group has specific conductances that range from 7,000 to 73,000 µ mhos. As conductivity increases all major ions increase, but there is a shift in cation dominance from Ca 2 + to Mg 2+ to Na + , and in anion dominance from HCO 3 − to SO 4 2− . This shift partly reflects a westward increase in climatic aridity, and partly a westward sequence of glacial drifts from noncalcareous to calcareous and thence to calcareous with abundant sulfur‐bearing minerals. Levels of pH, K, Cl, F, B, and SiO 2 also show a distinct westward increase. Concentrations of NO 3 − and Mn increase from east to west, but the trend is less distinct. Concentrations of Fe vary widely without any trend over the range of conductivity. Color, mostly from dissolved organic matter, is controlled chiefly by lake depth, except for lakes with extensive peatlands in their drainage basins.

Minnesota, North Dakota, South Dakota, Wisconsin↗
USGS1993

Geochemistry of surface sediments of Minnesota lakes

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 CaCO 3 , 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.

Minnesota↗