Mercury distribution in bedrock, native copper ore, and soils - Isle Royale National Park, Michigan
Cannon WF and Woodruff LG. Mercury distribution in bedrock, native copper ore, and soils - Isle Royale National Park, Michigan. U.S. Geological Survey. Reston, VA
In 1998 we began a study of mercury concentration in natural geologic materials on Isle Royale to determine if native copper deposits could be contributing to mercury-impacted lakes. These deposits and mine wastes do contain anomalous amounts of mercury. In contrast, typical bedrock of the island appears to be uniformly very low in mercury. We analyzed soil and glacial deposits in two test areas. Samples were taken from near the Mining Mine, and samples were taken within the drainage basins of Sargent Lake and Lake Wagejo, two lakes with elevated mercury in fish. Our results indicate that the very elevated mercury content of soils in the Sargent Lake - Lake Wagejo area is not caused by concealed native copper deposits because there is little or no elevated copper content of these soils comparable to the strong copper anomalies produced by the Minong deposit. Neither is there reason to conclude that local bedrock is the source for mercury, because all tested samples of the chemically very uniform bedrock have very low mercury content. The mercury content of the soils of Isle Royale seems very likely to result largely from airborne deposition.
- Type
- Unpublished Report
- Authors
- Cannon, William; Woodruff, Laurel
- Publisher
- U.S. Geological Survey
- Units
- ISRO
- Keywords
- Bedrock, copper ore, Deposition, Isle Royale National Park, mercury concentration, Michigan, Soils