High-resolution geophysical and sample data collected in the vicinity of Buffalo Reef, Michigan, within Lake Superior, U.S. Geological Survey Field Activity 2021-005-FA

In August 2021, the U.S. Geological Survey, in collaboration with the U.S. Army Corps of Engineers, collected high-resolution geophysical data, sediment samples, and bottom imagery to determine the distribution of historical mine tailings on the floor of Lake Superior. Large amounts of waste material from copper mining, locally known as “stamp sands,” were dumped into the lake in the early 20th century, with wide-reaching consequences that have continued into the present. Mapping was focused offshore of the town of Gay on the Keweenaw Peninsula of Michigan, where ongoing erosion and re-deposition of the stamp sands has buried miles of native, white-sand beaches. Stamp sands are also encroaching onto Buffalo Reef, a large area of cobble/boulder [...]