Map of the North American Laurentian Great Lakes Basin showing regions of karst limestone formations and regions of above ground limestone formations in Alpena County, MI and submerged sinkholes including the study sites.Map of the North American Laurentian Great Lakes Basin showing regions of karst limestone formations and regions of above ground limestone formations in Alpena County, MI and submerged sinkholes including the study sites.

Figure 1: This map of the North American Laurentian Great Lakes Basin shows regions of karst (limestone) formations and above-ground limestone formations in Alpena County, Michigan. It also includes submerged sinkholes, including the study sites — Misery Bay, containing the El Cajon Bay Blue Hole, Middle Island Sinkhole, and Isolated Sinkhole — in the Thunder Bay National Marine Sanctuary, Lake Huron. Image courtesy of Thunder Bay Sinkholes 2008, NOAA, OceanExplorer.noaa.gov

 

Related Links

Thunder Bay Sinkholes 2008

Thunder Bay Sinkholes 2008: Mission Plan

NOAA Ocean Explorer Gallery

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