A SURVEY OF TOMBOLOS IN LAKE SUPERIOR

A tombolo is a bar of sand that connects a larger body, typically either a larger island or mainland, to a smaller island. They most commonly occur along emergent marine coastlines where relative water levels are declining. In the Great Lakes, similar trends have occurred, with a general decline of water levels since the Nipissing Phase, 4500 years ago, thereby creating the framework for tombolo formation. Tombolos are of broader interest as they can provide niche ecological environments conducive to rare and/or threatened biomes. The objective of this investigation is to catalogue and compare tombolos in Lake Superior. This will provide context for a larger project with the goal of evaluating the formation and evolution of the Stockton Island tombolo in the Apostle Islands of Lake Superior. Shorelines of Lake Superior and its islands were surveyed using Google Earth and digital elevation models available through USDA Soil Explorer in an effort to locate tombolos. Using this approach, several tombolos were identified. This presentation will explicate the identified tombolos, focusing on their geomorphology and strandplains, if present. The results of this investigation will hone the project work on Stockton Island and streamline the data interpretations, such as correlating strandplain development to paleohydrologic records for Lake Superior.