Stromatolites

Banded Iron Formation, Lake Michigan's Left Coast, lakemichigansleftcoast.com, Elizabeth G Fagan

Stromatolites

North of the Great Lakes lies the Canadian Shield, a very ancient geologic feature that bears Banded Iron Formation (BIF). Formed 4 to 2.5 billion years ago, BIF is among Earth’s oldest rock formations. Some BIF contains fossils of Earth’s earliest life, stromatolites, which were algae mats formed on ancient seas. In recent Ice Ages, the glaciers that scoured the Canadian Shield brought rocks containing BIF and stromatolites to the southern shores of the Great Lakes.

NASA’s Perseverance rover landed on Mars on February 18, 2021. Its mission, in part, is to look for stromatolites. How lucky I am to find ancient BIF containing stromatolites along Lake Michigan’s Left Coast.


Elizabeth G Fagan, Lake Michigans Left Coast, lakemichigansleftcoast.com
Elizabeth G Fagan, Lake Michigan’s Left Coast, lakemichigansleftcoast.com


about the author

The 2012 superstorm Hurricane Sandy is mainly remembered for devastating New York City. Sandy was so massive she caused 25-foot waves on Lake Michigan in Chicago, some 900 miles to the west. Millions of stones washed up onto Montrose Dog Beach, the place where Fagan regularly walked her German Shepherd Rosie. A childhood interest was renewed as she collected rocks and fossils on that beach. She continues rockhounding on Lake Michigan’s Left Coast with her second-generation German Shepherd, Ruby.
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