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U-M divers retrieve 8,900-year-old piece of wood from Lake Huron
Annarbor.com (12/12)
University of Michigan researchers announced they have found a 5 1/2 foot long, pole-shaped piece of wood that is 8,900 years old in Lake Huron.
Internationally renowned ‘Ocean Doctor’ to speak in Grand Rapids
MLive.com (2/3)
Known as the “Ocean Doctor,” David Guggenheim will speak in Grand Rapids, Mich., about the many similarities between the threats to the oceans and to our Great Lakes.
SSC students taking part in marine science bowl
Arenac County Independent (1/31)
Teams of Michigan high school students will be heading to Ann Arbor this weekend to take part in the annual Great Lakes Bowl, a quiz event that focuses on questions about marine and freshwater systems and biology.
No aquarium for Windsor
CBC News (1/31)
Aquariums in Cleveland, Toledo, and Chicago prove to be too much competition for Windsor.
Clarkson receives $1.4 million to study contaminants in Great Lakes fish
North Country Now (1/31)
Clarkson University has received $1.4 million to monitor formerly untraceable contaminants to water supply by studying the effects on fish in each of the Great Lakes.
Great Lakes scientists educate communities; put research to work
Great Lakes Echo (1/26)
At the Lake Superior Estuarine Research Reserve, scientists study the usual Great Lakes issues – invasive species, pollution, habitat loss, and climate change. This research is then taken directly to the community, addressing local issues.
What's going on in your neighborhood this month? Meet other people and learn together at recreational and educational events! Our new dynamic calendar is updated daily with current educational events.
Introduction: Glaciers and more glaciers
Let's go to the beach!
The sandy dunes
Marshes, bogs, and swamps
Isle Royale
Human impacts and the future
References
Great Lakes Shoreline Geology
From the wetlands along Lake Ontario's shore, to the sand dunes along Lake Michigan, to the rocky shore of Lake Superior, the Great Lakes shoreline abounds in diversity. Millions of years of glacial formation, wind, lava flows, and changing lake levels have sculpted a unique and ever changing shoreline. These shoreline systems absorb the brunt of wind and wave energy from the lakes, helping to protect the inland areas. Let's explore!
Glaciers and more glaciers
Six hundred million years ago, during the Paleozoic Era, central North America was covered by a shallow sea. This sea deposited a lot of sand, salts, and silts, which, after time, were compressed into limestone, sandstone, shale, halite, and gypsum.
The sea retreated from the Great Lakes region before the end of the Paleozoic Era. Eventually, the earth cooled, and during the Pleistocene Epoch, about 1 million years ago, the ice ages began, and glaciers advanced and retreated many times over what is now the Great Lakes region. Being over one mile thick, these glaciers flattened and carved large holes in the land. Where they encountered more resistant bedrock, such as volcanic deposits, only the overlying layers were removed; but, the softer sandstone and shale allowed the glaciers to dig out the large basins that make up the Great Lakes today.
As the glaciers melted and began receding, their leading edges left behind high ridges and fascinating rock formations, some of which can be seen today in the cliffs of Door County, Wisconsin, and the "flowerpots" on Bruce Peninsula in Ontario. 
Huge lakes formed between these ridges from the retreating ice fronts. As many as 8-12 ice ages occurred, each lasting around 50,000 years; during the longer, warmer periods in between each ice age, plants and wildlife returned to the area.
The last glacier began retreating around 14,000 years ago, and the earth warmed considerably. As the glaciers melted, the resulting water, called meltwater, filled the huge holes left by the glaciers. During this time, the lakes were much larger than they are now, and they had different river outlets. But as the ice retreated, the St. Lawrence River Valley revealed itself as the outlet to the Atlantic Ocean, and the lake levels eventually dropped to current levels.
See the TEACH topic How the Lakes were Formed for a more detailed discussion on glacial formation.
Graphics: Miners Castle on Pictured Rocks National Lakeshore; glacial advance during the Pleistocene Epoch; and, a "flowerpot" on Flowerpot Island on Bruce Peninsula
