Download Here you are, in Northern Michigan, and you`ve decided to visit The

Here you are, in Northern Michigan, and you’ve decided to visit The Sleeping Bear Dunes
National Lakeshore, one of the most geologically fascinating and most beautiful natural areas in the world.
The park is bursting with examples of unique geographical features, such as extraordinary perched dunes,
rocks and minerals that are millions of years old and one of the deepest, biggest bluest fresh water lakes in
all the world.
Before one can grasp the geological wonder of the Sleeping Bear, one must first get a perspective
on geological history in general. Scientists say the earth is around 4.5 billion years old. Billion. How big
is a billion? Well, to count to a million would take about 11 days. To count to 1 million would take about
11 years. So, if you start counting now, and keep counting for 65 years you would be at the beginning of
the formation of the earth, thus the very beginning formation of the area that is the Sleeping Bear.
At that time, 4. 5 billion years ago, what is now the Sleeping Bear was covered in a series of
volcanoes. These volcanoes left rich deposits of minerals in the earth – deposits which would still be found
if a person would start digging a deep (deep) hole in one of the dunes or explore deep into the waters off
shore.
After billions of years of volcanic activity, came floods, which lasted more than 350,000 million
years. The flooding brought mud, sediment, and various forms of plant life and sea life some of which can
be found in fossilized form on the beaches of the Sleeping Bear today. The famed Petoskey stone is
actually fossilized coral from 350 million years ago. Many other types of beautiful and ancient stones are
seen on the beaches of the Sleeping Bear as well, including several colors of quartz, and any color of rock
that your heart desires. Please be advised that removal of rocks from the park is forbidden. No matter. Go
to a local book store, or to the National Lakeshore office in Empire to find yourself a rock identification
guide, collect pictures of the rocks for your scrapbook, or make a checklist of ones you’ve found.
After the time of the floods, came the time of dinosaurs, mastadons, birds, and flowering plants in
the area that is now the Great Lakes basin around the Sleeping Bear.
Ancient rivers formed during this time period, which was followed by series of ice ages. What we
know now as the Lake Michigan, the lake surrounding Sleeping Bear, was formed starting over 2 million
years ago. Glaciers as thick as one mile (that’s four times around a track!) covered the area that is the
modern day Sleeping Bear. Over the years, the giant “ice-cube” carved out grooves and lakes, and as the
glaciers melted, they left behind deposits of sand and gravel.
The dunes that one sees today at the Sleeping Bear dune climb were formed by these glaciers. If
you close your eyes and take yourself back in time, you can imagine the entire area, under water,
swimming with seas creatures and dinosaurs. Then the area freezes, and the dinosaurs die out. When the
glacier melts, it leaves behind its “baggage” of dirt and gravel, perched a top what was the ocean floor, and
what is now the sand dune.
It should be noted that most dunes are commonly formed by sand being carried across the lakes
and deposited on to land. These dunes at the Sleeping Bear were formed mostly by the action of the
melting glaciers, which makes these dunes unique. The Sleeping Bear Dunes are known as perched dunes,
because the sand that you see is actually “perched” atop a massive moraine or sediment deposit left over
from the retreating of the last ice age 12,000 years ago.
Lastly, think about the world’s fresh water, and the rarity of such a large, deep body of water in
one place. When you visit the Sleeping Bear, you are experiencing one of the largest freshwater lakes in all
of the world – the largest in the United States. The lakes were formed as the glaciers receded and their
waters melted to form this big fresh water bowl. Lake Michigan’s brilliant blue and green waters, caused
from reflection off the bottom of the lake and from floating sediments, are mesmerizing and magical. The
unique beach life and ecosystem found on the shores of The Sleeping Bear is one of the greatest treasures
the earth has to offer.
As with all national parks, Sleeping Bear represents a giant triumph in democracy: miles of shore
line, miles and miles of forests; fish-laden rivers and lakes are owned by each American, and so are open to
all. Go out and enjoy it. Fly a kite, climb a dune, take an geological auto tour (see Sleeping Bear Dunes
website for guide), build a sand castle with some of that millions year-old sand; go for a bike ride on some
of the many roads throughout the park, hike, camp, identify rocks, and let your imagination wind back to a
time when the park was inhabited by creatures much larger than ourselves.