Gratiot River Park Rocks!
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Take a virtual tour of the Park Amenities:
(click and drag photo below for a 360 degree view from the parking lot.)
Take a virtual tour of the beach rocks:
Can you find all of these rocks and minerals?
Each one plays a role in telling the Lake Superior Story...scroll down to see how!
The Superior Short Story
~over a billion years in the making~
GeoScavenger Hunt (click here ------------------------>)
GeoScavenger Hunt (click here ------------------------>)
This rock is gray to black (when it’s wet). It’s very abundant. It was created by lava flows.
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This rock is also gray/ black when it’s wet and can have pits or holes, but it came from Canada and was left here by glaciers.
Not as abundant as #1.
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This rock is reddish-pink and there are so many that the entire beach takes on this color. They were created by lava flows. ____________________
This rock is also pretty common on this beach, but it was probably washed or dumped here from Canada. It is speckled white with black. It does NOT fluoresce under a black light.
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This rock is speckled pink and green. It forms when granite is altered by hydrothermal activity. There is a lot of it on this beach.
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This rock is sedimentary and it is very abundant on this beach. You can see large formations jutting out into Lake Superior. It is fine-grained and can show wave patterns. It can be fissle (break off in flakes).
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This rock is also sedimentary, but it is a bit more course than #6 and can be gray to pinkish gray
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This mineral brought a lot of industry to this region. You can find flecks of it in the quartz matrix of some rocks or if you are lucky you can find a piece that is solid and pure (native).
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This mineral was formed by successive events of mineralization, which created bands that can vary in color, depending on what was mixed in with the quartz when it was deposited. They can be all white (and banded) or be quite colorful. ____________________
This specimen is made up of quartz so it is quite smooth, but the colors range from mustard yellow, white to tan and gray. You can sometimes find them imprinted with fossils.
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This mineral often fills in the vesicles of basalt and is dark green and fairly soft.
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If you have the right flashlight and you look at dusk, you may find these rocks fluorescing bright pink or yellow. ____________________
Gratiot River Park Rocks and Minerals Scavenger Hunt links:
About us
Horizons High School is a small public high school in Michigan's Keweenaw Peninsula. We are lucky to have this park so close to us and we consider it our front yard. Over the years we have spent many hours enjoying the park and helping to keep it clean.
We developed this resource to answer the questions that often get asked, namely...
What IS this rock ( or mineral)?
How does each rock tell the story of
Lake Superior formation?
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