It’s a long holiday weekend before school really kicks into gear. So how about a delightful quick trip that engages the youngsters? Let’s get going!
We headed to mid-Minnesota for our getaway. But this activity can be done almost anywhere there is a bit of water – puddle/stream/lake/ocean.
This trek mirrored a summer staple for many who vacation in our area. We met near Nisswa, Minnesota for some fishing, floating and boating time on the lake.
Nisswa is a charming, small town with boutiques, eateries and artisans that make it a popular destination. The town is surrounded by many lakes that are great for recreation and relaxation and we took advantage of it all.
Nisswa lies near the center of the state and there is plenty to do here: www.cityofnisswa.gov
The city got its name from the Ojibwe word “nessawae” (which means “in the middle” or “three”).
GEOLOGY
The geology here is characterized by a mix of glacial and post-glacial features:
Glaciation – The surface geology indicates significant glacial impact from the last Ice Age with large quantities of sand, gravel and clay present
Lakes and Other Bodies of Water – Lots of water here!
Foundation Stone – Precambrian rocks – some of the oldest rocks on Earth – form the bedrock of this geology, mostly comprised of granite and gneiss.
Granite = an igneous rock that is composed of quartz and feldspar and is coarsely grained. Common to this area
Gneiss = a metamorphic rock made of sedimentary or igneous rocks that were highly pressurized and heated (above 320 C) to form the gneiss. It is medium to coarsely grained and common to the area.
[For a detailed look at granite and gneiss, check out the blogs, My Own Backyard and The Mouth of Knife River/Lake Superior at Blog – Skin Of The Earth.]
On this lake trek we uncovered much more than just granite and gneiss. There were all kinds of rocks and minerals.
We swam in the lake then waded the shoreline to conduct our rock observations by looking, feeling, skipping and tossing our finds.
There was much excitement over the discoveries and some very astute observations:
“This one looks like a potato!”  | “This is a triangle poop!” |
Knowing I’m a sucker for good geo-finds, the little ones employed some unique bargaining strategies (as instructed by their parents) to lighten my wallet:
Kids: We’ll sell you these rocks for two thousand dollars!”
Me: “Uh…I’m gonna have to pass.”
Kids: “Fifty cents, then?”
Me: <Wow.>
We ended up with some great finds and plenty of laughs. And, since I turned down the hard-sell tactics of the young entrepreneurs, it was a pretty cheap excavation.
TIP 1: Make sure to have a cup, pail, small bag or pockets to store your booty.
TIP 2: Always keep your eyes open for interesting aquatic and wildlife. We saw a super-cute ‘otter.’
WHAT OTHER ROCKS DID WE FIND?
1. Many smooth volcanic basalt stones and other flat specimens that were perfect for skipping.
2. Some wonderful examples of calcite, including this beauty:
3. An unexpected delight in this gorgeous BIF = Banded Iron Formation (aka: ‘Triangle poop’ above). They’re sometimes referred to as GIFs = Granular Iron Formations in the Greal Lakes region. They have quite a story!
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Fascinating Information about Banded Iron Formations
Banded iron formations are some of earth’s oldest rock formations, created in oceans between @ 1.7 and 3.8 billion years ago. They are sedimentary rock composed of alternating layers of iron oxides that were formed in salt water. I say “were,” because these rocks are no longer formed. WHY? Check it out!
WOW FACTOR: These formations were created BEFORE there was oxygen in Earth’s atmosphere!
The formation of BIFs is closely tied to the evolution of Earth’s atmosphere and the rise of oxygen during the Great Oxidation Event around 2.4 billion years ago.
The American Museum of Natural History sums up the complicated process to BIF creation in layperson’s terms:
“This rock records a time from the Earth’s distant past, when evolving life profoundly influenced the planet’s evolution. The oxygen that is now in the Earth’s atmosphere was not there at the beginning. Early life began to generate oxygen by converting the Sun’s energy into food. That caused the iron that was dissolved in the oceans to precipitate out as iron oxide minerals. This rock, with its layers of red jasper and iron magnetite, was formed billions of years ago as part of that process. It is a reminder that life made our atmosphere breathable.”
https://www.amnh.org/exhibitions/permanent/planet-earth/how-has-the-earth-evolved/banded-iron-formation#:~:text=A%20nearly%203%2Dbillion%2Dyear,floor%2C%20creating%20banded%20iron%20formations.
Iron Ore & Where to Find BIFs
Banded iron formations provide most of the iron ore mined today (about 60%). These reserves can be found around the globe on all continents. In the United States, rich reserves can be found, particularly in the states of Michigan and Minnesota. Banded iron formation was first discovered in northern Michigan in the 1840s, and mining of these deposits prompted the earliest studies of BIFs. https://en.wikipedia.org/wiki/Banded_iron_formation
In the Lake Superior region there are a number of ranges with rich iron deposits. You may have heard the names: Mesabi, Marquette, Gogebic, Menominee and others. Some of these regions continue to be mined sources of iron ore. In northern Minnesota, the area encompassing the Cuyuna, Mesabi and Vermillion deposits are affectionately known simply as “The Range.”
For more information on Iron ore history or the deposits, check out Explore Minnesota:
Find Outdoor Adventures & Minnesota History on the Mesabi Iron Range | Explore Minnesota
If you’re outside the Midwest, see the US Geological Survey for your state at: www.usgs.gov, or check your country’s geological surveys to find Banded Iron Formations and other cool rock stuff in your area.
YOUR ASSIGNMENT: Get out there with yourself, your family, friends, neighbors – whoever wants to dig in the dirt and splash around in the late summer sun to ‘make some memories from the ground up.’
Thanks for joining this virtual geo adventure.
Please share your own experiences or comments in the comments section @ www.skinoftheearth.com. You can also email me directly at nancy@skinoftheearth.com
-Nancy
