Try Everything

Both trips had spectacular views

By Sandra Prickett

There is importance in trying new experiences even if you’ve already decided on a path. Gathering new experiences can show alternative ways to find a desirable career outcome, or further cement that you are already doing what you like most. New experiences can also be a much needed break form monotony and an opportunity to learn new things.

I consider new experiences to be mini-vacations.

As of writing this post, I am a biochemistry molecular biology major. I’m learning about the chemistry of living bodies. Biological chemistry happens rather fast, especially compared to the formation of mountains and granite which can take millions of years. My new experience that I tried is being a field geologist in a University of Wisconsin-Eau Claire (UWEC) Mineralogy and Petrology (Min-Pet) class. In this class, the reaction trends of mineral formation are covered, and field trips are taken to northern Wisconsin, and to the Black Hills, South Dakota, USA. A large part of what rock formations are covered are due to volcanic activity.

When I was younger, I only learned about active volcanoes.

I used to think that volcanoes were only in a few places, like Hawaii, or Mount St. Helens in Washington state, USA, and Vesuvius in Pompeii. I had only heard about the active volcanoes. Finding sites of old volcanoes that had expelled magma long ago is incredibly neat.

So when the first trip showed that Wisconsin was the site of many magma expelling vents, I was intrigued. Basalt is some of the densest rock on the Earth's crust which contributes to the red zones in the density survey on the cover of the field trip guide book.

It turns out that the area I live in was part of a continental rift where two sides of the plates pulled apart, thinning the crust. Then vents extruded tholeiitic basalt, layer upon layer, that weigh quite heavily on the thin crust, causing it to dip into the mantle. The depression made the basalt become the bottom of Lake Superior. Other vents also extruded magma, like squeezing a tube of fluid toothpaste from the bottom, and just kept covering a circular area. These vents formed the Porcupine Mountains in the Upper Peninsula of Michigan, USA as dome-like hills.

The Lake of the Clouds in the Porcupine Mountains, UP of Michigan. Viewed from the top of a Porcupine Mountain ridge at the end of highway 107. The rock underfoot is pinkish in color, and is a rhyolite metamorphic rock.

Both trips had spectacular views!

The Porcupine Mountains are a part of a wilderness zone. During the trip, we drove around to the other side of the zone and climbed a rhyolite quarry. The view during peak fall colors is spectacular. The UWEC geology department has permission to access these quarries. The silhouette of the mountains can be seen in the distance. The flat area between is a silver mine in a shale bed.

Top of the rhyolite quarry in the Porcupine Mountains

A pillow to rest your head on?

Other metamorphic rocks found are volcanic pillows. Bits of magma that cooled rapidly when exposed to water and pilled together to make a very distinct pattern in the rock.

The light rock is the core of each glob of magma that got to cool slower than the black outline that touched the water. In between, ash and silt built up in a sedimentary mechanism that glued each pillow together.

The pillows in the Midwest are an excellent example of volcanic pillows. So good an example that the next time I saw pillows in the Black Hills, I didn't recognize them.

At the Pactola Reservoir in South Dakota, there is a wall of mysterious rock across the highway from the water.

I and the other students were given the chance to try and identify the rocks, starting near the concrete retaining wall and along up the road. These rocks were so rusty and there were no clear patterns to indicate pillows, only that the rocks I was looking at were clearly metamorphic in nature. I was so focused on my task that I didn't get the chance to take pictures. The two above are from Google Earth.

Rocks are difficult to identify for a novice.

It is alright that I couldn't identify the rock, the purpose of the field trips were to introduce geologic field work to the students while they begin to learn how to identify rocks. Mineralogy and Petrology are typically taken during the second year of a geology major.

I had a lot of fun seeing many interesting mineral formations and being out in nature.

A climb up Little Devil's Tower in the Black Hills South Dakota.

The importance of trying new things lets me decide whether I want a career where I get paid to camp and look at rocks during the summer, compared to staying in a sterile lab all year long.

There are good arguments for why I should change track and become a geochemist, or stay in the biomedical engineering track. I clearly need to explore geology more to figure this out! I hope you enjoy the highlights from my Min-Pet trips this fall 2022.