Keweenaw Peninsula EarthCaches 


Calumet Glacial Striations & Segregation Cylinders 

Essential Lessons:

The Calumet School District grounds exhibit one of the best views of glacial striations available because of their ease of accessibility. This site clearly demonstrates the direction of the glacier moving across this region of the Keweenaw Peninsula and the strength of the different types of rock beneath your feet. It is also evident from the location of the school that we must be aware of our surroundings in order to protect valuable pieces of evidence from the Earth's past.

Earth Science Literacy Principles

Big Idea 1. Earth scientists use repeatable observations and testable ideas to understand and explain our planet.

1.3 Earth science investigations take many different forms.

1.6 Earth scientists construct models of Earth and its processes that best explain the available geological evidence.

Big Idea 2. Earth is 4.6 billion years old.

2.1 Earth's rocks and other materials provide a record of its history.

2.7 Over Earth's vast history, both gradual and catastrophic processes have produced enormous changes.

Big Idea 9. Humans significantly alter the Earth.

9.5 Human activities alter the natural land surface.

9.9 An Earth-science-literate public, informed by current and accurate scientific understanding of Earth, is critical to the promotion of good stewardship, sound policy, and international cooperation.

This glacial outcrop provides valuable evidence about the makeup of the rock beneath the Keweenaw Peninsula and the direction of travel that the glacier covering this region took. Without this evidence, it is difficult to determine the age of the different types of rocks, or what took place first – the lava flows or the glacier movement. With the school buildings and playground so close to this valuable piece of evidence of the Earth's history, it is quite evident how humans may impact the Earth and make it impossible for future generations to view this piece of history.

Common Misconceptions

Science is done by old white men.

Science is too complex for a layperson to understand.

Humans only have negative effects on the earth.

This site is so easy to get to and appears not to be damaged by the surrounding school grounds that it provides the opportunity for students of all ages to see what glaciers have done to the Earth and how humans might protect evidence of glacial movement. With the deep grooves present and sticking right out of the ground, it is hard to miss the glacial outcrop or not to wonder about what could have caused the grooves in seemingly hard rock. The striations are all approximately pointing in the same direction and are quite long, so telling the direction of movement is quite easy for the layperson.

National Earth Science Standards

Content Standard D

From NSES – grades 5-8 – Earth's history

From AAAS – grades K, 2, 3, 5, 6, 8, 9-12 – Processes that shape the Earth

Michigan State Science Content Expectations Addressed:

E.SE.06.12 Explain how waves, wind, water, and glacier movement, shapeand reshape the land surface of the Earth by eroding rock in some areas and depositing

sediments in other areas.

S.IP.M.1 Inquiry involves generating questions, conducting investigations, and developing solutions to problems through reasoning and observation.

S.IA.M.1 Inquiry includes an analysis and presentation of findings that lead to future questions, research, and investigations.

E.4.p3A Describe how glaciers have affected the Michigan landscape and how the resulting landforms impact our state economy.

To get to the site: Cross the Portage Lift Bridge from Houghton, Michigan and head north to Calumet on US 41. Approximately 12.5 miles from the bridge, turn left on Red Jacket St. and follow it for one block. The Keweenaw National Historical park office building will be immediately on the right. Turn right at the CLK Schools Entrance sign and continue to the farthest end of the parking lot near to the school. Walk along the side walk to the end of the Calumet Elementary Building (building is identified with a sign) to the furthest corner of the building from parking lot.

Coordinates

Average Coordinate Location: N 47 14.729′ W 88 26.827′



Name and Type of Land/Permission

The glacial striations are on public land and are a part of the Keweenaw National Historical Park on the grounds of the Calumet school buildings. The superintendent has been emailed about the EarthCache site and sent in this response:

"We are making a conscious effort to protect the scarring. When the new elementary was constructed in 1997 we made sure the contractors knew that we wanted nothing to happen to the scarring and same holds true with the current project. We make that very clear upfront before they even start. We also make sure our own people when driving the front end loader for snow removal is also careful."
Keweenaw National Historical Park
25970 Red Jacket Road
Calumet, MI 49913
Phone: (906)337 316

Public Schools of Calumet, Laurium & Keweenaw
Darryl A Pierce, Superintendent
57070 Mine St
Calumet, MI
Phone: (906) 337 0311
Content Explanation

This site presents glacial striations (or grooves) that were formed when the glaciers moved across the Keweenaw Peninsula in the last ice age. It is estimated that the ice may have been one to two miles thick in this region. While looking at the grooves, you will be able to determine the direction that the glacier was moving. It is important to remember that glaciers only advance, they do not move backwards.

These features are important data that help geologists understand the history of the Keweenaw region and Michigan in general. The Keweenaw region might not have been the large Copper mining area that it was if it weren't for the glaciers removing the majority of the rocks that used to be above the Copper-bearing rocks.

At this location the basalt from an earlier lava flow is exposed. What makes this particular site extremely valuable is that the segregation cylinders that formed when the lava flow cooled are exposed (average diameter of about 11.4 cm). Segregation cylinders are vertically arranged bubbly tubes which rise like the wax in lava lamps. They are typically found below the middle layers inside lava flows. The empty bubbles fill with quartz after the flow solidifies. These segregation cylinders are harder than the surrounding basalt because of the quartz inside the air pockets that formed while the lava cooled. Because of this difference in hardness of the rock, this sample is particularly good for showing how the ice was able to scrape away at parts of the rock and not other parts. The crests are spaced about 25 cm apart with amplitudes between three and five cm.

Use these mineralized segregation cylinders to figure out the direction that the glacier moved across this region. There will be a distinct part of the cylinder that shows where the glacier first hits – this will be ground out more with a higher ridge at the top and a tapered tail behind. This is because the harder rock protected the rock that was directly behind the cylinder. This is unusual because a lot of glacial grooves tend to be symmetrical, so this is an extremely good sample to determine the direction of glacial movement.

Logging Activities
  1. Travel to the GPS location of N 47 14.729' W 88 26.827. Use the segregation cylinders to figure out the direction of ice travel. You may need a compass for this activity. Record the direction of ice travel.
    1. Where might this glacier have originated?
  2. Look at the lowest points of the grooves compared to the highest rounded points. Where do the segregation cylinders tend to be located?
    1. In the trough or the crest of the grooves?
    2. Is this location common throughout the outcrop, or is it different in other places?
    3. How does this help to confirm that the segregation cylinders were made of harder rocks?
  3. How would you suggest that the school district try to preserve, yet make available this valuable asset?
    1. Record the relative distances from the playground/park and the school buildings.
    2. Is this site worth preserving and is it a difficult location to protect?
Content Based Diagrams and Pictures

1

Figure 1 – location of outcrop to new construction – Todd Waurio, photographer

2

Figure 2 – depth and length of the grooves – Todd Waurio, photographer

3

Figure 3 – approximate size of most of the segregation cylinders – Todd Waurio, photographer

Date Visited: July 15, 2011