GEOLOGYADVENTURE IN LEARNING LESSON

Lesson DescriptionThis lesson explores the geologic processes that form rocks at both the large scale of whole landscapes, and the small scale of individual rocks. Participants will watch a video or read a description highlighting the rock cycle with examples from the North Shore. They will also learn how events like the creation of rifts and glacial recession impact the landscape. Next, participants will interpret bedrock maps and create a model of the rock cycle.

Guiding QuestionHow do past geologic events shape our landscape today?

Concepts1. The landforms of Minnesota result from processes of erosion, deposition, weathering, crustal deformations, & volcanic eruptions.2. We can find evidence of these processes and geologic events in rock formations around Minnesota.3. Rocks are constantly moving through the rock cycle as a result of erosion, deposition, and other processes.

OutcomesUpon completion of this lesson the individual will be able to:• Categorize rocks they find by physical characteristics and interpret processes that formed them.• Interpret bedrock maps to support an explanation of how glaciers shape landscapes.• Create a model of the rock cycle.

Minnesota Academic Standards in Appendix

6 2 8 2 C r a n b e r r y R o a d | F i n l a n d , M N 5 5 6 0 3 - 9 7 0 0 | 2 1 8 - 3 5 3 - 7 4 1 4 | w w w. w o l f - r i d g e . o r g

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Here is an example of the StoryMap .Students scroll through the screens.

Three ways to do this Geology lessonRecommendedThe online Geology StoryMap presentation has everything you need! Click to start, then scroll through the pictures, questions, videos, and links. Do the suggested activities along the way. Follow this Geology StoryMap link, or have students start from the Geology Adventures in Learning web page on Wolf Ridge's website.

1. Read the following lesson plan for overview, activity information, and MN State Standards.

2. Share link to the lesson’s StoryMap, a virtual presentation with pictures, videos, questions, and links to activities.

3. Open the link and scroll through the StoryMap presentation and watch video.

4. Within the StoryMap, there are links to PDF’s containing activities.5. Additionally, the StoryMap contains links to worksheets with two

options for accessing:a. Link to PDF- Use this link if would like to print or respond to

questions in a journal.b. Link as a Google Doc (with force copy) - Use this link to create

a copy of the document in your Google Drive. We recommend saving the copied file as “student name – name of lesson”.

6. Once complete the student can be instructed to share the file with the teacher.

If Internet access is an issueThe teacher or parent reads through this lesson plan, then prints the handouts, to distribute. You are looking at the whole lesson plan right now, which includes all handouts. Here are links to individual handout pages if you prefer. Geology Story. Differential Erosion Activity. Rock Cycle Model Activity. Geology Extension Activities. Send printed materials to students for them to complete at home.

Only have 10 minutes?You can watch the video without using the accompanying educa-tional StoryMap or student activities.

Check back for more lessons and let us know if you have feedback!

StoryMap image

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Lesson Flow (for those who are NOT using the online StoryMap)

GeologyRead the Geology story found in the appendix.

Activity 1 - Differential ErosionSee attached differential erosion activity worksheet.

Students use the map provided to answer questions about differential erosion.

Activity 2 - Rock Cycle ModelSee attached rock cycle model worksheet.

From knowledge gained from watching the video or reading the geology story, students create a rock cycle model.

Geology Extension ActivitiesSee attached geology extension worksheet with additional activities.

AppendixMinnesota Academic Standards4th grade science• 4E.3.2.1 1 Identify evidence from patterns in rock formations and fossils in rock layers to support an explanation for

changes in a landscape over time. (P: 6, CC: 1, CI: ESS1) Examples of evidence from patterns may include rock layers with marine shell fossils above rock layers with plant fossils and no shells, indicating a change from land to water over time; and a canyon with different rock layers in the walls and a river in the bottom, indicating that over time a river cut through the rock.

6th grade science• 6E.1.1.1.2 Ask questions to examine an interpretation about the relative ages of different rock layers within a sequence of

several rock layers. (P: 1, CC: 1, CI: ESS1) Emphasis is on the interpretation of rock layers using geologic principles like superposition and cross-cutting relationships.

• 6E.3.1.1.2 Develop a model, based on observational evidence, to describe the cycling and movement of Earth's rock material and the energy that drives these processes. (P: 2, CC: 5, CI: ESS2) Emphasis of the practice is on using observations of processes like weathering and erosion of soil and rock, deposition of sediment, and crystallization of lava to inform model development. Emphasis of the core idea is on how these processes operate over geologic time to form rocks and minerals through the cycling of Earth’s materials. Examples of models may be conceptual or physical.

ResourcesCheck out these websites below for more interesting information.

• https://www.theartstory.org/movement/earth-art/ - Information on the earthworks movement and highlights of important artists.

• https://www.ely.org/_site_components/uploads/trailmaps/hegman_lake_pictographs.pdf - Information on the Hegman Lake pictographs

• Andy Goldworthy earthwork: https://www.architecturaldigest.com/gallery/andy-goldsworthy-book-ephemeral-works• Richard Long earthwork: http://www.richardlong.org/

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GEOLOGY STORYWelcome to the sixth episode in the Wolf Ridge Adventures in Learning series! Today, Wolf Ridge naturalists Caroline and Robby are exploring geology. They’re taking a tour of the geology of the North Shore and talking about the rock cycle, glaciers, lava eruptions, and more.

A great place to start thinking about Minnesota geology is with agates. They can be found all over the state; they’re actually the state gemstone!

Agates are a sedimentary rock that forms inside an igneous rock. Igneous rocks are created when liquid magma (lava) cools and hardens. Just like the bubbles in a can of pop, magma has air bubbles floating it. When the magma cools, those bubbles are trapped in the rock leaving air pockets. Over time, water flows into those holes in the igneous rock and deposits minerals in them. Layer after layer of these minerals accumulate until the hole is filled up. We see these layers in the stripes of the agates.

The Rock CycleThe agate example includes two of the three types of rocks: igneous and sedimentary. The third is metamorphic. All rocks can be put in one of these three categories, but they can also change to another type of rock if certain things happen to them. That’s why it’s a rock cycle.

Check out this model of the rock cycle to see what processes can transform a rock from one type to another.

• Igneous rocks come from magma or lava. As it cools it solidifies into igneous rock.

• Sedimentary rock is created by layers of sediment becoming smushed together to form a rock. For example if rain eroded a volcanic hillside, depositing smaller rock at the bottom. Over time these little pieces of sediment build up and slowly start to solidify. Eventually the bottom turns into sedimentary rock.

• If heat and pressure are added, the rocks minerals can melt slightly and rearrange into metamorphic rock. This happens when a rock gets buried deep in the earth. The pressure of all the rocks above it and the heat of the core of the earth cause it to get gooey and melt. A good example of how pressure creates heat is to press your hands together hard while rubbing them back and forth, which creates heat.

Geology of the North Shore

It’s time to find some real-life examples of these rock types. Geologist and Wolf Ridge Naturalist, Carrie Anderson, is here to help us.

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Sugarloaf Cove: Igneous Rock1.1 billion years ago a mid-continental rift that was 50-100 miles wide opened up where lake superior is today. This rift thinned the earth’s crust enough that lava bubbled up out of it and flowed across the land. The igneous rock the lava created makes up the north shore of Lake Superior.

These lava flows have distinctive shapes, textures, and colors that tell us about how it formed. As lava first flows out, it is really hot making it move fast and thin. This leaves a ropey texture and is the top of a lava flow. Below is the vesicular layer. This layer is full of gas bubbles. Then, the next layer down is called the massive layer where there are no bubbles. The bottom layer of a lava flow is full of pipe amygdules, tracks where gas tried to travel up the lava flow.

Some lava flows are only a few inches thick and others are several feet thick. Many places on the North Shore you can tell where a new lava flow starts because there is a huge wall of rock marking the edge of a newer flow, often with waterfalls cascading from one flow to another below.

Many places on the North Shore you can tell where a new lava flow starts because there is a huge wall of rock marking the edge of a newer flow, often with waterfalls cascading from one flow to another below.

Source: https://pages.mtu.edu/~raman/SilverI/MiTEP_ESI-2/Syncline.html

The steeply sloping shoreline of Lake Superior is evidence of how the lake was formed. The lava from the mid-continental rift flowed out and hardened like a pancake. Thousands of years later, glacial ice that was 2 miles thick slowly sunk the lava “pancake” down with its weight, creating the sunken bowl shape of Lake Superior. The steep shoreline and the hilly Sawtooth Mountains along the shore show where the edge of the lava rose up as the middle sunk.

vesicular layer

pipe amygdules

massive layer

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Cut Face Creek: Sedimentary Rock

sandstone layer

This wall of rock at Cut Face Creek near Grand Marais shows our second type of rock: sedimentary.

This sandstone is about 1 billion years old. It was formed by water eroding the top of the dark basalt underneath. You can find ancient ripple marks left behind by the flowing water that eroded the basalt and formed this sand. Over many thousands of years the sand slowly built up and started to solidify into sandstone. Once formed, sandstone is more susceptible to erosion than other rocks.

The reason the sandstone is so red is due to the iron in the stone that has rusted.

This layer of sandstone formed in between two major eruptions from the mid-continental rift. That’s the same rift we learned about at sugarloaf. The two lava flows created a rock sandwich with volcanic crust and a sedimentary rock filling! The pattern of these layers shows the Principle of Superposition. The Principle of Superposition describes a pattern of undisturbed layers where the oldest layer is at the bottom, and successively higher layers are successively younger. So here at Cut Face Creek we have the oldest bottom layer of basalt from the first lava eruption, then the sandstone layer that was deposited next, and finally the second eruption of lava that created another basalt layer.

Ely Greenstone: Metamorphic RockThe Ely greenstone originally formed 2.7 million years ago as basalt under a shallow sea. We know that because of these really distinctive “pillow” shapes on the rock which is created by lava being instantaneously cooled as it flows underwater.

After it was formed, it was slowly covered by layers and layers of other rocks, slowly pushing it deeper and deeper in the earth's crust. There, the heat and pressure cooked the rock and allowed some of the minerals in the rock to be rearranged, which changed it from basalt into greenstone. Then all the rock that was covering the greenstone eroded away until it was exposed to the surface. So deposition (rock being added) and erosion (rock being removed) were part of this rock cycle! Because this process takes so long, metamorphic rocks are often some of the oldest rocks in the world!

Glacial ErosionThe rock cycle tour showed us close-up examples of specific rock types. Now it’s time to take a step back and look at the big picture of how rocks shape the landscape.

Landscapes are changed though either the process of deposition (build up of new rocks) or erosion, wearing down existing rocks. One of the major events that shaped the North Shore was the last Ice Age, 10,000 years ago. During that time glaciers covered much of minnesota. A glacier is a giant sheet of ice that does not melt seasonally. During the last Ice Age, the ice covering Minnesota was a mile thick in places.

Glaciers were so powerful that we can still see marks of them today, both in the

sandstone layer

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Source: https://www.twincities.com/2016/10/03/ely-mn-pillow-rock-moving-2-7-billion-year-old-rock/

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landscape and on individual rocks. This rock here has a large glacial striation (a scratch mark) caused by a glacier slowly dragging other rocks stuck to its underside across this bedrock.

As the glaciers got more ice deposited on top of them, they got heavier and heavier until they began to move. As they slid across the landscape they acted like a giant piece of sandpaper. This is called scouring; the ice basically acts like a piece of sandpaper rubbing and smoothing across the ground. But just like sandpaper, the ice had a different amount of smoothing effect depending on how hard the rocks it moved across were. This caused different rocks to be smoothed away to nothing, while other harder rocks to be left behind. This process is called differential erosion, and it’s the reason that these tall ridges and hills exist at Wolf Ridge today.

Many of the high points at Wolf Ridge and along the North Shore are made of really hard rock. That’s because of differential erosion! If they were soft rock, they would have been eroded away by the glaciers and other forces since then.

Marshall Mountain and Mystical Mountain are two of these hard-rock peaks. They are both made of anorthosite, a hard igneous rock that formed from magma underground and floated to the surface because it was lighter than the rock surrounding it. Think of marshmallows floating to the top of hot cocoa.

The large crystals visible on the anorthosite tell us that the rock cooled slowly, allowing time for the crystals to form. Igneous rocks that cool quickly have small crystals.

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ACTIVITY: DIFFERENTIAL EROSIONYou learned about glacial scouring, where massive sheets of ice bulldozed across the landscape flattening softer rock and leaving harder rock exposed. The idea that harder rock can withstand erosion better than softer rock is called differential erosion and we see evidence of it in the hills and ridges of the North Shore.

Look at the map of different bedrock types at Wolf Ridge. Bedrock is rock that is solid all the way down to the earth’s mantle. Use the map to interpret how erosion and glacial scouring has shaped this landscape and answer the questions.

1. Use the key to find the main campus of Wolf Ridge - hint: it has a lot of trails and buildings. What type of bedrock is the main campus built on?

2. The black lines between different colors of bedrock show borders where two types of bedrock meet. At these borders would you expect the land to be flat or have a change in elevation? Look back at differential erosion to help you explain your answer.

3. Due to gravity, water is always drawn to the lowest spots on the landscape. With this understanding and your under-standing of differential erosion, what are two bedrock types that you think are softer than others around the Wolf Ridge campus?

4. Find Lake Superior to the southeast of Wolf Ridge on the map (Hint: you can find what direction north is in the upper left of the map). Lake Superior is at a lower elevation than all of the land on the map. Would you expect it to be on a hard or soft bedrock? Explain your reasoning.

5. Find the trail that leads southeast from the main campus of Wolf Ridge (it leads to two bright pink spots). As the key shows, the bright pink bedrock is anorthosite. Locate the other anorthosite bedrock spots. Anorthosite is a hard igneous rock. What would you expect the landscape to look like at these spots?

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GEOLOGY NATURE JOURNALINGCreate a new journal entry for today. Include the following in your journal entry.

Head outside and see what small (or large) rocks you can find in your yard or neighborhood. Draw or describe them here.

Sort your rocks into different categories based on their characteristics.Is there more than one way you could group them? Draw or describe your groups.

Record the different patterns you find among the rocks.

Can you make educated guesses about what type of rocks they are?

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ACTIVITY: ROCK CYCLE MODELIt’s time to make your own model of the rock cycle! In the video or geology story you saw examples of each of the three rock types and learned how they can move from one stage of the cycle to the next. Reference the geology story or video if you want a refresher.

Create a 2-D or 3-D model. You can make your model in your nature journal or anywhere else.

Your model should include:• title, your name, and date• visual representations of the three rock types that

show how they are created• explanations of how each rock type can change

to another type• color• labels• optional: examples of rocks in each rock type

(you could use ones from the video)

Here is an example 2-D model. You’ll notice that in this model, the arrows have questions written on them to help you think about explanations you’ll add.

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GEOLOGY EXTENSIONS

• Go for a walk in your neighborhood or somewhere else nearby. Can you see evidence of how the landscape has been shaped by geological forces?

• DIY Mohs Hardness Kit - Learn how to make your own kit for testing the different hardness of rocks: https://lifestyle.howstuffworks.com/crafts/science-projects/science-projects-for-kids-crystals-and-minerals1.htm

• National Geographic Geology For Kids - Dive deeper into how rocks shape our world: https://kids.nationalgeographic.com/explore/science/geology-101/