This self-guided field trip program allows teachers to use Black Canyon of the Gunnison National Park as their classroom for lessons about geology, plate tectonics, erosion, and conservation. You and your students can take a hike along the Rim Rock Nature Trail, have lunch at Tomichi Point, and explore the interactive exhibits at the South Rim Visitor Center.
Educational Activities in this Guide
Note: Activities marked with an asterisk (*) align with standards for 2nd grade. All other activities align with 4th and 5th grade standards.
Be prepared for high-elevation desert hiking. Wear a hat and sunscreen. Carry a full water bottle. Water is available in the campground and at the South Rim Visitor Center during the summer months. There is limited shade along the trail. Wear sturdy shoes with good tread, such as hiking boots or sneakers. Be aware of quickly changing weather conditions and be prepared to change your plan.
Park Rules and Field Trip Guidelines
Stay on the trail. The NPS protects all habitat, including fragile soils and plants along the trail. Do your part by staying on the trail.
Stay with your group.
Stay at least one body length away from the canyon edge.
Never throw or kick rocks over the edge of the canyon. There are hikers below.
Carry out all trash and be mindful of wind causing accidental littering.
Do not approach, feed, or yell at wildlife.
You may pick up rocks to look at them but put them back where you found them. Taking anything home from the park is illegal.
Use a soft voice. Visitors want to enjoy natural sounds, not students screaming.
Restrooms
There are vault toilets in the campground, about halfway along the trail at Tomichi Point, and at the South Rim Visitor Center.
Park Ranger guides students through what to bring and how to prepare for a field trip to Black Canyon of the Gunnison National Park or Curecanti National Recreation Area.
Map of Black Canyon of the Gunnison National Park's South Rim between the entrance station and visitor center.
NPS
Rim Rock Nature Trail
Location: The southern trailhead is near the entrance to Campground Loop C. The northern trailhead is the South Rim Visitor Center parking lot.
Length: 1.0 mile, one-way
Time: Approximately 1-2 hours, depending on stops
Description: This moderate, maintained trail takes a relatively flat path following the rim of the canyon. There are rocks in the path and uneven rock steps. Along this sunny route you will encounter a variety of plant life from sagebrush and Gambel oak to pinyon pine and Utah juniper. This trail allows many excellent views of the Gunnison River as well as the sheer walls of the canyon, the perfect setting to share the geologic story of Black Canyon with your students! Click here for more information about the Rim Rock Nature Trail.
The arrowhead National Park Service logo, which contains a bison, forest, river, and mountain.
NPS
Introduction to the National Park Service
Essential Question: What do parks protect?
You’ve likely seen this symbol. It’s at the park entrance, on signs, and rangers wear it on their uniforms. This is the symbol for the National Park Service, and it contains the resources we protect here at Black Canyon of the Gunnison National Park and at all the other national parks across the country. The National Park Service’s mission is to protect and preserve natural and cultural resources and values for this and future generations.
Ask students to discuss what it means to protect something. It means to take special care of something. Perhaps they have a bicycle or a book that they protect. Ask students what parks protect by finding the pictures within the symbol. What do these pictures stand for?
Answers include: the bison represents wildlife, the tree represents all plants, the mountain represents landforms (and today we’re going to be learning about another landform…), the lake represents water, which parks keep clean for plants, animals, and people, and the shape of the symbol is an arrowhead, which represents human history and the people who’ve come before us. Students might also say parks protect clean air, dark skies, natural sounds, etc.
The rocks in the canyon tell a story of deep geologic time.
Modified stratigraphic column from Wallace R. Hansen's "The Black Canyon of the Gunnison," USGS Bulletin 1191, published in 1965.
Activity #1: Geologic Time
Essential Question: How did Black Canyon form?
As you hike along the Rim Rock Nature Trail, your group will put together the story of how Black Canyon formed by looking at rocks and other landscape clues. You will learn about the geologic events that occurred in a specific order, resulting in the canyon we see today.
Geology is the study of the earth. Geologists study rocks, minerals, and landforms as clues to understand how the Earth has changed over time.
Essential Question: How long ago did the rocks that make up Black Canyon form?
Understanding geologic time can be hard. As humans, 10 years can feel like a long time ago, so it’s very difficult to understand going back in time 1 billion years. Show students the geologic timeline to the right. Compare how long ago the Earth formed (4.6 billion years ago) with the existence of dinosaurs and humans. To demonstrate geologic time, use your ‘wingspan’ as a model. Spread your arms out as far as you can and tell students this is representing a timeline of the Earth’s history by the distance between your fingertips.
If you start at your left hand, time passes to your left wrist before we know ANYTHING at all - all rocks and other evidence are lost before that time. Sometime between your wrist and elbow, it seems certain that simple, primitive, one-celled life forms appeared. Also, by this time, the earth's differentiation process had proceeded far enough to start building some mighty impressive continental land masses (probably nothing living on them, but they're getting ready). One-celled organisms stick around for quite a while (actually, they're still here), but by your shoulder the atmosphere begins to become enriched in free oxygen. The doom of one-cell supremacy is approaching. But it doesn't happen right away. Well past your head, and beyond the far reaches of your right shoulder, the earth finally sees two-celled critters. The expansion of life really picks up from here on, and we have evidence of some pretty complex beings by mid-forearm. It isn't until your right wrist that organisms developed hard parts (shells, bones, teeth) which could be preserved as "fossils" for us to find. Dinosaurs existed between the joints of your fingers. How about humankind? Take a nail file and gently scrape it along the fingernail of your longest finger. Way to go - you just wiped out all of human history (and more).
Essential Question: Which of the 3 rock types do we see at Black Canyon? How did these rocks form?
There are many, many different unique rocks in the world, but there are three categories based on how rocks formed. Can you tell us the three rock types? (Specimens 1-3)
Sedimentary rocks are formed by rocks being broken down into little pieces and then carried somewhere else by wind or water, deposited, and compacted over a long period of time. Sedimentary rocks are made in layers stacking up over time. While there were sedimentary rocks on top of this area in the past, they are mostly eroded away now. You can see good examples of these sedimentary rocks in Montrose and along the highway toward Grand Junction. [Layer by layer]
Ask students to find a spot where they can touch the dark gray rock.
Metamorphic rock was formed under intense heat and pressure, 25 miles under the surface of the earth. Imagine 25 miles of rock pushing down – that is some seriously intense pressure! These metamorphic rocks at Black Canyon are over 1.8 billion years old! Scientists figured out how old they are using radiometric dating. [Heat and pressure]
Ask students to find a place where they can touch the lighter, pink-colored rock.
Igneous rock is solidified magma. This particular kind or rock is called Pegmatite and it’s an intrusive igneous rock. It formed when the magma solidified underground, it never erupted like the volcanoes we see in the movies. Extrusive igneous rocks are formed when magma comes to the surface as lava or ash. [Flow and cool]
Collection of plate tectonic graphics
Activity #3: Uplift & Plate Tectonics
Essential Question: How did the rocks we see today move to the earth’s surface?
We learned that the metamorphic and igneous that make up Black Canyon were formed 25 miles under the surface of the earth. Today, we see these rocks on the surface. What earth process is powerful enough to push these rocks up to the surface?
Plate tectonics is the process by which the plates that make up the earth’s crust move over time. Use collection of plate tectonic graphics to help with understanding (Image 9)
The movement is driven by the convection currents in the earth’s mantle. These currents move the plates about 1 inch per year, about as fast as your fingernails grow. As the plates move, the different interactions at plate boundaries cause different landforms.
Three boundary types between tectonic plates.
Boundary types:
convergent boundary (push into each other, pushing up mountains or volcanoes)
divergent boundary (two plates pull apart, new rock may form between)
transform boundary (plates slide past each other, friction may cause earthquakes)
Activity:
When you call out one of the plate boundary types, students must get into groups to act out the process.
Convergent boundary – 2 students raise their arms and push against each other, over their heads
Divergent boundary – 3 students. Two pull apart, while the third (the magma!) emerges between the plates.
Transform boundary – 4 students. Pairs, side-by-side, slowly move past each other laterally. Bonus points for demonstrating an earthquake.
Activity #4: Gunnison River Downcutting, Eroding Through Rocks
Essential Question: How can water be powerful enough to cut through hard rocks?
Something had to be very powerful to cut through all these rock layers, just as if you were cutting through a layer cake. What could be powerful enough to cut through rocks? Water!
Water, in the form of rivers, is responsible for carving most of the greatest canyons on the planet. What other geologic force carves valleys? (Glaciers!) Some rivers, however, are more powerful than others. Is there a Grand Canyon of the Mississippi River?
Explain that you have brought a very technical modeling tool to demonstrate differences in power between the Gunnison and Mississippi Rivers. Ask for two volunteers. Take out your “Hydrologic Modeling Tool”—a piece of string and a clip. Place each volunteer at an end of the string. One volunteer puts the end of the string on the ground (sea level) and the other holds the end about a foot off the ground, holding the attached clip.
Explain to the class that this is the length of the Mississippi River, which over 2,300 miles, flows from its headwaters at 1,475 feet in Minnesota to the Gulf of Mexico. The depth of the Black Canyon right where we are standing is 1,800 feet—greater than what the Mississippi drops its entire length! We are going to help the river flow from Minnesota to Louisiana. When the volunteer lets go of the clip, everyone needs to cheer the clip on! Ready, set, go! The clip will need your assistance in moving down the string. The class should cheer until the clip gets to the ground—the Gulf of Mexico.
Does the Mississippi have a lot of erosive power? No! It is a long, lazy, gently sloped river with very little power and therefore, there is no Grand Canyon of the Mississippi.
Let’s compare the Mississippi with the Gunnison River. In contrast, it flows from 8,000 ft. elevation in Almont, CO to 4,500 ft. elevation in Grand Junction, CO, where it meets the Colorado River covering only 164 miles while dropping 3,500 feet! Let’s see how this affects our geology modeling tool. Shorten the string to about two feet in length and more than double the difference in height. Explain that the high side is Almont, CO and the low side is Grand Junction, CO. Remind the class that they need to cheer the clip on as it slides down the string and stop cheering when the clip stops. Ready, set, go!
What does this show about the Gunnison River? It is a relatively short, powerful river, with a very steep gradient. In fact, along the 14 miles that the Gunnison River flows through the Black Canyon of the Gunnison National Park, the gradient is exceptionally steep—losing an average of 96 feet per mile and in one, two-mile stretch, dropping 480 ft.! The steepness of the gradient accounts for the power of the river through the Black Canyon. Of course, volume also contributes to the river’s power. What happens to rivers in the spring in Colorado, when snow is melting in the mountains? Rivers rise. And what happens every afternoon in the summers in Colorado? Thunderstorms/monsoons. High flow events can also be a weathering force; at high flows, the river can pick up boulders and move them, crashing them on the bottom and sides of the river, picking away even more of the canyon walls.
Activity #5: Deposition, Weathering, Erosion
Essential Question: What processes are continuing to change the Black Canyon?
Look into the canyon and listen carefully. What do you hear? The Gunnison River deep below is rushing through the canyon. The Gunnison River has cut down through the hard metamorphic and igneous rocks of Black Canyon over the last 2 million years.
How can water cut through solid rock? Well, the river used to flow so fast that it could carry rocks the size of cars. Those rocks would bang against the canyon walls and floor, knocking more rocks loose. The powerful river was full of rocks, jackhammering more pieces off and carrying them downstream.
If the Gunnison River is eating away at the bottom of the canyon, what forces are weathering the sides of the canyons and the plateaus above the canyon? Weathering is rock material being broken down into smaller pieces by physical (like high flow events on the river), chemical, or biological processes.
Erosion is the movement of these smaller pieces of sediment or soil from one location to another. Deposition is when that material is left behind and accumulates in layers. To remember these vocabulary words, let’s sing a little song. Repeat after me!
Weathering breaks it
Erosion takes it
And when the movement stops, deposition drops
Weathering, erosion, and deposition work together to change landscapes and recycle rock material around the planet.
Ask your students to vote on examples in the erosion activity folder. Is it weathering, erosion, or deposition? Could an example be more than one? Weathering, erosion, and deposition work together to change landscapes and recycle rock material around the planet.
Activity #6: Effects of Human Activities on Black Canyon Geology
Essential Question: In what ways are human activities influencing the process of erosion at Black Canyon?
While it can feel like Black Canyon was made by geologic processes much larger than people, human activities are affecting the canyon today. Brainstorm with your class what human activities may affect Black Canyon’s geology. Some human activities are directly influencing erosion (hiking off trail), or indirectly (human-caused climate change causing drought, less snow, warmer winters, etc.).
Divide your class into four groups. Give each group one human activity from the list to discuss how it may affect Black Canyon and the erosional processes we’ve learned about today.
1. Dams -
a. How do dams affect the process of downcutting and erosion?
b. Background: The dams upstream of Black Canyon on the Gunnison River were designed and built to hold water in case of drought, supplying water for agriculture, power, and other human uses. Dams prevent flooding by managing how much water moves through the river. You’ve learned that Black Canyon was carved by the river, especially when the river used to swell with spring runoff. The dams prevent large spring runoff flows in the river, instead releasing water in a more constant flow throughout the year.
2. Warmer Winters/freeze-thaw erosion -
a. How does warmer winter weather affect erosion at Black Canyon?
b. Background: Human-caused climate change is causing warmer, drier, and shorter winter seasons.
3. Drought -
a. In what ways is drought affecting erosion at Black Canyon?
b. Background: Climate change is causing warmer and drier conditions. Over many years, these conditions lead to significant drought.
c. More info: https://www.drought.gov/states/colorado/county/montrose
4. Hiking off Trail/Human-caused erosion -
a. How are people affecting erosion processes at Black Canyon?
b. Background: When people hike off trail, they can speed up erosion processes by kicking rocks. Many footsteps in the same place can also kill grasses and plants, loosening their roots that hold soil in place. Then when rains come, the trail may erode more quickly than before.
Have students share what they discussed about human effects on erosion at Black Canyon.
Conclusion & Debrief
Essential Question: How did Black Canyon form?
Review the story of how Black Canyon formed and the major geologic processes.
Rocks formed deep underground
Tectonic plate movement pushed rocks up
River cut down through soft rock first, got trapped in its course
River keeps cutting down through hard rocks
Erosion continues to widen and deepen the canyon
Discussion
Besides being cool to learn, why is it important to understand the geologic history of Black Canyon?
Why does it matter today?
What evidence of geologic processes do you see near where you live?
How are human activities affecting geology at Black Canyon?
What questions do you still have about the geology of Black Canyon?
Thank you for visiting and learning about Black Canyon of the Gunnison! We hope to see you in the park again soon!
Colorado Dept. of Education Standards Alignment
2nd Grade - Standard 3. Earth and Space Science GLE 2. Wind and water can change
the shape of the land; models can show the shape and these changes to the land.
Teacher note: Activities 4 and 5 specifically meet this standard. Include or exclude other
activities at your discretion.
4th Grade - Standard 3. Earth and Space Science GLE 1. Earth has changed over time.
5th Grade - Standard 3. Earth and Space Science GLE 5. Societal activities have had
major effects on land, ocean, atmosphere, and even outer space
Last updated: February 9, 2023
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Contact Info
Mailing Address:
102 Elk Creek
(GPS/physical address = 9800 Highway 347, Montrose, CO)
Gunnison,
CO
81230
