Canyon Carvers

Calculate the carved-out depth of both valleys. Show your work!

Formula: \(\text{Depth} = \text{Erosion Rate} \times \text{Time}\)      (Remember: \(1,000 \text{ mm} = 1 \text{ meter}\))

Swift Current River (A)

1. After 10,000 Years:

2. After 100,000 Years:

Sluggish Creek (B)

1. After 10,000 Years:

2. After 100,000 Years:

Analysis & Synthesis:

Explain why Swift Current River (River A) carved a much deeper valley than Sluggish Creek (River B) over the same amount of time. Reference water speed and rock resistance.

PART 4 Exit Ticket: Scientific Synthesis

1. In a deep canyon, where (top layers or bottom layers) would you find the oldest fossil specimens, and which law of geology tells us this?

2. If a slow stream suddenly enters a steep mountain slope, explain how its velocity, sediment-carrying capacity, and rate of canyon carving will change.

CANYON CARVERS LESSON BUNDLE PAGE 2 OF 2

[ Sketch flat rock layers & young stream ]

PANEL 1: 0 YEARS Multiple sedimentary rock layers have settled flatly. A brand-new shallow stream flows across the top.

[ Sketch shallow cut through top layers ]

PANEL 2: 25,000 YEARS The moving water has cut through the top layer. Older layers beneath are now starting to get exposed.

[ Sketch deep canyon cut to the bottom layer ]

PANEL 3: 500,000 YEARS A majestic, deep canyon is fully carved. The river sits at the bottom, flowing against the oldest bedrock.

Expedition Debrief: What physical force in your storyboard model acts as the "carver," and how does geological time allow a slow rate of erosion to form such massive landscapes?

CANYON CARVERS EXPEDITION LAB PAGE 2 OF 2

Oldest Layer: Layer Alpha

Youngest Layer: Layer Delta

Beta vs. Gamma: Beta is Older

Part 2 Blank Fields:

• Cause 1 (Velocity): Sediment carried = Large heavy rocks | Erosion rate = Faster erosion
• Cause 2 (Rock Hardness): Granite layer = Steep vertical cliff | Soft clay layer = Gentle slope

Scenario Math Solutions (Part 3)

Formula: \(\text{Depth} = \text{Erosion Rate} \times \text{Time}\)    |    Conversion: \(1,000 \text{ mm} = 1 \text{ meter}\)

River A: Swift Current (1.5 mm/year)

• 10,000 yrs: \(1.5 \times 10,000 = 15,000\text{ mm}\)
  (= 15 meters deep)
• 100,000 yrs: \(1.5 \times 100,000 = 150,000\text{ mm}\)
  (= 150 meters deep)

River B: Sluggish Creek (0.3 mm/year)

• 10,000 yrs: \(0.3 \times 10,000 = 3,000\text{ mm}\)
  (= 3 meters deep)
• 100,000 yrs: \(0.3 \times 100,000 = 30,000\text{ mm}\)
  (= 30 meters deep)

Analysis/Synthesis Answer Guide: River A carves 5 times deeper because its faster velocity provides more kinetic energy to transport coarse, abrasive sediment, and its soft sandstone bedrock offers far less geological resistance to water downcutting.

Exit Ticket Answers & Storyboard Rubric

Exit Ticket Q1 (Oldest Fossils):

Oldest fossils are located in the rock layers at the very bottom of the canyon. This is dictated by the Law of Superposition, as bottom layers must deposit first.

Exit Ticket Q2 (Entering Steep Slope):

Its velocity increases due to gravity, its sediment-carrying capacity increases (carrying larger rock "teeth"), and its canyon-carving rate accelerates dramatically.

🎨 Storyboard Evaluation Criteria:

- Panel 1: Must show distinct horizontal strata. River is narrow and sits on top layer.
- Panel 2: Must show river cutting a small V-groove through the top 1-2 layers.
- Panel 3: Must show a deep gorge slicing through all layers. River sits at bottom on bedrock.

CANYON CARVERS TEACHER HANDBOOK PAGE 2 OF 2