WEEK 6 - Erosional Landforms Flashcards
1
Q
Guangxi Province (Southern China)
A
- Famous landscape: breadloaf-like mountains
- Often shown in ancient Chinese art
- Mountains have high peaks with round, exaggerated shapes
Example: Gao Kegung’s painting: “Mountains after Rain in Spring” (13th century)
2
Q
Why Does Guangxi’s Landscape Look The Way It Does?
A
- Thick carbonate rocks (limestone and dolostone) = easily dissolved
- Warm, moist climate = helps weathering
- Joints in rocks allow more weathering
- Gentle uplift of the region = faster stream downcutting, creating steep canyons
- Cave roof collapse = widens gaps between rock pillars
3
Q
Karst Topography in Guangxi (Type of Landscape)
A
- Limestone dissolves near the surface, causing sinkholes (caverns collapse)
- Uplift occurs, causing streams to cut deeper and lowering water levels
- More uplift, streams cut even deeper, and more rock dissolves
4
Q
Tsingy de Bemaraha (Madagascar)
A
- A “Stone Forest” made of sharp, jagged limestone
- It’s a smaller-scale version of tower karst
- Located in Madagascar’s Tsingy de Bemaraha National Park
5
Q
Roadrunner-Coyote Scenery (U.S. Southwest)
A
- Found in Colorado Plateau (dry southwestern U.S.)
- Features mesas and buttes (tall rock formations)
- Mesa = wide, flat-topped rock with steep sides (“table”)
- Butte = like a mesa but smaller and often pointy
6
Q
Uplift of the Colorado Plateau
A
- A huge area in the Southwest U.S. was slowly lifted up
- This made the Colorado Plateau
- The lift happened because hot magma rose up under the ground
- That magma also caused lava flows in places like Arizona
- Might be because part of a sinking tectonic plate broke off deep underground
7
Q
How Roadrunner-Coyote Scenery Forms
A
- Rivers cut deep valleys into the raised land (plateau)
- Rivers are trying to flow down to sea level
- This leaves behind flat high areas between deep valleys
- The edges of the flat areas are often curved where rivers once flowed around them
8
Q
Monument Valley: How It Got Its Look
A
- Streams keep eroding the land, making valleys wider
- Only small pieces of the original flat land are left behind
- These become buttes and mesas standing alone in flat land
- Little vegetation means erosion happens faster, especially during heavy rainstorms
9
Q
Grand Canyon: How It Formed
A
- Formed by uplift of land and deep cutting by the Colorado River
- River cuts down through rock over time
- Canyon gets wider from rock falling off the steep walls (mass wasting)
10
Q
Badlands: Development of Grand Canyon
A
- Badlands are dry, rocky areas with lots of gullies and ridges
- Found in places like Red Deer River and Milk River valleys (Southern Alberta)
- Formed by fast erosion of soft rock layers
- Very little vegetation, so erosion happens even faster
11
Q
Why Are They Called “Badlands”?
A
- Name comes from French: “terres mauvaises à traverser”
- Means “bad lands to travel through”
- Difficult to cross because of the rough, broken terrain
12
Q
Main Badlands Areas in Alberta
A
- Milk River Badlands
- Manyberries Badlands
- Drumheller Badlands
- Dinosaur Provincial Park Badlands
- All in Southern Alberta known for their dramatic erosion and rocky landscapes
13
Q
Badland in Ontario: Example
A
- Located in Cheltenham Badlands ~15 km northwest of Brampton, Ontario
- Formed by improper farming practices
- Uncontrolled erosion removed topsoil and exposed soft shale beneath
- A smaller-scale example of badland development, similar to Alberta’s
14
Q
Differential Weathering & Erosion: Ship Rock (New Mexico)
A
- Ship Rock is a volcanic neck (solidified magma from inside a volcano)
- It stands tall because it’s made of harder rock that weathers slower
- The softer surrounding rocks (pyroclastic and sedimentary) erode away faster
- This leaves the volcanic neck exposed above the landscape
15
Q
Devil’s Tower, Wyoming
A
- A tall, solid rock formation made of andesitic igneous rock
- Formed underground, then exposed as softer surrounding rock eroded away
- Stands 250+ metres tall
- Shows columnar jointing (long, straight columns formed when the rock cooled and cracked)
- Columns can be up to 3 metres wide
- Its rough, “scratchy” look inspired stories in Lakota legend
16
Q
Two Main Hypotheses for Devil’s Tower
A
- Volcanic Neck Hypothesis
- Lava Lake Hypothesis
17
Q
Devil’s Tower Hypotheses: Explained
A
Volcanic Neck Hypothesis (Old Idea):
- Magma hardened inside a volcano’s vent
- Volcano eroded away, leaving the solid rock core
- Lava Lake Hypothesis (New Idea):
- Formed from a lava lake in a crater
- Lava cooled and cracked into columns, like at Kilauea (Hawaii)
18
Q
Geology in the Movies – Devil’s Tower
A
- Devil’s Tower appears in the 1977 Spielberg movie Close Encounters of the Third Kind
- It was used as the landing site for the alien mother ship
19
Q
Half Dome, Yosemite Valley, California
A
- A type of exfoliation dome.
- Originally part of a larger igneous rock body.
20
Q
How The Half Dome Was Formed
A
- Glaciers carved a curved surface at the bottom of the dome (turning a V-shaped valley into a U-shaped one).
- The top cliff formed when a vertical crack caused rocks to collapse, and glaciers carried away the debris.
21
Q
What is the Sugarloaf in Rio de Janeiro?
A
- It’s an exfoliation dome.
- Made of metamorphic rock (gneiss).
- It’s what’s left after a larger rock body eroded away.
- The outside has a weathered “rind” — a rough outer layer from surface weathering.
22
Q
Statue in Sugarloaf (Pao de Acucar) , Rio de Janeiro
A
- Cristo Redentor (the big statue) stands on Corcovado Mountain.
- Built between 1922–1931 using concrete and soapstone.
- In the background is the Sugarloaf — an exfoliation dome made of gneiss.
23
Q
What are Hoodoos?
A
- Hoodoos are mushroom-shaped rock pillars.
- Formed by erosion of layered rocks with different hardness.
- Found near Drumheller, Alberta.
24
Q
How Hoodoos Form
A
- Soft shale at the base erodes faster than the hard sandstone cap.
- Water is the main cause of erosion; wind also helps shape them.
- This creates the tall, narrow shape with a cap on top.
25
Balanced Rock (Hoodoo Example)
- Balanced Rock is a hoodoo in Arches National Park, Utah.
- Formed by erosion wearing away softer rock below a large boulder.
- Looks like a huge rock "balancing" on a narrow stem.
26
Stone Arches – Arches National Park
- Stone arches form from sandstone walls.
- Erosion (wind + water) wears both sides, making a hole or “window.”
- Over time, the arch may collapse as erosion continues.
