1. Building the Appalachian Mountains

2. How did the Appalachian’s form?: Step 1: The Crustal Rocks Form
The crustal rocks of the Appalachian Mountains are more than 1 Billion years old.
These rocks formed when there was a single continent surrounded by ocean.
But then the supercontinent pulled apart. . .

3. How did the Appalachian’s form?: Step 2: Continental Drift
At first the pieces of the supercontinent drifted apart.
Copper, zinc, iron and sulfur were deposited on the sea floor.
Then, 470 Million years ago the motion--the continents began to move toward each other.
Volcanoes were frequent.
Some of the sea floor was pushed onto the continents.

4. How did the Appalachian’s form?: Step 3: Continental Collision
About 270 million years ago, the North American and African plates collided.
This is a convergent continental-continental boundary.

5. How did the Appalachian’s form
How did the Appalachian’s form?: Step 3 : Continental Collision (continued)
Since the plates have the same densities, they pushed most of the crustal rocks upward.
Some rocks were trapped below ground and were transformed into granite, quartz, emeralds, slate, and shale.

6. How did the Appalachian’s form
How did the Appalachian’s form?: Step 4: Effects of Continental Collision
Earthquakes were common.
Happens as crustal rocks slide along a fault.
Atlantic Ocean begins to form.

7. Changing the Appalachian Mountains: Erosion
Erosion via wind, water, and ice have affected the shape of the peaks
Originally high, steep, sharp
Now lower, gently sloped, and rounded

8. Changing the Appalachian Mountains: Glaciers
Glaciers have moved into the area 4 times during the past 2-3 million years:
Induced climate change
Carved into the mountains
Deposited sediment

9. Today’s North Carolina
Continued erosion of the peaks
Eroded material moves down the mountains into the Piedmont region but then stops.
The fall line is where the material stops.
This line separates the Piedmont and Coastal Plains regions.

10. Today’s North Carolina
Earthquakes
Very few occur
Less than 4.0 on the Richter scale
Gold
Once produced the most of any state
Changed with the California Gold Rush
Emeralds
Still being mined
Many of the world’s largest emeralds