Building the Appalachian Mountains

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. . .

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.

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.

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.

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.

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

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

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.

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