Download The Theory of Continental Drift

April 11, 2018 | Author: Anonymous | Category: , Science, Earth Science, Plate Tectonics
Share Embed


Short Description

Download Download The Theory of Continental Drift...

Description

Theory of Continental Drift Cornell Notes Pg. 95

• Alfred Wegener The Theory (1910) of Continental Drift • Formed a hypothesis that all the continents were once joined together and have drifted apart

What was Wegener’s evidence? • Evidence from: 1. Landforms—the continents fit together 2. Fossils—ancient plants and animals found in many different continents 3.

4.

Climate—Antarctica has plant fossils. Tropics have rocks with ice scratches from glaciers. Rock Types- similar rocks found were continents may have once been joined together.

Wegener’s DATA

Pangaea • Continents were joined together in one land mass • “The super continent” 245 mya

Which way are the continents moving today?

Plate Tectonics Timeline • page 98

The Theory of Sea Floor Spreading Page 99

Sea Floor • Harry Hess (1960) Spreading • as the ocean floor spreads apart, new crust material rises from the mantle and creates new sea floor to fill the “hole.”

HESS (1960)

• Sea floor spreading • Continents were moving (as Wegener had proposed) • Evidence 1. 2. 3.

1. The discovery of the Midocean Ridge

• Scientists mapped 47,000 miles of underwater volcanic ridges by using sonar

Map of Mid-ocean Ridges

2. Ocean floor shows Magnetic Poles reversing

3. Ocean floor samples—older crust is further away from ridges

View more...

Comments

Copyright © 2017 HUGEPDF Inc.