Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 1

New Vocabulary

Pangaea (495) – The supercontinent that all continents today were once a part of

Continental Drift (495) – A hypothesis that suggests that continents are in constant motion on the surface of

Earth

Pangaea

Each year, North America moves a few _____________________ farther away from Europe and closer to Asia.

Nearly 100 years ago, Alfred _________________ began an important investigation to know whether Earth’s

continents were fixed in their positions.

o He proposed that all continents were once part of a supercontinent called ____________.

o Over time Pangaea began_________________ __________________, and the continents slowly

moved to their present positions.

Wegener proposed the hypothesis of _____________________ drift, which suggested that continents are in

constant motion on the surface of Earth.

Evidence That Continents Move

The most obvious evidence for continental drift is that the continents appear to fit together like pieces of a

__________________________.

However, scientists were skeptical, and Wegener needed additional evidence

1. Apparent fit of the continents

2. Past ____________ Data

3. __________________ Correlation

4. _____________ and Mountain Correlation

Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 2

Climate Clues

When Wegener pieced Pangaea together, he proposed that South America, Africa, India, and Australia were

located closer to ___________________________ 280 million years ago.

He suggested the climate of the Southern Hemisphere was much ______________________ at the time.

o Glaciers covered most of these continents

Wegener studied the _______________ deposited by glaciers in South America, Africa, India, and Australia.

He discovered ________________ _______________, or deep scratches in rocks made as the glaciers moved

across the land on neighboring continents today.

Fossil Clues

Animals and plants that lived on different continents can be ____________________ to that continent alone.

o Kangaroos are exclusive to___________________ . Lions live in ________________but not S. America.

o Because ____________________ separate continents, these animals cannot travel from one continent

to another by natural means

However, _______________________of similar organisms have been found on several continents separated by

oceans.

Fossils of a plant called Glossopteris have been discovered in rocks from South America, ______________,

India, Australia, and________________________.

Evidence suggests these plants grew in a _____________________environment. Therefore, the climate of this

region, including Antarctica, was different than it is today.

o Antarctica had a warm and wet climate and changed drastically from _________ milllion years earlier

when glaciers existed.

Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 3

Rock Clues

Wegener also observed that ________________________ ranges and rock formations on different continents

had common origins.

Today geologists have determined that large-scale volcanic eruptions occurred on the western coast of

_________________ and the eastern coast of South America at about the same time hundreds of millions of

years ago

o These volcanic rocks are identical in both ____________________and ___________

The _____________________ mountain range in northern Europe and the Appalachian Mountains in eastern

N. America are similar in age, structure, and composition.

If you place the continents ______________________, these mountains would meet and form on long,

continuous mountain belt.

What is missing?

Wegener continued to support the continent drift hypothesis until his death in ______________

His ideas were not widely accepted until nearly 4 decades later, because he could not explain how they

________________.

One reason scientists questioned continental drift was because it is a ______________ process

It was not possible for Wegener to measure how ________________ the continents moved

o How could continents push their way through the ___________________rock of the sea floor?

o However at that time, the world was only beginning to understand what the seafloor looked like.

o It took many years after Wegener died before the evidence of plate tectonics hidden in the rifts on the

seafloor to be discovered.