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

New VocabularyPangaea (495) The supercontinent that all continents today were once a part ofContinental Drift (495) A hypothesis that suggests that continents are in constant motion on the surface of Earth

PangaeaEach 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 Earths continents were fixed in their positions.He proposed that all continents were once part of a supercontinent called ____________.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 MoveThe 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

Apparent fit of the continentsPast ____________ Data__________________ Correlation_____________ and Mountain Correlation

Climate CluesWhen 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.Glaciers covered most of these continentsWegener 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 CluesAnimals and plants that lived on different continents can be ____________________ to that continent alone.Kangaroos are exclusive to___________________ . Lions live in ________________but not S. America. Because ____________________ separate continents, these animals cannot travel from one continent to another by natural meansHowever, _______________________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.Antarctica had a warm and wet climate and changed drastically from _________ milllion years earlier when glaciers existed.

Rock CluesWegener 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 agoThese 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 ______________ processIt was not possible for Wegener to measure how ________________ the continents movedHow could continents push their way through the ___________________rock of the sea floor?However at that time, the world was only beginning to understand what the seafloor looked like.It took many years after Wegener died before the evidence of plate tectonics hidden in the rifts on the seafloor to be discovered.