Outline: Chapter 14.1: The Continental Drift Hypothesis

Outline: Chapter 14.1: The Continental Drift Hypothesis

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  Chapter 14 Lesson1 – 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
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  Chapter 14 Lesson1 – 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.
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  Chapter 14 Lesson1 – 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.