Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Earth Systems 3209 Unit: 4 The Forces Within Earth Reference: Chapters 4, 15, 16, 19; Appendix A & B

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Evidence supporting Continental Drift Unit 4: Topic 1.2 Focus on...  outlining and describing evidence to support continental drift.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Continental Drift  Alfred Wegener’s Theory of Continental Drift States:  Approximately 200 million years ago a supercontinent called Pangaea started to break apart. Laurasia was formed in the North and Gondwanaland was formed in the South. Over the past 150 million years, these land masses split apart to form the continents we see today.  Since the mid 1900’s, much evidence have been collected to support the theory of continental drift and plate tectonics. Text Reference: Pages

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 1)Fit of the Continents:  Continental coastlines appear to fit closely together, for example, South America and Africa.  With further investigation Alexander DuToit suggested that the continental shelves would fit better because of the absence of erosion beneath the oceans. Continental Drift - Evidence

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador 2)Fossil Correlation:  Wegener and other scientist had proof of similar organisms that existed in both South America and Africa.  Fossil evidence of a fern plant (Glossopteris) and an aquatic reptile (Mesosaurus) provided the best evidence that the continents were once together. Continental Drift - Evidence

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Fossil Evidence for the existence of Pangaea Continental Drift - Evidence

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Continental Drift - Evidence Similar Rock Types Continuous Mountains 3)Rock Types and Structures:  Scientist also noted that even though the continents appear to fit together, the overall picture has to be continuous from one continent to another.  This picture included the type of rock on neighboring continents and structural similarities such as mountains. For example, the Appalachian mountains.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Continental Drift - Evidence 4)Ancient Climates (Paleoclimates):  Glacial deposits were found in South America, Africa, India, and Australia.  These continents are presently not in cold climates, therefore must have been in a colder climate in the past and the continents later moved to the positions they are presently in today.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Example 1: Which of the following scientist contributed the greatest to the continental drift theory? a) Holmes and Huttonc) Wegener and Hutton b) Wegener and Holmesd) Wilson and Hutton Which two continental plates appear to have the best fit along their coastlines? a) Africa and Europec) North America and South America b) North America and Africad) South America and Africa

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Example 2: Which scientist proposed the continental drift theory? a) Alfred Wegenerc) Robert Deitz b) Harry Hessd) Tuzo Wilson

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Your Turn... Take the time and complete the following questions... (Solutions to follow) Question: Describe two pieces of evidence that Wegener used to support the theory of Continental Drift.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Solutions... Question: Describe two pieces of evidence that Wegener used to support the theory of Continental Drift. Answer: Two of the following four pieces of evidence could be discussed: 1) Fit of the continents – match up continental shelves, 2) Fossil correlation – match same fossil on neighboring continents, 3)Paleoclimatic evidence – parts of continents in southern hemisphere and India have glacial evidence, 4) Matching of rock types and mountains – rock composition and mountain chains appear to be continuous on neighboring continents.

Copyright © 2014 All rights reserved, Government of Newfoundland and Labrador Summary... Overview of Points covered: Evidence to support Wegener’s Continental Drift Theory: 1)Fit of the Continents 2)Fossil Correlation 3)Rock Types and Structural Similarities 4)Ancient Climates