Presentation on Continental Drift Theory

Transcription

1 Presentation on Continental Drift Theory Mr. S. S. Jadhav Dept. of Geography, M. J. College, Jalgaon Mob No:

2 The Theory of Continental Drift

3 The World

4 Introduction In 1915 Wegener Published a book The Origin of Continents and Oceans Alfred L. Wegener In 1912 Wegener published the first version & died defending his theory

5 Aim of the Theory Professor Alfred Wegner of Germany was primarily a meterologist. He propounded his concept on continental drift in the year But it could not come in light till Wegeners displacement hypothesis was based on the works and findings of a scientists such as geologists, palaeo-climatologists, Palaeontologists, geophysicists and others. The main objective of wegener behind his displacement hypothesis was to explain the global climatic changes which are reported to have taken place during the past earth history.

6 Assumption / Hypothesis 1. If the continents remained stationary at their places throughout geological history of the earth, the climatic zones might have shifted from one region to another region and thus a particular region might have experienced varying climatic conditions from time to time. OR 1. If land surface was stable, the climatic zones would have been displaced. from one region to another region and thus a particular region might have experienced 2. If the climatic varying zones climatic remained conditions stationary from time the to landmasses time. might have been displaced and drifted. OR 2. If the climatic zones were stable, the land surface would have displaced. But wegener did not accept the stability of land surface. Wegener opted for the second alternative as he rejected the view of the permanency of continents and ocean basins

7 Basic Premise of the Theory Wegener belived in three layers system of the earth:- Outer layer-sial Intermediate layer-sima Lower layer- Nife According to wegener sial was considered to be limited to the continental masses alone where as the ocean crust was represented by the upper part of sima. Continents of sialic masses were floating on sima without any resistance offered by sima.

8 Pangaea & Panthalassa If According to the theory of Continental Drift there as only one continent and one ocean about 250 million years ago. Pangaea:- all the landmasses were united together in the form of one landmass, which he named pangaea in Carboniferous period. Meaning: All Wegener named this continent- pangaea was supercontinent, which Contained all our present continents. # pangaea covered an area of about 150 Million sq.km. it spread equally between The two hemispheres. Panthalassa- Universal Ocean Pangaea Panthalassa

9 Laurasia:- North Continent, North America, Europe Asia Formed Northern Part of Pangaea Tethys Sea: Pangaea Pangaea Gondwanalad:- South Continent, South America, Peninsular India, Australia & Antarctica Represented the southern part of the pangaea. Panthalassa

10 The Theory of Continental Drift

11 Evidences in Support of the Theory Geographical (Jig Saw Fitting) Geological Climate Fossils and Vegetation Geodetic Evidences Glaciations Elevation of Everest Satellite Images

12 Evidences Found evidence for PANGAEA and proposed the theory of continental drift.

13 Continental Drift (p95 red book, 182 in Sciencesaurus) Theory that continents were once part of a single landmass that broke apart and have moved to their present locations. can drift apart from one another and have done so in the past For more information about what the continents looked like throughout the Earth s History go to: htttp://

14 Pangaea Pangaea is the name given to the single landmass that was present 200 million years ago Can you name the continents in Pangaea?

15 PANGAEA the large landmass that included all of Earth s present day continents

16 WEGENER S EVIDENCE Continents fit together like puzzle pieces

17 Support for Continental Drift 1. SHAPE OF THE CONTINENTS Continents fit together like puzzle pieces

18 WEGENER S EVIDENCE Fossil Evidence fossils are remains of living things that lived long ago. similar fossils have been discovered in matching coastlines on different continents.

19 WEGENER S EVIDENCE

20 WEGENER S EVIDENCE Mountains Some mountain ranges on different continents seem to match. Ex: ranges in Canada match Norway and Sweden Ex: Appalachian Mtn. match UK mtn

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22 WEGENER S EVIDENCE Climatic evidence such as glaciers in areas that are now close to the Equator

23 Evidence of Continental Drift Satellites used to measure the movement of continents Laser Geodynamics Satellite (LAGEOS)

24 Which way? 50 million years The Plates Move So what now?

25 CONTINENTAL DRIFT IN DOUBT Why didn t people believe in continental drift? People couldn t image how the earth could be millions of years old People couldn t image a force great enough to move the continents BUT by the 1960 s evidence would prove continental drift is TRUE and. The story continues (as does all good science!)

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