STAG1032: PHYSICAL GEOLOGY (Geologi Fizik) Continental Drift Concept (Konsep Hanyutan Benua) Hypothesis die Verschieburg der Kontinente Dr. Wan Zuhairi Wan Yaacob Program Geologi, UKM
Konsep Hanyutan Benua (Continental Drift Concept) Teori Tektonik keping (Plate Tectonics Theory)
Untold tragedies of Continental Drift.
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Point to ponder Did the continents originate at their present locations or did they drift to where they are today?"
Continental Drift Late 19 th century; Edward Suess Austrian Geologist 1885: proposed the name Gondwanaland Gondwana: supercontinent composed of southern landmasses. 1910: F.B. Taylor Geologist Published a paper on Continental Drift Little supporting evidence small impact
Continental Drift 1915: Alfred Wagener German Meteorologist & Geophysicist Published a book The Origin of Continents and Oceans Developed the hypothesis of Continental Drift all the continents had at one time been united into single super-continent
Alfred Wegener, a German meteorologist
Concept of Continental Drift 225-200 million years ago (Permian to Jurassic): Single supercontinent (Pangaea = All Land) Panthalassa (Pan =all; thalassa = sea) The Evidence: 1. Continental fit (South America v Africa) 2. Glacial Evidence / Ancient climates 3. Geographic distribution of fossils 4. Similarities of rocks and mountain ranges / structures
Laurasia Gondwanaland Key words:-- 1. Pangaea 2. Panthalassa 3. Laurasia 4. Gondwanaland
1. Continental fit (Jigsaw Puzzle) Similarity between coastlines: South America and Africa. Critics: modification by erosion & deposition But fit along the true geologic margin i.e. continental shelves (pelantar benua) (continental // oceanic crust) depth of 900m-2000m.
Continental fit along true geologic margin which is located along the margin of continental and oceanic crust (900-2000m)
A stamp commemorates the concept of Continental Drift
2. Glacial Evidence / Ancient climates Glacial deposits (till) & striations during Permian period (220-250 million years) Striations = scratch marks on bedrock beneath the till Southern hemisphere highly glaciated Northern hemisphere tropical climate (based on plant fossils) ICE: Present ocean to land (wrong!!); land to ocean Therefore, located near the South Pole
Striations or scratch marks - Evidence of an ice movement Glacial till rock
The continents as there are today. Evidence of old ice sheets Equator (tropical climate) If continents did not move: 1. How glaciers moved from ocean to land? 2. How large-scale continental glaciers formed near the equator?
If continents are reassembled as a single landmass with South Africa located at the south pole, the direction of continental glaciers movement makes sense (i.e. glacier moved radially outward from the pole)
3. Fosil Evidence Land Bridge South America Africa No remnants were found Glossopteris flora Mesosaurus Small freshwater reptile Permian age rocks Brazil and South Africa. Lystrosaurus & Cynogathus Triassic aged land dwelling reptiles Thesaurus (???)
Thesaurus Small dinosaur with so many words!!
Land Bridge
Small freshwater reptile Triassic aged land dwelling reptiles
4. Rocks & Mountain ranges Picture puzzle Fitting & picture Wagener : Torn pieces of a newspaper Same age /structure/style of deformation
The trend of Appalachian Mountains Continuous mountain range when continents position next to each other App. Mountains terminate abruptly at the Newfoundland coastline Mountain ranges of the same age and deformational style appear in another places
Similar rock sequence for all continents in Gondwanaland.
One problem with the hypothesis Its lack of a mechanism to explain how continents, composed of granitic rocks, could move through the denser basaltic oceanic crust??
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