Lecture 3: Plate Tectonics Flashcards
1858: Snider – existence of a great region of *
1890: Edward Suess – *
1915: Alfred Wegener – * {Challenge: not able to provide the mechanism on how continents drifted apart}
dry land before the Great Flood
breakup of supercontinent; Gondwanaland
Continental drift
- – existence of a great region of dry land before the Great Flood
- – breakup of supercontinent; Gondwanaland
- – Continental drift
1858: Snider
1890: Edward Suess
1915: Alfred Wegener
Challenge for continental drift
{Challenge: not able to provide the mechanism on how continents drifted apart}
All lands
Pangaea
All water
Panthalassa
Pangaea Breakup:
Laurasia {}
Gondwanaland {}
(North America, Europe, Asia)
South America, Africa, India, Australia, Antarctica
Evidence for Continental drift
- Global geography
- Rock sequences
- Fossil
- Paleoclimate
Clue from global geography
Continental fit
Coastlines of Africa + South America
{Challenge: coastlines are constantly modified by erosion and deposition}
What did Edward Buller use?
– used continental shelf
Clues from Rock Sequences
Mountain Ranges Appalachian Mountains (N America), British Isles, Caledonian Mountains (Scandinavia)
remains, trace, imprints of organisms that have been preserved in the Earth’s crust for 10,000 years +
Fossils
Fossil Distribution
- Mesosaurus – aquatic reptile; eastern South America and South Western Africa
- Lystrosaurus – strictly land-dwelling reptile; (Africa, Antarctica, Inda)
- Glossopteris “fossil seed fern” – too large to be carried by wind (Africa, Australia, India, South America)
aquatic reptile; eastern South America and South Western Africa
Mesosaurus
strictly land-dwelling reptile; (Africa, Antarctica, Inda)
Lystrosaurus
too large to be carried by wind (Africa, Australia, India, South America)
Glossopteris “fossil seed fern”
Glacial deposits – SA. Africa, India, Australia {tropical countries = rocks related to glaciers}; Coal fields in the northern hemisphere
Southern continents are joined together and located near the South Pole (Antarctica, Arctic}
Paleoclimate
Glacial deposits in
SA. Africa, India, Australia
Proponent of seafloor spreading
Harry Hess
Place of continuous generation of oceanic crust;
Mid-oceanic ridge:
ridge crest
7 major plates
African Plate Indo-Australian Plate Antarctic Plate Eurasian Plate North American Plate Pacific Plate South American Plate
MINOR PLATES
Somali Plate · Nazca Plate Philippine Sea Plate · Arabian Plate Caribbean Plate · Cocos Plate Caroline Plate · Scotia Plate Burma Plate · New Hebrides Plate
Elaborate Plate Tectonics:
Continental drift + seafloor spreading
*Earth is composed of lithospheric plates