Restless Continents
Terms
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- Continental drift also explained puzzling evidence left by...
- ancient glaciers.
- Continental drift
- theory that continents can drift apart from one another and have done so in the past.
- The Theory of Plate Tectonics
- theory that Earth's lithosphere is divided into tectonic plates that move around on top of the asthenosphere.
- Continental drift theory seemed to explain observations that...
- the continents looked like pieces of a puzzle that fit together.
- Convection
- hot material from deep within the Earth rises while cooler material near the surface sinks.
- They thought there wasn't a force in nature...
- that could move entire continents.
- Ridge Push
- At mid-ocean ridges, the oceanic lithosphere is higher than it is where it sinks beneath continental lithosphere.
- What was Pangaea?
- belief that all the separate continents of today were once a single landmass
- Ancient glaciers left grooves in the ground that indicate...
- the direction they traveled.
- evidence #2 that support continental drift
- Glacial grooves in the crust
- The proof of sea-floor spreading
- supported Wegener's idea that continents move.
- Alfred Wegener
- scientist who looked at the continents as pieces of a puzzle
- evidence #1 that support continental drift
- Continents fit together like puzzle
- Continental drift also explained...
- why fossils of the same plant and animal species are found on both sides of the Atlantic Ocean
- Example of sea floor spreading:The crust increases in age the farther it moves away from the mid-ocean ridge, which means (2))
- The oldest crust in the Atlantic Ocean is found near the edges of the continents.
- Three different ways plates are able to move:
- convection, slab pull, and ridge push.
- When did Wegener write about his theory of continental drift.
- Early 1900's
- Pangaea is Greek for
- "all Earth".
- Slab Pull
- Because oceanic lithosphere is denser than the asthenosphere, the edge of the oceanic plate sinks and pulls the rest of the tectonic plate with it in a process called slab pull.
- Sea floor spreading is
- the process by which new oceanic lithosphere is created as older materials are pushed away.
- evidence #3 that support continental drift
- Fossil evidence on different continents
- As tectonic plates move away from each other,
- the sea floor spreads apart and magma rises to fill the gap.
- The theory of sea-floor spreading
- helped to prove Wegener's theory.
- Mid-Atlantic Ridge
- a chain of submerged mountains running through the center of the Atlantic Ocean.
- Mid Ocean Ridges are where
- sea floor spreading occurs.
- Example of sea floor spreading:The crust increases in age the farther it moves away from the mid-ocean ridge, which means (1)
- newer rock is closest to the ridge and older rock is farther away.
- When Wegener put forth his theory of continental drift,
- many scientists would not accept his ideas.
- Mid-ocean ridges are
- underwater mountain chains that run through Earth's ocean basins.