12.1 Evidence for Continental Drift Flashcards
Who proposed the idea of continental drift?
German scientist Alfred Wegener
What is the Continental Drift Theory?
A theory that states that the continents have not always been in their present locations but have “drifted” there over millions of years.
What was Wegener’s first piece of evidence?
South America’s eastern coastline and Africa’s western coastline surprisingly fits well.
What’s the name for the giant land mass?
Pangaea
What else supported Wegener’s idea?
His analysis of rocks and mountains ranges.
Explain Wegener’s analysis of rocks and mountain ranges
- mountain ranges appear to continue on different continents
- similarities between rock structures are found on different continents
Other than rocks and mountain ranges, what else matches?
Fossils
What are glaciers
Vast masses of ice
Where are glaciers found
At the poles and high in the mountains
When glaciers retreat, what do they leave behind?
They leave behind large U-shaped valleys, deeply scratched rocks, and various types and patterns of rock formations.
Define paleoglaciation
The extent of ancient glaciers and to the rock markings they left behind.
What evidence does coal deposits in Antarctica give?
Coal usually forms from the decomposition of tropical swamp animals, and Antarctica certainly isn’t a tropical place. It suggests that Antarctica was once in a warmer location.
What was the problem of Wegener’s theory?
He couldn’t prove how the continents could move
Define tectonic plates.
The large slabs of rock that form Earth’s surface, moving over a layer of partly molten rock.
Define volcanoes.
Openings in Earth’s surface, that, when active, spew out gases, chunks of rock, and melted rock.
Define earthquake.
A sudden, ground-shaking release of built-up energy at or under Earth’s surface.
