Plate Tectonics and Earth's Structure
This is the outermost solid layer of Earth.
What is the crust?
This supercontinent once contained nearly all of Earth's continents.
What is Pangaea?
This is the underwater mountain range where new oceanic crust forms.
What is a mid-ocean ridge?
This era is known for dinosaurs dominating Earth's land ecosystems.
What is the Mesozoic Era?
This type of evidence can show that the same species once lived on continents now separated by oceans.
What are matching fossils?
At this type of plate boundary, two plates move away from each other.
What is a divergent boundary?
This scientist proposed that continents were once joined together and later drifted apart.
Who was Alfred Wegener?
This process creates new oceanic crust that moves away from a mid-ocean ridge.
What is seafloor spreading?
This era is associated with the diversification of mammals and the eventual appearance of humans.
What is the Cenozoic Era?
These marine ecosystems can preserve evidence of past ocean conditions and environments.
What are coral reefs?
This type of plate boundary is responsible for movement along the San Andreas Fault.
What is a transform boundary?
The coastlines of these two continents appear to fit together like puzzle pieces.
What are South America and Africa?
Ocean floor rocks closest to a mid-ocean ridge are generally this age compared with rocks farther away.
What are younger rocks?
This mass extinction was mainly caused by a large asteroid impact about 66 million years ago.
What is the Cretaceous extinction?
Ancient coral fossils found in a place that is now too cold for reef-building corals suggest this about the past.
The area may have had warmer conditions.
This process involves the slow movement of mantle material as heat moves through Earth.
What is mantle convection?
Matching fossils found on continents separated by oceans provided evidence for this idea.
What is continental drift?
This is the study of ancient magnetic records preserved in rocks.
What is paleomagnetism?
This mass extinction was associated with massive volcanic eruptions and severe environmental changes about 252 million years ago.
What is the Permian extinction?
Along the San Andreas Fault, stress builds as these two tectonic plates move past each other.
What are the Pacific Plate and North American Plate?
Explain how mantle convection helps move tectonic plates over long periods of time.
Heat causes mantle material to move slowly, helping drive the movement of tectonic plates.
Scientists initially rejected Wegener's theory because he could not adequately explain this.
How the continents moved.
Rock samples are 5 million years old at 50 km from a ridge and 15 million years old at 150 km. Explain what this pattern tells scientists.
Oceanic crust forms at the ridge and moves outward, so rocks become older with increasing distance.
This mass extinction was associated with major glaciation and falling sea levels about 444 million years ago.
What is the Ordovician extinction?
Explain how a mass extinction can change the course of life on Earth.
It eliminates many species, changes ecosystems, and creates opportunities for surviving groups to diversify.