Evidence of Plate Motions
Plant fossils of the same fern were found on five continents.
What is evidence of continental drift?
Hot melted rock rises, and cooler rock sinks in the mantle, forming currents that move the plates.
What is convection?
This type of stress pulls on Earth's crust , stretching the rock to make it thinner.
What is tension?
Type of volcano that is a more immediate threat.
What is active?
Fossils, land features, and ______ supported evidence of continental drift.
What is climate data?
At a convergent boundary, water may be trapped and may mix with the material in the mantle. This forms if the material reaches the surface before cooling.
What is a volcano?
This type of stress squeezes rock until it bends or breaks.
What is compression?
Type of volcano that poses little threat-sleeping.
What is dormant?
Mid-ocean ridges are the sources of the spreading. Molten rock flows up through a crack in Earth's crust, and hardens new strips of rock. Older rock moves farther away.
What is sea-floor spreading?
This type of crust is dense and found at the bottom of the ocean.
What is oceanic crust?
The energy released by an earthquake.
What is magnitude?
Type of volcano that poses very little threat-dead.
What is extinct?
The sinking of ocean crust back into the mantle, and occurs at ocean trenches.
What is subduction?
This type of crust is lighter and thicker than ocean's crust.
What is continental crust?
Volcano with slow, steady eruption. Massive and typically hot spot volcanoes.
What is a shield volcano?
Lava frequently erupts at the surface.
What is a 'hot spot'?
Wegener gathered evidence to support his hypothesis of continental drift. These are the three main categories of evidence.
What is evidence from land features, fossils, and climate?
These are the boundaries where plates move apart, plates come together, and plate slip past each other.
What are divergent, convergent, and transform boundaries?
Volcano that has large eruptions emptying the magma chamber, causing the top to collapse inward, and a lake fills it.
What is caldera?
Thick and sticky magma causing explosive eruptions.
What is high silica?