Common
Knowledge
Knowledge
At what rate of speed to continents come together or move apart.
a few cm per year
List two things that supported Wegengers hypothesis of continental drift.
rocks and fossils
The East- African Rift is an example of what?
continental rift
The downward part of a convection current causes a sinking force that does what to tectonic plates?
Pulls plates towards one another.
The existence of coal beds in Antarctica indicates that the continent once had what kind of climate?
Temperate, rainy
Why was continental drift not widely accepted by Wegener's peers?
Wegener could not explain why or how the continents moved
The alignment of iron minerals in rocks when they are formed reflects the fact that Earth’s _______ has reversed.
magnetic field
Scientists believe that differences in ____ cause hot, plasticlike rock in the asthenosphere to rise toward Earth's surface.
density
While studying the ocean floor, scientists found ____ bands of magnetism.
Alternating
Define Pangea
the supercontinent that once existed
Where is the youngest part of the ocean floor formed?
near ocean ridges
Define convergent plate boundaries.
where plates come together
Plates of the lithosphere float on the ____.
athenosphere
While studying the ocean floor, scientists found ____ bands of magnetism.
Slowly
Define plate tectonics
Earth’s surface is made of rigid slabs of rock
Define continental drift.
hypothesis that continents have slowly moved to their current locations
Define asthenosphere.
earths plastic like structure
What happens at oceanic-oceanic convergent plate boundaries?
old crust is recycled by subduction
Wegener believed that the continents were assembled as part of a supercontinent about how many years ago?
250 million years ago
Define mantle.
beneath the continents and the seafloor is made of molten rock
What is Glossopteris
fossil plant
What type of boundaries do volcanoes most likely form at?
convergent oceanic-continental
Define transform boundaries.
Plates that slide past each other
What is formed when two continental plates collide?
Mountains
The driving forces of tectonic plates are related to the convection currents in Earth’s ________.
mantle