Volcanoes and Earthquakes
This is a vent in Earth’s crust through which molten rock flows.
A volcano
This boundary occurs when two plates move away from each other
Divergent boundary
Earths surface is divided into large plates of rigid rock that move relative to each other according to this theory.
Theory of plate tectonics
These are preserved remnants or evidence of past living organisms.
Fossils
This scientist proposed the hypothesis of continental drift in 1912
Alfred Wegner
This is a column of mantle that is hotter than the surrounding material.
A hot spot
This boundary occurs when two plates collide
Convergent boundary
This layer is hot and semi plastic, allowing Earths tectonic plate to move over it
Mantle
This principle states that in undisturbed rock layers, the oldest rocks are on the bottom
Superposition
This was the name of the supercontinent that Wegner proposed all continents were once part of
Pangea
Tectonic plates moving over hot spots can create this
Chains of volcanoes
This boundary occurs when two plates slide past each other
Transform boundary
Scientist used echo sounded to determine the depth of this part of Earth
Seafloor
In an undisturbed sequence of rock layers, this layer is the oldest
The bottom layer
This hypothesis suggests that continents are in constant motion on Earths surface
Continental drift
These are vibrations in the ground caused by movement along breaks in Earths lithosphere
Earthquake
At this type of boundary a denser plate can sink beneath a more buoyant plate
Convergent boundary
Mid ocean ridges
This is the age of a rock compared with the ages of other rocks
Relative age
Wegner studied mountain formation, glacial deposits, glacial grooves, and these to find evidence of continental drift.
Fossils
During this event, Earths magnetic field reverses direction
Magnetic reversal
When continental plates collide over millions of years the crust can fold and form these
Mountains
This processes forms new oceanic crust along a mid ocean ridge while older crust moves away from the ridge
Seafloor spreading
Scientist can compare the layers above and below a rock layer to determine this
Relative age
Different rocks and fossils can help scientists determine what environment an area was once covered by, such as seas or these.
Glaciers