Earth Science Chapter 17 questions
isochron
a line on a seafloor map that connects points of equal age
What is thought to be the driving mechanism of plate movement?
convection currents in the mantle
continental drift
The theory of _____ explains how ocean crust is formed and destroyed.
slab push and ridge pull
How are the convection currents set in motion?
transform boundaries
Places where two tectonic plates are sliding past each other are called ________.
sinking of cooler material from the crust, rising of heated material from near the core
factor contributes to the convection currents in the mantle being sustained?
less than
The thickness of ocean sediments that are close to a mid-ocean ridge is __________ the thickness of ocean sediments that are far from mid-ocean ridges.
fossil deposits
What evidence did Wegener use to estimate the time of Pangaea's break up?
presence of coal beds
What evidence did Wegener use to suggest that Antarctica had once been closer to the equator?
Continental drift
What is the name of Alfred Wegener's hypothesis about moving landmasses?
subduction
What is the process called when one plate is forced beneath another at a convergent plate boundary?
He could not explain where the continents had moved.
What was one reason that Wegener's hypothesis of continental drift was rejected?
rift valley
When a divergent plate boundary forms on continents, a __________ forms.
glacial deposits
Which type of information was NOT collected by Wegener to support his continental drift hypothesis?
magnetometer
__________ is a device that can detect changes in the strength of the magnetic field.