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.