chapter 17 earth science

What is the study of the Earth's ancient magnetic record?

paleomagnetism

The supercontinent from Wegener's theory of continental drift is called ___________________________.

pangaea

The tremendous amount of heat within the Earth powers ___________________

plate tectonics

What causes the seafloor to spread?

rising molten magma

Harry Hess's theory of _________________________ explained how ocean crust is generated and destroyed.

seafloor spreading

LOOK AT THE FIGURE AND identify the subduction zone

D

Where are the youngest rocks on the ocean floor located?

at the mid-ocean ridges

The subduction of an oceanic plate beneath a continental plate produces a(n) ____________________________

chain of volcanic mountains

What is the name of Alfred Wegener's hypothesis about moving land masses?

continental drift

Places where two tectonic plates are moving away from each other are called _____________________________.

divergent boundaries

What evidence did Wegener use to estimate the time of the continent Pangaea's break up into smaller continents?

fossil data

What is an isochron ?

a line on a seafloor map that connects points of equal age

During the time of Pangaea, what had the greatest impact on Earth's climate?

it was a time of a giant global ocean

Which mineral may preserve magnetic patterns on the ocean floor, in support of tectonic plates?

magnetite

A ___________________ is a device that can detect changes in the strength of the Earth's magnetic field.

magnetometer

What two topographic features of the ocean floor were discovered only with the use of sonar?

mid-ocean ridges and deep-sea trenches

When a divergent plate boundary forms on a continent, (land), a ___________________forms.

rift valley

Much of the Earth's internal heat comes from ________________________

the decay of radioactive materials

A place where two plates slide laterally past each other is called a _______________________________

transform boundary

Rocks close to the mid-ocean ridge are _____________________ rocks far from the mid-ocean ridge.

younger than