Earth Science Chapter 4 Review

continents move slowly across Earth's surface

___, occuring in the upper mantle, are thought to be the force behind plate tectonics.

___ hypothesized that continents are in motion through continental drift.

If new crust is always being added at mid-ocean ridges, why doesn't our crust keep expanding?

uses pulses of light to measure distance

The Glomar Challenger helped scientists support the theory of seafloor spreading by

Which action occurs at the mid-ocean ridge?

Hess theorized that new seafloor is created at the ___.

This diagram shows ______.

Diamonds are used in some drill bits because they ___.

The rigid part of the plate of the ___ are made of oceanic or continental crust.

GPS and SLR both use satellites to study Earth; GPS uses radio signals, and SLR uses

uses sound waves to calculate distance

The mid-ocean ridge is important in understanding plate tectonics primarily because

The name ___ means "all land".

network of satellites used to determine locations on Earth

Which would best describe the speed of plate movement?

What provided scientists with evidence of magnetic polarity reversals?

What term describes the cycle of heating, rising, cooling, and sinking?

measures the strength of the magnetic field

Alfred Wegener started thinking about continental drift when he noticed ___.

Drilling discovered that the ___ rocks were in the center of the mid-ocean ridge.

Slab pull is caused by plates moving away from the ridges and ___.

What causes seafloor spreading?

___ studied the seafloor to see how the mid-ocean ridge was formed.

The ___ was a boat designed to drill and collect samples from the seafloor.

The first force behind plate movement is ___, which is caused by heat and differences in ___.

When scientists studied the mineral grains in seafloor rocks, what did they find had reversed?

Which best describes plate boundaries?

Evidence of the location of plate boundaries includes

GPS measure the speed and direction of tectonic plates by ___.

GPS is used to study plate ___.

If a scientist recorded the epicenters of earthquakes over years, she would probably find that

Where are the youngest rocks in the ocean floor located?

The theory that describes Earth's crust as being broken into sections is called ___.

If new seafloor is created at the mid-ocean ridge, rock there should be the ___on the seafloor.

How do scientists describe the orientation of the magnetic field today?

How do ocean floor rocks compare with continental rocks?

What provides the matter and energy for plate movement?

The second force behind plate movement is ___, which occurs at mid-ocean ridges.

What can occur when plates slide past one another?

Earth's ___ move around on the upper layer of the mantle.

Are fish fossils good evidence of continental drift?

Who proposed the seafloor spreading theory?

The three forces that factor into the movement of lithospheric plates are:

What forms the mid-ocean ridges?

Wegener's supercontinent was named ___.

a plate is forced into a mantle

Why have glacial deposits been found in Africa?

the force of gravity moves the plate down and away from the ridge