Chapter 7- Plate Tectonics

In order to complete a convection current, the rising material must eventually _________ Earth.

• stop inside
• cool
• sink back into

The result of plate movement can be seen at _____________.

• ocean margins
• plate centers
• plate boundries

Bands of rock on the seafloor showing alternating magnetic orientation indicate Earth's magnetic field has ___________.

• reversed itself in the past
• weakend
• become stronger

A ________ is a sensitive device used to detect magnetic fields on the seafloor.

• geologist's compass
• Glomar
• magnetometer

Active volcanoes are most likely to form at __________.

• divergent boundries
• the center of continents
• convergent oceanic-continental boundries

Seafloor spreading occurs because ___________.

• earthquakes break apart the ocean floor
• sediments accumulate at the area of spreading
• molten material beneath Earth's crust rises to the surface

Plates move apart at _________ boundaries.

• concergent
• stable
• divergent

Continental drift was not widely accepted when it was first proposed because __________.

• Wegener couldn't explain why or how the continents moved
• continental landmasses were too big to move slowly over Earth's surface
• magnetic and sonar data proved that Wegener's hypothesis was incorrect

Continental drift states that continents have moved __________ to their current location.

• vertically
• slowly
• quickly

Crust is neither destroyed nor formed along which of the following boundaries?

• convergent
• divergent
• transform