Ch 17 Plate Tectonics

The mechanisms thought to be associated with plate movements

The existence of coal beds in Antarctica indicates that the continent once had ____.

A landmass thought to have been comprised of present-day southern continents

____________________ is the process occurring in the area marked by the letter R.

A narrow, long depression in continental crust

Each cycle of spreading and intrusion of magma during seafloor spreading results in ____.

What is the area that results in a chain of volcanoes along the edge of a continental plate?

The process that helps to move an oceanic plate toward a subduction zone

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

Theory that states that Earth’s crust and upper mantle are broken into enormous slabs

The features marked by the letter Y are ___________________________________.

A narrow, elongated depression in the seafloor

In which compass direction have North and South America moved in relation to Africa?

A narrow, elongated depression in the seafloor is called a(n) _________.

What is the term for the boundary at which two tectonic plates are moving apart?

The magnetic pattern of ocean-floor rocks on one side of an ocean ridge is ____.

____ is a fossil fern that helped support Wegener’s hypothesis of continental drift.

rift valley

Type of boundary characterized by long faults and shallow earthquakes

A device that measures changes in Earth’s magnetic field

The downward part of a convection current causes a sinking force that ____.

A long, narrow, fault-bounded, continental depression is a(n) ____________________.

Hot magma is forced toward crust along an ocean ridge.

Volcanoes

Based on the figure, what type of polarity would you expect to find in the next epoch?

The magma hardens, to form a small amount of ocean floor.

The feature marked by the letter X is a(n) _________________________.

How does the size of the future Atlantic Ocean compare with its present size?

Convection currents transfer thermal energy ____.

Continental-continental plate collisions produce ____.

A vast, underwater mountain chain is called a(n) _________.

______________________________ are places where plates slide horizontally past each other.

_____________ is defined as the study of the history of earth’s magnetic field.

Isochron maps of the seafloor indicate that ocean crust is ____.

Hot magma fills the gap that forms at the ridge

Many early mapmakers thought Earth’s continents had moved based on ____.

Subduction zone

Highly-folded mountains

At this type of boundary, the process of subduction causes a deep-sea trench.

What plate boundary causes colliding continents to crumple, fold, and form mountain ranges?

The arrows in the mantle and oceanic crust indicate the direction of ____ beneath the plates.

How does the size of the Pacific Ocean on this map compare with its present size?

At an oceanic-oceanic convergent boundary, ____.