History of Continents

Question 1

Accreted terrane

Answer 1

An individual, geologically coherent grament of an amalgamation of odd pieces of crust – island arcs, seamounts; remnants of thickened oceanic plateaus; old mountain ranges; and othe rslivers of continental crust - that were plastered onto the leading edge of a continent as it moved across Earth’s surface.

Question 2

Accretion

Answer 2

A process of continental growth in whic h buoyant fragments of crust are attached (accreted) to continents during plate motions.

Question 3

Active Margin

Answer 3

A continental margin characterized by volcanic activity and frequent earthquakes and associated with subduction or transform faulting.

Question 4

Craton

Answer 4

A stbale nuclear composed of the roded remnants of ancient deformed rocks that comprises the continental shields and platforms.

Question 5

Cratonic keel

Answer 5

A part of the lithosphere that extends into the convecting asthenosphere at 100 to 200 km beneath the cratons like the hull of a boat into water.

Question 6

Epeirogeny

Answer 6

The gradual downward and upward movements of broad regions of crust without significant folding or faulting.

Question 7

Glacial rebound

Answer 7

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Question 8

Magmatic addition

Answer 8

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Question 9

Orogen

Answer 9

An elongated mountain belt arrayed around a continental craton and formed by a later episode of compressive deformation.

Question 10

Orogeny

Answer 10

Mountain building, particularly by the folding and thrusting of rock layers, often with accompanying magmatic activity.

Question 11

Passive margin

Answer 11

A continental margin far from a plate margin, with no active volcanoes and few earthquakes.

Question 12

Rejuvenation

Answer 12

Renewed uplift in a mountain chain on the site of earlier uplifts, returning the area to a more youthful stage.

Question 13

Shield

Answer 13

A large region of stable, ancient crystalline basement rocks within a continent.

Question 14

Tectonic age

Answer 14

The age of a rock that corresponds to the last major episode of crustal deformation; that is, to the last time the radiometric “clock” within the rock was reset by tectonic activity.

Question 15

Tectonic province

Answer 15

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Question 16

Wilson cycle

Answer 16

A general plate tectonic cycle that comprises (1) rifting during the breakup of a supercontinent (2) passive-margin cooling and sediment accumulation, during seafloor spreading and ocean opening (3) active-margin volcanism and terrane accretion during subduction and ocean closure, and (4) orogeny during the continent-continent collision that forms the next supercontinent.