Chapter 09 Vocab

Question 1

accretionary orogen

Answer 1

An orogen formed by the attachment of numerous buoyant slivers of crust to an older, larger continental block.

Question 2

anticline

Answer 2

A fold with an arch-like shape in which the limbs dip away from the hinge.

Question 3

axial surface

Answer 3

The imaginary surface that encompasses the hinges of successive layers of a fold.

Question 4

basin

Answer 4

A fold or depression shaped like a right-side-up bowl

Question 5

brittle deformation

Answer 5

The cracking and fracturing of a material subjected to stress.

Question 6

compression

Answer 6

A push or squeezing felt by a body.

Question 7

craton

Answer 7

A long-lived block of durable continental crust commonly found in the stable interior of a continent.

Question 8

cratonic platform

Answer 8

A long-lived block of durable continental crust commonly found in the stable interior of a continent.

Question 9

crustal root

Answer 9

Low-density crustal rock that protrudes downward beneath a mountain range.

Question 10

crustal thickening

Answer 10

The process by which the continental crust increases in thickness, becoming up to 70 km thick (vs. normal thickness of about 35–40 km); it can occur during continental collision.

Question 11

deformation

Answer 11

A change in the shape, position, or orientation of a material, by bending, breaking, or flowing.

Question 12

delamination

Answer 12

The process by which dense lithospheric mantle separates from the base of a plate and sinks into the mantle.

Question 13

displacement

Answer 13

The amount of movement or slip across a fault plane.

Question 14

dome

Answer 14

Folded or arched layers with the shape of an overturned bowl.

Question 15

ductile deformation

Answer 15

The bending and flowing of a material (without cracking and breaking) subjected to stress.

Question 16

epeirogeny

Answer 16

An event of epeirogenic movement; the term is usually used in reference to the formation of broad mid- continent domes and basins.

Question 17

exhumation

Answer 17

The process (involving uplift and erosion) that returns deeply buried rocks to the surface.

Question 18

exotic terrane

Answer 18

A block of land that collided with a continent along a convergent margin and attached to the continent; the term exotic implies that the land was not originally part of the continent to which it is now attached.

Question 19

fault

Answer 19

A fracture on which one body of rock slides past another.

Question 20

fault scarp

Answer 20

A small step on the ground surface where one side of a fault has moved vertically with respect to the other.

Question 21

Fold

Answer 21

A bend or wrinkle of rock layers or foliation; folds form as a consequence of ductile deformation.

Question 22

fold-thrust belt

Answer 22

An assemblage of folds and related thrust faults that develop above a detachment fault.

Question 23

foliation

Answer 23

Layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock.

Question 24

global positioning system (GPS)

Answer 24

A satellite system people can use to measure rates of movement of the Earth’s crust relative to one another, or simply to locate their position on the Earth’s surface.

Question 25

hinge

Answer 25

The portion of a fold where curvature is greatest.

Question 26

isostasy

Answer 26

The condition that exists when the buoyancy force pushing litho sphere up equals the gravitational force pulling litho sphere down.

Question 27

Joint

Answer 27

Naturally formed cracks in rocks.

Question 28

Limb (of fold)

Answer 28

The side of a fold, showing less curvature than at the hinge.

Question 29

monocline

Answer 29

A fold in the land surface whose shape resembles that of a carpet draped over a stair step.

Question 30

normal fault

Answer 30

A fault in which the hanging-wall block moves down the slope of the fault.

Question 31

orogen

Answer 31

A linear range of mountains.

Question 32

orogenic collapse

Answer 32

The process in which mountains begin to collapse under their own weight and spread out laterally.

Question 33

pressure

Answer 33

Force per unit area, or the “push” acting on a material in cases where the push (compressional stretch) is the same in all directions.

Question 34

reverse fault

Answer 34

A steeply dipping fault on which the hanging-wall block slides up.

Question 35

shear stress

Answer 35

A stress that moves one part of a material sideways past another part.

Question 36

shield

Answer 36

An older, interior region of a continent.

Question 37

strain

Answer 37

The change in shape of an object in response to deformation (i.e., as a result of the application of a stress).

Question 38

stress

Answer 38

The push, pull, or shear that a material feels when subjected to a force; formally, the force applied per unit area over which the force acts.

Question 39

strike

Answer 39

The angle between an imaginary horizontal line (the strike line) on the plane and the direction to true north.

Question 40

strike-slip fault

Answer 40

A fault in which one block slides horizontally past another (and therefore parallel to the strike line), so there is no relative vertical motion.

Question 41

syncline

Answer 41

A trough-shaped fold whose limbs dip toward the hinge.

Question 42

tectonic foliation

Answer 42

A planar fabric, such as cleavage, schistocity, or gneissic banding, that develops in rocks; caused by compression or shearing during deformation (e.g., during mountain building).

Question 43

tension

Answer 43

A stress that pulls on a material and could lead to stretching.

Question 44

thrust fault

Answer 44

A gently dipping reverse fault; the hanging-wall block moves up the slope of the fault.

Question 45

uplift

Answer 45

The processes that cause the surface of the Earth to move vertically from a lower to a higher elevation.

Question 46

vein

Answer 46

A seam of minerals that forms when dissolved ions carried by water solutions precipitate in cracks.