Chapter 09 Vocab Flashcards
accretionary orogen
An orogen formed by the attachment of numerous buoyant slivers of crust to an older, larger continental block.
anticline
A fold with an arch-like shape in which the limbs dip away from the hinge.
axial surface
The imaginary surface that encompasses the hinges of successive layers of a fold.
basin
A fold or depression shaped like a right-side-up bowl
brittle deformation
The cracking and fracturing of a material subjected to stress.
compression
A push or squeezing felt by a body.
craton
A long-lived block of durable continental crust commonly found in the stable interior of a continent.
cratonic platform
A long-lived block of durable continental crust commonly found in the stable interior of a continent.
crustal root
Low-density crustal rock that protrudes downward beneath a mountain range.
crustal thickening
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.
deformation
A change in the shape, position, or orientation of a material, by bending, breaking, or flowing.
delamination
The process by which dense lithospheric mantle separates from the base of a plate and sinks into the mantle.
displacement
The amount of movement or slip across a fault plane.
dome
Folded or arched layers with the shape of an overturned bowl.
ductile deformation
The bending and flowing of a material (without cracking and breaking) subjected to stress.
epeirogeny
An event of epeirogenic movement; the term is usually used in reference to the formation of broad mid- continent domes and basins.
exhumation
The process (involving uplift and erosion) that returns deeply buried rocks to the surface.
exotic terrane
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.
fault
A fracture on which one body of rock slides past another.
fault scarp
A small step on the ground surface where one side of a fault has moved vertically with respect to the other.
Fold
A bend or wrinkle of rock layers or foliation; folds form as a consequence of ductile deformation.
fold-thrust belt
An assemblage of folds and related thrust faults that develop above a detachment fault.
foliation
Layering formed as a consequence of the alignment of mineral grains, or of compositional banding in a metamorphic rock.
global positioning system (GPS)
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.
hinge
The portion of a fold where curvature is greatest.
isostasy
The condition that exists when the buoyancy force pushing litho sphere up equals the gravitational force pulling litho sphere down.
Joint
Naturally formed cracks in rocks.
Limb (of fold)
The side of a fold, showing less curvature than at the hinge.
monocline
A fold in the land surface whose shape resembles that of a carpet draped over a stair step.
normal fault
A fault in which the hanging-wall block moves down the slope of the fault.
orogen
A linear range of mountains.
orogenic collapse
The process in which mountains begin to collapse under their own weight and spread out laterally.
pressure
Force per unit area, or the “push” acting on a material in cases where the push (compressional stretch) is the same in all directions.
reverse fault
A steeply dipping fault on which the hanging-wall block slides up.
shear stress
A stress that moves one part of a material sideways past another part.
shield
An older, interior region of a continent.
strain
The change in shape of an object in response to deformation (i.e., as a result of the application of a stress).
stress
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.
strike
The angle between an imaginary horizontal line (the strike line) on the plane and the direction to true north.
strike-slip fault
A fault in which one block slides horizontally past another (and therefore parallel to the strike line), so there is no relative vertical motion.
syncline
A trough-shaped fold whose limbs dip toward the hinge.
tectonic foliation
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).
tension
A stress that pulls on a material and could lead to stretching.
thrust fault
A gently dipping reverse fault; the hanging-wall block moves up the slope of the fault.
uplift
The processes that cause the surface of the Earth to move vertically from a lower to a higher elevation.
vein
A seam of minerals that forms when dissolved ions carried by water solutions precipitate in cracks.
