Chapter 4- Plate Tectonics Flashcards
The thin and solid outermost layer of earth above the mantle
Crust
Are mainly made of the elements oxygen, silicon, and aluminum. This crust however has twice as much iron, calcium, and magnesium, which forms minerals that are denser. Usually found I never the ocean
Oceanic crust
Are mainly made of the elements oxygen, silicon, and aluminum. Usually found on land
Continental crust
The layer of rock between the earth’s crust and core
Mantle
The central part of earth below the mantle
Core
The solid, outer layer of earth that consists of the crust and the rigid upper part of the mantle
Lithosphere
The solid, outer layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it.
Asthenosphere
Literally, the “middle sphere”; the strong, lower part of the mantle between the asthenosphere and the outer core
Mesosphere
A block of lithosphere that consists of the crust and the rigid, outermost part of the mantle
Tectonic plate
The hypothesis that a single large landmass broke up into smaller land masses to form continents, which then drifted to their present locations; the movement of continents
Continental drift
The process by which new oceanic lithosphere (sea floor) forms as magma rises to earth’s surface and solidifies at a mid-ocean range.
Sea-floor spreading
The theory that explains how large pieces of earth’s outermost layer, called tectonic plates, move and change shape
Plate tectonics
The boundary between tectonic plates that are colliding
Convergent boundary
The boundary between tectonic plates that are sliding past each other horizontally
Transform boundary
Stress that occurs when forces act to squeeze an object
Compression
Stress that occurs when forces act to stretch an object
Tension
The rising of regions of the earth’s crust to higher elevations
Subsidence
A break in a body of rock along which one block slides relative to another
Fault
It causes the hanging wall to move down relative to the football. Usually occurs when tectonic forces cause tension that pulls rocks apart
Normal faults
It causes the hanging wall the move up relative to the footwall this movement is the reverse to a normal fault. Usually happens when tectonic forces cause compression that pushes rocks together
Reverse fault
A third major type of fault. Forms when opposing forces cause rock to break and move horizontally. If you were standing on one side looking across the fault when it moved, the ground on the other side would appear to move to your left or right.
Strike-slip fault
The bending of rock layers due to stress
Folding
Upward-arching folds
Anticlines
Downward, through-like folds
Synclines
Rock layers are folded so that both ends of the fold are horizontal
Monoclines
An instrument that records vibrations in the ground
Seismographs
A network of satellites that orbit the earth to measure positions on the earth’s surface
Global Positioning System or GPS
An area of deep cracks that forms between two tectonic plates that are pulling away from each other
Rift zones
When earth’s magnetic poles change places
Magnetic reversals
