Geol 101, Test 3

Front 1

Earth's layers by chemical composition

Back 1

crust
mantle
core

Front 2

Earth's layers by physical composition

Back 2

upper mantle (lithosphere, asthenosphere, transition zone)

lower mantle

outer core (liquid)

inner core (solid)

Front 3

another word for lower mantle

Back 3

mesosphere

Front 4

The Moho

Back 4

-separates crust from mantle
-change in velocity of p-waves

Front 5

p-wave shadow zone

Back 5

-core-mantle boundary
-35 degree wide belt where p-waves don't exist (bc are bended/refracted through the core)

Front 6

velocity

Back 6

increases through solids (ie. inner core)

Front 7

inner core rotation

Back 7

-rotates faster than Earth's surface
-axis of rotation offset about 10 degrees from poles

Front 8

geothermal gradient

Back 8

the rate at which Earth's temperature gradually increases with an increase in depth

Front 9

conduction

Back 9

-responsible for heat flow everywhere but the mantle

Front 10

mantle convection

Back 10

-propels lithospheric plates
-mantle exhibits 'plastic' behavior

Front 11

seismic waves travel...

Back 11

faster through cold rock, slower through hot rock

Front 12

oceanic crust

Back 12

-fairly similar composition everywhere

Front 13

continental crust

Back 13

-varying composition
-much older and thicker than oceanic

Front 14

mantle

Back 14

comprises most of Earth's volume

Front 15

core

Back 15

-makes up 1/3 of Earth's mass
-iron is most abundant mineral by mass
-inner core grows over time, as Earth cools

Front 16

convection

Back 16

transfers heat through movement of material (like water boiling)

Front 17

conduction

Back 17

transfers heat through collision of atoms or motions of electrons

Front 18

geoid

Back 18

surface of Earth

Front 19

geodynamo

Back 19

-magnetic force in outer core that is responsible for Earth's magnetic field

-important to protect Earth from Sun's solar winds

Front 20

passive continental margin

Back 20

-continental shelf
-continental slope
-continental rise (where trenches do not exist)

Front 21

active continental margins

Back 21

-mostly around Pacific Ocean
-leading edge of continent overruns oceanic lithosphere
-accretionary wedges
-narrow continental shelf
-deep-ocean trench

Front 22

accretionary wedge

Back 22

sediment scraped rom descending oceanic plate is plastered against the continent

Front 23

abyssal plains

Back 23

thick accumulations of sediments taht were deposited atop the low, rough portions of the ocean floor by turbidity currents

Front 24

seamounts

Back 24

volcanic peaks on the ocean floor that originate near oceanic ridges or in association with volcanic hot spots

Front 25

oceanic plateaus

Back 25

large flood basalt provinces similar to those found on continents

Front 26

mid-ocean ridges are characterized by...

Back 26

-elevated position
-extensive faulting
-volcanic structures

Front 27

turbidity currents

Back 27

found at the base of the continental slope; deposit sediments that form deep-sea fans

Front 28

deep-sea fans

Back 28

deposited sediments at the base of continental slopes

Front 29

guyots

Back 29

sunken, flat-topped seamounts

Front 30

longest topographic feature on Earth's surface?

Back 30

oceanic ridge

Front 31

rift zones

Back 31

relatively narrow zones where seafloor spreading occurs

Front 32

rift valleys

Back 32

the slower the spreading rate, the more prominent the rift valley (no rift valley with fast spreading rate)

steeper slope with slower spreading rate

Front 33

order of oceanic crust

Back 33

-deep-sea sediment
-basaltic pillow lavas
-sheeted dike complex
-gabbro
-peridotite

Front 34

slab suction

Back 34

-possible mechanism for continental rifting
-results from sinking of cold slab, causing trench to roll back due to flow in asthenosphere