Geology & Earth Systems – Lecture Review

60 fill-in-the-blank flashcards covering major concepts from cosmic origins through plate tectonics, minerals, rocks, volcanoes, sedimentary processes, metamorphism, and structural geology.

Earth's accepted age is __.

4.57 billion years

Far-away galaxies appear red because of the __ phenomenon.

red shift

The gradual buildup of planets from colliding dust and gas is called __.

planet accretion

__ discovered the red shift that proved universal expansion.

Edwin Hubble

The Universe began expanding in an event known as the __.

Big Bang

According to the Nebular Theory, collapse of a swirling cloud forms a central __.

protostar

Elements heavier than iron are primarily created during __ explosions.

supernova

Separation of Earth’s interior into core and mantle is termed __.

internal differentiation

The boundary between crust and mantle is the __.

Moho

The region shielded by Earth’s magnetic field is the __.

magnetosphere

Roughly __ % of Earth’s atmosphere is nitrogen.

78

Variation in sea-floor depth is known as __.

bathymetry

Earth’s outer shell is broken into about __ major plates.

20

At a __ plate boundary, plates move apart and lithosphere is created.

divergent

Deep-ocean trenches mark sites of __.

subduction

Symmetric magnetic stripes on the seafloor provided proof of __.

sea-floor spreading

The sinking pull of a dense, cold slab is called __.

slab pull

Continental drift was first rigorously proposed by __.

Alfred Wegener

Broad, gently sloping volcanoes built of mafic lava are __ volcanoes.

shield

High-viscosity, gas-rich magma produces __ eruptions.

explosive

In Bowen’s reaction series, olivine crystallizes __ in cooling magma.

early

A naturally occurring, inorganic crystalline solid is a __.

mineral

The basic building block of silicate minerals is the __ tetrahedron.

silica (SiO₄)

Rock made of cemented fragments of pre-existing rock is a __ rock.

clastic sedimentary

Turning loose sediment into solid rock is the process of __.

lithification

Beds that grade from coarse at bottom to fine at top display __.

graded bedding

Metamorphic rocks with a preferred mineral orientation are __.

foliated

Low-grade foliated rock derived from shale is __.

slate

In a __ fault, the hanging wall moves down due to tension.

normal

An up-arching fold with limbs dipping away from the hinge is an __.

anticline

Mountain-building events are termed __.

orogeny

The change in wave frequency due to motion is called the __ effect.

Doppler

Charged particles trapped in Earth’s belts are in the __ radiation belts.

Van Allen

Rigid crust plus uppermost mantle forms the __.

lithosphere

The weak, flowable mantle beneath the lithosphere is the __.

asthenosphere

Earthquake foci down to ~660 km define the __ zone.

Wadati-Benioff

Oceanic crust is __ near the mid-ocean ridge.

youngest

A fast, water-rich volcanic debris flow is a __.

lahar

A large intrusive body exceeding 100 km² in area is a __.

batholith

Rapidly cooled volcanic glass is called __.

obsidian

The fine-grained mafic rock forming most ocean floor is __.

basalt

Lithified calcium-carbonate shells form __.

limestone

A sedimentary rock of angular gravel-size clasts is __.

breccia

Evaporite minerals such as halite form during significant __.

evaporation

Chemical weathering in which water converts feldspar to clay is __.

hydrolysis

Oxygen makes up about __ % of Earth’s crust by weight.

46.6

The most abundant mineral group in the crust is the __.

silicates

A banded metamorphic rock of light and dark minerals is __.

gneiss

A trough-shaped fold with limbs dipping toward the hinge is a __.

syncline

Stress that squeezes rock masses is called __.

compression

Steep-sided volcanoes built of alternating lava and ash are __.

stratovolcanoes

Lava erupted under water at mid-ocean ridges forms pillow __.

basalts

Old, stable continental interiors composed of ancient rock are __.

shields

A point where three plate boundaries meet is a __ junction.

triple

An overturned-bowl-shaped upwarp is a geological __.

dome

Welded volcanic ash consolidates into a rock called __.

tuff

Gravity sliding of lithosphere away from an elevated ridge is __ force.

ridge push

A crack in rock with little or no movement is a __.

joint

Sedimentary facies that deepen upward record a marine __.

transgression

Shape change without breaking under high T and differential stress is __ deformation.

plastic