Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

332 Cards in this Set

  • Front
  • Back
Similar to Jupiter, rings long but very thin, made up of ice and dust fragment debris controlled by its moons/shepherd moons
Greatest mass (almost a star), rapid rotation, gives off more heat than sun provides, H and He atmosphere, 67 moons (Io, Ganymede, Europa, and Callisto) H gas compressed as inner liquid rocky core
Rotates on side, blue color from methane, dark rings of dust and ice. H and He atmosphere

Similar to Uranus, blue color from methane, dynamic atmosphere with winds, 13 moons

"Earth's twin", hottest planet, thick atmosphere of sulfuric acid, young volcanic surface, few impact craters, rotates opposite direction, 80% lava flows, rotates slowly

Smallest, rotates slowly, no atmosphere, heavily cratered (old surface), smooth plains, dense core
CO2 atmosphere, red color= iron oxide, dust storms/hurricane winds, polar ice caps frozen CO2, inactive surface, weathering/erosion, 2 moons
Confirmed Copernican model, constructed own telescope, once moving- objects continue motion without application of forces. Discovered moon's surface to be not smooth, sunspots on sun, 4 Jupiter moons, Earth is not center of universe, planets not light they are circular disks like Earth, Venus has phases like moon

Supported Copernican model, used Tycho's observations of Stellar Parallax (shift of nearby stars relative to further stars)


Star constellations, 850 stars, divided into 6 groups according to brightness measured length of a year within minutes


Measured Earth's circumference


Proposed Heliocentric model (sun-centered) for universe, sun much larger than Earth and greater distance


Earth is a planet and all planets revolve around sun, circular orbits (sun doesn't move)


Earth-centered, sun moon, planets circular motion around Earth, provided explanation to retrograde (planets moving backwards)

Big Band Theory

Origins of universe and universe expanding constantly
How many stars and light-years is Milky Way?

200 billion stars, 100,000 light-years across 1 of billions of galaxies

Milky Way shape and location of Earth

Spiral shape, in Local Group, Earth is located on the side, not near the center

The two different results of supernova massive stars

Neutron star or black hole

End of massive stars and why?

Produce high energy, destructive, hotter and faster stars with short lifespans

End of Sun-like star

White dwarfs

Star stability

Balance of gas pressure and gravity


Where stars are formed

3 Types of Nebulae

Emission- absorb ultraviolet radiation and emit visible light called fluorescence

Reflective- dense clouds reflect nearby stars and dust

Dark- blocking out light from stars further away, layers of expanding gas

White dwarfs

Sun-like stars (yellow stars), interior collapses and explodes

Red giants

Runs out of nuclear energy, gravity takes over, heats up, cools down, and then expands

Hertzsprung-Russel Diagram

Stars related in color, temperature, and brightness
Red stars vs Blue stars

Red: low temp, low mass, long wavelength, long life, slow nuclear consumption

Blue: high temp, high mass, short wavelength, short life, fast nuclear consumption

Absolute Magnitude

The brightness of stars, temperature, size

Light Year

Light travels in one Earth year

Sun's energy

H and He, nuclear fusion + H= He


Outer most part of sun, hottest, ionized gas

The red, thin layer of plasma (incandescent gas)

Sun rays we see on Earth, visible

Cecelia Payne

Determined composition of stars, by analyzing the light emitted

Fluorescence Gas

Light from colorful emission nebula

Color and Wavelengths

Violet and Blue: hot, bright, short wavelength

Red and Orange: cool, dim, long wavelength


Electromagnetic radiation, different types are determined by wavelengths

Hypothesis of Solar System

Sun and all planets formed from gravitational contraction of dust and gas

Minor bodies of rock and metallic


"Dirty snowballs", loose masses of ice and dust/rock material, left over debris from formation of solar system
Asteroid Belt

Between Mars and Jupiter

Kuiper Belt
Outside Neptune and in dwarf planets (including Pluto)
Dwarf Planets

Can't clear away most smaller bodies along orbital path
Eruptions produced by melting of ice rather than silicate rock

Young surface, ice with liquid water, deep tidal forces heating core, highly fractured ice, Earth's moon size


Most volcanically active body, silicate-based lava, tidal flexing for internal heat, Earth sized

Orbital spacing

Mars, Venus, Earth, Mercury= closer together

Jupiter, Saturn, Uranus, Neptune= far apart

Craters and Marias

Earth's moon

Maria: dark plains, huge amounts of basaltic lava

Craters: high velocity impacts (meteors)

Water on Mars

Canyons, sedimentary rock, gravel, stream beds, cannot hold liquid form b/c low temperature and pressure


Keeps planets in orbit, gravity locks into place, depends on mass

Orbits result from both inertia and gravity

Astronomic Unit

Distance from Earth to Sun

Educated guess, reasonable explanation not fully accepted until tested

Objective, empirical evidence, verified carefully measured

Large body of into encompasses well-tested and verified hypothesis that explain observations


General statement about relationships of natural quantities that tested over and over, not contradicted
Stars emit...

Dark-line spectrum

Brightest body in solar system, young and old surface, ice, tectonic deformation of surface (ridges)
Biggest Saturn moon, liquid methane lakes, thick nitrogen atmosphere and hydrocarbon compounds, dirty ice, hydrocarbon ice, erosion, bigger than Mercury

Laws of motion and gravitation govern all bodies in universe

Newton's Laws

1. Law of Inertia: objects continue in state of rest or uniform speed in straight line unless acted by force

Mass= quantity of matter (constant)

Weight= force due to gravity

2. Law of Gravitation: body in universe attracts other bodies with force

Directly proportional to mass inversely proportion square distance of center mass

Kepler's 3 Laws

1. Path planet around sun is ellipse with sun as focus

2. Planet revolves so imaginary lines connecting it to sun, sweep over equal areas in equal time

3. Orbital periods planets and distances to sun are proportional

Perturbation: variance in orbit of body from predicted path

First Greek to propose sun-centered model solar system


Model implying sun, moon, and all planets follow perfect orbits around stationary Earth (Earth-centered)

3 Laws of Planetary Motion
Derived the Law of Universal Gravitation


First law of Planetary Motion, the shape of the path a planet follows around sun

An ellipse with the sun located at one focus
Second law of Planetary Motion

Planets move faster when they are closest to sun

3 Truths about the Law of Gravitation

1. Orbits of planets are affected by gravitational attractions between planets

2. Massive planets (Jupiter) have greater gravitational pull than less massive planets

3. Distance between the centers of two objects is doubled, then force due to gravity is 4 times weaker

Planets with greater density and lower mass


Why is Venus hot

Very dense atmosphere of CO2 and traps heat

4 Truths about Mars

1. Very large volcanoes on surface, are extinct

2. Branching drainages and dry stream beds

3. Polar ice caps and frozen CO2

4. Atmosphere is too thin to allow existence of life

Jupiter moon most volcanically active


Planet rotates on side


Saturn's Rings

Made up of ice and rock fragments sized from boulders to dust

Titan and Life

Composed of thick nitrogen-rich atmosphere that contains organic compounds

Pluto not a planet because...

Has not cleared away other bodies and debris within orbit
Most widely accepted hypothesis

The sun and the planets formed from gravitational contraction of interstellar cloud of dust and gas
Radio waves, infrared, visible light, x-rays

They are all forms of electromagnetic radiation that are defined by differences in wavelength

Astronomers currently have a way to knowing compositions of stars even though they can't sample them directly

Use light, temp, and size
Sunlight we see emitted from sun's layers

Sun has magnitude of 5 and a star has magnitude of 1.5, which is bigger?
1.5 is bigger than 5
The distance of other stars is measured in what units?

Light years

Emission Nebulae

Interstellar clouds of gases are fluorescing as ultraviolet light from nearby stars and is absorbed, converted into visible light
Death of a star like Sun

It will collapse into a white dwarf and shed outer layers forming a planetary nebula

Milky Way Shape

Sun located on one of the outer spiral arms and is one of 200 billion stars

Two most abundant elements in Sun

H and He

Orbital period for Earth

365 days

Why Jovian planets formed thick atmosphere

Have thick gases that trap heat from inner core

Evidence that strongly supports Big Bang Theory

Universe is expanding

Type of Volcanism found on Saturn's moon Enceladus
Jupiter's red spot

Hurricane lasted for 300 years between two atmospheres

One other dwarf planet than Pluto


Reason why some stars are brighter and have different magnitude

The size and temperature may vary

Where is Kuiper Belt located

Outside, past Neptune, holding dwarf planets
Moment Magnitude Scale

Determines total strain energy released along an entire fault surface

More precise for determining energy release in large earthquakes

Moment Magnitude Scale Determined by...

1. Area of displacement along fault

2. Rupture of surface

3. Shear strength of rock and the amount of energy rock can store before it slips

Richter Scale

Based on amplitude of largest seismic wave recorded on seismogram (height of waves)

Waves weaken with distance from focus

Richter Scale Number Correspondence

10in fold increase wave amplitude

32in fold increase energy release

Distance measured to Amplitude= Magnitude

Pacific Northwest Earthquake Evidence On-Land
Drowned forests in tidal marshes/beaches, tsunami deposits, massive landslides, ghost forests, liquefaction geysers and sand deposits between growing sediments
Pacific Northwest Last Major Earthquake

1700, greater than 8.5 magnitude, lasted several minutes

Shadow Zone

Belt around earth where no p-wave and s-wave are detected

Earth's Layers and Physical Characteristics of Seismic Waves

P-waves can travel through solid, liquid, gas: crust, mantle, outer core, and inner core

S-waves can only travel through solid: crust and mantle

Seismic Gaps

Where earthquakes have not recently released elastic energy, risking a future earthquake

Long-Range Predict

Give the probability of a certain magnitude earthquake occurring, important for nationwide knowledge and up the standards for designing resistant structures

Quakes reoccur in the same places

Short-Range Predict

Identifying possible precursors such as changes in stress/strain in rocks along fault

Recognizing foreshocks (before the big earthquake)

Tsunami Starter

Subducting plate sends vibration upward through ocean

Caused from earthquakes, underwater landslides, or volcanic eruption

Earth can wobble up to 2.5cm on axis of rotation temporarily


Slopes and cliffs, slick layers of clay breaking into blocks, used to be above sea level, dust clouds on mountain slopes from aftershocks


Water-saturated sediments turn into a mobile fluid around rivers, swamps, and lakes

Structures collapse and sink, pipes float up to surface, geysers of sand/mud shoot up from ground, loose sediment rock and materials

Earthquake records

Chile: 9.5

Alaska: 9.4

Sumatra: 9.3

*All subduction zones

Vertical shifts in elevations above sea level or below in subduction zone

Richter vs Moment Magnitude Scales

Richter: cannot distinguish between sizes of larger earthquakes (8.0-9.0 magnitude)

Mercalli Intensity Scale

Based on the kind of ground one was standing on, eyewitness, create maps/scales of earthquakes

P-waves vs S-waves

P-waves: fastest travel, push-pull (compress- expand), fastest on the sea floor, the denser the rock the faster, travel through solids, liquids, gas

S-waves: second fastest, side-side (sheer waves), only go through solids, temporarily change shape of material instead of volume


Study of earthquake waves, seismometer: instrument that amplified and records earthquake waves on chart

Richter scale: sits in bedrock and scribbles movements of plates


Smaller earthquakes that precede a major earthquake in days/years, warning earthquakes, big earthquake follows after signs of small pockets of energy being released


Smaller earthquakes due to movements along fault and neighboring faults, disrupting other plates' stress, after major earthquake, take days or months
Theory of Elastic Rebound

Cause earthquakes along faults, force deforms crustal rocks storing energy, friction resistance, creating vibrations and focus point (ruler bend)

Earthquake define

Occur when energy is released, slippage along fault in crust, plates continue along fault line and will happen again, energy radiates outward from focus in form of seismic waves

Shallow earthquakes more destructive than deep earthquakes


Fractures in crust which movement occurs (not perfectly straight lines), elastic rebound theory within faults, majority of earthquakes occur along tectonic plates

Point on earth's surface vertically above the focus point of earthquake

Origins of earthquake, releasing vibration along fault, wave fronts go in all directions outward from focus
Indonesia Chain

Most dangerous subduction zone in world

Largest Earthquake occurrence is where?

Subduction zones
Cascadia Subduction Zone

Offshore from pacific northwest, cascades associated with plate
Mountains Continent-Continent Convergence

Continental collisions= mountains


Himalayas: highest peak on earth (Mt Everest)

Urals: oldest ancient boundaries separating Asia and Eurasia


Make crescent shape from plate boundary from buckling and folding of plate, vertical lift

Continent-Based Hotspots

Melting rock making continental crust, explosive magma b/c of crust on ground (shallows parts of mantle)

ex: Yellowstone

Ocean-Based Hotspots

Hotspots stay stationary as plate moves over hotspot, forming new island/volcanoes, once hotspot leaves, islands may erode under sea level

ex: Hawaiian Islands


Volcanic heat flow associated with a plume of hot mantle (mantle plume), can exist in middle of plate tectonic, mantle plume interacts with lithosphere creating volcanoes

Ring of Fire

Large number of volcanoes erupt and earthquakes occur in the basin of pacific ocean, 90% of all earthquakes occur there

Volcanic Arc

Arc shaped chain of volcanoes that form adjacent to subduction zones

ex: cascade range

Lithosphere in Plate Boundary Movements

Divergent: creates lithosphere

Convergent: destroys lithosphere

Transform: neither

Transform Plate Boundaries

Plates slide horizontally past one another, lithosphere isn't created nor destroyed, actively along faults dividing oceanic ridges into sediments

ex: San Andreas Fault (California)

Subduction Zone

Lithosphere descends into underlying asthenosphere, only ocean lithosphere subducts, lithosphere colder, denser, thinner sinking than continental crust, surface expressions of subduction zones are oceanic trenches

Convergent Plate Boundaries

Two plates move towards each other, one plate plunges beneath the other, subduction zones and continental collisions
Divergent Boundary: Sea Flood Spreading

New lithosphere forms at oceanic ridges, hot rising mantle comes to surface creating new sea floor, lithosphere thickens as moves away becoming thicker, denser, and cooler, new sea floor is thinner and less dense

Divergent Plate Boundaries
Two plates move apart, located on oceanic ridges, longest topographic feature on surface, causes continental rifts, can be in ocean or on surface, separating of continents

Driving Force of Plate Motion

Convection in mantle, soft and malleable, warm water rises, cools, becomes denser as it moves away

Plate Tectonics

Slabs of lithosphere, rigid lithosphere plates move on asthenosphere, softer and capable of flow, holding both continental and oceanic crust

Magnetic Surveys

Alternating high and low magnetism in rocks, sea floor spreading from opposite field of ridges, patterns of stripes due to spreading and magnetism level (young to old)

Sea Floor Spreading

Sea floor younger than continents, youngest is by ridges, oldest is further out, lithosphere forms and sinks back into mantle, diverging overtime as magma moves up and recycles back into earth, floor moves and spreads outward (moving continents)
Theory of Plate Tectonics

Lithosphere is divided into plates that move about on soft, gradual flowing rocks of asthenosphere, developed by Harry H Hess, sea floors spreading: new lithosphere forms at oceanic ridges

Pangaea Evidence

Fossil similarities, rock age, plant life similarities, glacial deposits similar age, swamp zone deposits, mountain range similarities

Best evidence: ocean floors: thinner crust constantly recycling, sea floor spreading

Continental Drift Hypothesis
Developed by Alfred Wegener, worlds continents once joined together as supercontinent Pangaea, broke apart 200 million years ago
Continental More Elevated to Ocean Floor
Thicker crust is more elevated than thinner crust, continental is less dense and thicker

Inner Core

Solid iron-nickel alloy, inner most sphere of Earth

Outer Core
Liquid iron-nickel, generates Earth's magnetic field, only layer completely molten
Lower Mantle

Strong, rigid mantle rock, rocks may undergo movement


Soft, weak mantle rock, capable of gradual flow, rock is near melting point, convection of mantle rocks allows for movement of plate tectonics


Rigid outer part of earth, cool rock, includes crust and upper mantle, forms plate tectonics

Curst: Oceanic

Composed of basaltic rock (dark rock), high density, 7km thickness, 180 million years old (younger), constantly recycling by plate tectonics
Crust: Continental

Composed of granitic rock (light rock), low density, 35-40km thick, 4 billion years old (older)

Core (chemical)
Iron-nickel alloy, average density: 13g/cm2
Crust (chemical)

Continental: granitic, light and less-dense, silicate minerals

Oceanic: basaltic, dark and denser silicate minerals

Average density: 2.7-3.0 g/cm3


Study of record of earth's magnetic field preserved in rocks and sea flood spread, lava cools (basalt= sea floor), and rocks solidify, aligned with magnetic field a little off-set from rotation of earth, change over time b/c shifts on crust

Seismic Waves Used To...

Determine the properties of Earth's interior

Mantle (chemical)

Dense iron and magnesium silicate minerals, upper mantle rock= peridotite

Average density: 3.4 g/cm3

Plate Boundaries
More concentrated earthquakes on plate boundaries, along ridges and trenches on sea floor, mantle flows over time to create old/new surface, 1968 theory was accepted
Types of Waves

Surface waves: travel across earth's surface (more destructive)

Body waves: travel through earth's interior (less felt)

P-waves: primary waves, fastest traveling

S-waves: secondary waves, second fastest

Arrival of P/S waves

Determined by distance, greater distance= greater distance to epicenter

Triangulation: location of epicenter found when distance to epicenter is known, at least 3 different seismograph stations

Intensity vs Magnitude

Intensity: degree of earthquake shaking at a location based on observed effects (eyewitness)

Magnitude: amount of energy released determined by calculations from seismic records (technology)


Seismic sea wave: vertical displacement of ocean floor along fault or by submarine landslide (convergent boundary)

As the ground becomes shallower, the wave size increases

Destruction of Earthquakes

Amount of damage depends on intensity, duration, nature of material underneath, design of structures

Buildings: need to be wood or steel (flexible)

brick and concrete are BAD

Nature of surface: soft unconsolidated sediments are best (silt or sand)

mud and gravel are BAD

Earthquake Predicting

Presently, we cannot reliably predict the timing of an earthquake within a narrow span of time

Pacific Northwest Source of Earthquakes

Subduction zone, crustal faults, deep earthquakes in subducted plate, goes from Northern California to British Columbia

Pacific Northwest Cascadia Subduction Zone

Produces large earthquakes with tsunamis, pacific plate subducting under north American plate, mountains (volcanic arc) parallel with Juan De Fuca subduction zone

Pacific Northwest Earthquake Evidence Ocean-Based

Offshore Evidence, turbidity current sediment deposits (turbidites), submarine landslides/avalanches (fine sediments, silt, mud)

Record of Earthquakes from Turbidites

19 major earthquakes in 10,000 years, large earthquakes occur in clusters and reoccur every 300-500 years, southern subduction zone more likely to rupture than the entire length

Earthquake's moment magnitude can be accurately determined by...

Amount of displacement along fault AND the surface area of the rupture
Magnitude of earthquake on richter scale determines if...

Distance of epicenter AND amplitude of largest wave recorded on the seismogram
What would not create a tsunami?

Horizontal displacement along transform fault

How much more energy is released during a mg 9 earthquake and mg 8?


Parameters that define a mineral

1. Natural occurring: part of the earth

2. Solid substance: not liquid/gas

3. Orderly crystalline structure: atoms/molecules bond

4. Definite chemical composition: chemical compound

5. Generally inorganic: no biological activity

Rock define

Solid mass of mineral matter that occurs naturally as part of the planet, can be composed of one mineral, most are several minerals, some composed of non-mineral matter (glass or organic matter)
Two most abundant elements in Earth's crust
Oxygen and Silicon combine to make silicates
Silicate minerals and their building block
Building block is silicon tetrahedron, 4 oxygen and 1 silicon
Rocks that make up most of Earth's crust

Silicate minerals

Element define

Substance that cannot be broken down into simpler substances by chemical or physical means, composed entirely of one atom

Compound define

A substance (mineral) consisting of atoms of different elements
Chemical bonds
When atoms share electrons to become stable, ionic bonds are most commonly found, and covalent bonds are less common
Crystal form or Crystal habit
External expression of a mineral's internal arrangement of atoms, holds a geometric shape based on how molecules are arranged (quartz)
Silicon Tetrahedron
One Si and four O atoms are the fundamental building block of silicates, Fe, Mg, K, Na, Ca can join to silicate structures
2 most abundant silicate minerals

Quartz, Feldspar: hold 50% of Earth's crust
Nonsilicates define
Less abundant in Earth's crust, many of economic importance (rubys and diamonds), found in sedimentary rocks (calcite, gypsum, and halite)
3 categories of rocks

Igneous, Sedimentary, and Metamorphic
How rocks of each group are formed

Igneous rocks form from molten rock, partial melting rocks in upper mantle and lower mantle

Sedimentary rocks form from compact sediments and dissolved materials into rock (layers)

Metamorphic rocks form from intense heat and pressure

What is magma and it's materials

Melt: liquid portion of magma body composed mainly of freely moving atoms of elements found in silicate materials

Solids: mineral crystals

Volatiles: gases dissolved in magma such as water vapor and CO2

Intrusive vs. Extrusive rocks

Intrusive rocks formed below surface (magma)

Extrusive rocks formed above surface (lava)

Intrusive rocks are slower cooling (coarse grain)

Extrusive rocks are rapid cooling (fine grain)

Relationship between cooling and rate of crystal size in igneous rocks

Fine-grained: rapid cooling= formation to crystals too small to see, common texture for extrusive igneous rocks

Coarse-grained: slow cooling= formation of large visible crystals, common texture for intrusive rocks

Igneous rock texture

Fine-grained: rapid cooling

Coarse-grained: slow cooling

Porphyritic: large crystals embedded in small crystals

Frothy: gas escape from magma, pockets

Glassy: no crystals, random ions

Vesicles: lava rocks gases come out of magma

Igneous rock compositions

Felsic: granitic (fine grained)

intermediate: andesitic (mix)

mafic: basaltic (coarse grained)

Identify Igneous rock's composition
Amounts of light and dark colored silicate minerals can indicate it
Which igneous compositions have a greatest amount of silica (SiO2) and which have the least
Greatest to Least: felsic, intermediate, mafic, ultramafic
What igneous rock compositions make up continental crust and oceanic crust

Continental: granitic (felsic)

Oceanic: mafic (basaltic)

What rock type makes up Earth's upper mantle


Peridotite is main rock in upper mantle

Light vs. Dark silicate minerals in the Bowens reaction series
Darkest to Lightest: ultramafic, basaltic (mafic), andesitic (intermediate), granitic (felsic)

Based on Bowens reaction series, which igneous rock compositions have the higher and lower melting/crystallization temperatures

High to Low: ultramafic, basaltic, andesitic, granitic

How magma is formed at divergent (oceanic ridges) and convergent (subduction zones) plate tectonic boundaries

Divergent: decompression melting

Convergent: volatiles, water in rock

Magma compositions are formed from partial melting of mantle rocks vs. partial melting of continental crust

Ultramafic rocks: mafic (basaltic) magma, basaltic volcanism

Continental crust: felsic (granitic) from assimilation mixing create intermediate magma

The common compositions of magma erupted at oceanic ridges vs. subduction zones

Oceanic ridges (and Hotspots): decompression melting, crystallized magma, mafic

Subduction zones: volatiles, intermediate (andesitic) magma

Sedimentary rocks define

Continent rocks, layers of sediment on land/ocean floor, sandstone, mudstone used to be underwater, contains fossils, subduction buckled upward

Sedimentary rock examples

Conglomerate, sandstone, limestone (biological), slate (mudstone clay and silt)

Metamorphic rock define
Temperature, pressure, presence of chemically active fluid

Metamorphic rock examples

Schist (mudstone recrystallized), gneiss (granitic), marble (limestone), slate (slate/mudstone)
Igneous rock define

Cooling and crystalized magma above and below surface, magma buoyantly rises and sometimes reaches the surface as lava

Extrusive Igneous rock/volcanic rocks

Form when molten rock solidifies at the surface, large masses of magma may require tens of thousands of years to solidify (granite), erosion exposes magma rocks over time

Intrusive Igneous rock/plutonic rocks
Formed when magma crystallizes below the Earth's surface, magma loses its mobility before reaching the surface
Fine-grained rock examples
Lava rocks that contain gas bubbles called vesicles (basalt)
Minerals within magma

Do not crystalize at the same rate at the same time during cooling, some crystals may grow large before others form (fine-grained and coarse-grained), common igneous rocks have variety
Porphyritic texture

Fine-grained, matrix (dark), phenocrysts (light)

If molten material is quenched almost instantly...

There is no time for ions to arrange themselves into crystals, forms glass (obsidian), common volcanic glass, magnesium-oxide is mostly silica (makes for best weapons)
Single element minerals

Native minerals (copper, gold, silver, nickel, lead, iron, zinc)
Aggregate and Compound Define

Aggregate: rock made of more than one mineral

Compound: mineral made of more than one element

Two types of rock from volcanoes

Obsidian: glassy silica, cooled very fast, best for weapons

Pumice: frothy glass with gas pockets, buoyant

Fe, Mg, K, Na, Ca Light vs. Dark Silicates

Dark: rich in Fe and Mg, low silica (thin and runny magma)

Light: rich in Na, K, Ca, high silica (thick and sticky magma)

Common compositions of rock in continental, oceanic, and volcanic arcs

C: felsic extrusive rock

O: basalt and gabbro extrusive rock

V: intermediate andesite extrusive rock and diorite intrusive rock

Ultramafic composition

Olivine and pyroxene

Peridotite: upper mantle rock, rarely found on the surface

Pegmatite composition

Unusually large crystals, granitic, lots of silica, from fluid-rich magma, look like veins in rock, contain rare earth element for jewelry and electronics
Bowen's Reaction Scale crystallizing rocks

High temp and Dark and Low silica content

Low temp and Light and High silica content

Role of pressure in Magma

Greater pressure: greater melting temp, why rocks remain solid in earth's interior, decompression melting

Role of temperature in Magma

Geothermal gradient: change in temp with depth

Role of volatiles in Magma
Water lower the melting temp of rocks, how magma forms along subduction zones
Igneous Composition Tectonic Setting

Felsic: continental rifts, subduction zones, hotspots

Intermediate: most subduction zones

Mafic: oceanic ridges, continental rifts, hotspots

Igneous Composition Common Origins

Felsic: partial melting of continental crust

Intermediate: mixing of mafic and felsic

Mafic: partial melting of mantle rocks

Igneous Composition Volcanic Landforms

Felsic: lava domes, explosive calderas and ash flow (pyroclastic flow)

Intermediate: composite cones

Mafic: shield volcanoes, basalt plateaus, cinder cones if gas is high in magma

Igneous Composition Lava Flows

Felsic: very short, thick lava flows

Intermediate: short, thick lava flows

Mafic: runny fluid-like lava flows

Igneous Composition Styles of Volcanic activity

Felsic: explosive when full of gas

Intermediate: explosive when full of gas

Mafic: less explosive, gas escape more easily

Igneous Composition Melting Temp

Felsic: low

Intermediate: moderate

Mafic: high

Igneous Composition Viscosity

Felsic: greatest

Intermediate: high

Mafic: lowest

Igneous Composition Silica Content

Felsic: high

Intermediate: moderate

Mafic: low

Igneous Composition General Mineralogy

Felsic: most light silicates (K-feldspar, quartz)

Intermediate: light silicates (plag, biotite)

Mafic: most dark silicates (pyroxene, olivine)

Most magma cools and crystallizes where?

Below the surface (plutons)
Plutons Rock

Intrusive, slowly cooled below surface, ex: dikes, sills, laccoliths, batholiths, volcanic pipes/necks

Sheet-like that cut across existing rock, vertical, formed when magma injected into fractures


Sandwich between sedimentary rock, horizontal, formed when magma injected between rock


Similar to sills, by are dome shaped in rock layers, composed of viscous magma

Massive intrusive rock surface exposures, multiple plutons in continental crust, formed from cores of mountain system

Volcanic Pipes

The neck of volcano, connect volcanic bents to underlying magma chamber

Volcanic neck
Volcanic pipe left behind after erosion removed the overlying volcanic cone

Factors that determine the nature of volcanic eruptions

Magma viscosity (explosiveness) the degree of resistance to flow, the amount of dissolved gas (volatiles)

The more gas= the more explosive

More viscosity= more sticky/thick lava

Factors affecting viscosity of magma

Temp: higher temp= lower viscosity

Composition: more silica= greater viscosity

Lava is thick when cold and then runny when hot

Silica content vs. viscosity

High to Low silica: felsic, intermediate, mafic, ultramafic

High to Low viscosity: felsic intermediate, mafic, ultramafic

Felsic= most explosive

Extrusive Igneous activity

Affects volatiles, as magma moves up to lower pressure, gases escape as expanding bubbles

Like opening a can of soda

Common Volcanic Gas

Water vapor, SO2 (sulfur-dioxide), CO2
Mafic compositions in Volcanoes

Gases escape with ease to low viscosity and propel incandescent lava into air (lava fountains)

Hawaiian island

Felsic to Intermediate compositions in volcanoes

High viscous magma upward migration of expanding gases, internal pressure builds in a series of explosions

Magma with gas= bubble nucleation= fragmentation (foamy)= explosions (volcanic ash)= eruption column (plume ash/gas mushroom)

Pyroclastic flow composition

Explosive material, fragments of volcano, rapid expansion in releasing gases
Volcanic Ash
Fine particles of pulverized rock and glass ejected from volcanic vent, rapidly chilled magma (no crystals), pumice

Welded Tuff
Hot ash settles, glassy chards fuse to form rock
Lapilli and Cinders
Pyroclastic material range in size, little pieces of pumice

Pyroclastic Materials

Blocks: fragments of hardened lava large chunks

Bombs: fragments of incandescent lava, arcs path, spinning motion (football)

Spatter: fluid fragments of lava, bubbles of gas pop and explode (spatter cones)

Lava Flows

Basaltic flow: low silica and viscosity, runny fluid lava flow

Andesitic flow: moderate thin fluid, slightly more silica and viscosity

Rhyolitic dome: moderate thick fluid, slightly less silica and viscosity

Rhyolitic spire: high silica and viscosity, thick/sticky lava flow

Basaltic Lava Flows

Travel great distances, streams of lava, low viscosity, thin flow


Basaltic lava, smooth outer skin that wrinkles as the molten interior flow continues, glassy skin

Ancient pahoehoe craters of the moon national monument

Basaltic lava, rough surfaces of jagged blocks and rubble, thicker flow, slow moving, high viscosity due to lower temp so topples pahoehoe
Pillow Lava
Rounded structures, extrusion of lava underwater, glassy surface
Columnar Joints

Lava flow cools and contracts, develops shrinkage fractures produce pillar-like columns, thick lava flow, hexagon shape vertical pillars

Can also occur in felsic to intermediate lava

Felsic (rhyolite and obsidian) Lava Flows

Felsic: high viscosity, slow flowing lava can't stray far from vent, thick and sticky, piles up around vent forming domes and steep lava flows
Largest Peak Volcano

Lassen Peak
Volcano Structures

Activity begins when fissure develops in crust as magma forces to the surface, fountains of basalt lava

Conduit or Pipe

Magma's path to surface in a circular pipe


Surface opening of volcanic conduit

Volcanic Cone
Structure formed from the accumulation of lava and pyroclastic material around vent

Craters Form
Steep-walled depressions formed by accumulation of material around central vent (build rim) and excavation by explosions, at the summit

Collapse structure formed during draining of magma reservoir under surface, a collapse of a composite volcano (crater lake)
Small vents primarily emit gases, smells of rotted egg (sulfuric-oxide)
Shield Volcanoes define

Broad shield, produced by accumulation of fluid basaltic lava, not steep, gentle slopes, low viscosity, no dangerous explosions

Shield Volcanoes Lava Flows

Aa type flows (lava discharged from summit and fissures) and pahoehoe flows (thick and slow lava)

Basalt caves

Steep-walled calderas

East Rift Zone
Active area, huge active volcanoes
Cinder Cone

Small, simple volcanic cone, built from pyroclastic material, one time eruption then expands (extinct), smallest volcano

Cinder Cone Composition

Scoria: a product of gas-rich basaltic magma

Some made from pumice and ash from gas-rich felsic magma

Composite Cones

Lava flows AND pyroclastic material (both explosive and effusive eruptions), tall and steep, Ring of Fire (volcanic arcs), most dangerous volcanoes, thick flows of lava, high viscosity (felsic)
Volcanic Ash Impacts

Aviation hazard (jet engines)

Respiratory problems

Collapse of structures

Short-term climate impacts (cooling effect, no sun)

Lighting attacks

Ash cloud plumes in atmosphere

Pyroclastic Density

Most dangerous, glowing avalanches of hot gases with incandescent ash and large rock fragments, fast and far distances (over water), above boiling point, gravity driven, ash propelling up

Pyroclastic Surges

Fast moving, higher proportions of gas and rock, travel downslope along low areas (hills and ridges), broken rock and pumice, turbulence helps propel and move down slopes until it runs out, buoyant gas
Causes of Pyroclastic Flows

Collapse of eruption: gravity overcomes initial upward thrust, lava dome and lava flows on volcano summit (steep and unstable), lateral blasts from side of volcano
Volcanic activity present or not, rapid melting of ice, mudslides but haul boulders and trees and ash, from river channels or canyons
Lahar Causes

Hot pyroclastic flows mixing with snow and ice, earthquakes, heavy rainfall/snowmelt
Signs of Impending Eruption
Earthquakes under volcano, magma forces up through cracks (create bulge in summit, swelling), fumarole activity and steam eruptions, change in composition in gas emissions, deform of volcanic structure

Rocks from summit, broken up rock from landslide, major hazards in cascade mountain range (Mt. Reiner tallest peak)
#13 Mount Saint Helens

Largest landslide recorded
#12 Pinatubo
2nd largest in 20th century, volcano collapse (caldera)
#11 Laki Fissure Eruption

Largest fissure (lava flow), major health problems (toxic haze), hydrofluoric acid

#10 Novarupta

Largest in 20th century "valley of 10,000 smokes"

#9 Krakatau

Final explosion considered to be the loudest sound in recorded history

#8 Mazama

Largest part holds crater lake formation, composite collapse

#7 Santorini
May inspired legend of Atlantis
#6 Taupo

Highly explosive known to volcanologists, extreme violence, huge pyroclastic flows over adjacent mountains
#5 Tambora

Largest eruption in recorded history, caldera, "year without summer" (blocked out sun, freezing cold climate, killed a culture)
#4 Long Valley Caldera

Ash deposits mapped out to Eastern Nebraska to California

#3 Yellowstone Caldera

Ash deposits cover central U.S.

#2 Toba

Largest explosive eruption 25 million years ago with drastic impacts on climate

#1 La Garita Caldera

Largest known explosive eruptions in history (26-28 million years ago)
Crater Lake

Explosive, empty magma out, collapse composite volcano (Mazama), deepest lake in North America, 7,700 years erupted, lake is from melted ice and water

Yellowstone Caldera

Collapse large area where land collapsed, discharge of large volume of felsic pyroclastic along fractures, still active, no pattern to predict eruptions, world's largest hydrothermal system, hotspots (future: Yellowstone will not be active), forming caldera volcano

Hydrothermal System

Magma close to surface, large concentrated geysers, explosions risky (earthquake trigger)
Ring Fractures (Yellowstone)

Ring shaped eruptions, volcano collapse, crust sinks, opening more fractures, catastrophic impacts, creating caldera

Flood Basalts

Greatest volumes of lava erupted from fissures (divergent) that open in Earth's crust, low viscosity (basalt), outpourings of basalt lava, large scale features (like dark spots on moon)

ex: Columbia river basalts

Shield Volcano examples
Mauna Loa and Kilauea (Hawaii) hotspots
Composite Cone examples

Cascades, Ring of Fire (subduction zones)
Cinder Cone example

Wizard Island, Lava Butte
Viscosity in the three volcanoes

Composite: steep-side, high viscosity

Shield: less steep, low viscosity

Triggers of Mt. Saint Helens

Volcanic landslides at the summit, mini earthquakes under surface, bulge growing on side
Caldera Types

Crater Lake: collapse of summit (composite), eruption empty magma chamber= collapse

Yellowstone: pyroclastic material and gas discharged along ring fractures= collapse (hotspot)

Shield: magma to outer flanks= roof collapse= fissure eruptions

What do the catastrophic eruptions of Pinatubo, Tambora, and Novarupta all have in common?
All formed calderas, erupted magma (felsic), located on subduction zones, result of high viscosity magma
What type of igneous intrusion is a vertical slide?
Which pluton rock is massive intrusion that covers more than 100 km2?
Batholith (extensive plutons, granitic)
What is the term used for pyroclastic fragments that are larger than ash but smaller than walnuts?
Which of the magma composition will have the highest silica content?

Felsic (explosive and rhyolite)

Which of the magma compositions will have the highest viscosity?
Felsic (explosive and rhyolite)
Nonexplosive eruptions of magma composition?
Mafic (basaltic)
What type of basalt lava flow sideways lumpy lava?
What type of basalt lava flow is jagged and sharp lava?


Which would produce the shortest, thickest lava flows?

Magma Compositions and Lava Flows

Felsic: thick, short lava flows (playdoh), lava domes

Intermediate: mix, lava domes

Mafic: runny, fast lava flows (liquidy)

What kind of eruptions do shield volcanoes produce?

Not explosive, ooze out lava, mostly lava (no pyroclastic thrusts)

Composition of lava flows from shield volcanoes?
Mafic (not explosive), runny magma
What is composite volcano composed of?

Both pyroclastic material and lava flows

What is a cinder volcano composed of?

Pyroclastic materials

What is a shield volcano composed of?

Lava flows
Composite volcanoes are the product of the eruption of: (viscosity)?
High viscosity magma
Composite vs Shield Compositions

Composite: (intermediate to felsic) greater viscosity, steep slopes

Shield: (mafic) lower viscosity, gentle slopes

Will cinder cone volcanoes erupt again?

What type of plate boundary are composite on?

Convergent (subduction zones)
Avalanche of hot gases infused with glowing hot ash and rock fragments?

Pyroclastic flows
Major eruption of Mt. Saint Helens?
Massive landslide, followed by blast from side of volcano
Silica and Color

Felsic: lightest, high in silica, low melting temp

Mafic: darkest, low in silica, high melting temp

Magma compositions in volcanic flows

Composite: intermediate (andesite)

Shield: mafic (basalt)

Cinder: felsic (granitic) (rhyolite)

Most Explosive Magma compositions when they contain abundant gases

Felsic (rhyolite)

High silica

Greatest viscosity

Explosive caldera (magma) (Yellowstone)

Moderate explosive magma compositions when they contain abundant gases

Intermediate (andesite)

Pyroclastic portion of composite cones (cascade)

Least explosive magma compositions when they contain abundant gases

Mafic (basalt)

Low silica

Lowest viscosity

Cinder cones (lava butte, wizard island)

Magma compositions containing low amounts of gas

Felsic: very short, thick flows, lava domes

Intermediate: short, thick flows (composite cones)

Mafic: extensive fluid-like flows (shield volcanoes)

Mafic (basalt) High vs Low gases

High: cinder cones

Low: shield volcanoes

Volcanic arcs magma composition
Composite volcanoes (intermediate, andesite)