Geology Ch. 4-5, Geology: Overview of the Physical Earth, Bowens Reaction Series, Rocks, Quiz Questions

A geologist finds an igneous rock consisting of microscopic mineral grains of olivine, pyroxene, and plagioclase. This rock...

a) probrably cooled quickly b) would probably be named a basalt

proto star

a star that is almost a star, a big lump of hydrogen/helium, not a star just yet

Felsic magmas tend to have the lowest viscosity because of their...

none of these are correct, felsic magmas have the highest viscosity

solar bodies

objects seen in our own solar system. (asteroids)

oceanic-continental convergence

oceanic lithosphere will always subduct below the continental lithosphere, caused by the density difference between the oceanic (3.0 g/cm3) and continental (2.7 g/cm3) lithosphere, oceanic plate melts and turns into hot magma which burns its way through the continental plate → creating a volcano and causing many earthquakes

Volcanic arcs are often formed at these plate boundaries

oceanic-continental convergent boundaries

Three types of convergent plate boundaries

oceanic-continental, oceanic-oceanic, continental-continental

Early in the history of the solar system, our sun eventually became hot enough to give off light because...

of nuclear fusion in the core. The Earth is hot, in part, because of radioactive elements in the crust and mantle. The sun is hot due to collisions that turn hydrogen into helium (nuclear fusion).

The interior of the Earth is extremely hot because...

of radioactive elements in the crust and mantle. Earths interior is hot for a number of reasons -but nuclear fusion in the core is not one of them. Only stars are large enough to have nuclear fusion processes at work.

valence shell

outermost electron shell

Earth's crust is made of

oxygen, silicon, and aluminum

noble gases

perfectly ok by themselves, meaning their electrically neutral

The asthenosphere is made of

peridotite, which is mafic

Fractional Crystallization

since each mineral begins to crystallize at different temperature, if these minerals are removed from the magma liquid the liquid composition will change; can change a mafic magma into a felsic magma; crystals can be removed by sinking or by floating depending on density

nebulae

space dust containing hydrogen/helium

During decompression melting of the mantle beneath a mid-ocean ridge...

the magma that forms has more silica than the rock that melts

The inner planets are much smaller than the outer planets because...

they formed inside the "frost" line. Radiation from the sun, coupled with solar wind (particles emitted by the sun), drove lighter gases like hydrogen and helium into the outer parts of the solar system.

cosmic bodies

things seen beyond the solar system (stars, galaxies)

What makes up a galaxy?

cosmic bodies, solar bodies, black holes, nebulae

Why is the Earth's core not a source of magma?

* Need definition

Large explosive caldera like the one at Yellowstone National Park...

-are more common above felsic magma chambers - have the potential to modify global climate if they erupt large volumes of sulfur into the atmosphere

Magma

created by melting of rocks

For something to be classified as a mineral it must...

-be solid -have regular repeating geometry of atoms

Why is our planet warm?

-heated collisions -radioactive decay

Transform plate boundaries...

-might connect two offset mid ocean ridges -might connect two offset subduction zones -might connect the tip of a mid ocean ridge with the tip of a subduction zone

The outer planets

-mostly hydrogen and helium -formed in a collapsing nebula that also formed our sun

As mafic magmas rise towards the Earth surface and cool...

-olivine would grow first, causing the remaining magma to be enriched in silica - the magma could become intermediate in composition over long periods of time

Oceanic crust...

-tends to be much younger than continental crust -has less silica than continental crust

Which of the following are true of Earth's interior?

-the amount of iron increases from the crust to the core -the amount of oxygen increases from the core to the crust

The Doppler Effect ...

1) explains why a car horn moving toward you would sound higher pitched than one moving away from you 2) states that sound waves from a car horn are compressed in front of the moving car

The Big Bang Theory can be used to explain

1)Red Shift 2)Cosmic Background Radiation

The Big Bang Theory ...

1)explains how the universe formed 2)explains why distant stars and galaxies appear to be moving away from Earth

Groups of Silicate Minerals

1. Dark (ferromagnesian) Silicates 2.light (nonferromagnesian) silicates Light silicates have more silica than dark silicates

Circumstances under which magma formation occurs

1. Decompression: during convection the hot mantle rises to lower pressure or depth and carries its heat with it; melting occurs at progressively higher temperatures with increased depth 2. Addition of Water: water causes rocks to melt at a lower temperature; generates magma at convergent plate boundaries where cool slabs of oceanic lithosphere descend into the mantle (subduction zones) 3. Transfer of Heat: magmas that were generated by some other mechanism intrude into cold crust they bring the heat with them; repeated intrusions can transfer enough heat to increase the local geothermal gradient and cause melting of the surrounding rock

What are the different types of plate tectonic boundaries?

1. Divergent 2. Convergent 3. Transform

Types of Textures

1. Glassy Texture (Obsidian) 2. Porphyritic Texture (2 different crystal sizes) 3. Phaneritic (coarse grained): you can see mineral grains without a microscope 4. Vesicular texture: extrusive rock containing voids left by gas bubbles that escape as lava solidifies (Pumice) 5. Pyroclastic (fragmental): fragments that consolidate that were ejected during an explosive volcanic eruption 6. Aphanitic (fine-grained): crystals that are too small for the individual eye to see; need a polarizing microscope

Steps of the Rock Cycyle

1. Igneous Rocks undergo weathering/erosion 2. they form sediments 3. lithification occurs 4. sedimentary rocks are formed 5. metamorphism occurs and metamorphic rock is formed

Signs of Volcanic Eruption

1. Increased seismic activity 2. Ground bulge upward 3. escape of volcanic gases 4. increased surface temperature because of heat from magma may result to hydrothermal springs activity or melting snow

Why Should we study Volcanoes

1. Lava flows build up volcanic islands like hawaii; Creates new land 2. Geothermal energy: underground heat is generated by igneous activity 3. effect on climate: very large eruptions can result in measurable global cooling resulting in crop failures and famines

Types of Magma

1. Mafic/Basaltic: Low in silica content, low viscosity (thin/runny), higher temperature 2. Intermediate/Andesitic: medium level of silica content, intermediate viscosity, medium temperature 3. Felsic/Granitic: high silica content, high viscosity (thick/slow) lower temperature

Magma formation in relation to plate tectonics

1. Mid Ocean Ridge: main process for magma formation is compression; at divergent boundaries basalt and gabbro are commonly formed 2. Convergent Boundaries: water addition; Andesite comes from partial melting of oceanic crust; Granite comes from partial melting of lower continental crust 3. Intraplate Igneous Activity: rising mantle plumes produce localized hotspots and volcanoes when they produce magmas that rise through oceanic/continental crust (Hawaii); mafic igneous rock usually formed at hotspots (basalt) 4.

Types of Volcanic Eruptions

1. Quiescent eruptions: calm oozing of magma out of the ground produces lava flows. Usually associated with basaltic lavas of low viscosity 2. Explosive eruptions: produces rapidly cooled rock fragments called pyroclasts, size ranges from dust (ash) to boulders (blocks and volcanic bombs) Usually associated with felsic lava of higher viscosity

Determinants of Viscosity

1. Temperature: the hotter the lava, the lower the viscosity; the cooler the lava the higher the viscosity 2. Composition (silica content): the more mafic the lava (less silica) the lower the viscosity; the more felsic the lava (more silica) the higher the viscosity. 3. Volatile content (gases dissolved in the lava): lava may contain up to 6% or more of their masses as gases; the two most abundant gases in lava are water vapor and carbon dioxide; there is also nitrogen, sulfur dioxide and carbon dioxide; the HIGHER the volatile content the LOWER the viscosity; the LOWER the volatile content the HIGHER the viscosity.

Igneous Rocks Chemical Composition

1. Ultramafic (less than 45% silica) composed entirely of dark colored ferromagnesian minerals 2. mafic rocks (45-50% silica) contain dark colored minerals that are abundant in iron, magnesium, calcium 3. Intermediate rocks (50-65% silica) contents b/w mafic and felsic 4. felsic (silicic rocks greater than 65% silica) contain light colored minerals abundant in silica, aluminum, sodium, and potassium

Plate tectonics and Volcanism

1. Volcanic activity at divergent boundaries (mid ocean ridges) b/c of decompression melting; causes eruption of basaltic magmas and pillow lavas; forms most of the sea floor 2. Volcanic activity at convergent boundaries results in most well known composite volcanoes with viscous andesitic lavas 3. Within plate volcanic activity- mantle plumes (hot spots) result in basaltic magmas/lavas

How do we classify pyroclastics?

1. Volcanic bombs 2. Volcanic ash

Magma components

1. liquid portion (melt): composed mainly of mobile ions from common elements in the earth's crust 2. solids (if any): crystals of silicate minerals; "crystalline mush" 3. Volatiles (gaseous component): dissolved gases in the melt that vaporize at surface pressure and may propel the magma from the vent

Magma types

1. mafic magmas: will crystallize into basalt or gabbro if early formed minerals are not removed 2. intermediate magmas: will crystallize into diorite or andesite if minerals are not removed 3. felsic magmas: will crystallize into granite or rhyolite if separation of early formed ferromagnesian minerals increases silica content

characteristics of magma

1. magmas parent material is igneous rocks 2. magma is formed by partial melting in the earth's crust 3. magma at the surface is called lava

Factors influencing igneous rock texture

1. the rate at which molten rock cools 2. the amount of silica present in the magma 3. the amount of dissolved gases in the magma

Silica enrichment

1..Olivine grows as the magma cools 2. Remaining magma becomes enriched in silica 3. The remaining magma rosters through the crust, continuing to cool off 4. Silica enrichment continues to occur as minerals grow

According to astronomers, the universe is approximately...

13-14 billion years old

Earth's physical make up

30% Oxygen 35% Iron 15% Silicon 13% Magnesium

oceanic crust

7km, much thinner than the continental crust, rocks in the oceanic crust have much less silica, but more iron and magnesium present. Has the composition of basalt. (-50% silica). Younger rocks.

High temperature feldspar

Calcium rich

Lahar

A destructive mudflow of pyroclastic material on the slopes of a volcanoes. Mixtures of ash and water that can flow at excess speeds.

Plagioclase Feldspar

A feldspar containing sodium and/or calcium in addition to aluminum, silicon, and oxygen.

Volcanic necks

A long string of dykes that lead up to a volcanic neck source

Melt Viscosity

A measurement of resistance to flow

Nebular Theory

A model for the origin of the solar system that supposes a rotating nebula of dust and gases that contracted to form the Sun and planets.

divergent boundary

A plate boundary where two plates move away from each other.

convergent boundary

A plate boundary where two plates move toward each other.

Vesicular Basalt

A porous rock formed by solidified lava with trapped bubbles. Igneous

The East African Rift

Active divergent boundary located in Africa, adding more land and, therefore, increasing its size

crystallization

A process that reverses the events of melting; the temperature of the liquid drops and the ion rate of movement slows so they pack closer together and silicon oxygen tetrahedra's are formed

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Red shift

A shift toward longer wavelengths of the spectral lines emitted by a celestial object that is caused by the object moving away from the earth.

cinder cone volcano

A small, steeply sloped volcano that forms from moderately explosive eruptions of pyroclastic material.

island arc

A string of volcanoes that form as the result of subduction of one oceanic plate beneath a second oceanic plate.

Lithosphere

A strong rigid layer made up of the uppermost part of the mantle and the crust. has crack that meet at boundaries, known as plates.

Pumice

A type of igneous rock that contains air bubbles. A rock that floats because it is not dense. Holes in the rock make it flatter like styrofoam

Volcano

A vent which transfers molten rock known as magma from the subsurface to the earth's surface; a natural way the earth and other planets have of cooling off and releasing internal heat and pressure

Dike

A vertical slab of volcanic rock formed when magma forces itself across rock layers

scientific theory

A well-tested explanation for a wide range of observations or experimental results. Models of how a system operates and has been thoroughly tested. 1. It has to predict something 2. Should be a test that falsifies 3.Has to be overwhelmingly accepted by the science community

Intrusive Igneous Rocks

Also called plutonic rocks; form when magma crystallize at depth

Partial melting...

Always produces a higher silica magma than the original rock you were melting.

black hole

An object in space whose gravity is so strong not even light can escape.

Doppler effect

An observed change in the frequency of a wave when the source or observer is moving. Higher pitches = shorter wavelengths. Lower pitches = longer wave lengths

mid-ocean ridge

An underwater moutain chain where new ocean floor is formed

Crystalline

Attends have a regular geometric repeating pattern. External crystal form

What does this leftover magma do?

Becomes more silica rich becomes you melt the minerals with the the most silica forest

Which of the following are types of ferromagnesium silicates?

Biotite andmuscovite can be classified as mica minerals because the y will split into thin sheets. However, biotite can also be classified as a ferromagnesium m ineral- along with amphibole, pyro xene, and olivine -because it contains iron and magnesium in its chemical formula.

Partial melting + silica enrichment during the cooling process

Causes the magma to look differently before rushing to the surface as magma by selectively removing elements as different minerals crystallize. Enriching the silica in the process by drawing out more magnesium and iron and not as much silica.

Magma Differentiation

Change in composition of a magma to produce a wide variety of different igneous rocks; change in the composition of a magma body, which can occur by assimilation, magma mixing, fractional crystallization

Big grains/visible

Cooled slowly, underground

Tiny, microscopic grain

Cooled very rapidly

Big Bang Theory

Cosmological model that explains the sudden development of the universe through expansion from a hot, dense state.

Intrusive Igneous

Course grained

Phaneritic rocks

Course-grained rocks; form in the earths surface; crystallize/cool slower

Cinder cones

Paricutin; small, conical in shape, steeply sloping, composed of almost all pyroclastic material

Andacites

Extrusive volcanic rocks. A magma body is plutonic or intrusive

Composite Volcanoes

Felsic

Degasses Poorly

Felsic

Explosive Eruptions

Felsic

High Silica (65+%)

Felsic

High Viscosity

Felsic

High Water Content

Felsic

Light Color

Felsic

Low Density

Felsic

Low Melting Point

Felsic

Pyroclastic Material (ash, cinders, bombs)

Felsic

Thick Magma

Felsic

Aphanitic Rocks

Fine Grained rocks; form from lava on or near the surface; crystallize rapidly

Lava domes

Form from eruptions of felsic magma

Caldera volcanoes

Form from eruptions which partially empty the magma chamber

shield volcano

Form from low viscosity lava flows (mafic) and have gentle slopes

Extrusive Igneous Rocks

Form when magma solidifies at Earth's surface (lava)

If it cold underground it would make

Gabbro

Volcanic gas

Gases that escape out of a magma

Volcanic gas

Gases that escape out of a magma's chamber of a volcano

Micas

Grow in sheets and separate in sheets •biotite - dark •muscovite -light

Common Volatiles in Magma

H20 (Water vapor), CO2 (Carbon Dioxide), SO2 (Sulfur Dioxide)

Shield Volcanoes

Hawaii, Mauna Loa; large, gentle sloping, composed of almost basalt; 90% of the volcano is lava rather than pyroclastic material

sill

Horizontal sheet pluton intrusion

Peridotite

Igneous rock that contains mostly olivine and pyroxene; considered ultramafic

Extrusive rock

Igneous rocks which form by the crystallization of magma at the surface of the Earth.

Continental arc

Line of volcanoes on a continental plate; the volcanoes are on a continent above a subducting oceanic plate.

backarc basin

Little divergent plate boundaries being the arc of a continental arc

What evidence do we have that supports the Condensation theory?

Inner planets are small and made up of rocks and metals; have very few low temperature elements. Outer planets are the farthest away from the sun and are made up of low temperature elements (hydrogen and helium) Also the orbital pattern of the planets is consistent with the Nebular Theory.

Andesitic Composition (intermediate)

Intrusive: Diorite Extrusive: Andesite

Basaltic Composition (Mafic)

Intrusive: Gabbro Extrusive: Basalt

Granitic Composition (Felsic)

Intrusive: Granite Extrusive: Rhyolite

Ultramafic Composition

Intrusive: Peridotite Extrusive: Komatite

What's has silica enrichment done fire our planet?

It has built our continents

If the magma cools above ground

It will make basalt

Orthocase

K spar

Pahoehoe lava

Kind of Lava which flows slowly, like wax dripping from a candle, forming a glassy surface with rounded wrinkles

Plutons

Large intrusive bodies of igneous rocks

Peridotite (Igneous)

Large visible plutonic rocks that are ultramafic. Usually green

Volcanic Hazards

Lava flows, pyroclastic flows, ash falls (Pompeii), Lahars (mudflow made up of volcanic debris), Gases can be toxic (Co2, SO2, H2S)

In partial melting...

Lower temperature materials are melted first, but it solidifies last. Olivine crystallizes before pyroxene.

What does water do the the melting point of a rock?

Lowers it

Dark Color

Mafic

Degasses Easily

Mafic

High Density

Mafic

High Melting Point

Mafic

Lava Flows

Mafic

Low Silica (45-52%)

Mafic

Low Viscosity

Mafic

Low Water Content

Mafic

Quiet Eruptions

Mafic

Shield Volcanoes

Mafic

Thin Magma

Mafic

If a mafic magma cooled off to form an igneous rock, that rock would...

Mafic magmas cool off to form plutonic (intrusive) igneous rocks .Basalt is an extrusive (volcanic) igneous rock and forms from cooling lava flows. The correct answer to this question would have been gabbro.

Difference between magma and lava

Magma is melted/molten rock in the subsurface, lava is molten rock on the earth's surface

Assimilation

Magma passes through a cooler rock and may partially melt the surrounding rock and incorporate this melt into the magma; addition of this melt to magma will make it more siliceous ex: peridotite xenolith in basalt

Magma Mixing

Magmas with different compositions come in contact with each other and mix; the mixed magma will have a composition somewhere between that of the original two magma compositions

Why do we get magma at hotspots?

Mantle plumes. Also the pressure drops because you're melting peridotite again, which result in mafic magma forming.

The very top of the Earth's mantle is the..

Mohorovicic discontinuity. Although the asthenosphere is near the top of the mantle, it is not the very top of the mantle. The boundary between the crust and mantle (chemical subdivisions) is within the lithosphere (physical subdivision) at the Moho.

Origin of Magma

Most magma originates in earth's uppermost mantle usually by divergent plate boundaries (sea floor spreading) Magma can also be generated when crustal rocks are heated to melt or when the oceanic lithosphere descends into the mantle

composite volcanoes

Mount st. Helens, Mount Etna; also called stratovolcanoes; moderately to steeply sloping; half lava half pyroclastics; composed primarily of intermediate composition (andesite & Dacite)

Rock

Naturally formed, consolidated and composed of one or more minerals

Ferromagnesium silicate

Olivines, pyroxene, amphiboles

Why are the inner planets so small?

Once you take away the hydrogen and helium, we are left with the leftover materials that make up our planets, not saying we do not have any, but not nearly as much as the other planets.

Partial melting

Only melting part of the rock and not the whole thing

Vent

Opening through which lava erupts

Volcanic hotspot

Places within the mantle where rocks generate magma

Planetary Revolutions (Orbits)

Planets all orbit counterclockwise (as viewed from the Earth's north pole, exactly as expected if they originally formed in a rotating nebula.) *Venus and Uranus ROTATE clockwise.

Lava

Produced when magma reaches earth's surface

What would happen if you partially melted continental crust?

Quartz would melt first because it has the highest silica. High silica, low temperature minerals writing be melted first.

stock

Regular magma blob cooling off

What does melting pyroxene do?

Releases more silica and oxygen into forming magma than melting olivine.

Rock Cycle

Representation of how rocks are formed, broken down, and processed in response to changing conditions. Processes may involve interactions of the geosphere with hydrosphere, atmosphere and/or biosphere

Intrusive

Rocks formed from magma forced into older rocks at depths within the Earths crust

When rocks are subducted deep into the Earth and subjected to intense heat and pressure they ...

Rocks subducted into the mantle and subjected to intense heat and pressure (and affected by chemically active fluids) will be metam orphosed. Lithification is a process that turns sediment into sedimentary rock and occurs in the upper couple of kilometers of the surface. Rocks subducted into the Earth are heated up, but pressure increases so much that it actually be comes more difficult for the rocks to melt.

Feldspar

Silica rich rock

Ferromagnesium silicate mineral

Silicate minerals in which cations of iron and magnesium form essential chemical components. The term is used to cover such minerals as the olivines, pyroxenes, amphiboles, and the micas biotite and phlogopite.

Common elements in Igneous Rocks

Silicon, Oxygen, ions of Aluminum, Calcium, Sodium, Potassium, Magnesium, and Iron

Lower temperature feldspar

Sodium rich

Pyroclastics

Solid volcanic materials such as ash and rocks

Geothermal Gradient

Temperature increases with depth in the earth along a gradient; averages 25C per KM in the upper crust; under normal conditions the geothermal gradient is not high enough to melt rocks; most rocks melt between 800-1200C

Igneous Texture

Texture is the overall appearance of a rock based on size, shape, and arrangement of mineral grains

transform boundary

The boundary between tectonic plates that are sliding past each other horizontally

Pyroclastic Flow

The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption

How does temperature affect viscosity

The higher the temperature, the higher the viscosity

The largest eruptions of lava

The largest outpourings of lava in Earth history are associated with fissure eruptions

Rock Cycle and Plate tectonics

The lithosphere comes closer to the surface and melts. At the mid ocean ridge solid rocks in the crust and upper mantle start to melt and form a new oceanic crust

With enough silica enrichment...

The magma can become intermediate

The thicker the crust

The more time the magma's has to rise and become enriched in silica

Bowen's Reaction Series

The order in which minerals crystallize from a basaltic magma depends on temperature; Olivine and Ca-rich plagioclase crystallize first and the olivine reacts to produce pyroxene Shows how if the process of removing minerals continues an originally basaltic magma can change to andesitic and then rhyolitic with falling temperature

continental crust

The portion of the earth's crust that primarily contains granite, is less dense than oceanic crust, and is 20-50 km thick

Viscosity

The type of explosion depends on the viscosity of lava. Viscosity is a fluids resistance to flow. Viscosity is determined by temperature, composition, and dissolved gases. The more viscus the lava and the greater the volume of gas content the more violent the eruption

Felsic magma

Thick Lower temperature high silica magma

Caldera

Volcanic depression much larger than the original crater, has a diameter of atleast 1 km. Usually formed by the collapse of land following a volcanic eruption

Volcanic tsunami

Volcanic flank crashes into the sea. A tsunami forms and propagates to distant coastlines

Volcanic aerosols

Volcanic particles in the atmosphere preventing energy from getting to the Earth. 1. Block energy and bounces it back into space 2. Absorb the energy above our heads

Why do Volcanoes erupt?

Volcanoes erupt because of density and pressure; the lower density of the magma relative to the surrounding rocks causes it to rise, as it rises bubbles start to form from the gas dissolved in the magma which exerts tremendous pressure and brings magma to the surface and forces it into the air

transform boundaries

a boundary where two plates slide past one another without creating or destroying lithosphere. Most are located on Mid-Ocean ridge segments

When oceanic crust subducts beneath continental crust...

a continental arc might form on the overriding plate

Batholith

a huge series of overlapping magma's chambers at latest 40 sq miles.

A galaxy is...

a large accumulation of stars and nebulae

A geologist finds an igneous rock consisting of large mineral grains, visible without magnification. This rock...

a) would be plutonic b) would be intrusive

During the rock cycle a sedimentary rock...

a)might undergo melting to eventually become an igneous rock b)might be subjected to intense heat and pressure to become a metamorphic rock c)might undergo weathering and erosion to eventually form a new sedimentary rock

Nebular Condensation Theory

a)states that the sun and planets formed in a contracting and rotating nebula b)explains why most asteroids in the solar system are found between Mars and Jupiter c)explains why all the planets orbit the sun in the same direction

proto-planets

almost a planet, lumps of hydrogen/helium orbiting in the solar system. Occur when nuclear fission does not take place

Andesitic Composition

also called Intermediate composition; 25% dark silicate minerals mainly amphbinole, pyroxene, biotite mica; associated with volcanic activity on volcanic island arcs

extrusive igneous rocks

also called volcanic rocks; form when molten rock solidifies at the surface or when volcanic debris falls on the Earth's surface

Submarine Eruptions

always basaltic, mid ocean ridge eruptions, form underwater, pillow basalts

Volcanoes

an opening in the Earth's crust through which molten lava, ash, and gases are ejected.

The inner planets - those closest to the sun (Mercury, Venus, Earth and Mars)...

are much smaller than the planets farthest from the sun

Which of the following are physical subdivisions of the Earth?

asthenosphere

Which of the following are types of igneous rocks?

basalt granite

Atoms in a magma's body

bond together to make minerals

Moho

boundary between crust and mantle

If a low silica, high temperature lava flow cooled off to form an igneous rock, that rock would...

c) probably be basalt

Lahars

can form even when a volcano isnt erupting

Nebula

collapsing disk of hydrogen and helium; positive feedback loop

Basaltic Composition

contain a high percentage of ferromagnesian minerals; referred to as mafic; have a high iron content; make up the ocean floor as well as many volcanic islands in ocean basins; basalt forms extensive lava flow on continents

Chemical Layers of Earth

crust, mantle, core

Stock

deep, intermediate intrusive body formed of coarse grained igneous rock; commonly granitic in composition; smaller than a batholith larger than a laccolith

Batholiths

deep, large intrusive body formed of coarse grained igneous rock; commonly granitic in composition

laccolith

deep, small intrusive body formed of coarse grained igneous rock, commonly granitic in composition; injected between sedimentary strata causing the overlying strata to arch upward

Mafic

describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color. Gabbro

Volcano size

determined by the total volume of lava that has erupted

Which of the following rocks might make up a sill?

diorite. Sills -along with dikes, stocks, and batholiths form from cooling magma. Thus, they are made up of plutonic igneous rocks. Both tuff and obsidian are volcanic igneous rocks.

Pyroclastic materials

ejected from the volcano as ash or solid fragments that often solidify as they leave the volcanic vent or fly through the air

Volcanic Domes

extremely high viscosity, degassed, felsic lavas (i.e. obsidian)

intermediate

fall in the category between felsic and mafic rocks

The most common mineral in the Earth's crust is...

feldspar

Extrusive

fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface. Vitric. Can be a mixture of different flows

Composite Volcanoes (Stratovolcanoes)

formed from explosive eruptions of pyroclastic material, followed by quieter flows of lava; have broad bases and sides that get steeper toward the top

Sedimentary Rocks

formed from particles of sand, pebbles, shells, and other fragments of material (sediments). Gradually the sediment accumulates in layers and over a long period of time hardens into rock (sandstone, limestone, shale)

Igneous Rocks

formed when magma (molten rock in the earth's interior) cools and hardens (Granite)

pyroclastics (tephra)

fragments expelled explosively from a volcano, quite common with felsic magma (explosive eruptions)

Crater

funnel shaped over the vent at the summit of the volcano

ALL mass exorts...

gravitational pull. The larger the object, the larger the pull.

Continental continental convergence

happens where 2 continental plates collide and push up creating mountain ranges

oceanic-oceanic convergence

happens where 2 oceanic plates push against one another, causing the colder, denser, older plate to buckle up and sink into the mantle. Hot magma comes from where the plate sank, creating new crust.

Active Volcano

has had at least one eruption in the past 10,000 years

Inactive (extinct) volcano

has not had an eruption for at least 10,000 years

Granitic Composition

have dominant minerals of quartz and potassium feldspar (light colored silicates); referred to as being felsic; Granitic rocks are rich in silica (70%) and constitute a large part of the continental crust

If a felsic magma chamber exploded, erupting molten material into the air...

he airborne melt would cool to form pyroclastics. Both basalts and andesites form from cooling lava flows. Pyroclastic material (e.g. ash)deposited during volcanic eruptions form the igneous rock "tuff".

The Big Bang Theory

helps us understand cosmic background radiation

high silica

high viscosity

Shortly after the Big Bang, energy began to coalesce into matter. The first atoms to form were...

hydrogen atoms

subduction zone

in tectonic plates, the site at which an oceanic plate is sliding under a continental plate.

Plutonic

intrusive

The Red Shift ..

is the observation that light from distant stars is shifted toward the long wavelength end of the spectrum

In volcanically - active regions dominated by felsic magma...

lahars would be common

volcano shape

largely determined by the type of lava that has erupted and its viscosity

blue shift

light shifted towards the short end of a spectrum.

5 layers of earth

lithosphere, asthenosphere, mesosphere, outer core, inner core

low silica content

low viscosity

Mafic magma

low viscosity, high temperature. Basaltic

Which of the following minerals would likely grow first in a cooling magma chamber?

plagiocase

Bowen's Reaction Series

shows us where rocks were formed and the temperature and silica content of the magma's it formed in.

Metamorphic Rock

result of a transformation of a pre-existing rock (igneous/sedimentary). The original rock is subject to very high heat and pressure, which causes obvious physical and/or chemical changes

Tuffs

results of pyroclastic material coming or raging from the sky due to volcanic eruptions

Condensation Theory

rocks and metals condense, hydrogen compounds stay vaporized. Hydrogen compounds and metals condense. If you're an atom closer to the sun, you're warmer and have more energy, you do not chemically bond with other elements. Certain alloys and metals are more stable the closer they are to the Sun.

volcanic neck

shallow intrusion formed when magma solidifies in the through of a volcano

dike

shallow, tabular intrusive structure that cuts across any layering in host rock

sill

shallow, tabular intrusive structure that parallels layering in host rock

In volcanically-active regions dominated by mafic magma...

shield volcanoes would be common

Aa lava flow

surface rough; jagged blocks & spiny projections; lower temperature, less fluid

xenolith

suspended blocks of host rock found in plutons

The Big Bang theory predicts...

that rapid energy that got carried through space eventually evolved into cosmic background radiation

magma chamber

the body of molten rock that feeds a volcano

Moho

the boundary between the earth's mantle and crust

Geothermal gradient

the gradual increase in temperature with depth in the crust

Planetary Accretion

the idea that there are planetary losers and winners. Winners are considered planets that swept up other planets in their interaction.

Flood Basalts

very fluid basalts, extremely large in volume, creates extensive lava plateaus, some parts of the world are covered by thousands of square KM of thick basalt lava flows

Obsidian

volcanic glass

ductile

when solids have fluid like behaviors

continental collision

when two continental plates collide pushing the continental crust up to form mountains

Magmas with low viscosity...

would be very runny

Magma forms at

•continental rifts •divergent plate boundaries •hotspots