Earth Science 3/28/17
Oceanic Hot Spots and mid-oceanic ridges are generally associated with this type of magma that originates in the Upper Mantle.
Basaltic Magma
This magma type is very high in iron and magnesium, as much as 50%. As a result it can be described as very MAFIC.
Basaltic Magma
Peléean eruptions
Gases trapped in sticky magma build up tremendous pressure, as pressure is released, rocks and ash are thrown around
regional metamorphism
Metamorphism associated with large scale mountain building
Where do mid-ocean ridges form?
Mid-ocean ridges form long, underwater mountain ranges that sometimes have a rift valley down their center.
Intermediate igneous rocks
Midway betwen the felsic and mafic ends of the scale. These rocks are neither as rich in silica as the felsic rocks nor as poor in it as the mafic rocks. We find the intermediate intrusive igneous rocks to the right of granite.
Dike
Pluton that cuts across preexisting rocks and often forms when magma invades cracks in surrounding rock bodies
dike
Pluton that cuts across preexisting rocks and often forms when magma invades cracks in surrounding rock bodies.
Sill
Pluton that forms when magma intrudes parallel rock layers
sill
Pluton that forms when magma intrudes parallel rock layers.
Felsic Rocks
Poor in Iron and magnesium and rich in felsic minerals that are high in silica. Minerals include quartz, orthoclase feldspar, and plagioclase feldspar.
Ion
Positively and negatively charged atoms
Subduction
Process by which one tectonic plate slips beneath another tectonic plate
Decompression Melting
Produces the greatest volume of magma anywhere on Earth. It is a the process by which most basalts form on the seafloor.
Ex. Mount Vesuvius & Pompeii
Pyroclastic flow
Silicate minerals
Quartz, feldspars, muscovite, and biotite micas, amphiboles and pyroxenes, and olivine - form a systmeatic series. Felsic minerals are the highest in silica: mafic minerals are the lowest in silica. Mafic minerals crystallize at highter temperatures - that is, earlier in the cooling of a magma - than felsic minerals.
Laccolith
Relatively small, mushroom - shaped pluton that forms when magma intrudes into parallel rock layers close to earths surface
laccolith
Relatively small, mushroom-shaped pluton that forms when magma intrudes into parallel rock layers close to Earth's surface.
Magma chamber
Reservoirs for magma from where they erupt
>60% silica, high viscosity, high explosivity. Hot spots under continents. Very low temperature
Rhyolitic Magma
The most powerful explosions, such as the Yellowstone eruption 630,000 years ago have been linked to this type of magma.
Rhyolitic Magma
This magma type has the highest silica content of all magma types.
Rhyolitic Magma
Where does volcanoes also occur?
Volcanoes also occur where an oceanic plate is subducted beneath a continental plate.
Where is another place that volcanoes can occur?
Volcanoes can also occur where two plates push together,or converge.
Where can volcanoes occur?
Volcanoes can occur where two plates pull apart,or diverge.
What does volcano form?
Volcanoes form a regular pattern on Earth.
Where do volcanoes form?
Volcanoes form along the mid-ocean ridges,where two plates move apart.
What decreases the melting temperature beneath spreading ridges?
Water
What does the water in the sinking plate eventually leaves?
Water in the sinking plate eventually leaves the crust and rises into the wedges of the mantle above it.
What helps form magma?
Water that is brought down with the sinking plate eventually helps to form magma,which rises to the surface.
Continental drift
Wegener's hypothesis that earths continents were joined as a single landmass called Pangaea, that broke apart about 200 Mya and slowly moved to their present positions
Magnetic reversal
When earths magnetic field changed polarity between normal and reversed
What is a skylight?
When part of the roof of a lava tube collapses and people can look in and observe or access can be gained t an inactive lava tube.
What determines the rate of cooling and what the rocks will look like?
Where magma crystalizes determines their rate of cooling and the rate of cooling determines what the igneous rock will look like.
Laccolith
a lens-shaped pluton with a round top and flat bottom. Compared to batholiths and stocks, they are relatively small
Rift Valley
a long, narrow trough bounded by normal faults. It represents a region where divergence is taking place.
Subduction Zone
a long, narrow zone where one lithosphere plate and transported into the mantle
Ring of Fire
a major belt of volcanoes that rims the Pacific Ocean
Mantle Plume
a mass of hotter-than-typical material that ascends toward the surface, where it may lead to igneous activity. These plumes of solid yet mobile material may orginate as deep as the core-mantle boundry.
Laccolith
a massive igneous body intruded between preexisting strata
sheeting
a mechanical weathering process that is characterized by the splitting off of slablike sheets of rock.
Slab Pull
a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along.
shield volcano
a mountain with a broad, gently sloping sides, and a nearly circular base. form when layers of lava accumulate during nonexplosive eruptions. the largest types of volcanoes
Shield Volcano
a mountain with broad, gently sloping sides and a nearly circular base, stays active as long as the hot spot is still active, located at hot spots, if oceanic contains basaltic lava, if continental contains rhyloitic magma. Ex: Mauna Loa, Yellowstone
Natural Disaster
a natural event that causes great damage and/or loss of life
bedding plane
a nearly flat surface that seperate two beds of sedimentary rock. Each bedding plane marks the end of one deposit and the beginning of another having different characteristics
Dike
a pluton that cuts across preexisting rocks, form when magma invades cracks in surrounding rock bodies, range in size from a few centimeters to several meters wide and can be tens of kilometers long
An igneous rock with a mixed texture of coarse grains (phenocrysts) surrounded by fine crystals (groundmass) is termed a. porphyritic b. phaneritic c. aphanitic d. necrotic
a porphyritic
facies
a portion of rock unit that possesses a distinctive set of characteristics that distinguishes it from other parts of the same unit
magmatic differentiation
a process by which rocks of varying composition can arise from a uniform parent magma--occurs because different minerals crystallize at different temperatures
Carbonization
happens when an organism is buried, followed by compression, that squeezes out gases and liquids leaving a thin film of carbon; Impressions remain in the rock when the carbon film is lost; effective at preserving leaves and delicate animals.
rhyolite
extrusive equivalent of granite--has a fells composition and light color, but it much more fine grained
andesite
extrusive series--the volcanic equivalent of diorite
evaluate the following statements. volcanoes are only found along coastlines.
false,most found along plate boundaries and hotspots.
What are ultramafic rocks composed of?
ferromagnesian silicates.
differentiation
forces that are unequal in different directions
flood basalts
form when lava flows out of long cracks in Earth's surface
seismic waves
formed during earthquakes; stored up energy is released and the waves radiate in all directions from the focus
Laccolith
forms when magma intrudes into parallel rock layers
Sill
forms when magma intrudes parallel to layers of rocks. Can range from only a few centimeters to hundreds of meters in thickness
dike
forms when magma invades cracks in surrounding rock bodies
types of weathering
forst wedging, salt crystal growth, sheeting and unloading, biological activity
principle of fossil succession
fossils are arranged according to their age
passive margin
found along most coastal areas that surround the Atlantic Ocean; not associated with plate boundaries; experience little volcanism and few earthquakes; include: continental shelf, continental slope, continental rise
fault
fractures in the rocks where rocks on one side of the fault are displaced relative to the rocks on the other side of the fault
Volatile
gaseous components of magma dissolved in the melt. Volatiles will readily vaporize at surface pressures.
deformation
general term that refers to all changes in shape or position of a rock body in response to stress
Composite volcano
generally cone-shaped with concave slopes
composite volcano
generally cone-shaped with concave slopes; built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers
composite volcano
generally cone-shaped with concave slopes; built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers. much larger than cinder cones.
earthquake
ground shaking caused by sudden rapid movement of one block of rock sliding past another
shear
motion similar to slippage that occurs between playing cards when the top of the stack is moved relative to the bottom
Rifting
moving apart forming cracks, breaks, or fissures
Geologic Hazard
natural processes that become hazards only when people try to live where these processes occur
rifting
new ocean basin begins with a continental rift— an elongated depression where the lithosphere is stretched and thinned; when lithosphere is thick and cold, rifts are narrow; when lithosphere is thin and hot, the rift can be very wide
Dip slip fault*
occurs when movement is parallel to the inclination
what tectonic setting created mt. vesuvius?
oceanic continental convergent boundaries
thickness of crust
oceanic: averages 7 kilometers thick. continental: thickest- 70 kilometers, thinnest- 20 kilometers
There are three different forms
of volcanoes.
The form of a volcano depends
on the composition of its magma and the amount of water vapor and other trapped gases.
ductile
once the elastic limit of a rock is surpassed it bends
brittle
once the elastic limit of a rock is surpassed it breaks
granite
one of the most abundant and intrusive igneous rocks, contains about 70% silica.
pumice
one volcanic rock type, that is a frothy mass of volcanic glass in which a great number of spaced remain after trapped gas has escaped from the solidifying melt
cementation
one way in which sedimentary rocks are lithified. As material precipitates from water that percolates through the sediment, open spaces are filled and particles are joined into a solid mass.
environments of metamorphism
ontact or thermal, hydrothermal, burial, subduction zone, regional
vent
opening in Earth's crust through which lava erupts and flows out onto the surface
Vent
opening in Earth's crust through which lava flows out onto the surface
vent
opening in earth's crust through which lava erupts and flows and flows out onto the surface
humus
organic matter in soil that is produced by the decomposition of plants and animals
age of earth
our understanding of radioactivity helps us accurately determine numerical dates for rocks that represent important events in Earth's distant past. The earth is about 4.6 billion years old.
Mantle
over 82% of the earths volume is in the mantle; solid rocky layer.
Volcanoes are powerful displays of earth in action
scientists have determined that three forces within earth can create a volcano
What is the primary constituent of magma?
Silica.
Flood basalt
Huge amounts of lava that erupt from fissures
Caldera
Huge holes left by the collapse of a volcanic mountain (empty magma chamber)
What is the definition of Lava?
It is magma that reaches the Earth's surface.
What are the three types of plutons?
1) tabular,
Outer core
A liquid layer of Earth's core that surrounds the solid inner core, composed of iron & nickel
<50% silica, low viscosity, non-explosive, rifts and ocean hot spots, Very Very hot, hottest of the three magma types
Basaltic Magma
Tectonic plate
Huge pieces of earths crust that cover its surface and fit together at their edges
Transform Boundries
(transform fault boundary) a boundary in which two plates slide past one another without creating or destroying lithosphere
Lithosphere
"sphere of rock" the entire crust plus the uppermost portion of the mantle; forms the cool, rigid outer shell, 100-250 km thick
asthenosphere
"weak sphere" 400km deep, small amount of melting; mechanically detached from lithosphere, which can move independently
Thrust fault*
(convergent plate boundaries) have angles less than 45 degrees so the overlaying plate moves almost horizontally (most pronounced along convergent plate boundaries)
reverse fault*
(convergent plate boundary) hanging wall moving up relative to the footwall (compressional stress as the crust shortens)
Trench
(deep-ocean trench) a narrow, elongated depression of the seafloor
Normal fault*
(divergent plate boundaries) the wall movie down relative to the footwall (tensional stress)
Strike slipt fault
(transform plate boundaries) placement that is horizontal and parallel to the strike of the fault; Right lateral: as you face the fault, the opposite side of the fault moves to the right. Left-lateral: as you face the fault, the opposite side of the fault moves to the left
Volcanic Arc
(volcanic island arc) a chain of volcanic islands generally located in a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another
What are the two types of lava flows?
1) Pahoehoe (pah-hoy-hoy): ropy surface like taffy
What are the two ways magmas can crystalize?
1) Rapid Cooling 1100-1200 degrees celcius (aphanatic fine grained texture)
Four ways in which Sill differs from lava flows and pyroclastic deposits
1) They lack the ropy, blocky, and vesicle-filled structures that characterize many volcanic rocks
What are the two branches that Bowen's reaction series consists of?
1) a discontinuous branch
What are the three main parts of magmas?
1) high temperature mix of crystalizing solids (minerals),
What are the two separate processes that account for how igneous rocks form?
1) magma or lava cools and crystalizes to form aggregates of minerals.
reasons for the variation in the composition of magmas
1. rocks in the upper mantle undergo partial melting to produce basaltic magmas
ways sill differs
1. they lack the ropy, blocky, and vesicle filled structures that characterize many volcanic rocks
divergent boundary
2 plates pull apart from each other
Volcanic island arc
A long, curved chain of volcanic islands, common in the pacific ocean where they border deep ocean trenches, part of the ring of fire, formed by 2 oceanic plates colliding
Lava Flow
90% is basaltic lava, <10% of lava is andesitic lava and 1% is rhyolitic lava
Ring of fire
A belt of volcanoes around the rim of the pacific ocean, encircles the pacific basin
Divergent Boundries
A boundry in which two plates move apart, resulting in the upwelling of material from the mantle to create new seafloor
Covergent Boundries
A boundry in which two plates move together, resulting in oceanic lithosphere being thrust beneath a continent. Example: andes and the cascades
Strike-slip fault
A break in rocks due to shearing force where rocks on either side of the fault line move past each other without upward or downward movement.
Shield volcano
A broad volcano with gently sloping sides, built by quiet eruptions of fluid basaltic lava which spreads out in flat layers
Shield volcano
A broad, gentle slopping volcano made of layers of lava rock, in the middle of dangerous
Magnetic Reversal
A change in the earths magnetic field from normal to reverse or vice versa
What is the mid-ocean ridge?
A long, underwater valley that winds through the oceans, along the ridge, lava pours out of cracks in the ocean floor
Gabbro
A coarse-grained, dark gray intrusive igneous rock. It has an abudance of mafic minerals, especially pyroxenes. It contains no quartz and only moderate amounts of calcium-rich plagioclase feldspar.
Reverse fault
A compression fracture in rocks. Rocks above the fault surface are forced up over rocks below the fault surface.
Rock cycle
A cycle where rocks are continuously changed from one type to another in a never ending cycle
Fumarole
A fountain of hot gases or steam
Geyser
A fountain of hot water and steam that shoots into the air at intervals
Continental drift
A hypothesis by Alfred Wegener, which states that continents have moved around the globe, over time, to their present locations
Caldera
A large opening formed at the top of a volcano when a crater collapses into the vent following an eruption.
Granodiorite
A light-colored rock that looks something like granite. It is similar to granite having abundant quartz,but is predominant feldspar is plagioclase, not orthosclase.
What does lahar mean?
A mudflow composed of pyroclastic materials such as ash.
Magmatic differentiation
A process by which rocks of varying composition can arise from a uniform parent magma.
Normal fault
A pull apart (tension) fracture in rocks. Rocks above the fault surface drop downward in relation to rocks below the fault surface
Hot spot
A region of volcanic activity in the middle of a tectonic plate, here, material from the mantle rises, forming magma that erupts, is subduction and is caused by magma melting into the core of earth
Sill
A sheetlike body formed by the injection of magma between parallel layers of bedded country rock.
When magmas spread out parallel on a plain of weakness what is that called?
A sill
What can cause laccoliths?
A sill inflating can cause laccoliths.
A cinder-cone volcano
A steep sided, cone-shaped volcano made of small rock particles and cinder, explosive, most dangerous
Hot spring
A stream of hot, bubbling water that flows out of the ground continually, occurs when magma heats water in the ground
Viscosity
A substance's internal resistance to flow
viscosity
A substance's internal resistance to flow.
Composite volcano
A symmetrical cone with steep inward-curving sides made of layers of ash, lava, cinders, and rock, least dangerous
Conduit
A tubelike structure that allows lava to reach the surface
Composite volcano
A type of volcano built of silica-rich lava and tephra layers accumulated from alternating cycles of tephra & lava eruptions
Pegmatites
A vein of extremely coarse-grained granite, crystallized from a water-rich magma in the late stages of solidification, that cuts across much finer grained country rock and may contain rich concentrations of rare minerals.
Volcano
A vent in the Earth's surface that often forms a mountain built of lava & volcanic ash, which erupts and builds up
Side vent
A vent in the side
Volcano
A vent/weak spot in earth's surface through which materials are forced out
Pumice
A volcanic rock type that has a frothy mass of volcanic glass in which a great number of spaces remain after trapped gas has escaped from the solidifying melt.
Where do a volcano forms?
A volcano forms above a hot spot when magma erupts through the crust and reaches the surface.
Obsidian
A wholly glassy volcanic rock type; unlike pumice; it contains only tiny vesicles and so is solid and dense. Chipped or fragmented obsidian produces very sharp edges, and the Native Americans and many other hunting groups used it for arrowheads and a variety of cutting tools.
cool, slow moving lava on land forms blocky in appearance
AA https://o.quizlet.com/.qmtpK1uUKeeJ2Edokt3Jw_m.jpg
How are magma types classified?
According to their silica content (50%-Basaltic, 60%-Andesitic, 70%-Rhyolitic)
Four stages of volcanoes
Active, dormant, extinct, and intermittent
What forms after the magma and lava cools?
After magma and lava cool,they form solid rock.
Where do most volcanoes occur?
Along diverging plate boundaries, mid-ocean rivers, or in subduction zones around the edges of oceans
What happens along the rift valley?
Along the rift valley,lava pours out of cracks in the ocean floor.This process gradually builds new mountains.
What is a volcanic neck?
An erosional remnant of the material that solidified in a volcanic pipe.
Basalt
An igneous rock that forms from lava
Porphyry
An igneous rock that has a mixed texture in which large crystals "float" in a predominately fine-grained matrix. Large crystals are called phenocrysts, which form in magma while it is still below Earth's surface. They before other crystals can grow, a volcanic eruption bring the magma to the surface, where it cools quickly to a finely crystalline mass.
Seismograph
An instrument used by seismologists to record primary, secondary, & surface waves from earthquakes
Tsunami
An ocean wave (seismic sea wave) that begins over an earthquake focus. (can reach 30 m high)
Types of Magma
Basaltic (50%), Andesitic(60%), Rhyloitic(70%)
Pangaea
Ancient landmass made up of all the continents that began to break apart about 200 mya
Granite
And igneous rock that forms below earth's surface
What rock do Composite Volcanoes form after cooling?
Andesite
50-60% silica, medium viscosity, medium explosivity. Subduction boundaries
Andesitic Magma
This type of magma generally results from the melting of the combination of oceanic and continental lithosphere.
Andesitic Magma
What is country rock?
Any preexisting rock that has been intruded by a pluton or altered by metamorphism.
Veins
Are deposits of minerals found within a rock fracture that are foreign to the country rock.
Fissure
Are long cracks in earth
Dikes
Are the major route of magma transport in the crust. Much like sills which are sheetlike igneous bodies, but dikes cut across the layers in bedded country rock and so are discordant intrusions.
Hot spot
Areas in Earth's mantle that are hotter than neighboring areas, forming melted rock that rises toward the crust
What happens as the discontinuous branch of Bowen's Reaction Series continues to cool?
As it continues to cool, reactions take where the minerals continuously change into another form moving it fro one type of magma to another.
What happens as the plates push together?
As the plates push together,one plate can sink beneath the other plate.
Smallest form of tephra
Ash
What can erupt from volcanoes that can fall to Earth forming pyroclastic igneous rocks?
Ash and ejecta.
Three types of lava
Ash, cinders, and bombs
Ophiolite Suites
Assemblages consist of deep-sea sediments, submarine basaltic lavas, and mafic igneous intrusions
How and where do magmas form?
At places in the lower crust and mantle where temperatures are high enough for partial melting of rock. Because minerals within a rock melt at different temperatures, the composition of magmas varies with temperatures, the composition of magmas varies with temperature. Pressure raises the melting temperate of rock, and the presence of water lowers it. Because melted rock is less dense than solid rock, magma rises through the surrounding rock, and drops of magma come together to form magma chambers.
Splish Splash! It is the largest of all igneous intrusions measure over 100 km2.
Batholith
irregularly shaped mass of coarse-grained igneous rocks that cover at least 100km2 and take millions of years to form. Common in interior of mountain chains.
Batholith https://o.quizlet.com/qQTaXlE-tcsmFxjKjdsFYQ_m.jpg
Vulcanian eruptions
Begin with huge, loud explosions followed by smaller ones, ash, dust, and other volcanic materials are blown into the air
Largest tephra
Blocks and bombs
Who published Bowen's findings?
Bowen had died at a young age and his coworkers published his findings crediting him.
Crater
Bowl - shaped depression that forms around the central vent at the summit of a volcano
crater
Bowl-shaped depression, usually less than 1 km in diameter, that forms around the central vent at the summit of a volcano.
Craters
Bowl-shaped depressions
Shield volcano
Broad volcano with gently sloping sides built by non explosive eruptions of basaltic lava that accumulates in layers
shield volcano
Broad volcano with gently sloping sides built by nonexplosive eruptions of basaltic lava that accumulates in layers.
What is pillow lava?
Bulbous masses of basalt resembling pillows formed when lava is rapidly chilled under water.
How are volcanoes created?
By powerful forces within earth, when two tectonic plates move together and one goes under the other. The rock in the mantle melts and becomes the magma. Melting rock produces gases that mix with magma. Rising magma soaks in a weak part of rock, and creates a magma chamber
In the continuous Branch of Bowen's Reaction Series, what crystalizes first?
Calcium-rich Plagioclase crystalizes first.
Also called scoria cones, these explosive volcanoes are noted for their small size and steep sides.
Cinder Cone Volcanoes
This type of small volcano is linked with eruptions of mostly pyroclastic material (i.e, not so much of other ejecta) that piles up around the vent.
Cinder Cone Volcanoes
Batholith
Coarse - grained, irregularly shaped, igneous rock mass that covers at least 100 km2, generally forms 10-30 km below Earth's surface, and is common in the interior of major mountain chains
Peridotite
Coarse-grained, dark greenish gray rock made up primarily of olivine with smaller amounts of pyroxene.
batholith
Coarse-grained, irregularly shaped, igneous rock mass that covers at least generally forms 10-30 km below Earth's surface, and is common in the interior of major mountain chains.
What do the collisions of this type produce?
Collisions of this type produced the volcanoes of the Andes Mountains in South America.
Also known as strato-volcanoes, these volcanoes include many of Earth's most destructive, including Mt. St. Helen's and Krakatoa.
Composite Volcanoes
Subduction zones are often lined with this type of volcano that dominates the Cascade mountain range.
Composite Volcanoes/ Startovolcanoes
This type of volcano forms from alternating layers of pyroclastic material and lava flows.
Composite Volcanoes/ Stratovolcanoes
What 4 landforms are created from ash and lava?
Composite volcanoes, lava plateaus, cinder cone volcanoes, and shield volcanoes
Ultramafic Rocks
Consist primarily of mafic minerals and contain less than 10 percent feldspar
Mafic rocks
Contain large proportions of pyroxense and olivines. These minerals are relatively poor in silica but are rich in magnesium and iron, from which they get their characteristic dark colors.
Diorite
Contains sill less silica and is dominated by plagioclase feldspar, with little or no quartz. Contain a moderate amount of the mafic minerals biotite, amphibole, and pyroxene. They tend to be darker than granite or granodiorite.
Volcanism
Describes all the processes associated with the discharge of magma, hot water, and steam
Divergent zones where lithosphere thinner and exert less pressure (cause of magma to form in notes)
Decrease in pressure
When do plutons cool?
Depending on their size and depth, they may not cool for thousands or millions of years.
Magnetometer
Device used to map the ocean floor that detects small changes in magnetic fields
These igneous intrusions cut through layers of sedimentary rock and may result from past fissure eruptions.
Dike
a pluton that cuts across pre-existing rock (layers)
Dike
How do dikes and sills differ?
Dikes are discordant and Sills are concordant. They are both tabular or sheetlike igneous bodies.
Crystallization
During crystallization, the water molecules take up fixed positions in the solidifying crystal structure, and they are n longer able to move freely, as they did when the water was liquid. All other liquids, including magmas, crystallize in this way. The first tiny crystals form a pattern. Other atoms or ions in the crystallizing liquid then attach themselves in such a way that the tiny crystals grow larger. Crystals grow large only if they have time to grow slowly. If the liquid solidifies very quickly, as a magma does when it erupts onto the cool surface of Earth, the crystals have no time to grow. Instead, a large number of tiny crystals form simultaneously as the liquid cools and solidifies.
What is another source of magma?
Earth's upper mantle, which is composed of rocks that contain mostly ferromagnesian silicates.
Type of lava: ash
Fine, rock particles (sand)
Intermittent volcano
Erupt at a fairly frequent intervals
Active volcano
Erupt constantly
Marine volcanoes
Erupting lava and other material piling up on an overriding plate to form these volcanoes
All crystaline rocks are igneous-True/False
False
All of the earth's internal heat was acquired very early in its history through meteoric impact and differentiation of the core. The earth's interior loses heat to space but does not currently receive heat through any known process- True/False
False
Igneous rocks include rocks deposited on lava flows by running water-True/False
False
In metamorphic rocks some melting is always required-True/False
False
Lithification is a metamorphic process-True/False
False
The 'texture' of a rock refers just to its feel-True/False
False
The colored strata layers of the Grand Canyon are said to be a form of foliation-True/False
False
The composition of a rock can be described as either being equant or inequant-True/False
False
When rock is melted within earth, typically the entire volume of rock is transformed from a solid state to a liquid- True/False
False
Pahoehoe
Fast, quick lava
Granite as slow cooling (evidence)
Fine-grained igneous rocks are evidence of former volcanism.
Extrusive Igneous Rocks
Fine-grained texture or glassy igneous rock formed from magma that erupts at Earth's surface as a lava and cools rapidly
Rapid cooling lava:
Forms either a fine-grained rock or a glassy one in which no crystals can be distinguished
What does the fractures in the crust allow magma to do?
Fractures in the crust allow magma to reach the surface.
Composite volcano
Generally cone shaped with concave slopes; built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers
seafloor spreading
Harry Hess; occurs along the crest of oceanic ridges; newly formed melt slowly rises toward the surface; most melt solidifies in the lower crust, but some escape to the seafloor and erupts as lava
Dormant volcano
Have become inactive, but people are not certain that they will erupt
Extinct volcano
Have not erupted within recorded history
How is magma made?
Heated rock in the sub-ducted plate melts into magma
High percentages of silica is linked with this type of viscosity.
High Viscosity
Lava plateau
High level areas where thin runny lava flows out of several rocks, made up of layers of lava
Flows less easily (high silica low temperature)
High vicosity
Unusually hot regions of the Earth's mantle where high temperature plumes of magma rise to Earth's surface
Hot Spot
Which one is formed in the highest temperature, igneous metamorphic or sedimentary rocks?
Igneous rocks
How are igneous rocks classified
Igneous rocks can be divided into two broad textural classes: coarse-grained rocks, which are intrusive and therefore cooled slowly; and fine-grained rocks, which are extrusive and cooled rapidly. Igneous rocks can also be classified on the basis of their silica content using a scale that runs from felsic (rich in silica) to ultramafic (poor in silica).
Where do igneous rocks form?
Igneous rocks form at spreading centers where plates move apart, along convergent boundaries where one plate descends beneath another, and at "hot spots" where hot mantle material ascends to the crust.
Isochron
Imaginary line on a map that shows points of the same age; formed at the same time
What is the best known volcanic catastrophy?
In 79 A.D. Mount Vesuvius erupted destroying the thriving Roman communities. Pompei was buried in 3m of pyroclastic materials. Herculaneum was buried in 20m of pyroclastic materials. It has erupted 80 times since.
Seismic wave
In an earthquake, the energy waves that move outward from the earthquake focus and make the ground quake.
Magnitude
In earthquake studies, a measure of energy released by an earthquake, measured by the Richter scale.
Pyroclasts
In more violent eruptions, pyroclasts form when fragments of lava are thrown high into the air. Volcanic ash is made up of extremely small fragments, usually of glass, that form when escaping gases force a fine spray of magma from a volcano. Bombs are larger particles hurled from the volcano and streamlined by the air as they hurl through it. As they fall to the ground and cool, these fragments of volcanic debris may stick together to form rocks.
Plate
In plate tectonics, a section of the Earth's lithosphere (crust & upper mantle) that moves around
Subduction zone
In plate tectonics, the area where an ocean-floor plate collides with a continental plate, and the denser ocean plate sinks under the less dense continental plate
Divergent boundary
In plate tectonics, the boundary between two plates that are moving away from each other
Convergent boundary
In plate tectonics, the boundary between two plates that are moving toward each other
Vent
In volcanic regions, an opening in Earth's surface through which can flow lava, ash, cinders, smoke, & steam
Hot spots (cause of magma to form in notes)
Increase in temperature
(cause of magma to form in notes)
Increase in water in the asthenosphere
Increasing pressure will do this to the melting point of rocks.
Increase it (more temperature would be needed to melt a certain material)
pluton
Intrusive igneous rock bodies, including batholiths, stocks, sills, and dikes, formed through mountain-building processes and oceanic-oceanic collisions; can be exposed at Earth's surface due to uplift and erosion.
Pluton
Intrusive igneous rock body, including batholiths, stocks, sills, and dikes, forms through mountain - building processes and oceanic-oceanic collisions; can be exposed at earths surface due to uplift and erosion
What are pyroclastic materials?
It is lava flows that is forcefully ejected into the atmosphere as particles. Pyroclastic materials the measure less than 2mm are called volcanic ash.
What happens to iron and magnesium if minerals crystalize simultaneously along the two branches of Bowen's Reaction Series?
Iron and Magnesium are depleted because they are used up in ferromagnesian silicates where calcium and sodium are used up in plagioclase feldspars.
stock
Irregularly shaped pluton that is similar to a batholith but smaller, generally forms 10-30 km beneath Earth's surface, and cuts across older rocks.
Stock
Irregularly shaped pluton that is similar to a batholiths but smaller, generally forms 5-30 km beneath earths surface, and cuts across older rocks
Intrusive Igneous Rock
Is one that has forced its way into the surrounding rock (called the country rock) and solidified without reach Earth's surface
Rhyolite
Is the extrusive equivalent of granite. This light brown to gray rock has the same felsic compositon and light coloration as granite, but it is much more fine-grained. May rhyolites are formed largely or entirely of volcanic glass.
Bowen's Reactions Series is supposed to account for what?
It accounts for the derivation of intermediate and felsic magmas from mafic magma.
Pressure below spreading ridges decreases causing what?
It causes the temperature to exceed the melting temperature, because pressure decreases.
When does a conduit known as a lava tube within a lava flow form?
It forms when the margins and upper surface of the flow solidify.
What does Intermediate magma contain?
It has a composition between felsic and mafic magma.
What does a laccolith look like?
It has a flat floor and is domed up in its central part giving it a mushroom-like geometry.
What is crystal settling?
It involves the physical separation of minerals by crystilization and gravitational settling. Once magma forms, it's composition may change by crystal settling.
What is a crater?
It is a circular depression at the summit, which most volcanoes have.
What is a mantle plume?
It is a cylindrical plume of hot mantle rock that rises from perhaps near the core-mantle boundary.
What is a shield volcano?
It is a dome-shaped volcano with a low, rounded profile built up mostly by overlapping basalt lava flows.
What is a volcano?
It is a hill or mountain that forms around a vent where lava, pyroclastic materials, and gases erupt.
What is a hot spot?
It is a localized zone of melting below the lithosphere that probably overlies a mantle plume.
What is assimilation?
It is a process by which magma reacts with preexisting rock called country rock, with which it come in contact.
What is stopping?
It is a process where rising magma detaches and engulfs pieces of country rock.
A belt of volcanoes and plutons is a result of what plate movement?
It is a result of an oceanic plate being subducted beneath either a continental plate or another oceanic plate.
What is a cinder cone?
It is a small, steep sided volcano made up of pyroclastic materials resembling cinders that accumulate around a vent.
What is a sill?
It is a tabular or sheetlike concordant pluton.
What is a composite Volcano?
It is a volcano composed of lava flows and pyroclastic layers, typically of intermediate composition and mudflows.
What is a batholith?
It is an irregularly shaped discordant pluton with at least 100 km^2 of surface area.
What is the definition of magma?
It is any mass of molten rock material below Earth's surface.
What is welded tuff?
It is ash paricles that are fused together.
What is the reason lava and magma retain heat so well?
It is because rocks conduct heat so poorly.
What is magma composed of?
It is composed of silicon and oxygen with lesser amounts of several other chemical elements.
The fact that assimlation occurs is indicated by what?
It is indicated by inclusions, incompletely melted pieces of rock that are fairly common in igneous rocks.
Igneous Rock
It is linked to the rate, and therefore the place, of cooling.
What does Mafic Magma contain?
It is silica poor and contains proportionately more calcium, iron, and magnesium. (Bassalt-Gabbro are the aphanatic and phaneritic rocks that crystalize from mafic magma. Bassalt is aphanatic. Gabbro is Phanaritic.)
What does Felsic magma contain?
It is silica rich and contains considerable sodium, potassium, and aluminum, but little calcium, iron and magnesium.(Rhyolite-Granite are the igneous rocks that crystalize and form from Felsic magma.)
What is the longest recorded volcanic eruption in shield volcanoes?
It is the Kileuea volcano in Hawaii which has been erupting since January 3, 1983.
What is a volcanic pipe?
It is the conduit connecting the crater of a volcano with an underlying magma chamber.
What is rhyolite Tuff?
It is the consolidation of ash, which forms pyroclastic tuff which is silica rich and light colored.
What are lava flows?
It is the magma that does not reach the surface and issues forth as streams of lava.
What is a laccolith?
It is the overlying rocks bowing upward forming an igneous body.
What are discordant plutons?
It is the plutons with boundaries that cut across the country rock's layering.
What is viscosity?
It is the resistance to flow.
What is the term for volcanic smog that residents of Hawaii came up with?
It is vog.
What is the geothermal gradient?
It is when the Earth's temperature increases with depth which relates to the origin of magma.
What is an aphanatic texture in minerals?
It is where individual minerals are too small to be seen without magnification. They usually indicate an extrusive origin.
What are columnar joints?
It is where mafic lava flows have a distinctive pattern of columns bounded by fractures.
What is the definition of volcanism?
It is where magma and associated products ascend through the crust and extrude onto the Earth's surface. (the magma ascends through fracturing that occurs.)
What is a phaneritic texture in minerals?
It is where minerals are clearly visible. They usually indicate an intrusive origin.
What is a porphorytic texture in minerals?
It is where minerals of markedly different size are present in the same rock.
What is a pressure ridge?
It is where pressure on the solidified crust of a still-moving lava flow causes the surface to buckle.
The plagoiclase forming under the rapid cooling conditions is zoned. What does that mean?
It means that is has a calcium rich core surrounded by zones progresivley richer in sodium.
What does it mean if a volcano is active?
It means that it has erupted during historic time.
What does it mean if a volcano is dormant?
It means that it has not erupted during historic time but could in the future.
What does a concordant pluton mean?
It means that plutons can have boundries that parallel the layering in the country rock.
Some pegmatites are mafic or intermediate in composition meaning they are what kind of igneous rocks?
It means they are baggro and diorite pegmatites.
Where does most magma originate in correspondence to Earth?
It originates within the Earth's upper mantle or lower crust at or near divergent and convergent plate boundaries.
What is the volume of a magma chamber?
It ranges from a few to many hundreds of cubic kilometers of molten rock within the otherwise solid lithosphere.
What is a pegmatite igneous rock?
It refers to a particular texture rather than a specific composition, but most pegmatites are composed mostly of quartz, potassium felspar, and sodium rich plagioclase, thus corresponding closely to granite.
What happens if lava cools to fast?
It's constituent atoms do not have time to become arranged in the ordered, three-doimensional frameworks of minerals.
Uniformitarianism
James Hutton's principle that the physical, chemical, and biological laws that operate today have also operated in the geologic past (the present is the key to the past)
Mushroom shaped, these intrusions are bigger than sills, often up to 16 km across.
Laccolith
lens-shaped pluton with a round top and flat bottom. Mushroom Shape (shield shape; shield volcano)
Laccolith https://o.quizlet.com/qQTaXlE-tcsmFxjKjdsFYQ_m.jpg
intrusive (underground) igneous rock bodies
Pluton
Medium sized tephra
Lapilli
Caldera
Large crater, up to 50 km in diameter, that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption
caldera
Large crater, up to 50 km in diameter, that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption.
Plutons
Large igneous bodies formed deep in Earth's crust. They range in size from a cubic kilometer to hundreds of cubic kilometers.
Magma chambers
Large pools of molten rock that form in the lithosphere as rising magmas melt and push aside surrounding solid rock.
Where are large volcanoes found?
Large volcanoes are found along the Great Rift Valley in East Africa.
hot spot
Large, sloping volcano built by violent eruptions of volcanic fragments and lava that accumulate in alternating layers.
Slow cooling lava:
Larger crystals are formed
Aa and pahoehoe are types of these...
Lava Flows
Which eruptions are some of the most violent and destructive?
Lava dome eruptions.
What kind of eruptions are the most and least dangerous?
Lava flows are the least dangerous and explosive eruptions are very dangerous.
Tephra
Lava that is blasted into the air by violent volcanic eruptions & solidifies as it falls to the ground as ash, cinders, & volcanic bombs
Pipe
Long tube in the ground that connects magma chamber to surface
Rift valley
Long, narrow depression that forms when continental crust begins to separate at a divergent boundary
Fissures
Long, narrow vents
Flows easily (Low silica high temperature)
Low viscosity
Lava
Magma that flows out into earth's surface
All igneous rocks derive from?
Magma.
Magmas form in a number of geologic environments including?
Magmas can form in hot spots, divergent plate boundaries and subduction plates.
What are the major island arcs?
Major island arcs include apan,New Zealand, the Aleutiansand, and the Caribbean islands.
Where is a common place for cinder cones to form?
Many cinder cones form on the flanks or within the calderas of larger volcanoes and represent the final stages of activity, particularly in areas of basaltic volcanism.
Where do many volcanoes form near?
Many volcanoes form near converging plate boundaries,where two oceanic plates collide.
Fluid-induced melting
Melting of rock induced by the presence of water that lowers its melting point. Water content is a significant factor in the melting of sedimentary rocks, which contain an especially large volume of water in their pore spaces, more than is found in igneous or metamorphic rocks.
Magma
Molten, or hot and melted rock below earth's surface
Where was the worlds largest eruption since 1912?
Mount Pinatubo in the Pillippines erupted on June 15 in 1991 where huge quantities of gas and ash were discharged. 722 deaths.
Does the majority of magma reach Earth's surface?
NO. The majority of magma cools and crystalizes underground forming different types of igneous bodies called plutons.
Mineral
Naturally occurring; Generally inorganic; solid substance; orderly crystalline structure; definite chemical composition example: quartz, hornblende, feldspar
Does a mineral have to reach all three types of magma in order to crystalize?
No it could be at any type during crystalization and suddenly be ejected onto the surface as lava.
Does cool magma or lava move more readily than hotter magma or lava?
No it does not. It is the other way around.
This is the largest known volcano in the Solar System. (Don't need to know)
Olympus Mons (on Mars)
Granite
One of the most abundant intrusive igneous rocks, contains about 70 percent silica. Mineral composition includes abudant quart and orthoclase feldspar and a smaller amount of plagioclase feldspar. These light-colored felsic minerals give granite its pink or gray color. Granite also contains small amounts of muscovite and biotite micas and amphibole.
Does the lava in shield volcano's pose threats to humans?
No the lava usually rises to the surface with little explosive activity posing little danger to humans. They are usually quiet eruptions.
Do minerals crystalize simultaneously from cooling magma?
Not all of them crystalize simultaneously from cooling magma. They crystalize in a predictable sequence.
H20 and Co2 dissolved in magma. Easily escape basalt magma since so hot and fluid , explosive escape andesitic and rhyolitic magma since less hot and fluid (Extra info just type ok in box)
Ok
vent
Opening in Earth's crust through which lava erupts and flows out onto the surface.
Vent
Opening in earths crust through which lava erupts and flows out onto the surface
Vents
Openings through which volcanic materials erupt out
Hot, quick flowing lava on land forms ropelike in appearance
Pahoehoe https://farm3.staticflickr.com/2162/2342203011_3e07d5d9cf_m.jpg
Type of lava: cinders
Pebble-sized particles
Lava underwater forms pillow-like appearance
Pillow Lava/ Basalts https://o.quizlet.com/ztsP6aoQVUEUtPnIwwTH3Q_m.jpg
Divergent boundary
Place where two of earths tectonic plates are moving apart; is associated with volcanism, earthquakes, and high heat flow, and is found primarily on the sea floor
Convergent boundary
Place where two tectonic plates are moving toward each other; is associated with trenches, islands arcs, and folded mountains
Transform boundary
Place where two tectonic plates slide horizontally past each another; is characterized by long faults and shallow earthquakes
What are the only minerals in the Continuous Branch of Bowen's Reaction Series?
Plagioclase feldspars which are nonferromagnesian silicates are the only minerals.
What does plate movement cause?
Plate movements cause the crust to fracture.
What causes a decrease in pressure on the already hot rocks at dept, thus initiating melting?
Plate separation at ridges.
This godly name is the general term for underground igneous bodies of rock.
Pluton
What does lava harden into?
Rock
Tephra
Rock fragments, classified by size, that are thrown into the air during a volcanic eruption and fall to the ground
tephra
Rock fragments, classified by size, that are thrown into the air during a volcanic eruption and fall to the ground.
What happens to the melting temperatures of rocks at depth in Earth?
Rocks at depth are hot but remain solid because their melting temperature rises with increasing pressure.
Partial melting
Rocks do not melt completely because the minerals that compose them melt at different temperatures. The fraction of rock that has melted at a given temperature is called a partial melt.
Sedimentary rocks
Rocks made of bits and pieces of other rocks
Metamorphic rock
Rocks that were once igneous, sedimentary, or metamorphic rock that has been exposed to pressure or heat. Often forms under water
What strongly controls magma and lava's viscosity?
Silica content controls magma and lava's viscosity.
These large volcanoes have broad gentle slopes resulting from basaltic magma.
Shield Volcanoes
This is the largest type of all volcanoes.
Shield Volcanoes
What kind of volcanoes are the most common in ocean basins?
Shield Volcanoes
These flat intrusions form when magma squeezes into parallel cracks in between layers of sedimentary rock.
Sill
magma that intrudes parallel to layers of rock (typically horizontal; window sill)
Sill
Type of lava: bombs
Size of baseball oars
Aa
Slow, quiet lava
Stocks
Smaller plutons
Why is the processes in magma that brings about chemical change important?
So magma may evolve from one kind into another.
Where do some hot spot volcanoes lies?
Some hot spot volcanoes lie close to plate boundaries. Others lie in the middle of plate.
What are some volcanoes results?
Some volcanoes are the result of "hot spots" in Earth's mantle.
Cinder cone
Steep sided, generally small volcano that is built by the accumulation of tephra around the vent
cinder-cone volcano
Steep-sided, generally small volcano that is built by the accumulation of tephra around the vent.
The irregular shaped plutons are similar to, but smaller than batholiths...
Stocks
similar to batholiths but smaller in size (>100km2)
Stocks
Paleomagnetism
Study of earths magnetic record using data gathered from iron - bearing minerals in rocks that have recorded the orientation of earths magnetic field at the time of the formation
Fault
Surface along which rocks break & move.
Pyroclastic flow
Swift moving, potentially deadly clouds of gas, ash, and other volcanic material produced by a violent eruption
pyroclastic flow
Swift-moving, potentially deadly clouds of gas, ash, and other volcanic material produced by a violent eruption.
Slab pull
Tectonic process associated with convection currents in earths mantle that occurs as the weight of the subducting plate pulls the trailing lithosphere into a subduction zone
Ridge push
Tectonic process associated with convection currents in earths mantle that occurs when the weight of an elevated ridge pushes an oceanic plate toward a subduction zone
What are the most important controls on the mobility of magma and lava?
Temperature and composition.
This is another name for pyroclastic material, including particles of varied sizes.
Tephra
Some of the most economically important mineral deposits in the world are formed by differential settling of crystals in magma chambers. Examples would be:
The Bushveld deposit in South Africa and and the Stillwater deposit in Montana, just north of Yellowstone National Park.
Where does the Ring of Fire includes volcanoes?
The Ring of Fire includes the volcanoes along the coasts of North and South America and those in Japan and the Philippines.
Ring of Fire
The area around the Pacific plate where volcanoes & earthquakes are common due to tectonic movement
metamorphism
The changes in mineral composition and texture of a rock subjected to high temperatures and pressures within earth.
What are the common and uncommon places volcanism occurs?
The common places volcanism occurs are at divergent and convergent plate boundaries. The uncommon places volcanism occurs at are ocean basins and on continents that are not near either of these boundaries.
sorting
The degree of similarity in particle size in sediment or sedimentary rocks
Inner core
The dense, solid center of the Earth, formed mostly of iron & nickel.
Convection current
The driving force of plate tectonics, in which hot, plastic-like material from the mantle rises, moves horizontally, cools, and sinks back to the mantle
What happens if magma cools to rapidly?
The early formed minerals do not have time to react with the melt therefore the ferromagnesian silicates in the discontinuous branch can be in one rock.
What happens when atoms in a solid which are in constant motion are heated?
The energy of motion exceeds the binding forces and the solid melts.
How do scientists study volcanoes?
The eruptions according according to their violence and how often they erupt
Seafloor spreading
The hypothesis that new ocean crust is formed at mid - ocean ridges and distorted at deep sea trenches; occurs in a continuous cycle of magma intrusion and spreading
Batholiths
The largest plutons, are great irregular masses of coarse-grained igneous rock that, by definition, cover at least 100 km2
What happens to the continuous branch of Bowen's Reaction Series if it continues to cool?
The magma will continue to cool and the calcium-rich plagioclase will react with the melt, and plagioclase containing porportionatly more sodium crystalizes until all of the calcium and sodium are used up.
Basalt
The most abundant igneous rock of the crust, and it underlies virtually the entire seafloor. This dark gray to black rock is the fine-grained extrusive equivalent of gabbro.
What are dikes intruded into?
They are intruded into preexisting fractures pr where fluid pressure is great enough for them to form their own fractures as they move upward.
What are sills intruded into?
They are intruded into sedimentary rocks, and piles of volcanic rock. They are intruded between layers in country rock when the fluid pressure is great enough for the magma to actually lift the overlying rocks.
Earthquake
The movement of the ground caused by waves from energy released as rocks move along faults
Pangea
The name Alfred Wegener gave to the large landmass, made up of all continents, that he believed existed before it broke apart to form the present continents
What happens when an oceanic and continental plate collide?
The oceanic plate slides under the continental plate, this causes a volcano to form
Crust
The outermost layer of Earth, from 5 km to 60 km thick
What plays an important role in determining the mineral composition of igneous rocks?
The parent magma.
What is used to explain the origin of magma at subduction zones?
The phenomenon of partial melting is used to explain the origin of magma at subduction zones.
Focus
The point in the Earth's interior where earthquake energy is released
Epicenter
The point on the Earth's surface directly above an earthquake's focus
What happens to the pressure when magma rises toward the surface for a volcanic eruption?
The pressure is reduced and the contained gases begin to expand. This could expand big enough to cause an explosion (eruption).
Fractional crystallization
The process by which the crystals formed in a cooling magma are segregated from the remaining liquid rock.
Stokes' Law
The rate at which crystals settle depends both on their density and size and on the viscosity of the remaining magma. That rate can be calculated using a mathematical relationship:
parent rock
The rock from which a metamorphic rock formed.
Country Rock
The rock surrounding an igneous intrusion
Crater
The steep-walled depression at the top of a volcanic vent
What are plutons?
They are intrusive igneous bodies.
What are calderas?
They are larger rimmed depressions on volcano's. They form following voluminous eruptions where a magma chamber drains and the mountains summit collapses into the vacated space. ex(crater lake)
Plate tectonics
The theory that Earth's crust & upper mantle (lithosphere) are broken into sections, called plates, that slowly move around
Seafloor spreading
The theory that magma from Earth's mantle rises to the surface at mid- ocean ridges and cools to form new seafloor, which new magma pushes away from the ridge
Mantle
The thickest layer of Earth, between the outer core & the crust, described as plastic-like
Andesite
The volcanic equivalent of diorite. Andesite derives its name from the Andes, the volcanic mountain belt in South America.
The magma is thick and sticky when...?
There is a lot of silica
Geothermal energy
Thermal energy from magma bodies inside Earth used to produce electricity with very little environmental pollution
What do all volcano's have beneath the surface?
They all have conduits leading to a magma chamber beneath the surface.
What are fissure eruptions?
They are a volcanic eruption in which lava or pyroclastic materials issue from a long, narrow fissure (crack) or group of fissures.
What are lava domes?
They are bulbous steep-sided mountains formed by viscous magma moving upward through a volcanic conduit.
When are Plutonic and Intrusive igneous rocks formed?
They are formed when magma cools below the surface, that is, from magma intruded into the crust.
How are interconected pillows formed?
They are formed when the remaining fluid from inside one pillow lava breaks through the crust of the pillow where it repeats the process resulting in interconnected pillows.
What do we know about the origin of the largest plutons?
They are not fully understood yet.
What are basalt plateaus?
They are plateau built up by horizontal or nearly horizontal overlapping lava flows that erupted from fissures.
What are magma chambers?
They are the reservoirs where magma accumulates.
What are pyroclastic sheet deposits?
They are vast, sheetlike deposits of felsic pyroclastic materials erupted from fissures.
What are both obsidian and pumice varities of?
They are volcanic glass.
What are vesicles?
They area small holes or cavities formed by gas trapped in cooling lava.
What can some volcano eruptions be caused from?
They can be caused from the injection of sills.
What can the extrusive and intrusive members of each pair be distinguished by?
They can be distinguished by texture.
What are other things volcano's can errupt?
They can errupt lapilli-pyroclastic materials that measure from 2-64mm, blocks-angular pieces of rock ripped from volcanic conduit, and bombs- which have a twisted streamlined shape which shows they were ejected as globs of magma.
What kind of rocks does a pyroclastic or fragmental texture characterize?
They characterize igneous rocks formed by explosive volcanic activity.
How do Composite Volcanoes differ from Shield volcanoes and cinder cones?
They differ in shape and composition.
Where do magma chambers exist?
They exist below spreading ridges where the crust in thin. They are at a depth of about a few kilometers.
When do Intrusive igneous bodies called plutons form?
They form when magma cools below the Earth's surface.
How do all igneous rocks form?
They form when magma or lava cools and crystalizes, or by the consolidation of pyroclastic materials ejected during explosive eruptions.
How do lahar's form?
They form when rain falls on unconsolidated pyroclastic materials creating a muddy slurry that moves downslope.
What do the members of a pair of rocks have in common and what don't they have in common?
They have the same composition but different textures.
Igneous rocks look different depending on what?
They look different depending on where they are during the crystalizing stage.
What parts of the continent do igneous rocks make up?
They make up large parts of the continent and all of the oceanic crust, which forms continuously at divergent plate boundries.
Why do lava flows rarely cause fatalities?
They rarely cause fatalities because they move so slow and because they are fluid, they follow existing low areas. Once a volcano erupts, determining its path it easy leaving plenty of time for evacuation.
How long do lava flows and pyroclastic flow deposits remain hot for?
They remain hot for months or years.
What do geologists use to classify igneous rocks?
They use texture and composition.
Strombolian eruptions
Thick magma in the vent and builds pressure and this eruption turns into a cinder cone volcano
What is the discontinuous branch of Bowen's Reaction Series?
This branch contains only ferromagnesian silicates, where one mineral changes to another over specific temperature ranges. A temperature range has to be reached before a mineral will begin to crystalize.
Magmatic stopping
Three ways magma makes space for itself:
What happens through subduction?
Through subduction,the older,denser plate sinks into the mantle and creates a deep-ocean trench.
"All lava is magma is truer than "all magma is lava"-True/False
True
Bedrock covered in oil is not an outcrop of rock-True/False
True
Compaction and cementation is a sedimentary process-True/False
True
Sand is not a rock-True/False
True
Very early in earth's history, it was so hot that the surface was likely entirely molten-True/False
True
sediment
Unconsolidated particles created by the weathering and erosion of rock by chemicl precipitation from solution in water, or from the secreations of organisms, and transported by water, wind, or glaciers
hot spot
Unusually hot area in Earth's mantle that is stationary for long periods of time, where high-temperature plumes of mantle material rise toward the surface.
Hot spot
Unusually hot area in earths mantle where high - temperature plumes of mantle material rise toward the surface
The internal resistance to flow of a material is that minerals...
Viscosity
when the magma in a volcano conduit solidifies
Volcanic Neck https://o.quizlet.com/qQTaXlE-tcsmFxjKjdsFYQ_m.jpg
Where do volcanic belts form?
Volcanic belts form along the boundaries of Earth's plates.
Dacite
Volcanic equivalent of granodiorite
Lavas
Volcanic rocks formed from flowing lavas range in appearance from smooth and ropy to sharp, spiky, and jagged, depending on the conditions under which they are formed
What are extinct or inactive volcano's?
Volcano's that show no sign of ever erupting.
Where is another place that volcanoes form?
Volcanoes also form along diverging plate boundaries on land.
Are volcanic gases dangerous?
Yes. Most of them dissipate into the atmosphere really fast however on some occasions they have been fatal.
Is it common for the magma to cool to fast in the continuous branch of Bowen's Reaction Series?
Yes. Often times the cooling is too rapid for a complete transformation from calcium-rich to sodium-rich plagoiclase to take place.
temperature silica content
___________ and _______ affect the viscosity of magma
Oxide
a binary compound of oxygen
Magma
a body of molten rock found at depth, including any dissolved gases and crystals
unconformity
a break in the rock record produced by non deposition and erosion of rock units
Hydrolysis
a chemical weathering process in which minerals are altered by chemically reacting with water and acids
diagenesis
a collective term for all the chemical, physical, and biological changes that take place after sediments are deposited and during and after lithification
soil
a combo of mineral and organic matter, water and air, the portion of the rigolith that supports plant growth
interface
a common boundry where different parts of a system interact
Granitic
a compositional group of igneous rocks indicating that the rock is composed of almost all light colored silicates
Basaltic
a compositional group of igneous rocks indicating that the rocks contains substantial dark silicate minerals and calcium rich plagioclase fledspar
Bowens Reaction Series
a concept proposed by N. L. Bowen that illustrates the relationships between magma and the minerals crystallizing from it during the formation of igneous rocks
Mid Ocean Ridge
a continuous mountainous ridge on the floor of all the major ocean basins and varying in width from 500 to 5000 kilometers (300 to 3000 miles). The rifts at the crests of these ridges represent divergent plate boundaries.
rift valley
a deep, down-faulted structure that exists on the axis of most ridges which is a broad linear swell along divergent plate boundary
what is the definition of a caldera?
a depression that is formed when the sides or top of volcano collapse into the emptied magma chamber
Crater
a funnel-shaped depression at the summit of most volcanic cones, generally less than 1 km in diameter
Molecule
a group of atoms bonded together
Continental Drift
a hypothesis credited to alfred wegener, which suggested that all present continents once existed as a single supercontinent. Further beginning about 200 million years ago, the supercontinent began breaking into smaller continents, which then drifted to their present positions
Theory
a hypothesis that has survived extensive scrutiny when other competing hypotheses have been eliminated; well-tested and widely accepted view that the scientific community agrees best explains certain observable facts
Seafloor Spreading
a hypothesis, first proposed in the 1960s by Harry Hess, which suggested that new oceanic crust is produced at the crests of mid-ocean ridges, which are the sites of divergence.
Batholith
a large mass of igneous rock that formed when magma was emplaced at depth, crystalized, and subsquently exposed to erosion
breccia
a sedimentary rock composed of angular fragments that were lithified.
conglomerate
a sedimentary rock composed of rounded, gravel size particles
clastic
a sedimentary rock texture consisting of broken fragments of preexisting rocks
Mohs Hardness Scale
a series of 10 minerals used in determining hardness
island arc
a string of volcanoes that form as the result of subduction of one oceanic plate beneath a second oceanic plate
cross-bedding
a struture in which relativley thin layers are inclined at an angle to the main bedding. Cross-bedding is formed by currents of wind or water.
Viscosity
a substance's internal resistance to flow
viscosity
a substance's internal resistance to flow
viscosity
a substances internal resistance to flow
Periodic Table
a table of elements found on Earth.
Sill
a tabular igneous body that was intruded parallel to the layering of preexisting rock
hypothesis
a tentative or untested explanation for how or why things happen in the manner observed
Vesicular
a term applied to aphanitic igneous rocks that contain many small cavities called vesicles
foliation
a term for linear arrangement of textural features often exhibited by metamorphic rocks.
Condult
a tubelike structure that allows lava to reach the surface
conduit
a tubelike structure that allows lava to reach the surface
dike
a tubular shaped intrusive igneous feature that cuts through the surrounding rock
compaction
a type of lithification in which the weight of overlying material compresses more deeply buried sediment. It is most important in the fine grained sedimentary rocks like shale.
Caldera
a volcanic crater that has a diameter of >1 kilometer and is produced by a collapse following a massive eruption (3 types; crater lake, Hawaiian, and yellowstone)
volcano
a weak spot in the crust where magma has come to the surface
A sill is a. a sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock b. a cooled layer of lava c. an intrusion formed within the magma chamber of a volcano d. a sheetlike intrusion that cuts across preexisting layers
a. a sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock
c. komatiite d. rhyolite
a. andesite
Is a laccolith a. concordant or b. discordant as an intrusion?
a. concordant
As compared to coarse grained igneous rocks, all fine grained igneous rocks a. cool and solidify more quickly b. cool and solidify more slowly c. solidify at higher temps d. solidify at lower temps
a. cool and solidify more quickly
Which type of magma has the greatest silica content a. felsic b. intermediate c. mafic d. ultramafic
a. felsic
If a body of magma becomes for felsic, its viscosity will a. increase b. decrease c. stay the same
a. increase
When magma crystallizes, ____ are formed. a. intrusive igneous rocks, b. volatiles c. extrusive igneous rocks d. pyroclastic debris
a. intrusive igneous rocks
Due to fractional crystallization and assimilation of surrounding host rock, most magmas that rise slowly through the crust evolve chemically to become a. more felsic b. more mafic c. dominated by nonsilicate minerals
a. more felsic
In Bowen's discontinuous reaction series, the first mineral to crystallize from a mafic melt is a. olivine b. plagioclase c. pyroxene d. quartz
a. olivine
Stoping by magmas occurs when a. pieces of surrounding country rock are broken off and assimilated b. the magma stops flowing and starts to solidify c. the magma becomes fully solidified to form intrusive rock d. the magma alters a thin rind of surrounding country rock
a. pieces of surrounding country rock are broken off and assimilated
Cooling rate
affects crystal size
Differentiation
all of the processes by which earth came to its present interior structure
what is volcanism?
all the processes associated with the discharge of magma, hot fluids, and gases
If a body of magma is subjected to fractional crystallization, the rock that results is expected to be a. identical in chemical composition to the magma b. more mafic than the magma c. more felsic than the magma
b. more mafic than the magma
Composite Volcano
also called a stratovolcano, large, but smaller than a Shield Volcano, located at convergent boundaries, last as long as their is a convergent boundary going on, predominantly andesitic lava. Ex: Mount St. Helens
shock metamorphism
also known as impact metamorphism, shock affects on rocks
talus
an accumulation of rock debree at the base of a cliff
hotspot
an area where magma from deep within the mantle melts through the crust above it
magnitude
an estimate of the amount of energy released at the source of the earthquake; measured by the Richter scale which measures the amplitude of the largest seismic wave recorded on a seismogram; Moment magnitude measures the total energy released during an earthquake
spheroidal
any weathering process that tends to produce a spheroidal shape from an initially blocky shape.
Hot spots
areas in Earths mantle that are hotter than neighboring areas, are also the sites of volcanoes.
decompression melting
as material rises and the pressure decreases below a critical point, the solid rock melts spontaneously, without the introduction of any additional heat--this produces the greatest volume of magma anywhere on Earth
ophiolite suites
assemblages that consist of deep sea sediments, submarine basaltic lavas, and mafic igneous intrusions.
pillow lava
at the divergent boundary on the ocean floor, eruptions often form huge piles of lava
crater
at the top of a volcano, around the vent, a bowl-shaped depression is formed
radiation
atoms with unstable nuclei that break apart over time, producing smaller particles in a process called radioactivity
Most commonly, felsic igneous rocks a. contain more iron and magnesium than intermediate rocks b. are lighter in color than mafic rocks c. are darker in color than mafic rocks d. are found in oceanic crust
b. are lighter in color than mafic rocks
Coarse grained gabbro is most similar in mineral composition to fine grained a. andesite b. basalt c. komatiite d. rhyolite
b. basalt
If the volatile content of magma is increased, its viscosity will a. increase b. decrease c. stay the same
b. decrease
Is a dike a. concordant or b. discordant as an intrusion?
b. discordant
When rock is partially melted, the chemistry of the melt is a. more mafic than the original chemistry of the rock b. more felsic than the original chemistry of the rock c. identical to the original chemistry of the rock d. completely unpredictable
b. more felsic than the original chemistry of the rock
Bowen's continous reaction series describes the crystallization behavior of a single mineral a. olivine b. plagioclase c. pyroxene d. quartz
b. plagioclase
A blob like igneous rock body that has cooled beneath the surface of Earth is called a a. guyot b. pluton c. lava flow d. andesite
b. pluton
Pegmatites, which occur in dikes, are unusual among shallow intrusive rocks in that they _ a. possess porphyritic texture b. possess exceptionally coarse grains c. are mineralogically identical to the extrusive rock basalt d. are glassy, cooling so rpaidly that crystals do not have time to form
b. possess exceptionally coarse grains
The geotherm is the rate of change of a. pressure with depth in Earth's interior b. temp with depth in earth's interior c. temp with altitude in earth's atmosphere d. temp with latitude on earth's surface
b. temp with depth in earth's interior
discordant intrusions
batholiths and stocks (cut across layers of the county rock that they intrude)
principle of lateral continuity
beds originate as continuous layers that extend in all directions until they eventually thin out or grade into a different sediment type
compare and contrast batholith and laccoliths
both forms of pluton.both below earth's surface. batholith larger. laccoliths smaller and are lens shaped. both are generally comprised of granite
moho
boundary between the crust and the mantle; P wave velocities increase at the Mojo, Seismic waves refracts as they cross the Mojo
D" layer
boundary between the rocky lower mantle and the liquid outer core
crater
bowl-shaped depression that forms around the central vent at the summit of a volcano
Crater
bowl-shaped depression that forms at the summit of a volcano
crater
bowl-shaped depression that's forms around the central vent at the summit of a volcano
shield volcano
broad volcano with gently sloping sides built by nonexplosive eruptions of basaltic lava that accumulates in layers
Shield volcano
built by nonexplosive eruptions; accumulates in layers
All other factors being equal. intrusive rocks that form deep within earth __ than intrusive rocks that cool near the surface a. are more felsic b. contain a smaller proportion of volatiles c. cool more slowly d. cool more rapidly
c cool more slowly
Radioactive isotopes, differentiation of Earth's iron core, gravity-driven compression, and meteoric bombardment all caused early earth to a. glow brighter than the sun b. be much cooler than at present c. be much hotter than at present d. be much more oblong than at present
c. be much hotter than at present
Volatiles refer to substances that a. crystallize most rapidly out of a melt b. melt immediately upon contact with a hot body of magma c. have a tendency to evaporate and are stable as gases
c. have a tendency to evaporate and are stable as gases
Geologically, melts are equivalent to both a. felsic and mafic magmas b. felsic and mafic lavas c. lavas and magmas d. fine grained and coarse grained igneous rocks
c. lavas and magmas
The difference between lava and magma is that a. magma is light in color and lava is dark b. magma usually has mafic composition an lava usually has felsic composition c. magma is found beneath the Earth's surface, whereas lava has reached the surface d. magma flows more quickly than lava
c. magma is found beneath the Earth's surface, whereas lava usually has reached the surface
A volcano emits ash, which falls from the sky, settles in layers and is eventually cemented. The resultant rock is termed a. pumice b. granite c. tuff d. ignimbrite
c. tuff
Important volatiles in magmas include a. iron and magnesium rich minerals b. potassium and aluminum c. water and carbon dioxide d. ricrinitrotoluene and nitroglycerin
c. water and carbon dioxide
refraction
change in the direction of waves as they enter shallow water; the portion of the wave in shallow water is slowed which causes the waves to bend and align with underwater contours
contact metamorphism
changes in rock caused by the heat from a nearby magma body
Density
defined as mass per unit of volume; determines how plates react at subduction zones,
hydrothermal metamorphism
chemical alterations that occur as hot, ion rich water circulates through fractures in rock.
Ring of Fire
circum pacific ring of fire where most active volcanoes are found
gabbro
coarse-grained, dark gray intrusive igneous rock--abundant mafic minerals
peridotite
coarse-grained, dark greenish gray rock made up primarily of olivine with smaller amounts of pyroxene
Batholith
coarse-grained, irregularly shaped, igneous rock mass
batholiths
coarse-grained, irregularly shaped, igneous rock mass that covers at least 100 km2, generally forms 10-30 km below earth's surface, and is common in the interior of major mountain chains
upper mantle
composed of peridotite, an iron and magnesium rich rock ; extends from the Mojo to 660 km thick.
the most explosive volcanoes are known as...?
composite volcanoes
P waves
compression waves; can travel through all materials; first to arrive at a recording station but have the lowest amplitude.
Trace Elements
concentration of one type of rock
mafic rocks
contains large proportions of pyroxenes and olivine. relatively poor in silica but rich in magnesium and iron (dark in color)
diorite
contains less silica and is dominated by plagioclase feldspar, with little or no quartz.
These two things
control the force of a volcano's eruption.
batholith
course-grained, irregularly shaped igneous rock mass that covers at least 100 km squared, generally forms 10-30 km below earth's surface, and is common in the interior of major mountain chains
Mold
created when a shell is buried and then dissolved by underground water.
carbonic acid
created when carbon dioxide dissolves in raindrops
Cast
created when the hollow spaces of a mold are filled
A dike is a. a sheetlike intrusion that lies parallel to surrounding layers of sedimentary rock b. a cooled layer of lava c. an intrusion formed within the magma chamber of a volcano d. a sheetlike intrusion that cuts across preexisting layers
d. a sheetlike intrusion that cuts across preexisting layers
Igneous rocks a. are formed through the freezing of a melt b. can be produced at the surface of the earth as well as deep below the surface c. are the most common type of rocks within earth d. all of the above
d. all of the above
Obsidian a. is volcanic glass b. possesses conchoidal fracture c. typically is felsic in composition d. all of the above
d. all of the above
The formation of magma within earth is not caused by which of the following processes? a. decompression b. addition of volatiles c. transfer of heat from adjacent magma or very hot rocks d. loss of volatiles to the atmosphere
d. loss of volatiles to the atmosphere
Coarse grained granite is most similar in mineral composition to fine grained a. andesite b. basalt c. komatiite d. rhyolite
d. rhyolite
As compared to mafic igneous rocks, all felsic igneous rocks a. cool and solidify more quickly b. cool and solidify more slowly c. solidify at higher temps d. solidify at lower temps
d. solidify at lower temps
Mafic
dark silicates and calcium rich fledspar, higher density than granitic rocks, comprise the ocean floor and many volcanic islands
density
density of rocks increases towards the center of the planet; upper mantle rocks density=3.3 g/cubic cm; lower mantle rocks=5.6 and undergo mineral phase change
800 c and 1200 c
depending on their composition, most rocks begin to melt at temperature between
veins
deposits of the minerals found within a rock fracture that are foreign to the country rock.
Volcanism
describes all the processes associated with the discharge of magma, hot fluids, and gases
volcanism
describes all the processes associated with the discharge of magma, hot fluids, and gases
volcanism
describes all the processes associated with the discharge of magma, hot water, and steam
Lithology
descripition of a rocks physical characteritics
classification of sedimentary rocks
detrital, chemical, and organic
compression
differential stress that shortens a rock body
Agents of Chemical Weathering
dissolution when certain materials dessolve in water, oxidation when oxygen combines with iron to form iron oxide, hydrolysis when any substance reacts with water, spheroidal weathering wears down sharp edges making them rounded
Syncline
down folded or troughs of rock layers (youngest strata are in the center)
Basin
downwarped circular features; younger rocks are in the center (type of fold)
tephra
erupted materials from a volcano
tephra
erupted materials. It can be pieces of lava that solidified during the eruption, or pieces of the crust carried by the magma before the eruption
nonexplosive
eruption at divergent tend to be ________
andesitic
eruption intermediate
rhyolitic
eruption very
fold
evidence that rocks can bend without breaking; usually the result of deformation in high-temperature and pressure environmnets and compressional stress
Oblique- slip fault
exhibit both a strike-slip movement and a dip-slip movement
Shield
expansive, flat region composed largely of deformed igneous and metamorphic rocks
plutons
exposed at Earth's surface as a result of uplift and erosion and are classified based on their size, shape and relationship to surrounding rocks
lower mantle
extends from the transition zone to the liquid core; earths largest layer, 56% of earths volume; olivine and pyroxene are converted into perovskite.
flood basalts
extensive thick sheets of basalt form large plateaus
pegmatites
extremely coarse grained granite cutting across much finer grained country rock--crystallize from a water-rich magma in the late stages of solidification
subduction
happens when overall density must be greater than underlying asthenospher; lithosphere sinks into the mantle; lithospheric mantle drives subduction
Amber
hardened resin of ancient trees; effective at preserving insects
Shield volcanoes
have sides with gentle slopes. They are made of basaltic lava.
Cinder Cone Volcanoes
have steep sides and are generally small, composed of any type of magma depending on the location, has a short "life cycle" at most can last for decades. Ex: Paricutin (Mexico)
Composite volcanoes
have steep sides and are made of silica-rich lava and tephra. Their eruptive forces vary.
Cinder cone volcanoes
have steep sides. They are made of tephra, lava cooled into different size pieces.
infer the composition of the magma in the mt. vesuvius eruption in 79 AD. why?
high silica and high gas content. very explosive eruption.
Flood basalt
huge amounts of lava that erupt from fissures
flood basalt
huge amounts of lava that erupt from fissures
flood basalts
huge amounts of lava that erupt from fissures
Earth's Sphere
hydrosphere (the water portion); atmosphere (gaseous envelope); geosphere (solid earth); biosphere (totality of all plant and animal life on our planet)
Extrusive
igneous activity that occurs on earths surface
Intrusive
igneous rock that formed below earths surface
porphyry
igneous rock that has mixed texture in which large crystals gloat in a predominantly fine grained matrix
pressure water
in addition to to temperature, _______ and the presence of __________ also affect the formation of magma
denser hot mantle
in an oceanic- continental subduction zone, the ________ plate slides under the continental plate into the ________ ______
principle of superposition
in an undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below; this also applies to lava flows and beds of ash
Convection Currents
in the mantle, where warm, buoyant rocks rise and cool, dense rocks sink, is the underlying driving force of plate tectonics (the transfer of heat by the mass movement or circulation of a substance)
pressure
inceases in with depth due to weight of overlying rock and temperature also increases which causes substances to melt although the lower crust and upper mantle doesn't usually melt
principle of inclusions
inclusions are fragments of one rock unit that are enclosed within another rock unit; the rock containing the inclusion is younger
Trace fossils
indirect evidence of prehistoric life; includes: tracks, burrows, coprolites, and gastroliths
plutons
intrusive igneous rock body, including batholiths, stocks, sills, and dikes, formed through mountain-building processes and oceanic-oceanic collisions; can be exposed at the earth's surface due to uplift and erosion.
plate boundaries
most volcanos form at
pluton
intrusive igneous rock body, including batholiths, stocks, sills, and dikes, formed through mountain-building processes and oceanic-oceanic; can be exposed at earth's surface due to uplift and erosion
Pluton
intrusive igneous rock body; exposed due to uplift and erosion
Layers Of Earth
iron-rich core (outer and inner), mantle (upper and lower), and the thin crust
Stock
irregularly shaped pluton that is similar to a batholith but smaller
stocks
irregularly shaped pluton that is similar to a batholith but smaller, generally forms 5-30 km beneath Earth's surface, and cuts across older rocks
Stocks
irregularly shaped plutons that are similar to batholiths, but smaller in size
stock
irregularly sharped pluton that is similar to a batholith but smaller, generally forms 5-30 km beneath earth's surface, and cuts across older rocks
Viscosity
is a measure of a material's resistance to flow (ex: syrup is more viscous than water)
volcanic ash
is made up of extremely small fragments, usually of glass, that form when escaping gases force a fine spray of magma from a volcano
What is a lava tube?
it is a tube beneath the solidified surface of a lava flow through which lava moves also the hollow space left when the lava within a tube drains away.
What is magma mixing?
it is the process by whereby magmas of different composition mix together to yield a modified version of the parent magmas.
What is an ash flow?
it is when a cloud of ash and gas flows along or close to the land surface. They can move fast and cover vast areas.
caldera
large crater, up to 50km in diameter that can form when the summit or side of a volcano collapse into the magma chamber during or after an eruption
Caldera
large crater; can form when summit or side of a volcano collapses.
calderas
large craters, up to 50 km in diameter, that can form when the summit or side of a volcano collapses into the magma chamber during or after an eruption
plutons
large igneous bodies formed deep in earth's crust--they range in size from a cubic kilometer to hundreds of cubic kilometers
batholiths
large plutons are great irregular masses of coarse grained igneous rock that cover at least 100 km^2. they are thick, horizontal, sheetlike bodies extending from a funnel saved central region.
Monocline
large, steplike folds in otherwise horizontal sedimentary strata; as blocks of basement rocks are displaced upward, the ductile sedimentary strata drape over them
calderas
larger depressions that can be up to 50 km in diameter and often formed after the magma chamber beneath a volcano empties from a major eruption
bombs
larger particles hurled from the volcano and streamlined by the air as they hurtle through it
Batholiths
largest plutons, are irregularly shaped masses of coarse-grained igneous rocks that cover at least 100 km2 and take millions of years to form. Common in the interior of mountain chains
blocks
largest thrown from a volcano
volcanic rock
lavas--volcanic rocks formed from flowing lavas range in appearance from smooth and ropy to sharp and spiky
basaltic
less than 50% in silica content
granodiorite
light colored rock that looks something like granite
Felsic
light colored silicates, composed almost entirely of quartz and potassium fledspar, high silica content, major constituent of continental crust
types of coal
lignite, bituminous, antracite,
isoline
line on a chart or map connecting points of equal value
outer core
liquid based on the absence of S waves traveling through the core
lava
liquid magma that reaches the surface
basaltic
location both ocean and continental crust
rhyolitic
location continental crust
andesitic
location subduction zones
fissure
long cracks in Earth's surface
fissures
long cracks in earth
Fissure
long cracks in the earth
fissures
long cracks in the earth
liquefaction
loosely packed waterlogged sediments behave as fluid during the intense shaking of an earthquake
Burial metamorphism
low-grade metamorphism that occurs in the lowest layers of very thick accumulatios of sedimentary strata
mineral phase change
lower mantle rocks undergo this as minerals are compressed under higher pressures
lava
magma flowing out onto Earth's surface
fissures,cracks, and the rock
magma moves from a chamber deep within earth to earth's to what (3)
Lava
magma that reaches earth surface
geodynamo
magnetic field caused by spiraling columns of rising fluid in the outer core; primarily dipolar; patterns of convection change rapidly enough so that the magnetic field varies noticeably over our lifetime
dikes
major route of magma transport in the crust--they are sheetlike igneous bodies that cut across the layers in bedded country rock and are so discordant intrusions. form by forcing open existing fractures in the country rock, but more often create channels through new cracks opened by the pressure of rising magma
correlation
matching rocks of similar ages from different regions, provides a more comprehensive view of the rock record
thermal contraction
materials connect when they are cooled
thermal expansion
materials expand when they are heated
fluid induced melting
melting of rock induced by the presence of water that lowers its melting point--water content is a significant factor in the melting of sedimentary rock, which contain an especially large volume of water in their pore spaces, more than is found in igneous or metamorphic rocks
intermediate igneous rocks
midway between fells and mafic--these rocks are neither as rich in silica as the fells rocks nor as poor in it as the magic rocks
Permineralization
mineral rich groundwater flows through porous tissue and precipitates minerals. Ex: Petrified wood.
partial melting
minerals that compose rock melt at different temperatures. as temperature rises, some minerals melt and other remain solid.
turbidity current
mixture of sediment and water that carry sediments of a continental rise down submarine canyons
basalt
most abundant igneous rock of the crust, and it underlies virtually the entire sea floor (dark gray to black rock). fine-grained
oceanic-continental
most volcano located on the land result from what subduction
strata
parallel layers of sedimentary rocks
black smokers
particle filled clouds that are precipitated on the seafloor when hot groundwater dissolves ions of various metals from the rock—interactions between seawater and oceanic crust
volcano
parts of the plate melt and magma rises, eventually leading to the formation of what
relative dates
place rocks in a sequence of formation; Ex: The Hermit Shale is older than the Coconino Sandstone
Dike
pluton that cuts across preexisting rocks
dike
pluton that cuts across preexisting rocks and often forms when magma invades cracks in surrounding rock bodies
dike
pluton that cuts across preexisting rocks. often form when magma invades cracks in surrounding rock bodies. range in size from a few centimeters to several meters wide
Sill
pluton that forms when magma intrudes parallel rock layers
sill
pluton that forms when magma intrudes parallel rock layers
sills
pluton that forms when magma intrudes parallel rocks layers
epicenter
point on the ground surface directly above the focus
felsic rocks
poor in iron and magnesium and rich in fells minerals that are high in silica
Pyroclastic flow
potentially deadly clouds produced by a violent eruption
ultramafic rock
primary of mafic minerals and contain less that 10 % feldspar
Volcanism
processes associated with the discharge of magma, hot water, steam.
shear stress
produces a motion similar to slippage that occurs between individual playing cards when the top of the stack is moved relative to the bottom
Plate Tectonics
proposes that Earth's outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, volcanoes, mountains, and the crust itself
tensional stress
pulls apart a rock and lengthens it
basaltic
quiet eruptions
extrusive igneous rock
rapid cooling at Earth's surface produced the fine grained texture or glassy appearance of extrusive igneous rocks
pyroclastic flows
rapidly moving clouds of tephra mixed with hot, suffocating gases
pyroclastic flows
rapidly moving clouds of tephra mixed with hot,suffocating gases
Scoria
reddish/brown porous rock from frothy basaltic and andesitic lava
mantle plume
regions of hotter than normal mantle rise, experience decompressing melting, create basalts that triggers hot-spot volcanism on the surface; mantle plumes concentrate under the which continental crust which traps heat in then mantle; eventually cause the overlying crust to dome and weaken
laccoliths
relatively small, mushroom- shaped pluton that forms when magma intrudes into parallel rock layers close to Earth's surface
laccolith
relatively small, mushroom-shaped pluton that forms when magma intrudes into parallel rock layers close to earth's surface
Igneous
rock formed from the crystallization of magma
Tephra
rock fragments thrown into the air during a volcanic eruption
tephra
rock fragments, classified by size that are thrown into the air during a volcanic eruption and fall to the ground
intrusive igneous rock
rock that has forced its way into surrounding rock, called country rock , and solidified without reaching Earth's surface
hot spots
unusually hot regions of Earth's mantle where high-temperature plums of magma rise to the surface
organic
sedimentary rock composed of organic carbon from the remains of plants that died and accumulated on the floor of a swamp. Coal is a primary example.
detrital
sedimentary rocks that form from the accumulation of materials that orginate and are transported as solid particles derived from both mechanical and chemical weathering
nonconformity
sedimentary strata overlay metamorphic or igneous rocks
S waves
shear waves; can only travel through solid material; second to arrive at a recording station.
sill
sheetlike body formed by the injection of magma between parallel layers of bedded country rock--sills are concordant intrusions, which means their boundaries lie parallel to the country rock layers, whether or not those layers are horizontal.
what is a broad gently sloping volcanoes with low energy eruptions?
shield volcano
Types of Volcanoes
shield volcanoes, cinder cones and composite volcanoes
andesitic
silica content 50 to 60%
rhyolitic
silica content is more than 60%
type of volcanic rock it forms as lava cools
silica content of magma determines not only its explosively and viscosity but also
stocks
small plutons
Mediterranean Belt
smaller belt that includes Mount Etna and Mount Vesuvius, two volcanoes in Italy. Outline corresponds to the boundaries between the Eurasian, African and Arabian Plates
ash
smallest fragments less than 2mm is called
Residual Soil
soil developed directly from the weathering of the bedrock directly below
transported soil
soil that forms unconsolidated deposits
pillow lavas
some magmas rise through the narrow cracks that open where the plates are spreading and erupts into the ocean, that form basaltic pillow lavas that cover the sea floor
hot spot
some volcanoes form at
absolute date
specific date something occurred
compression
squeezes a rock and shortens it
compressional stress
squeezes a rock and shortens it
cinder cone
steep -sided, generally small volcano that is built by the accumulation of tephra around the vent
submarine canyon
steep sided valley cut into the seafloor of a continental slope
cinder cones
steep sided, generally small volcano that is built by the accumulation of tephra around the vent
continental slope
steep structure that marks the boundary between the continental and oceanic crust
confining pressure
stres is applied equally in all directions
differential stress
stress is applied unequally in all directions
pyroclastic flow
swift-moving, potentially deadly clouds of gas,ash, and other volcanic material produced by a violent eruption
higher
temperature decreases the viscosity is what
lower
temperature increases the viscosity is what
size
tephra are classified by
composition of magma
the _____________ determines a volcanos explosively, which is how it erupts and how its lava flows
tensile strength
the amount of force something can withstand before breaking
half-life
the amount of time required for half of the radioactive isotope to decay; radioactive parents isotopes decay to stable daughter isotopes; when the ratio of parent to daughter is 1:1, on half life has passed
ring of fire
the circum pacific belt's other name
metamorphic grade (regonize rocks)
the degree thst which a parent rock changes during metamorphism. It varies from low grade (low temp and pressure) to high grade (high temp and pressure)
stress
the force that deforms rocks; when stresses acting on a rock exceed its strength, the rock will deform by flowing, folding, fracturing, or faulting; magnitude is a function of the amount of force applied to a given area.
recrystallization
the formation of new mineral crystals in a rock tend to be larger than the orginal crystals.
what is a hotspot?
unusually hot regions on the earth's surface. hot because of magma built up in the mantle. thin crust by hot spot.
Geothermal Gradient
the gradual increase in temperature with depth in the crust. The average is 30 degrees celcuis per kilometer in the upper crust
craton
the interior of a continent, the oldest part
the circum pacific belt
the largest of the 2 major convergent plate boundaries
Regolith
the layer of rocks and minerals fragments that nearly everywhere covers earths land surface.
covergent and divergent
the majority of volcanos form at what boundaries and what boundaries
viscosity
the measure of a liquid's resistance to flow, increases as silica content increases. important in the behavior of lavas
magma
the molten mixture of rock-forming substances,gases,and water from the mantle
increases
the more silica the viscosity what
water vapor
the more what added to the magma would melt at lower temperature
Silicate
the most common type of minerals. They account for >90% of Earth's crust. Silicon and oxygen make up the basic building blocks of silicate minerals
Paleomagnetism
the natural remnant magnetism in rock bodies. The permanent magnetization acquired by rock that can be used to determine the location of the magnetic poles and the latitude of the rock at the time it became magnetized
Pacific Ring of Fire
the outline of this belt corresponds to the outline of the Pacific Plate
fractional crystallization
the process by which the crystals formed in a cooling magma are segregated from the remaining liquid rock--this segregation happens in several ways, following a sequence commonly described as Bowen's reaction series
lithification
the process, generally involving cementation and or compaction, of converting sediments to solid rock
geothermal gradient
the profile of earths temperature at each depth; carries within earths interior (Crust: 30 C per km of depth. Mantle: 0.3 C per km— exception is the D"layer)
fissile
the property of splitting easily into thin layers along closely spaced, parallel surfaces, such as bedding planes in shale
Pangaea
the proposed supercontinent that 200 million years ago began to break apart and form the present landmasses
reflection
the redirection of some waves back to the surface when seismic waves hit a boundary between different earth materials
elastic
the rock returns to nearly its original size and shape when stress is removed
Ophiolite complex
the sequence of 4 layers composing the oceanic crust; Layer 1: deep sea sediments and sedimentary rocks. Layer 2: pillow basalts. Layer 3: numerous interconnected dikes called sheet dikes. Layer 4: gabbro
porphyroblasts
unusually large grains, are surrounded by fine grained matrix of ther minerals
lithosphere
uppermost part of the mantle that extends down to 200 km plus the crust
country rock
upward movement is accomplished by stoping, where the overlying blocks sink through the magma
decompression melting
upwards movement of earths mantle to an area of lower pressure
dome
upwarped circular features; oldest rocks are in the center (type of fold)
radiometric dating
uses the decay of isotopes in rocks to calculate the age of that rock
Texture
the size, shape, and distribution of particles that collectivly consistute a rock
mediterranean belt
the smaller belt of the 2 major convergent plate boundaries
paleontology
the study of fossils and history of life on earth
Mineralogy
the study of minerals
bathymetry
the topography (shape) of the ocean floor; early bathymetric profiles were used using echo sounders which bounced off an object to determine distance; Sonar is also used to measure distance to the ocean floor
tension
the type of stress that tends to pull a body apart
dacite
the volcanic equivalent of granodiorite
2
the volcanos associated with convergent plate boundaries form at how many major belts
composition
the what of magma determines the characteristics of a volcano's eruption
Vesicles
they are bubbles found inside of fossils/rocks
basaltic
this magma viscosity is low
angular unconformity
tilted rocks are overlain by flat lying rocks
fossil
traces or remains of prehistoric life preserved in rock
conduction
transfer of heat through a material; through the collision of atoms or through the flow of electrons; material conduct heat at different rates; conduction is not an efficient way to move heat around the earth (most rocks are poor conductors of heat)
convection
transfer of heat where hot materials replace cold material (or vice-versa); Primary means of heat transfer within the earth; convection cycles occur within the mantle and outer crust (mantle plumes are the upward flowing arm of the cycle); similar to a pot of boiling water; material must flow in a convection cycle
Surface waves
travel in rock layers just below the earths surface; 2 general directions of motion; one causes the ground to move up and down; similar to the movement of ocean cells; the second causes the ground to move side to side and causes the greatest destruction;lowest velocity, are the last to arrive at a recording station and have the highest amplitude.
Anticline
unfolded pr arched sedimentary layers (oldest strata are in the center)
Hot spot
unusually hot area in Earth's mantle
hot spot
unusually hot area in earth's mantle where high-temperature plumes of mantle material rise toward the surface
hot spots
unusually hot regions of Earth's mantle where high temperature plumes of magma rise to the surface
isotope
varieties of the same element that have as different mass numbers; their nuclei contains the same number of protons but different numbers of neutrons
Isotope
varieties of the same element that have different mass numbers, their nuclei contain the same number of protons but different number of neutrons
andesitic
viscosity intermidiate
rhyolitic
viscosity is high
Cinder Cone
volcano that is built by the accumulation of tephra around the vent
major belt
volcanoes associated with convergent plate boundaries form this
Pyroclastic
volcanoes eject pulverized rock and lava fragments called pyroclastic materials (particles range in size from fine dust, to sand-sized ash, to very large rocks)
Quiescent
volcanoes that are quiet. They do not erupt
asthenosphere
weak layer beneath the lithospheric mantle
magmatic stoping (how magma rises)
wedging open the overlaying rock, melting surrounding rock, breaking off large blocks of rocks (known as xenoliths)
conduit
when lava reaches the surface by traveling through a tube-like structure
vent
where lava emerges through an opening
magma chamber
where lava is formed and stored in a volcano
hypocenter (focus)
where rock slippage originates in the ground
active margin
where the oceanic lithosphere is being subducted beneath the continent: often associated with deep-ocean trenches; located primarily around the Pacific ocean; features include: deep-ocean trenches, abyssal plains, seamounts and guyots, oceanic plateaus
Volcanoes can occur
where two of earth's plates converge, or rub together.
Volcanoes can also occur
where two plates diverge, or move apart.
obsidian
wholly glassy volcanic rock type, that contains only tiny vesicles and is so solid and dense
index fossil
widespread geographically and limited to a short period of geological time
agents of erosion
wind, water, gravity, or ice wear away or break rocks
principle of cross-cutting relationships
younger features cut across older features