Geology Midterm 2
False
The texture of a rock refers to just it's feel. True or False
felsic
The walls of Yellowstone Canyon are_____ash (felsic, mafic)
quartzite and marble
Two common metamorphic rocks that typically lack foliation are : . a..slate and phyllite b..gneiss and migmatite c..quartzite and marble d..schist and metaconglomerate
T
Very early in Earth's history, it was so hot that the surface was likely entirely molten. (T or F)
ash
Volcanic ash is mostly what?
Mt. Pelee
Volcanic eruption where 2 people survived. Little girl and prisoner.
Lake Nyos
Volcanically derived carbon dioxide gas bubbled from the lake and suffocated people and animals nearby.
tephra
What is a cinder cone made of?
silicon and oxygen
What is magma made of (2 biggest).
Drowning
When Krakatoa blew, most deaths were caused by (a) drowning (b) burning (c) burial (d) explosion
F
When rock is melted within Earth, typically the entire volume of rock is transformed from a solid state to a liquid. (T or F)
pressure, volatiles, heat
Why magma forms. Decrease in______, adding______, _____transfer from rising magma.
B
Would it be reasonable to say that (a) granite comes mainly as the liquid phase from fractional crystallization of mafic magmas or (b) granite is mainly a product of partial melting of metamorphic rocks (A or B)
dynamic
____ metamorphism: shear taking place along a fault. rock deforms plastically so the minerals in the rock recrystalize
burial
______ metamorphism: due only to the consequences of very deep burial
mafic, felsic
_____magma less viscous than ____ magma. (type of magma)
hot, cold
___magma is less viscous than ___magma. (temperature)
block
a chunk of prexisting rock as a pyroclastic deposit
graded bed
a layer of sediment in which grain size varies from coarse at the bottom to fine at the top
metaconglometate
a protolith of conglomerate becomes this under metamorphic conditions. pebbles and cobbles flatten into a pancake shape without cracking
metamorphic rock
a rock that forms when a preexisting, or protolith, undergoes a solid-state change in response to the modification of its environment
dormant
haven't erupted for hundreds of years
conduit
how magma travels from magma chamber to the surface
texture
how the crystals fit together in an igneous rock
felsic
if magma cools slowly allowing fractional crystalization (mafic or felsic)
mafic
if magma solidifies quickly before fractional crystallization (mafic or felsic)
fragmented texture
igneous chunks or shards packed together
oceanic, continental
igneous rocks make up all _____ crust, and most_______crust.
assimilation
incorporating chemicals or blocks from the surrounding rock (contamination)
stoping
assimilation of rock wall, not all rocks melt completely, become xenoliths
delta
topset beds of gravel, foreset beds of gravel and sand silty bottomset beds
oxidation
transfer iron-bearing minerals into a rusty brown mixture
lithification
transformation of loose sediment into rock
landslides
tsunamis generated from hawaii come from (a) underwater eruptions (b) underwater caldera collapse (c) landslides (d) earthquakes
True
"All lava is magma" is truer than "All magma is lava" True or False
hydrothermal
-____metamorphism: fluid rises through the crust near the mid ocean ridge causing this
Mt. Vesuvius
. In 79 C.E., the citizens of Pompeii in the Roman Empire were buried by pyroclastic debris derived from an eruption of
at places in continental interiors termed shields
. Precambrian metamorphic rocks are exposed at the surface : . a..on Mars and Venus, but nowhere on Earth b..at places in continental interiors termed platforms c..at places in continental interiors termed shields d..at the bottom of the deep sea
False
A Strobolian eruption is more dangerous than a Plinian eruption (true or false)
felsic
A lava dome is (mafic, felsic, intermediate)
Tuff
A volcano emits ash, which falls from the sky, settles in layers, and is eventually cemented. The resultant rock is termed ___
F
All crystaline rocks are igneous (T or F)
F
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. (T or F)
Porphyritic
An igneous rock with a mixed texture of coarse grains (phenocrysts) surrounded by fine crystals (groundmass) is termed
Flood basalts
At continental rifts, vast bodies of basaltic lava flow forth from fissures, forming
columnar jointing
Basalt lava flows contract and may fracture in roughly hexagonal columns.
T
Bedrock covered in soil is not an outcrop of rock (T or F)
Plagioclase
Bowen's continuous reaction series describes the crystallization behavior of a single mineral (with variable chemical composition) a. olivine b. plagioclase c. pyroxene d. quartz
Granite
Coarse grained Silicic rock
Gabbro
Coarse grained mafic rock
T
Compaction and cementation is a sedimentary process (T or F)
Dry magma
Contains no volatiles
Basalt
Fine grained Mafic rock
Rhyolite
Fine grained Silicic rock
Hot spot island chain
Hawaiian Island chain is an example of what?
A
Humis had decayed further and mixed with minerals. Water percolates causing chemical weathering. (zone of leaching)
increase
If a body of magma becomes more felsic its viscosity will (increase or decrease)
H2O and CO2
Important volatiles in magma
Martinique
In 1902, a famous, deadly volcaniclastic flow killed thousands of people on the Caribbean island of (Puerto Rico/ Martinique/ Aruba/ Jamaica)
Olivine
In Bowen's discontinuous reaction series, the first mineral to crystallize from a mafic melt is
F
In metamorphic rocks some melting is always required (T or F)
discordant
Is a dike a concordant or discordant intrusion?
concordant
Is a laccolith a concordant or discordant intrusion?
True
Is it true that urban areas of Tacoma lie above lahar deposits from Mt. Rainier (true or false)
Mars
Larges volcano in the solar system is on which planet?
shield volcanoes
Largest of the volcanoes in Area
Igneous
Lava cools to form this type of rock
False
Lithification is a metamorphic process. True or False
Io
Most volcanic place in the solar system
stratovolcanoe
Mt. Fuji is an example of this type of volcano
False
One of the reasons volcanic eruptions are so deadly is that there is no way to predict where an eruption will occur in the near future. true or false
Hotter
Radioactive isotopes, differentiation of Earth's iron core, gravity-driven compression, and meteoric bombardment all caused early Earth to be much_____ than at present. (Hotter or Colder)
Intrusive igneous rock
Rock formed from the cooling and solidification of magma beneath Earth's surface. In magma chambers, cracks, or columns.
extrusive igneous rock
Rock that forms from the cooling and solidification of lava at Earth's surface. Lava flows, pyroclastic debris
intermediate magma
Rock with a chemical content between felsic and mafic compositions.52-66% silica
Igneous Rock
Rocks formed through the freezing of a melt. They can be produced above or below ground and are the most common type of rock within Earth.
T
Sand is not a rock (T or F)
low, basaltic
Shield volcanoes have (high/low) viscosity (basaltic/mafic) flows
continental hot spots
Simultaneous eruptions of basalt and rhyolite can occur where?
foliation
Slaty cleavage, schistosity, and compositional banding are all examples of : . a..mineral cleavage b..foliation c..recrystallization d..sedimentary structures
source rock
Solid from which magma is derived
Io
Surface resembles a pizza because of the sulfur gasses.
Exodus
The Biblical chapter that possibly describes a volcanic eruption is (a) Genesis (b) Psalms (c) Exodus (d) Corinthians 2
felsic
The Morro such as Bishop Peak are compositionally...(mafic, felsic, intermediate)
younger
The black parts of the moon's surface are ____ than the lighter parts
High pressure but relatively low temperature
The blueschist facies is a metamorphic realm of : . a..high temperature and pressure b..low temperature and pressure c..high temperature but relatively low pressure d..high pressure but relatively low temperature
F
The colored strata layers of the Grand Canyon are said to be a form of foliation (T or F)
F
The composition of a rock can be described as either being equant or inequant
schistosity
The development of a preferred orientation of large, flaky mica crystals within metamorphic rock is termed ...
True
The devil's tower has its undisputed origin as a lava pipe in the center of an old volcano (True or False)
False
The eruption of Mt. St. Helens in 1980 was the greatest explosive eruption in the last two hundred years of world data. a. true b. false
ignimbrite
The lithification of material from a pyroclastic flow forms a rock called
False
The long valley caldera has shown no sign of activity in the last century (true or false)
hydration
absorption of water into the crystal structure of minerals, causing expansion and weakening
volcaniclastic deposits
accumulations of fragmental igneous rock
breccia
angular fragments with sharp edges
composite
another name for stratovolcano
bombs
apple to refrigerator sized lapilli
stratification
arrangement of sediment into beds
tuff
ash mixed with lapilli when burried and transformed into coherent rock
convergent boundaries
effusive or pyroclastic eruptions. yield composite volcanoes. (geological setting)
continental hot spot
basaltic and rhyolitic pyroclastic debris, partially melts the crust (geological setting)
oceanic hot spot
basaltic magma, broad dome shaped shield volcano (geological setting) [not sure about this one]
Olympus Mons
biggest shield volcano in the solar system. Located on Mars
pluton
blob shaped intrusion
bedding plane
boundary between two beds
shield
broad gentle dome with low viscosity basaltic flow (type of volcano)
conglomerate
burial and lithification of rounded and broken breccia. Final stage is a rounded rock
extinct
can no longer erupt
clastic sedimentary rocks
cemented together solid fragments and grains derived from preexisting rock
chemical weathering
chemical reactions that alter or destroy minerals in rock
crater
circular depression at top of volcanoe
gneiss
compositionally layered metamorphic rock, typically composed of alternating dark and light layers that range in thickness from milimeters tometers. stripped
chalk
consisting of plankton shells
soil
consists of rock or sediment that has been modified by physical and chemical reaction with organic material and rain water over time to produce a substrate that can support the growth of plants
Peleos hair
consists of thin strands of basaltic pyroclastic debris
Basaltic
contain more iron and magnesium than rhyolitic lavas
continental rifts
curtains of lava, basaltic fissure eruptions, array of different volcano types (geological setting)
metamorphic foliation
defined by the patallel alignment of platy minerals and the presence of alternating light and dark colored layers
sorting
degree to which clasts in a rock are the same size
magma mixing
different magmas from different sources can combine in one magma chamber
metamorphic aureole
distinct belt of metamorphic rock that forms around an igneous intrusion
cross beds
distinct internal laminations inclined at an angle to the boundary of main sedimentary layers
mid ocean ridge
erupts basalt which turns into pillow-lava mounds (geological setting)
pumice
felsic volcanic rock containing abundant vesicles (very light0
phyllite
fine grained metamorphic rock with a foliation caused by the prefered orientation of very fine grained white mica
tuff
fine grained pyroclastic composed of volcanic ash
James Hutton
first one to really study metamorphic rocks
platy
flat or broad
low viscosity
flows easily
mylonite
foliation that roughly parallels the fault. Made during dynamic metamorphism
thermal expansion
forest fire heats up outer rock but inner rock stays cool so the outer layer pops off
vesicles
form in high viscosity magma, bubbles
jointing
form of weathering, natural cracks that form in rocks dur to removal of pressure or cooling
slate
forms by metamorphism of shale or mudstone under relatively low pressures and temperatures. Finest grained foliated metamorphic rock
Quartzite
forms by the metamorphism of pure quartz sandstone.
sediment
forms by weathering of preexisting rock
pyroclastic rocks
fragmental rocks composed of debris that has been blasted out of volcanoes or vents. Already solid when stuck together
Pyroclastic debris
fragmented material that sprayed out of a volcano and landed on the ground or sea floor in solid form. Large fragments formed in the air. Includes volcanic ash.
migmatite
gneiss may begin to melt producing felsic magma, if it freezes again before flosing out of source area a mixture of igneous and metamorphic rock form called...
metamorphic texture
grains in a metamorphic rock have grown in place within the solid rock.
lava tube
insulated tunnel like conduit within a flow through which lava moves
explosive
intermediate and felsic magma is _______ (unexplosive or explosive)
andesitic lava
intermediate viscosity lava, higher silica content than some lava, solidifies into a jumble of rubble
laccolith
intrusions inject between layers and dome up
stratovolcano
large and cone shaped, steeper near the sumit. Alternating layers of lava, tephra, and debris
volcanic breccia
large fragments of volcanic debris that either fall through the air and accumulate or form when a lava flow breaks into pieces
dunes
large ripples
Melt
lava and magma (phase?)
fissure
lava erupts as a curtain from a long crack
pyroclastic debris
lava which cools in the air
C
layer of material derived from substrate that has been chemically weathered but hasn't undergone leaching or accumulation, grades down into bedrock
sedimentary structures
layering of sedimentary rocks, surface features on layers formed during deposition and arrangement of grains within layers
active
likely to erupt soon
geotherm
line of temperature as you go deeper into the earth
arkose
lithified mixture of quartz and feldspar
shale
lithified mud
siltstone
lithified salt
thermal metamorphism
local metamorphism caused by igneous intrusion (also known as contact metamorphism)
sediment
loose fragments of rocks or minerals broken off of bedrock, mineral crystals, and shells
Flood Basalt
low viscosity sheets of basaltic lava. Form when a mantle plume underneath a region undergoes rifting and erupts spectacularly
chert
made from tiny quartz crystals from shells of silica secreting plankton
scoria
mafic volcanic rock that contains abundant vesicles (darker and harder than pumice) the "scum" of lava
Felsic magma
magma with a high silica content and large volume of gas (explosive eruptions) 66-76% silica
mafic magma
magma with a low silica and gas content (non explosive eruptions) 45-52% silica
Ultramafic magma
magma with a very low silica and gas content. contains about 38 to 45% of silica
obsidian
mass of solid felsic glass
schist
medium to coarse grained metamorphic rock that posses a type of foliation defined by the prefered orientation of LARGE mica flakes
high
metamorphic rocks that form at a relatively high temperature (above 600C): ____ grade
low
metamorphic rocks that form at a relatively low temperature (250C-400C): ____ grade
regional metamorphism
metamorphism affecting a large area
dynamothermal metamorphism
metamorphism involving heat and shearing
marble
metamorphism of limestone. calcite composing the protolith recrystalize and distinction between grains and cement disappear
dissolution
minerals dissolve in water
volatiles
more _____ make lava less viscous
rhyolitic lava
most viscous type of lava, accumulates above the vent in a lava dome or in short bulbous flows. Broken and blocky surfaces when cooled.
Organic (O)
mostly organic matter, few minerals (layer of soil profile)
turbidity
muddiness created by stirring up sediment or having foreign particles suspended
metamorphic minerals
new minerals that grow only under metamorphic mineral assemblage
Hornfels
nonfoliated rock that contains a variety of metamorphic minerals.
inequant
not the same dimensions in all directions
batholith
numerous plutons in a region making up to 100km of igneous rock
partial melting
only part of an original rock melts. Tends to be more felsic than the original rock
magma chamber
open space that holds large quantities of magma
coal
organic chemicals in ____ come from plant remains
lapilli
pea to plum sized fragments of glassy lava and scoria, type of pyroclastic debris
diagenesis
physical, chemical, and biological processes that transform sediment into sedimentary rock and alter these characteristics
ptotolith
preexisting rock from which metamorphic rocks are formed
deposition
process by which sediment settles out of the transporting material
evaporites
products of saltwater evaporation
dolostone
replacing calcite with dolomite
tavertine
rock composed of crystalline calcium carbonate formed by chemical precipitation from groundwater that has seeped out at the found surface in springs or in the wall of caves
sedimentary rock
rock formed at or near the surface by cememting together loose grains that had been produced by weathering of preexisting rock, precipitation of minerals, cementing of shells, or by growth of masses of shell-producing organisms
xenolith
rocks which are broken off of country rock and fall into magma but do not melt completely
porphyritic rocks
rocks with large crystals surrounded by smaller crystals
Salt Wedging
salt water precipitates and grows crystals in open pore spaces breaking off particles(type of weathering)
equant
same dimensions in all directions
formation
sandstone, consists of solid grains stuck together to form a distinct solid mass of sedimentary rock
mafic
scoria would most likely be found with ___ lava. (felsic, intermediate, mafic)
sedimentary basin
sediment filled depression
stratigraphic formation
sequence of strata which can be traced across a large region
strata
several beds together
ash
shards of glass and pumice fragments
tabluar
sheet like intrusions (no particular direction)
ignimbrite
sheet of tuff
bed
single layer of sedimentary rock
subsidence
sinking of the lithosphere
ripple marks
small elongated ridges that form on a bed surface at right angles to the current flow
glassy
solid mass of tiny crystals, not crystaline structure
cinder cone
steep pile of tephra, type of volcano
sand dune
strong winds can more dust and sand to accumulate into sand dunes
B
sub-soil, ions and clay accumulate
a'a'
surface layer freezes and breaks forming sharp angular fragments, type of basaltic lava
dike
tabular intrusion that cuts across preexisting layers. Perpendicular to direction of stretching that occurs during rifting
sill
tabular, injects parallel to layering
sphericity
the degree to which a rock is equidimentional
quartz
the last mineral to survive in a river
rift basin
the name of the troughs which fill with sediment
magma chamber
the pocket beneath a volcano where magma collects
exhumation
the process by which deeply burried rocks come back up to the surface
erosion
the process by which rock fragments are separated from its substrate
metasomatism
the process of changin a rock's chemical composition by reactions with hydrothermal fluids
metamorphism
the process of changing from one rock into another
foliation
the repetition of planar surfaces or layers in a metamorphic rock
angularity
the roundness of a rock
scoria
the scum formed by oxidation at the surface of molten metals
volcanic ash
tiny particles of glass that form when a spray of lava erupts and freezes instantly
caldera
top of volcano collapses into emptied magma chamber
welded tuff
tuff formed when the ash particles remained hot enough to fuse; consists mainly tiny glass shards. tuff which contains flatened bits of obsidian
pyroclastic
type of eruption made by cinder cones
effusive
type of eruption made by shield volcanoes
effusive and pyroclastic
type of eruption made by stratovolcano
effusive
type of eruption. Produces lava flows with low viscosity, basaltic lava.
explosive
type of eruption. produce clouds and avalanches of debris
basaltic
type of lava flow with low viscosity, flows quickly on steep slopes
tephra
unconsolidated deposits of pyroclastic grains
E
undergone leaching but not yet mixed with organic material
Limestone
usually formed by accumulations of shells made from CaCO3 (biochemical)
soil profile
vertical sequence of soil layers
micrite
very fine mud
lahar
very wet mixture of ash that quickly flows downstream
pahoehoe
warm pasty surfaces of lava wrinkle into smooth glassy rope like ridges, a type of basaltic lava
hydrolysis
water chemically reacts with minerals and breaks them down to form other minerals
Frost wedging
water getting into pores of rock and freezing and pushing it apart
alluvial fan
wedge shaped apron of gravela nd sand deposited by the stream
weathering
what breaks up and corrodes solid rock turning it into sediment
fractional crystalization
when minerals in magma crystalize at different rates
regression
when sea level drops, the coast migrates seaward
transgression
when sea level rises, the coast migrates inland
zone of leaching
where rainwater carries dissolved ions and clay flakes downward
tephra
which is the most all encompassing term (tephra or tuff)
transportation
wind, water, or ice move sediment