MRRE Exam 2
igneous, hydrothermal (not biological precipitation), metamorphism, precipitation, evaporation
5 key words for categories of carbonate formation:
color, texture, density, fracture, vesicle content
5 ways to classify igneous rocks
Alkali Feldspars
(K,Na,Ba)AlSi3O8; also includes albite
olivine
(Mg,Fe)2SiO4, can also have Ca at very low concentrations; Nesosilicate due to the 1:4 ratio.
pyroxene
(Mg,Fe,Ca)2Si2O6 - has M1 (CN=6) and M2 sites, the M2 sites can be either 6 or 8 coordinated; octahedral and tetrahedral layers
diatreme
A structure formed when a volcanic vent and the feeder channel below it are left full of breccia as an explosive eruption wanes
Tectosilicates (Framework Silicates)
1:2 silica to oxygen ratio, feldspars
trioctahedral
3 out of 3 octahedral sites are occupied in the O layer of a sheet silicate
increase temperature, decrease pressure, or add water
3 ways to get melting started:
dike
A slab of volcanic rock formed when magma forces itself across rock layers
daughter isotope
the stable isotope produced by the radioactive decay of the parent isotope
recrystallization
the term "metamorphism" in the context of carbonates mean that carbonates can form from the _____________ of carbonate-rich sediments
8 coordinated
the x sites in garnets are ____ ___________
6 coordinated
the y sites in garnets are ___ _____________
decreased
total radiogenic heat flow of the earth has _______ over time
melting and degassing (change in phase)
two common processes that fractionate/change the ratios of isotopes are...
forsterite and fayalite
two end members for olivine
enstatite and diopside
two end members for pyroxene
melilite group
another example of a sorosilicate (group)
color index
A number that represents the percent by weight or volume of dark-colored minerals in a rock
alpha particle
A 4He particle can also be referred to as an ________ ________
pluton
A body of magma that has hardened underground
Peridotite
A coarse-grained ultramafic rock.
Basalt
A fine-grained, mafic, igneous rock.
Feldspathoids
A group of minerals (e.g. leucite, nepheline, and sodalite) that are similar in composition to the feldspars (also tectosilicates), but contain less silica. They are rich in K, Na, Ca
Pahoehoe
A hot, fast-moving type of lava that hardens to form smooth, ropelike coils
zeolites
A large group of hydroaluminosilicate minerals that are analogous in composition to the feldspars(have Na,K, Ca). They form at low temperatures
M2
A larger cation like Ca would prefer the __ site in olivine
Super volcano
A massive volcano with eruptions that are rare but incredibly powerful. Thousands of cubic kilometers of matter can be ejected in the form of dust and ash that can cool the world's climate for years.
alpha decay
A nuclear reaction in which an atom emits an alpha particle consisting of two protons and two neutrons. This decreases the atomic number by 2 and the mass number by 4.
obsidian
A usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by rapid cooling of lava. Very silica rich despite the dark color.
amphibole
A0-1B2C5Si8O22(OH)2 - double chain silicate A = Na and K B = Ca, Na, Mn2+, Fe2+, Mg, and Li in the M4 sites C = Mn2+, Fe2+, Mg, Fe3+, Al, and Ti4+ in the M1, 2 and 3 sites
epidote
A2M3(Si2O7)(SiO4)O(OH) where the A site is highly coordinated cations like Ca and M site is octahedrally coordinated Al or Mg. Example of a sorosilicate
Pyrophyllite
Al2Si4O10(OH)2, sheet/phyllosilicate with a layered structure similar to mica
lahar
An avalanche of volcanic water and mud down the slopes of a volcano
pyroclastic texture
An igneous rock texture resulting from the consolidation of individual rock fragments that are ejected during a violent volcanic eruption.
isotope
Atoms of the same element that have different numbers of neutrons
aragonite group
CO3 complex structure combined with large divalent cations results in orthorhombic structure, occurs in calcite and aragonite, Calcium ion larger for calcite, overtime aragonite turns to calcite
Convective thrust region
Constant release of thermal energy from internal ash
felsic
Describes magma or igneous rock that is rich in feldspars and silica and that is generally light in color.
stable isotopes
Do not change or decay over time
corner linked and edge linked
M2 sites in olivine are both ___________ _________ and _______ _____________
Metamict
Mineral originally crystalline, now amorphous due to radiation damage. (process = Metamictization)
halides
Minerals that contain a halogen ion plus one or more other elements (typically electropositive cations)
Pleochroism
Pleochroism is an optical phenomenon in which a substance appears to be different colors when observed at different angles with polarized light. (changes with crystallographic orientation)
decay constant
Probability of decay of a nucleus per unit time, lambda
Quartz, alkali feldspar, plagioclase, feldspathoid
QAPF, plutonic (intrusive) igneous rock classification where more silica is the QA and less silica is the PF
Vesicular texture (igneous)
Rock that has a spongy appearance due to trapped gas bubbles in the lava.
total alkali silica
TAS classification for volcanic (extrusive) rocks
West Lake Landfill
The _______ ________ ________ is an example of unhealthy dumping of radioactive waste
latent heat of fusion
The amount of energy required to change a unit mass of a substance from solid to liquid
dispersion
The angular separation of the various frequencies in a beam of light by refraction, as with a prism. Refractive index varies as a function of wavelength.
Refraction
The bending of a wave as it passes at an angle from one medium to another
reflection
The bouncing back of a wave when it hits a surface through which it cannot pass.
radioactive decay
The breakdown of a radioactive element, releasing particles and energy
pyroclastic flow
The expulsion of ash, cinders, bombs, and gases during an explosive volcanic eruption
umbrella region
The point when the ash column from a volcanic eruption has the same density as the atmosphere and begins to billow out from the main ash column
as catalysts, water treatment material, and gas separation material
Three ways that zeolites are used industrially are...
andesitic magma
Type of magma with a medium amount of silica content.
Actinium Series
What radioactive decay series begins with uranium-235 and ends with lead-207
micas
X0-1Y2-3(Si4O10)(OH,F,Cl,O)2 x sites = Na, K, Ca (ideally 12-coordinated) y sites = Mg, Fe2+, Fe3+, Al, Li (6 coordinated)
garnet
X3Y2(SiO4)3 - nesosilicate X sites = Mg, Ca, Fe2+ y sites = Al, Cr, Fe3+
tourmaline
XY3Z6(Si6O18)(BO3)(OH,F)4 where: X sites = Na,Ca,K Y sites =Fe,Mg,Li,Al,Mn Z sites =Al usually or Fe example of a cyclosilicate
halides
_______ commonly form in evaporite deposits
sulfates
_________ commonly occur as the products of the oxidation of sulfides
evaporation
____________ is a relatively rare process for forming carbonate minerals
volcanic cone
a cone-shaped structure built by successive eruptions of lava and/or pyroclastic materials
fire fountain
a continuous spray of disrupting magma through a vent to form a persistent fountain of molten magma above the vent
Birefringence
a difference in the two indices of refraction exhibited by most crystalline materials (nmax-nmin). Waves split into two and become out of phase, they interfere, and the interference is analyzed.
Feldspar
any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium (KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8)
Scoria
a glassy, mafic, igneous rock containing abundant air-filled holes
caldera
a large crater caused by the violent explosion of a volcano that collapses into a depression
laccolith
a mass of igneous rock, typically lens-shaped, that has been intruded between rock strata causing uplift in the shape of a dome. Has a flat bottom
decay series
a series of radioactive nuclides produced by successive radioactive decay until a stable nuclide is reached
Gibbsite
a single octahedral layer (just O) that is dioctahedral
Brucite
a single octahedral layer (just O) that is trioctahedral
sill
a slab of volcanic rock formed when magma squeezes between layers of rock, along zones of weakness (flat on both sides)
more silica rich
a thicker overriding plate means the magma at that convergence is _________ ______-_____
less silica rich
a thinner overriding plate means the magma at the convergence is _____ ______- ____
pumice
a very light and porous volcanic rock formed when a gas-rich froth of glassy lava solidifies rapidly.
Phreatomagmatic
a violent eruption due to the contact between groundwater and magma, steam driven
plagioclase series
albite (Na) and Anorthite (Ca) are part of the _________ ______ of feldspars
energetic
alpha decays are highly ___________, and lead to metamictization
sheet silicates
also called layer or phyllosilicates, 2:5 silica to oxygen ratio.
Kyanite, Andalusite, Sillimanite
aluminosilicate polymorphs (Al2Si2O5)
4 and 6
aluminosilicates have both __ and __ coordinated aluminum
slower
an RI of 2.4 would indicate that light travels 2.4 times ______ than in a vacuum
fissure eruption
an eruption in which lava is extruded from narrow fractures or cracks in the crust, spattering rampart
intermediate
an igneous rock midway in composition between mafic and felsic, neither as rich in silica as felsic rock nor as poor in it as mafic rock
temperature
an important distinction is that lowering the melting temperature is not the same as the actual ____________ (you can raise the melting temperature while the actual temperature stays constant)
convergent plate boundaries
andesitic magma is associated with back arc basins at ______________ _______ _____________
a type
anorogenic (far from mountain building) or post-orogenic (after mountain building)
Beryl
another example of a cyclosilicate
phenocryst
any of the large crystals in the porphyritic igneous rock, caused by high viscosity melt breaking off pieces of the host
high pressure
aragonite is the preferred structure for calcite when at _____ __________
decreases
as the silica content increases in a rock, generally, the Fe and Mg content...
silica rich
as the temperature of the melt decreases, the melt becomes more _______ ______
temperature and pressure
as you go farther down in the earth, _________ and __________ increases
gas thrust region
ash is powered upwards by high pressure from expanding gases
xenoliths
assimilation of the host rock can occur, creating chunks of the host that crystallize with the magma and are called...
M type
associated with island arcs
I type
associated with island arcs and backarcs
divergent plate boundaries
basaltic magma is associated with ______________ _____ _____________
normative composition
based on measured chemistry, idealized set of standard minerals. Gives the percentage of minerals in a rock based on the percentages of common chemistry groups
crystal systems
birefringence differs between different _______ ________
structures (arrangements)
calcite and aragonite have the same chemical composition, but different ____________
precipitation
carbonates can form by ______________ from low temperature solutions, which is biologically mediated
Porphyritic Texture
characterized by large, well formed crystals surrounded by fine-grained crystals
phyllosilicate
clay minerals are another type of...
phaneritic
coarse grained (intrusive)
granite
coarse-grained, felsic rock
diorite
coarse-grained, intermediate rock
Gabbro
coarse-grained, mafic rock
lopolith
concordant igneous intrusion that is lenticular in shape, flat top and curved bottom
phosphates
contain (PO4)3- anions. They are found as igneous accessory minerals, marine sediments, in human bones, and are a key component of fertilizers
intrusive (plutonic)
cools slowly, typically growing larger crystals, coarse grained
hot spots and mid-ocean ridges
decompression melting happens at ____ _____ and _______-________ ________
mafic
describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color; more silica rich than ultramafic
single chain silicates
each tetrahedron shares corner oxygen atoms with two others, 1:3 Silica to Oxygen ratio
alkali-rich
feldspathoids form in ________-_______ environments compared to feldspars
Aphenitic
fine grained (extrusive)
Extrusive (volcanic)
fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface
rhyolite
fine-grained, felsic rock
Andesite
fine-grained, intermediate rock
Komatiite
fine-grained, ultramafic rock
older
for a graph of radiogenic growth, the steeper the line the _______ the age
y axis
for a radiogenic growth graph, the daughter is usually on the _ ____
decreases
for an alpha decay, the atomic number ________ by 2
4
for an alpha decay, the mass number decreases by __
2:1
sheet silicates with alternating TOT units are _:_ layer silicates
weak
for sheet silicates with the structure TOTTOT, the interlayer site (between the T's) is very _______ bonding, like Talc
double chain silicates
form when two single chains of tetrahedra link to each other by sharing oxygen atoms, 4:11 silica to oxygen ratio
volatiles
gaseous components of magma dissolved in the melt. They will readily vaporize at surface pressures
S type
granite associated with continent-continent plates
Radiogenic heat
heat energy produced by the spontaneous breakdown, or decay, of radioactive elements
gravitational differentiation
heavier crystals sink to the bottom of the melt while light-enough crystals rise to the top creating the flotation cumulate.
Calcite Group
hexagonal minerals created by triangular shape of CO3 structure, rhombohedral cleavage, most common at earth's surface, primary mineral of limestone and marble
granitic magma
high in silica, light colored, high viscosity, & explodes as ash/rock
fumaroles
holes or cracks serving as escape vents for underground gases, create sulfur structures
refractive index
how much slower light travels in a crystal than in vacuum (Vv/Vm - Velocity vacuum/velocity medium)
weathering and alteration
hydroxides and oxyhydroxides typically form by __________ and _____________ in near-surface environments
more intense
if the waves interact constructively when examining birefringence, the colors are ______ __________
ultramafic
igneous rock composed mainly of iron and magnesium-rich minerals
Isochron
imaginary line on a map that shows points of the same age; formed at the same time
Na and K
in general, as silica content increases, so does the __ and ___ content
larger
in general, larger cations prefer ________ coordinated sites
Al
in general, silica can substitute with another element like...
4 coordinated
in general, the "z" sites are usually occupied by Si or Al and are thus __ _____________
Bowen's Reaction Series
in magmatic differentiation, the highest melting temp igneous rocks will crystallize first and move downward. This is called:
molecular sieves
inorganic or organic materials with cavities into which small molecules enter and are partially retained (are found in zeolites)
amphibole
is an example of a double chain silicate
pyroxene
is an example of a single chain silicate, rich in Mg and Fe
low temperature
kyanite is characterized by ______ _________ of formation
high pressure
large coordination in a mineral structure requires _____ __________ during formation, which happens deep in the mantle (e.g. garnet)
Aa
lava that hardens into rough, jagged rocks (basalt) with a crumbly texture (more viscous than pahoehoe)
half-life
length of time required for half of the radioactive atoms in a sample to decay
volatiles
low pressure melt cannot contain as many __________ as melt at high pressure
edge linked
m1 sites in olivine are only...
magmatic differentiation
magma chamber slowly cools from the edges with contact to the surroundings. the slow crystallization changes the composition of the melt
basaltic magma
magma that has low viscosity and low silica and gas content; eruption is non-explosive
decompression melting
melting due to a drop in confining pressure that occurs as rock rises
sulfides
metallic and semi-metallic elements bonded with S2- (and S2−2). They are typically soft and are good electrical conductors.
hydroxides
metallic elements combined with the hydroxyl ion (OH-). They are softer and less dense than oxides
carbonates
metallic or semi-metallic elements bonded with (CO3)2-. They are relatively soft and are a common biochemical precipitate.
oxides
metals or semimetal cations ionically bonded to O2-. Typically in closely packed structures and are opaque, dense and hard.
sulfates
minerals that contain oxidized sulfur (SO4)2- and are mainly combined with metal cations
viscosity
more water content in the melt, the lower the _________
plagioclase
most abundant mineral group in the crust
Snell's Law
n1sinθ1 = n2sinθ2
Bragg's Law
nλ=2dsinθ
high temperature
sillimanite is characterized by ______ __________ of formation
dioctahedral
only 2 out of the 3 octahedral sites are occupied in the O layer of a sheet silicate
atmosphere and hydrosphere
outgassing associated with volcanism replenishes ____________ and ____________
complex oxides
oxides of multiple metals
simple oxides
oxides of one metal
Sorosilicates
paired silicate tetrahedra, 2:7 silica to oxygen ratio
mafic and ultramafic
plagioclase, pyroxene, and olivine are common minerals found in ______ and _______ rocks
felsic and intermediate
plagioclase, quartz, and feldspars are common minerals found in _______ and ________ rocks
beta decay
radioactive decay in which an electron is emitted, the atomic number increases by 1 and the mass number stays the same
Thorium series
radioactive decay series of Thorium-232 to Lead-208
bimodal volcanism
refers to the eruption of both mafic and felsic lavas from a single volcanic center with little or no lavas of intermediate composition. The felsic melt results from the partial basalt melt
feldspathic
rich in feldspar
cyclosilicates
ring silicates, each silicate tetrahedron is linked to the two adjacent tetrahedra. 1:3 silica to oxygen ratio
tetrahedral sheet and octahedral sheet
sheet silicates always have at least one __________ sheet and one ___________ sheet
1+ cation
sheet silicates can have additional items in the inter layer site, which can be both another octahedral site (TOT-O-TOT) or a __ ________ (TOT-X+-TOT)
TO
sheet silicates have different patterns of alternating __ units like TOTO-> TOTTOT-> TOTOTOT->
1:1
sheet silicates with alternating TO units are _:_ layer silicates
talc
softest mineral on Mohs hardness scale due to van der waals bonds in the interlayer site
C12, C13, C14
stable isotopes of carbon
O16, O17, O18
stable isotopes of oxygen
Mg, Fe, or Mn
the M2 sites in pyroxene are 6-coordinated if it is occupied by __ , __ or __ due to their smaller size
Ca or Na
the M2 sites in pyroxene are 8-ccoridnated if it is occupied by __ or __ (due to the larger size)
ionic to metallic
the ________ to _________ bonding in sulfides gives way to characteristics like opaque, metallic luster, distinctive color and distinct streak
modal composition
the actual percentage of minerals in a rock, measured by optical or Xray means
age
the carbon isotope is useful for determining the ___ of environmental samples
polarization
the confinement of the electric field oscillation to a single plane (normally has random orientation)
geothermal gradient
the gradual increase in temperature with depth in the crust
temperature
the higher the ____________, the less viscous the melt
parent isotope
the isotope that undergoes radioactive decay
dimensions
the kinds of ions/molecules that enter the pores of zeolites is determined by the ____________ of the structure
silica content
the melting temp of igneous rocks increases with decreasing...
viscous
the more silica-rich the magma is, the more __________ the melt
partial melting
the process by which different minerals in rock melt at different temperatures
X-ray diffraction
the scattering of X-rays by the regularly spaced atoms of a crystal, useful in obtaining information about the structure of the crystal.
Uranium Series
the series of steps in the naturally occurring decay of uranium-238 to lead-206
lower
volatiles (like water) also _______ the melting temperature
exsolve
volatiles __________ when they reach the surface
soils
volcanic rocks produce rich and productive ____
lowers
water _______ the melting temperature of the magma
Al
when a layer has the dioctahedral form, the cations in the two sites are 3+ cations like...
2+
when a layer has the trioctahedral form, the cations all have a ____ charge, as the charge needs to sum to 6
channels and cages
zeolites have large _______ and _________ that allow for ion-exchange and gas molecule exchange
activated
zeolites have the ability become _________, meaning they are dry and able to take up water and cations
