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