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erth midterm 1 Flashcards

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1
Q

Earth is composed of what 5 different components

A

atmosphere (air), hydrosphere (water). cryosphere (frozen water/glaciers), biosphere (life supporting layer), and geosphere (solid part of planet)

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2
Q

what is bathymetry

A

sea-floor variations, it defines mid-ocean ridges, abyssal plains, and deep ocean trenches

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3
Q

what elements are most abundant on Earth

A

Iron (35%) and oxygen (30%)

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4
Q

who created the idea that earth was like an egg, and what does this mean

A

Emil Wiechert. Thin, light crust (eggshell). thicker, denser mantle (egg white). innermost, very dense core (yolk)

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5
Q

how are mountains formed, and what are they made of

A

by tectonic plates pushing and sliding against each other. the more dense plate will go down, forcing the other one up. made of calcium carbonate

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6
Q

explain the idea that the strain released during an earthquake is like the snapping of a bent stick. what does the speed tell us?

A

when the rocks under the surface break and slip along a fault, the shock waves generated will travel out, forming an earthquake. Their (seismic waves) speed tells us about the composition of Earth’s interior

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7
Q

what are the layers of the earth and what consistency are they

A

inner core (hottest, but solid), outer core (liquid), lower mantle (pressure and heat keeps it from forming a liquid, almost a plastic consistency. can move), upper mantle (split into transition zone and upper mantle. forms tectonic plates, plasticky.)

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8
Q

what is the transition state?

A

separates upper and lower mantle but is part of upper. minerals undergo major phase changes cause of pressure and these changes affect how seismic waves travel through earth

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9
Q

what generate the Earth’s magnetic field

A

convection in the liquid outer core

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10
Q

explain the lithosphere vs athenosphere

A

lithosphere: outermost. is rigid, composed of crust and upper mantle, makes up tectonic plates.
athenosphere: upper mantle below lithosphere. shallow under oceanic lithosphere, deeper under continental. soft solid

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11
Q

what is a mineral (and further, a crystal and grain)

A

mineral is naturally occurring crystalline solids. Crystal is a single mineral with geometric faces, it is always solid with a orderly structure. Grains are irregularly shaped fragments of larger crystals

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12
Q

what are glasses

A

non-crystalline solids. rapid cooling which is too fast for crystal growth

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13
Q

what are rocks and the 3 types with each definition

A

combination of minerals, grains, and/or glass. igneous (cooled from a liquid - melt), sedimentary (debris cemented from existing rock) and metamorphic (rock altered by pressure and temp)

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14
Q

what is sediment

A

accumulation of loose mineral grains (weathered/eroded from preexisting rocks)

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15
Q

what are metals (and alloys

A

solids composed of metal atoms. High density, shiny, conducts energy. Alloys contain more than one type of metal atom

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16
Q

what are melts and the two different molten rocks

A

rocks heated to a liquid. Magma is molten rock beneath surface and Lava is molten rock at the surface

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17
Q

what are volatiles

A

materials that turn into gas at the surface, are released from volcanos

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18
Q

what are most rocks on earth

A

silicates (Si and O), which are felsic

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19
Q

what are the four classes of igneous silicate rocks and what are they based on

A

Felsic, Intermediate, Mafic, Ultra-mafic. based on proportion of silica to Iron + Magnesium. more silica, less dense

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20
Q

what are the four classes made of

A

felsic is most Si rich, like granite (continental crust, made of felspar and quartz). mafic is oceanic crust (gabbro and basalt), ultra-mafic is peridotite (course-grained)

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21
Q

explain gabbro and basalt

A

basalt cools very fast and is a fine grain rock, gabbro doesn’t cool fast and is a course grain rock

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22
Q

what is moho

A

the base of the crust, which has both felsic rocks and mafic rocks (continental crust and oceanic crust)

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23
Q

who made the hypothesis about the continents fitting together and what was his name for it

A

Alfred Wegener, called Pangea.

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24
Q

what are evidence of past glaciers? And where are the Permian glacial deposits and striations found

A

Glacial striations. in regions where glaciers do not occur today.

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25
what preserves evidence of ancient climate belts and what do they align as?
late Paleozoic rocks, align in a sensible manner, like the climate belts today, when Pangea is fit together.
26
how does Pangea explain fossil distribution
animals that could not have travelled an ocean but are found on land separated by one
27
how is sea-floor bathymetry measured, what what is bathymetry
sonar (time it takes for sound wave to travel down and back up). bathymetry is the measure of depths and shapes of underwater terrain
28
what happens to the sediment as you get further from the mid-oceon ridge
gets older and thicker
29
What did Harry Hess do
compiled evidence that new seafloor is created at mid-ocean ridges, moves away from ridge, and then subducts back into mantle
30
explain seamounts (guyouts)
underwater mountains that do not reach surface. guyouts are seamounts with flat top from wave erosion. can be volcano, that moves away from hotspot and sinks. Hawaii is above ground example, will eventually sink.
31
what is declination
a small angle between geographic north and magnetic north. it changes over time and is generated from the outer core b/c it is moving
32
what is geographic north vs magnetic north (and where does a compass point)
not parallel, a compass points to magnetic north not true north. Geogrpahic does not changed and is fixed, points to axis which earth rotates. Magnetic aligns with Earth's magnetic field.
33
what is the axis of rotation
the magnetic axis runs through the earths magnetic poles and the axis of rotation runs through geographic poles. difference between the two is declination
34
T/F the magnetic axis is not parallel to the rotational axis
True
35
Explain the wandering North Pole.
earths magnetic pole position has moved around in the past 1800 yrs but stays near the geographical pole.
36
describe inclination
The tilt towards or away from Earth's surface cause by the curve of the magnetic field lines. The effect changes with latitude.
37
if you stood at the equator, the lines are _. If you stood at the poles they are _
horizontal, vertical. Imagine they go straight up from the pole and curve around to the other pole, therefore making the middle point between the two (the equator) where the line are flat.
38
explain how land moving affects the pole position
as landmass moves, the magnetic inclination at that location changes. Example: a rock that is found on a moved continent. the inclination of that rock will not match today.
39
explain how rocks in a lab can have evidence of inclination and declination
rocks can have magnetic minerals that lock in the direction of earth' magnetic field when they were formed. specifically mafic, because they are rich in magnesium and iron.
40
explain magnetic dipoles in hot magma
they are randomly oriented and no magnetization is possible. But, as the magma cools the dipoles inside the iron-bearing minerals become aligned with Earth's magnetic field. then the magnetic signature is frozen in the rock
41
what tested the magnetic fields of the sea-floor
magnetometers, the positive (strong) and negative (weak) lined up with the stripes on ocean floor.
42
transform fault
ridge being broken by a series of faults that are going in opposite directions, sliding
43
anomalies going in the same direction vs opposed
positive anomaly - when seafloor rock have the same polarity as the normal magnetic field. negative is opposing polarities
44
what is the width of magnetic stripes in the seafloor basalt proportional to
the duration of normal or reversed magnetic field conditions
45
lithosphere
rigid, composed of crust and upper mantle. thicker under the continents and thinner under the oceans.
46
athenosphere
is below lithosphere, soft and able to flow
47
explain a load on the lithosphere
it bends and cracks (glaciers or volcanos) and the asthenosphere flows
48
continental shelf
top surface of a passive-margin basin, the sediment of the basin overlies stretched lithosphere
49
where do earthquakes occur
in the belts that define tectonic plate boundaries. it is more stable if you're not near the plate boundary but may feel the aftershock.
50
what are passive margins and active margins
pacific coast is passive, atlantic and gulf coasts are active
51
What is the EEZ
Exclusive economic zone: offshore areas in which the bordering country owns all resources.
52
divergent boundary
2 plates move away from each other. seafloor spreading creates new seafloor at a mid ocean ridge.
53
mid ocean ridge
magma pushes up when they diverge, protrudes upwards. can form black smokers: water enters the fractured rock and magma heats it. the hot water dissolves minerals and gets pushed out the rocks.
54
explain the lithosphere during divergence.
thickens as it gets pushed away, deepens. thinner near ridge, is youngest
55
Convergent boundaries
plates move toward each other. one plate is downgoing, pushes beneath overriding plate. this is subduction.
56
what does subduction along the edge of a continent produce
a continental volcanic arc. when it involves two oceanic plates a volcanic island arc forms. the subducting plate hits the asthenosphere and melts, this melt is puhed to surface for volcano
57
transform boundary
slides past each other, nothing new forms or is consumed. active faulting only occurs in part of fracture zone between ridge axes.
58
triple junciton
where 3 plate boundaries intersect.
59
hot-spot volcanos
consequence of mantle plumes. as a plate drifts over the hot-spot, a chain of extinct volcanoes forms
60
what happens when these hot-spot islands erode and subside
eventually sink below sea level to form a seamount. Guyots are flat topped seamounts.
61
The Basin and Range Province is a _
rift.
62
polar wander
the apparent tendency of the north or south magnetic poles to vary in position over time
63
Earth's magnetic poles do not align exactly with Earth's _ pole. The difference is_
geographic, magnetic declination
64
Why can't continental crust subduct
it is too buoyant
65
What happens when 2 continents converge
rock undergoes compression and shearing and mountain range develops
66
In plate driving forces why does slab pull develop
old oceanic lithosphere is more dense than underlying asthenosphere so it sinks
67
which two ways can the velocity of plate motion be described
1. relative plate velocity describes motion of one plane relative to another 2. absolute plate velocity describes motion compared to a fixed reference point beneath the plate
68
hydrothermal vent
fissure on the seafloor where superheated, mineral-rich water is released from beneath Earth’s crust
69
wadati-benioff zone
sloping region of earthquake activity that traces the path of a subducting tectonic plate as it sinks into the mantle beneath another plate (at convergent plate boundaries)
70
why do hotspots exist
no one knows why
71
What did Hess do
-seafloor spreading hypothesis. provided mechanism for continental drift. -new crust forms at mid-ocean ridges and is destroyed at trenches
72
What did Wegener do
-continental drift -once united in Pangaea
73
What did Tuzo do
-introduced idea of transform faults -proposed that some volcanic island chains (like Hawaii) are explained by mantle plumes
74
explain salt found in Himalayans
salt is only found in water, so they were once underwater
75
What are minerals
They must occur in nature and be naturally formed. If you make it, it is synthetic make up all the rocks/sediments on earth
76
industrial, ore, and gem minerals
industrial: raw materials for manufacturing ore: sources of valuable metals gem: attract human passions
77
where do ionic bonds form
between positive sodium and negative chloride (Na+ and Cl-). sodium gives up one electron to chlorine, filling both shells and making halite
78
what is salt's composition
halite (NaCl)
79
covalent bonds
form when carbon atoms share electrons so that all have filled electron shells *SHARED* ionic is *TAKEN*
80
what is a polymorph
minerals with same chemical composition but different crystal structures
81
crystalline and glasses
most solid materials. solids lacking internal atomic order are glasses
82
What are the compositions of halite, diamond, quartz, and calcite.
NaCl, C, SiO2 (silicon dioxide), and CaCO3 (calcium carbonate)
83
euhedral vs anhedral
euhedral: good shape (had room to grow and perfect internal structure). hollow anhedral: bad shape, opposite. solid crystals like geodes
84
explain x ray diffraction
used to identify minerals. high power source, it determines the spacing of lattice planes inside minerals
85
What are the two polymorphs of carbon, and what is their hardness
diamond (most hard), graphite (least hard)
86
What is a cleavage plane
where you have the weak bonds. cannot cut strong bonds
87
solidification
occurs when molten rock cools and different minerals then grow.
88
mafic melts that cool rapidly have _ crystals
small. with time they will grow
89
Igneous and mafic rocks
igneous rocks form when magma or lava cools and solidifies. Mafic are igneous rocks that are rich in magnesium and iron
90
how is sulfuric acid made from volcanos
sulfur from volcano goes to the water, bonds with the hydrogen
91
precipitation
can occur from volcanic gas. for example sulfur crystals. also when water in salty desert evaporates.
92
biomineralization
the production of minerals by organisms. Reef organisms extract irons from water to make shells
93
diffusion
atoms migrate through and new minerals grow inside the rock. happens slow
94
diamond and graphite are formed as a result of different types of _
carbon bonding
95
what is streak
the colour of a mineral in powder form. some come in many colours, like quartz, but the powder will tell you what it is
96
what is the hardness from
strength of their bonds
97
the specific gravity and the crystal habit
1. weight of mineral 2. their shape. useful property of euhedral crystals
98
fracture vs cleavage
cleavage is perfect and every break will be the exact same. fracture is nothing of importance and can break in any way
99
hardness scale
talc, gypsum, fingernail, calcite, fluorite, apatite, glass, steel, quartz, topaz, corrundum, diamond.
100
how to test hardness
it is scratching resistance. so, whatever does the scratching is harder than what is being scratched.
101
luster, metallic, and nonmetallic
luster: refers to the way that a mineral surface scatters light. 2 main subdivisions of luster are metallic and nonmetallic: metallic looks like metal, nonmetallic is glassy, dull, silky
102
wulfenite crystals
very thing, tabular plates. orangish lead
103
ammolite
gemstone made of aragonite
104
cleavage and differences between crystal faces and cleavage
tendency for a mineral to break along lattice planes w weaker atomic bond. creates flat and shiny surfaces. cleavage is through, faces are only external surfaces
105
what are some hazardous materials
minerals containing chemicals that can poison people, like asbestos or pulverized silicates.
106
asbestos
fibrous silicate that can embed in lungs and cause cancer
107
what did JJ Berzelius do
said minerals can be separated by the principle anion (neg ion), or anionic group (negative molecule)
108
whats the most abundant mineral class
silicates (SiO4^4-) we only look at the end for classification
109
what common mineral reacts with acid
calcite
110
who created the mineral classes
Georgius Agricola
111
if is isnt a sulfide it is a _
sulfate (SO4 instead of SO)
112
what are halides
halite and fluorite (NaCl and CaF2)
113
what are combonates
CO3^-2, calcite and dolomite
114
what are some oxides
they are metal cations bonded to oxygen: magnetite (Fe3O4) and hematite (Fe2O3)
115
what are some sulfides
metal cations bonded to a sulfide anion: pyrite (FeS2, fools gold), galena (PbS)
116
What are some sulfates
SO4^-2 metal cation bonded to sulfate anionic group, many form by evaporation of seawater. Gypsum (CaSO4 * 2H2O), anhydrite (CaSO4)
117
native metals/pure masses of a single metal
copper (Cu), gold (Au), and silver (Ag)
118
The SiO4^4- anionic unit is also known as _
the silica tetrahedron, a fundamental building block of silicate minerals can be depicted as an atomic diagram, a ball model, a ball and stick model, or as geometric sketch.
119
solid state diffusion
atoms/ions move through solid material w/out it melting. particles migrate through rigid crystal lattice of solid
120
the most dominant substances
silicate minerals, making up Earth's crust and mantle
121
explain silicate minerals with isolated tetrahedra
don't share any oxygen atoms. they're instead bonded by cations. olivine and garnet no cleavage
122
single-chain silicates
2 of 3 basal oxygens are bonded. pyroxene
123
double-chain silicates
like 2 single chains that share oxygens where tetrahedra touch. amphibole
124
sheet silicates
share oxygens along base of tetrahedra, but not at top (2 dimensional sheet). can cut here. mica
125
framework silicates
all oxygen are shared between adjacent tetrahedra (3d) quartz and feldspar. no cleavage
126
faceting machine
cut and polish gems. not natural faces or cleavage planes but add to luster of gems. cutting gems is to reflect light
127
what is geology
the study of rocks and earth's systems
128
what drives earth's process
internal and external processes.
129
aurora caused by
composition of atmosphere. moon brings things up and out, causes deposits
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