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earth materials Flashcards

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1
Q

It is the transition zone between
SIAL (silica aluminum), upper crust and SIMA
(silica magnesim ), lower crust

A

Conrad Discontinuity

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2
Q

discontinuities in the layers of earth

A

co
mo
re
gu
le

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3
Q

_________ are composed largely of dark colored mafic rocks enriched in _____ of _____, ____, and _____ relative to average crust

A

oceanic crust ; oxides ; iron, magnesum, and calcium

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4
Q

Composed largely of dark colored, mafic rocks enriched in oxides of magnesium, iron and calcium
( FeO and CaO) relative to average crust

A

oceanic crust

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5
Q

thickness of oceanic crust (depth to moho)

A

5-7 km

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6
Q

under some oceanic islands, oceanic crust can extend its thickness up to:

A

18km

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7
Q

primary rocks found in oceanic crust

A

basalt and gabbro

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8
Q

t or f: oceanic crust are older relative to the age of the earth

A

F (younger)

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9
Q

slices of ocean crust thrust onto continental margins

A

ophiolites

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10
Q

can be generalized as granitic in composition enriched in K2O, Na2O, and SiO2

A

continental crust

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11
Q

continental crust is enriched in oxides of:

A

Potassium, Sodium, and Silica

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12
Q

oldest well documented continental crust

A

4.03 Ga

from the northwest territories of canada

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13
Q

t or f: continental is thicker than oceanic crust

A

T

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14
Q

the great age of some continental crust results from its

A

buoyancy

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15
Q

silica composition of continental crust

A

approximately 60%

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16
Q

silica composition of oceanic crust

A

approx 50%

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17
Q

thickness of continental crust

A

30 km, under mountains is 80 km

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18
Q

age of oceanic crust

A

up to 180 Ma, 3.5% of earth’s history

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19
Q

age of continental crust

A

up to 4000Ma, 85-90% of earth’s history

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20
Q

t or f: oceanic crust have relatively lower surface elevation than oceanic crust

A

t

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21
Q

oceanic crust are mostly submerged _____sea level while continental crust are mostly emergent _____ seas level

A

below ; above

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22
Q

thickness of earth’s mantle

A

2900 km

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23
Q

radius of the earth

A

6370 km

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24
Q

earth’s mantle constitutes how many percent of earth’s volume

A

approx 83%

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25
silica composition of earth's mantle
40-45%
26
the earth's mantle has an _____ composition
ultrabasic
27
sublayers of earth's mantle
upper mantle and transition zone lower mantle
28
MgO content of mantle
30-40%
29
depth of low velocity zone
100-250 km
30
marks the contact between strong lithosphere and weak asthenosphere
low velocity zone
31
the uppermost part of the mantle and the crust together constitute the relatively rigid _____
lithosphere
32
the asthenosphere is more _____ and _____, rather than rupturing when subjected to stress
plastic ; flows slowly
33
lithosphere is strong enough to _____ in response to stress
rupture
34
minerals found in transition zone
ringwoodite and garnet
35
minerals found @660km depth
perovskite and periclase
36
minerals found @410km depth
olivine, wadleysite
37
major minerals found in mesosphere
perovskite and periclase; ilmenite; ferrite; stishovite; magnesiowustite;
38
complex zone near the core-mantle boundary, where anomalous seismic signals are common
D" layer
39
our knowledge of the deep mantle continues to expand largely based on ________ deep within the earth
anomalous seismic signals
40
D'' discontinuity ranges from
130-340 km
41
heat sources in the earth
1. residual heat from formation 2. frictional heat 3. decay of radioactive elements
42
these sporadic ULVZ may be related to the formation of _______within the lower mantle
deep mantle plumes
43
percent composition of iron in earth's core
approx 85%
44
percent composition of nickel in earth's core
5 %
45
density of outer core
10-12 g/cm^3
46
density of inner core
appox 13g/cm^3
47
refers to the non-uniform seismic velocities in the core
seismic anisotropy
48
amount of heat that can arise from accretion of small bodies, forming proto-earth
10,000 kelvins
49
heat produced by descent of iron-rich materials
2,000 kelvins
50
long-lived radioactive isotopes
235U, 238U, 232Th, and 40K
51
goldschmidt classifications
lithophile-rock loving siderophile - iron loving chalcophile - sulfur loving atmophile - gas loving
52
what does HREE/LREE stand for?
Heavy Rare Earth Elements; Light Rare Earth Elements
53
what does LILEs stand for?
Large Ion Lithophile Elements
54
what does LFSEs and HFSEs stand for?
Low Field Strength Elements ; High Field Strength Elements
55
the substance of which any physical object is composed of
matter
56
controlling factors of state of matter
temperature and pressure
57
layers of electrons that orbit around the nucleus are called
orbitals or energy-level shells
58
an atom that has gained or lost electron
ion
59
smallest particle that defines an element
atoms
60
consists of elements that combine in a specific ratio
chemical compound
61
covalent bonds have electronegativity of
less than 1.68
62
ionic bonds have electronegativity of
greater than 1.68
63
4 types of bonding
covalent ionic metallic Van der Waals
64
very weak bonding
Van der Waals Bonding
65
what is a mineral
Naturally occuring inorganic homoenous solid definite chemical composition crystalline structure
66
most abundant silica group
feldspar (plagioclase) 39%
67
abundance of quartz
12%
68
arrange silica in terms on increasing abundance
plag ortho quartz pyroxene (non silicates) amphibole mica clays other silicates
69
involves circulation and exchange of elements and minerals within the ecosphere and its environment
biogeochemical cycle
70
t or f: asthenosphere is solid but mobile
T
71
depth of transition zone
410-660km
72
depth of upper mantle from the crust
410km
73
depth of lower mantle from the crust
660km
74
depth of outer core from the surface
2900km
75
depth of inner core from the surface
5150
76
it is a strong rigid layer
lithosphere
77
layers of ophiolite
layer 1 - sediments layer 2 - pillow basalts and sheeted dikes layer 3 - gabbro layer 4 - layered ultramafic rocks
78
depth of asthenosphere
100-660
79
smallest quantity of a compound
molecule
80
4 types of bonding
covalent ionic metallic Van der Waals
81
element abundances in the crust
46.6 27.7 8.1 5.0 3.6 2.8 2.6 2.1

Geohazard (25 decks)

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