MODULE 2: ROCK CYCLE CONT'D: SEDIMENTARY, METAMORPHIC, GEOLOGIC TIME Flashcards
1
Q
Weathering
A
breaking down or alteration
2
Q
Erosion
A
removal, initial transport
3
Q
Weathering rates depend on… (3)
A
composition, chemistry, and climate
4
Q
Differential Weathering
A
different rocks weather at different rates
5
Q
Composition of Parent Material
A
minerals present in rock
textures and structures of rock
6
Q
What mineral is least prone to weathering?
A
Quartz, because it is most stable at Earth’s surface
7
Q
What is an alternate way to form a mountain? (Not tectonic)
A
differential weathering, the strongest mineral is left behind as others are weathered away
8
Q
Monadnock
A
an isolated rock hill, knob, ridge, or small mountain that rises abruptly from a gently sloping or virtually level surrounding plain
9
Q
(T/F) Distribution of joints influence how fast a rock mass weathers
A
True
10
Q
Joints
A
a fracture of rock, along which no appreciable movement has occurred
11
Q
Mechanical Weathering
A
the breakdown of rock into solid fragments by physical processes (chemistry of rock is not changed)
12
Q
Chemical Weathering
A
13
Q
Pressure Release (Sheet Jointing)
A
a mechanical weathering process where large curved sheets/slabs of rock peel off from the surface of an intrusive igneous rock
14
Q
Crystal Growth (Frost Wedging)
A
when water crystalized (freezes), it expands, prying rocks apart
15
Q
Where is frost wedging the dominant weathering process?
A
Cold climates
high latitudes and high altitudes
16
Q
Haloclasty
A
salt crystal growth - produces honeycomb pattern
17
Q
Abrasion
A
mechanical scraping caused by friction between rocks and moving particles
18
Q
Ventifact
A
sandblasting
19
Q
Thermal Stress
A
expansion and contraction of a rock due to temperature changes
20
Q
Root Wedging
A
winds may cause tree to sway, and widen the crack, wedging apart the bedrock
21
Q
Ion-exchange/Hydrolysis
A
exchange of Hydrogen ions for other cations
22
Q
Oxidation
A
reaction between Oxygen(O2-) and cation-rich minerals such as Iron(Fe2+) and Magnesium(Mg2+)
23
Q
Dissolution
A
process by which minerals are dissolved, separation of materials into ions in solution by a solvent (water or acid)
24
Q
Climate
A
moisture (annual average rainfall)
temperature (annual average)
25
Modes of Transportation (2)
dissolved ions
clasts (solid particles)
26
Media of Transportation (4)
wind, waters, glacier, gravity
27
Deposition
laying of sediment:
terrestrial and marine
28
Lithification
turning sediment in to rock
29
Mechanical weathering is stronger in (cold and dry/hot and wet) climates.
cold and dry
30
Chemical weathering is stronger in (cold and dry/hot and wet) climates.
hot and wet
31
99.9% of all fossils are in what type of rocks?
Sedimentary
32
Three "C"s of Lithification
1. Compaction
2. Cementation
3. reCrystallization
33
Terrestrial environment
above sea level
| includes lakes, rivers etc. yes water but above sea level
34
Marine environment
at or below sea level
35
What water depository environments are transitional?
beaches and deltas
36
Compaction
squeezing
37
Cementation
gluing
38
reCrystallization (sedimentary)
CaCO3 in marine shells at Earth's surface is called Aragonite
as temp and pressure gets more intense, structure shifts to Calcite
39
Clastic
accumulation of *particles* from preexisting rocks
40
Boulder, cobble or pebble-sized particles become...
| >2mm
Conglomerate (rounded clasts)
Breccia (angular clasts)
| breh-ch-ah
41
Sand-sized particles become...
| 0.0625mm-2mm
sandstone
42
Silt-sized particles become...
| 0.004mm-0.0625mm
siltstone (little grit)
43
Clay-sized particles become...
| 0.001mm-0.004mm
claystone/mudstone or shale (like flour)
44
Protolith
parent rock
45
(T/F) Large clasts stay close to their protolith.
true
46
(T/F) Small clasts stay close to their protolith
False, small clasts can travel farther away from protolith
47
Three "S" of sedimentary shapes
Sphericity
Smoothness
Sorting
48
Sheet jointing occurs in what rock type?
granite
49
Which gravestone weathers faster?
Marble/Granite
marble
49
Coral reefs require three general conditions to survive.
1. relatively shallow water
2. clear, debris-free water
3. warm, subtropical water temperatures
50
What is the bedrock underneath BGSU?
silurian limestone (dolostone)
Lockport Dolomite
51
What is the secret ingredient that changes Clay/Mudstones to Shales?
dead marine algae/plankton
ORGANIC MATTER
52
Is shale a clastic or biogenic sedimentary rock?
Clastic
53
What is shale made up of?
quatrz, feldspars, and ORGANIC MATTER
54
Fissile
platy and crumbly
55
Ohio shale has...
carbonate concretions
56
Shale fire
natural weathering of pyrite releases heat/sparks that can ignite pertroleum in the shale
57
Transgression
sea levels rising
58
Regression
sea levels falling
59
Chemical Sedimentary Rocks
inorganic precipitation of minerals dissolved in waters (Evaporites: salts/chlorides and sulfates)
60
Evaporites
formed withing a evaporating salty lake or sea from dissolved chemicals within the water
61
Biogenic Sedimentary Rocks
accumulated remains of organisms (e.g. shells, bones, teeth, wood, roots, leaves)
62
Foraminifera
| Makes Limestone
biogenic sediment, marine microorganisms with calcite shells
63
Limestone
made from calcite shells of aquatic organisms
64
Coccolithospores
| Make Chalk
microscopic Calcite-walled algae (phytoplankton)
65
Chert/Flint
made of algae, made of microcrystalline Silica
66
Diatoms
microscopic silica-walled algae (phytoplankton)
67
Coal
combustable, made of decomposed, compressed plants
68
(T/F) More Carbon caused coal to burn out faster.
False, more carbon caused longer burn lengths
69
Metamorphism
when solid rock changes (w/o melting) in composition &/or texture due to changes in temp, pressure, &/or fluids
70
What is another name for metamorphic source rocks?
parent rocks/protoliths
71
What is the region of diagenesis?
where sediments turn into sedimentary rocks
72
The Metamorphism of Shale...
Shale-->Slate-->Phyllite-->Schist (Mica Rich) OR Gneiss (Mica Poor)
73
Garnet
aluminosilicate mineral that grows during high-grade metamorphism
74
What different protoliths can Gneiss come from?
Sedimentary - Shale
Igneous - Granite/Diorite
75
Foliation
banded, platey, linear
| only occurs when mica is present
76
Migmatites
gneiss brought to the surface after being right at the brink of melting
77
Sheet silicates align (perpenticular/parallel) to applied pressure.
perpendicular
78
4 Different Regions of Metamorphism
1. burial metamorphism
2. subduction-zone metamorphism
3. regional metamorphism
4. contact metamorphism
79
Facies
group of minerals resulting from different metamorphic pressure and temperature conditions
80
Burial metamorphism
when temperatures and pressures are low
| zeolite
81
Subduction-Zone metamorphism
specific region of low temperatures and high pressures
| blueshisct facies and eclogite facies
82
Regional Metamorphism
two plates colliding at a convergent boundary (no subduction)
proportional/equal incr in temp and incr in pressure
| greenschist, amphibole, granulite facies
83
Contact Metamorphism
a specific region of high temperatures and low pressures
| hornfels facies
84
Impact Metamorphism
occurs where greatest temps, pressures, &/or stress exists even for brief time periods
| meteorite craters, atomic bomb sites, fault zones, even large fires
85
Shocked Quartz
high pressure deformation found only at impact craters and atomic bomb blast sites
86
6 Principles of Stratigraphy
1. Original Horizontality
2. Superposition
3. Lateral Continuity
4. Cross-Cutting Relationships
5. Inclusions
6. Fossil Succession
87
Principle of Original Horizontality
sediments are initially deposited horizontally
88
Stress
| a force
the force acting on a surface may be greater in certain directions than in others
89
Strain
| a deformation
change in shape or volume of a rock in response to stress
90
Pressure
uniform stress in all directions
91
3 Different Stresses
1. tensional <-- **O** -->
2. compressional --> **O** <--
3. shear (above) <-- ***O*** --> (below)
92
Deformation can be... (2)
temporary or permanent
93
Brittle deformation
cold, breaking
94
Ductile deformation
warm, bending
95
Anticline (/\)
limbs of fold inclined AWAY from one another, older rocks in the core
96
Syncline (\/)
limbs of fold inclined TOWARD one another, youngest rock in the core
97
Hinge Lines
peaks and troughs of the "clines"
98
Attitude
linear symbols depicting rock strata orientation
99
Strata
rock layer/unit
100
Contact
lines separating different rock strata
101
Strike
long line parallel to the contacts between rock units
102
Dip
short line pointing toward the direction the strata are inclined
103
Anticlines make (good/poor) structural petroleum traps.
Good
104
Plunging
Third Dimension tilt (look like V)
105
Recumbent Folds
has an essentially horiszontal axial plane, when the 2 limbs of a fold are essentially parallel to each other
106
Priciple of Superposition
younger layers are deposited on top
107
Thrust Fault
reverse fault where old stuff is thrust up and over the young stuff (much softer angle)
108
Princile of Lateral Continuity
sediment is deposited in continuous layers - a layer of sediment will extend horizontally as far as it was carried by water that deposited it
109
Principle of Cross-Cutting Relationships
rocks that are disrupted are oldre than the cause of disruption (igneous intrusions & faults)
110
Faults
brittle deformation (strain) of rock strata (due to stress) where there has been displacement along a fracture
111
Fault Scarp
rock exposed by fault
112
Hanging Wall
l/ - moving wall
113
Foot Wall
/l - anchor wall
114
Normal Fault
hanging wall moves down relative to the footwall as a result of tensional stress
115
Reverse Fault
hanging wall moves up relative to the footwall as a result of compressional stress
116
Strike-Slip (Transform) Fault
fault caused by shear stress
| San Andreas
117
Principle of Inclusions
a chunk of rock in another rock.
the chunk is older
118
Principle of Fossil Succession
fossils can be used to date rocks9
119
Unconformity
a break or gap in rock record caused by either nondeposition or erosion
120
3 Types of Unconformities
1. Angular
2. Nonconformity
3. Disconformity
121
Angular Unconformity
parallel sedimentary rock are deposited on top of tilted and layers that have been eroded
122
Nonconformity
sedimentary rock on top of an igneous or metamorphic surface that has been eroded
123
Disconformity
sedimentary strata that are parallel, but with an irregular surface that has been eroded between them
124
Radioactivity
| aka Radioactive or Nuclear Decay
procces in which an atom spontaneously releases energy and matterfrom its nucleus *at a constant rate or half life*
125
Radioactive decay
UNSTABLE parent isotope changes or decays into a STABLE daughter isotope
126
Radiocarbon (C14) Dating
a method used to determine the age of Carbon-containing materials
127
Animal aquire Carbon through photosynthesis. (T/F)
FALSE
Plants aquire carbon thru photo synthesis
Animals aquire carbon thru eating plants
128
Half life
the length of time required for 50% of the parent isotopeto decay into the daughter isotope.
Fixed rate of decay
| half life of C14 = 5730 years
129
How far back can C14 date something?
50-60,000 years ago (8-10 half lives)
130
Decay chain
a series of several radioactive decays which eventually leads to a stable isotope
131
Electron capture
a proton in the nucleus captures an electron from one of the electron shells and becomes a neutron
132
Beta decay
a neutron breaks into a proton and electron
133
K40-Ar40 decay
absolute age dating method used on igneous rocks older than 100,000 years old
