Earth Science Flashcards
1
Q
What is geology?
A
the science that deals with the earth’s physical structure and substance, its history, and the processes that act on it.
2
Q
These rocks are formed when magma (molten rock) from the Earth’s interior cools and solidifies.
A
igneous rock
3
Q
A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions.
A
Metamorphic rock
4
Q
A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
A
Sedimentary rock
5
Q
Rock that forms when magma cools above the surface of the Earth
They cool quickly and are fine-grained or lack crystal growth.
A
Extrusive igneous rock
6
Q
igneous rock that formed below Earth’s surface.
They cool slowly and as a result form visible crystals (coarse-grained.)
A
intrusive Igneous rock
7
Q
The process that converts sediments into solid rock by compaction or cementation.
A
Lithification
8
Q
What are the two main branches of geology?
A
physical and historical
9
Q
What is historical geology?
A
study of the physical processes and changes of the Earth through time.
Changes = Evolution
Studies the origin and evolution of the earth, its continents, oceans, atmosphere, and LIFE
10
Q
Volcanic Activity -> Weathering -> Transport (Erosion) -> Deposition -> Metamorphism -> Melting -> Magma
A
Rock Cycle
11
Q
Dentrital and Chemical
A
Methods of Classification
12
Q
foliated and non-foliated
A
Metamorphic rock classification
13
Q
Constructive = Building
Destructive = Erosive
A
Two main geological processes
14
Q
a coherent explanation for one or several related natural phenomena supported by a large body of objective evidence.
In other words, it is a hypothesis that has been tested many times and nothing has disproved it. Explains why
A
Theory
15
Q
965 -1040 AD
Born in Iraq, lived in Egypt & Spain most of his life.
Scientist:
Optics, Physics, Astronomy, and Mathematics
Called by many the father of the scientific method
A
Alhazen
16
Q
a method of procedure that has characterized natural science since the 17th century, consisting of systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.
A
What is the scientific method?
17
Q
Define a question -> Background research -> Hypothesis -> Test Hypothesis -> Analyze Data -> Interpret Data -> Conclusions -> Publish -> Retest
A
The Scientific Method
18
Q
generalizes a body of observations, nothing has disproved it yet- doesn’t explain why
A
Law
19
Q
does not imply causation
A
Correlation
20
Q
complex, conscious thought
A
What distinguishes humans from all other species?
21
Q
What is the universe defined by astronomers?
A
All of the space and matter and energy within
22
Q
The theory is that the universe originated in a huge explosion that released all matter and energy.
A
Big Bang Theory
23
Q
What is cosmology?
A
The scientific study of the universe
24
Q
The universe is expanding and background radiation
A
Evidence for the Big Bang
25
1929
Velocity increases proportionally
Spectral Lines
Doppler Effect
Edwin Hubble (1889-1953)
26
high frequency, short wavelength (compressed)
Blue light
27
low frequency, long wavelength (spread out)
Red light
28
What happened after the Big bang (Step 1)?
Basic forces emerged such as gravity, electromagnetism, and strong & weak nuclear.
29
What happened after the Big bang (Step 2)?
100% Hydrogen (H) and Helium (He) --> 98% Hydrogen (H) and Helium (He) & 2% all other elements
30
part of the milky way galaxy
Solar nebula theory
Our solar system
31
How are heavier elements formed?
Stelluar nucleosynthesis and elements formed past Iron (Fe) are formed in a supernova.
32
The ball at the center grows dense and hot --> Fusion reactions begin, the sun is born --> Dust in the rings condenses into particles --> Particles coalesce to form planetesimals.
Formation of the Solar System
33
Anything that has mass and takes up space
What is matter?
34
A substance that cannot be broken down into simpler substances
What is an element?
35
The basic unit of matter; structure, atomic number, and atomic mass, made of protons and neutrons and surrounded by electrons with a nucleus in the center.
What is an atom?
36
Atoms of the same element that have different numbers of neutrons
Isotopes
37
electrons in the outermost shell
valence electrons
38
2 or more elements chemically combined
Compounds
39
A group of atoms bonded together
Molecule
40
Ionic = Transfer
Covalent = Share
Chemical bonds
41
unequal sharing of electrons
Polar Covalent
42
Why is Polar Covalent important in nature?
Water
43
a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition
What is a mineral?
44
minerals that contain silicon and oxygen and usually one or more other elements.
Ex: Quartz, feldpars, (orthoclase and plagioclase), olivine, pyroxenes, amphiboles, and biotite.
Silicates (SiO2)
45
No Si (Silicon) and O (Oxygen)
Ex: Carbonates, Halidies, Native Elements, Oxides, Sulfates, and Sulfides.
Non-silicates
46
The arrangement of atoms and shapes varies based on bonds.
Crystalline structures
47
silicon-oxygen tetrahedron
Silicate Structures
48
form rings by sharing oxygen atoms
ring silicates
49
form a chain by sharing oxygen atoms
single chain silicates
50
form when two single chains of tetrahedra link to each other by sharing oxygen atoms
double chain silicates
51
Varying chemistry - many crystal forms
Cubes, hexagons, etc
Tetrahedrons are possible but not around Si (Silicon)
Properties determined by crystal pattern - native elements have closely spaced atoms = high density
Non-silicate structures
52
Study of Earth time
Geochronology
53
the branch of geology concerned with the order and relative position of strata and their relationship to the geological time scale. (Putting Geological events in order)
Stratigraphy
54
The study of the vertical layering of rock types. (Using rocks)
Lithostratigraphy
55
a relative dating technique based on the regular changes seen in evolving groups of animals as well as the presence or absence of particular species. (using fossils)
Biostratigraphy
56
absolute ages of rocks, as agreed upon by an international team of geologists (Using radioactive dates)
Chronostratigraphy
57
Determines how old something is in relation to something else.
(Not a number).
Ex: I am older than my brother but younger than my father
relative age dating
58
superposition, original horizontality, lateral continuity
Steno's laws
59
the principle that in undisturbed rock layers, the oldest rocks are on the bottom
Superposition
60
layers of sediment initially extend laterally in all directions
Lateral Continuity
61
The principle states that sedimentary rocks are deposited in horizontal or nearly horizontal layers.
original horizontality
62
Younger layer slices through the older surrounding layers (Fault line, Magma, etc).
Cross-Cutting (Hutton)
63
a piece of older rock that becomes part of a new rock
Inclusion
64
Fossil organisms succeed one another in a definite and determinable order, and any time period can be recognized by its fossil content.
fossil succession
65
an unconformity in which younger sediment or sedimentary rocks rest on the eroded surface of tilted or folded older rocks
angular unconformity
66
A gap in sedimentary rock record due to subaerial exposure.
Disconformity
67
Sedimentary rocks sit on metamorphic or igneous rocks.
Non-conformity
68
units in unbroken vertical succession record environments that would have been laterally adjacent
- implies TIME TRANSGRESSION during depositional events
Walther's Law
69
a method that enables scientists to determine the actual age of certain rocks and other objects
Ex: Dendrochronology, Ice core measurements, written accounts/records.
absolute age dating
70
The process of counting tree rings to determine the age of a tree
Dendrochronology
71
A spontaneous process in which unstable nuclei lose energy by emitting radiation. Alpha Decay, Electron Capture; Have loss of subatomic particles leading to a change in the structure and potential charge.
radioactive decay
72
Determining the age of a rock or mineral through its radioactive elements and decay products.
isotope dating
73
The time it takes for half of an isotope to decay
half-life
74
What percent of Carbon-14 would you expect from a sample from 11,000-12,000 years ago?
Reference: Half-life for Carbon-14 is 5,730
25%
75
A sample shows 35% Carbon-14 at 20,000 years is this correct?
Reference: A Half-life for Carbon-14 is 5,730 years
No, it is not correct because 50% and 25% of the parent material in Carbon-14 ranges from 5,730 years to 11,460 years.
76
isotope age dating lab conditions:
Assumes closed system
No one leaks out
No one leaks in
All products produced by decay
Clean lab conditions
Cost and Economic pressures
77
Not a new idea.
Continental fit
Plant fossils
Glaciations
Seuss
78
Continental movements
Mountains = lateral movements
Taylor
79
German Meteorologist & polar explorer
Continental drift
Pangea
Tons of Data!
Alfred Wegener
80
Wegener supporter
Further developed continental drift hypothesis
Climate paradox
Laurasia
Alexander Du Toit
81
Evidence of Late Paleozoic glaciers found on five continents.
Some of this evidence is now far from the poles.
These glaciers could not be explained unless the continents had moved.
Glacial Evidence
82
Placing Pangaea over the Late Paleozoic South Pole:
Wegener predicted rocks defining Pangea climate belts.
Tropical coals
Tropical reefs
Subtropical deserts
Subtropical evaporites
Paleoclimatic evidence
83
identical fossils found on widely separated land masses.
Mesosaurus-- A freshwater reptile
Glossopteris-- A subpolar plant with heavy seeds
Lystrosaurus-- A nonswimming, land-dwelling reptile.
Cynognathus- A nonswimming, land-dwelling mammal-like reptile.
Fossil Evidence
84
A physical phenomenon resulting from the spin of electrons in some solids--particularly those of iron-- and moving electricity
Magnetism
85
An area in which magnetic substances such as iron are affected by lines of magnetic force emanating from the earth.
Magnetic field
86
difference between geographic north and magnetic north.
Depends on:
The absolute position of the two poles and longitude
Declination
87
The angle between the magnetic field line and the surface of the earth.
Depends on:
Latitude
Inclination
88
the study of fossil magnetism
Paleomagnetism
89
-high temp-no magnetization
-thermal energy of atoms is very high
-magnetic dipoles are randomly oriented
hot magma
90
- Low Temp: permanent magnetization
- Thermal energy of atoms slows
- Dipoles align with Earth's magnetic field
- Magnetic dipoles become frozen in alignment with the field
cooled magma
91
Before World War II, little was known about the sea floor
*Echo-sounding (sonar) allowed rapid sea-floor mapping
-Sea-floor maps created by ships crossing the oceans.
-Bathymetric maps are now produced using satellite data.
Sea Floor Bathymetry
92
The oceanic crust is covered by sediment-
Thickest near the continents-
Thinnest (or absent) at the mid-ocean ridge
The oceanic crust consists primarily of basalt-
Lacks a variety of continental rock types
Heat flow is much greater at the mid-ocean ridges.
The Oceanic Crust
93
The process by which molten material adds new oceanic crust to the ocean floor; Old ocean floor sinks into the mantle and magnetism in sea floor rocks varied farther from MOR
sea-floor spreading
94
Changes in Earth's magnetic field over geologic time, recorded in ocean-floor rocks and continental basalt flows- Reversals occur at uneven intervals- Longer intervals (500 to 700+ Ka) are called chrons- Shorter intervals (~200 Ka) are subchrons
Magnetic reversals
95
It provides a unified mechanism explaining:
◦The distribution of earthquakes and volcanoes.
◦Changes in past positions of continents and ocean basins.
◦The origins of mountain belts and seamount chains.
A unifying theory
96
A theory stating that the earth's surface is broken into plates that move - the earth's outer shell is broken into a rigid plate that moves.
Plate motion defines three types of plate boundaries.
Plate Tectonics
97
A rigid layer made up of the uppermost part of the mantle and the crust. Continental - 150km thick, Oceanic - 100km
in motion over the asthenosphere
Bends elastically when loaded
Asthenosphere flows plastically when loaded
Lithosphere
98
Where land meets the ocean
continental margin
99
Tectonic plates move apart.
Forming either rift valleys or mid-ocean ridges (MOR)
divergent boundary
100
Tectonic plates move together
Causes uplift or subduction
convergent boundary
101
Tectonic plates slide sideways.
Transform boundary
102
Magma from deep within the mantle melts through the crust above it.
Hot spots
103
The driving mechanism of plate tectonics
Convection
Ridge-push
Slab-pull
104
An episode of intense rock deformation, or mountain building, results in compressive forces generated by collision.
Orogeny
105
The relationship between mountain building and the opening/closing of ocean basins.
Wilson Cycles
106
Importance of sedimentary rocks
preserve evidence of surface processes responsible for deposition, many contain fossils that are rare or absent in most other rocks, and many are resources or host rocks.
107
Sedimentary rocks form at or near Earth's surface in one of several ways:
Cementing loose clasts (fragments) of preexisting rock.
Cementing together loose shells and shell fragments.
Accumulation of organic matter from living organisms.
Precipitation of minerals dissolved in water.
108
Clastic: Loose rock fragments (clasts) cemented together.
Organic: Carbon-rich remains of once-living organisms.
Biochemical: Cemented shells of organisms.
Chemical: Minerals that crystalize directly from the water.
Geologists define four classes of sedimentary rocks
109
Classified on the basis of texture and composition:
Clast (grain) size
Clast composition
Angularity & Sphericity
Sorting
Character of cement
110
the degree of edge or corner smoothness
Negligible transport (younger)
angularity
111
the degree to which a clast nears a sphere
Long transport distances (Older)
Sphericity
112
the uniformity of grain size
Sorting
113
all clasts have nearly the same grain size
Well-sorted
114
clasts show a wide variety of grain sizes
poorly sorted
115
features that developed during or shortly after the deposition of the sediments
sedimentary structures
116
Sedimentary rocks are usually layered or stratified.
Arranged in planar, close-to-horizontal beds.
The boundary between two beds is a bedding plane.
Several beds together constitute strata.
Bedding and stratification
117
Why does bedding form?
Bedding reflects changing conditions during deposition.
118
Bedding forms due to changes in:
Climate
Water Depth
Current Velocity
Sediment Source
Sediment Supply
119
bedding or stratification
A sequence of beds
120
Water or wind flowing over sediment creates
bedforms
121
Bedform character is tied to
Flow velocity
Grain size
122
cm-scale ridges and troughs.
Develop perpendicular to flow
Frequently preserved in sandy sediments
Found on modern beaches
Found on bedding surfaces of ancient sedimentary rocks
ripple marks
123
similar to ripples except for much larger
Form from water or wind-transported sand.
Occur in streams and in desert or beach regions.
Range in size from tens of cm to hundreds of m
Often preserve internal cross beds.
Dunes
124
created by ripple and dune migration; sediment moves up the gentle side of a ripple or dune; sediment piles up, then slips down the steep face
Cross beds
125
Sediment moves on a slope as a pulse of turbid water.
As pulse wanes, water loses velocity and grains settle.
Coarsest material settles first, medium next, then fines.
This process forms graded beds in turbidite deposits
Turbidity currents and graded beds
126
occur after deposition while sediment is still soft
Bed surface markings
127
polygonal desiccation features in wet mud, indicate alternating wet and dry terrestrial conditions
Mudcracks
128
troughs eroded in soft mud by current flow
Scour marks
129
evidence of past life
footprints
Shell impressions
Fossils
130
Locations where sediment accumulates. They differ in:
Chemical, physical, and biological characteristics. Sediment delivery, transport, and depositional conditions. Energy regime.
Environments include Terrestrial,Coastal, and Marine.
depositional environment
131
large areas where sediment accumulates.
Thin to absent where nonsedimentary rocks outcrop
thicken to 10-20 km in sedimentary basins
Sedimentary basins
132
sinking of the land during sedimentation
Subsidence
133
Craton side of the collisional mountain belt
The weight of the mountain belt pushes down the crust's surface
Foreland basin
134
Divergent (pull-apart) plate boundaries.
downward slip on faults produces narrow troughs
Rift basin
135
Interiors far from margins.
the basin forms in the interior of a continent, perhaps over an old rift
intracontinental basins
136
Continental edge is far from the plate boundary.
subsidence occurs over thinned crust at the edge of an ocean basin
passive margin basin
137
flooding due to sea-level rise.
Sediment belts shift landward; strata "deepen" upward.
transgression
138
Exposure due to sea level fall
Regression
139
Physical, chemical, and biological changes to sediment.
Lithification is an example of it.
As sediments are buried, pressure and temperature rise.
Diagenesis
