Geology (Midterms) Flashcards
is grounding shaking caused by the sudden and rapid movement of one block of rock slipping past another along fractures in Earth’s crust
Earthquake
fractures in earth’s crust called
faults
it tends to occur along pre-existing faults where internal stresses cause the crustal rocks break into two or more units
earthquake
the location where slippage begins
hypocenter or focus
the point on Earth’s surface directl above the hypocenter
epicenter
a form of energy that travels through the lithosphere and earth’s interior
seismic waves
the energy carried by these waves causes the material that transmits them to shake
seismic waves
The famous San Francisco Earthquake
What energy is released that can generate earthquake - like waves
volcanic eruptions, massive landslides, and meteorite impacts
it have been discovered thousands of meters above sea level
fossils of marine organisms
he conducted a landmark study following the 1906 San Francisco earthquake
Harry F. Reid
it was accompanied by horizontal surface displacements of several meters along the northern portion of the San Andreas Fault
San Francisco earthquake
it keeps the fault from rupturing and slipping
friction resistance
a series of earthquake waves radiate outward as it slides
snap back
numerous earthquakes if lesswe magnitude that ahpoen after the strong earthquale
aftershocks
result from crust along the fault surface adjusting to the displacement caused by the main shock
aftershocks
small earthquakes which often, but not always, precede major earthquakes by days or, in some cases, several years
foreshocks
three types of faults
normal fault
reverse fault or thrust fault
strike-slip fault
block of rock below the fault
foot wall
block of rock about the fault
hanging wall
a fault wherein the hanging wall moves down relative to the foot wall
normal fault
a fault wherein the hanging wall moves up relative to the foot wall
reverse fault
thrust fault
a fault wherein two blocks of rocks slide past one another
strike-slip fault
mos of earth’s strongest earthquakes occur along large faults associated with _
convergent plate boundaries
the convergent plate boundary separating a subducting slab of oceanic lithosphere and the overlying plate forms a extensive fault zone
megathrust fault
faults in which dominant displacement is horizontal and parallel direction of the fault trace
strike-slip faults
gradual displacement
fault creep
are similar to the instruments used in ancient china
seismographs or seismometers
has a weight freely suspended from a support that i securely attached to the bedrock
seismograph
the records obtained from seismgraphs
seismograms
provides useful information about the nature of seismic waves
seismograms
two main types of seismic waves are generated by the slippage of a rock mass:
body waves
surface waves
travel through earth’s interior
body waves
travel in the rock layers just below Earth’s surface
surface waves
body waves are further divided into two types
primary waves or p waves
secondary waves or s waves
are push/pull waves; they momentarily push and pull rocks in te direction the waves are traveling
primary waves
solids, liquids, and gases resists stresses that change heir volume when compressed and, therefore, elastically spring back once the stress is removed
primary waves
it can travel through all these materials
primary waves
these waves “shake” the particles at right angles to their direction of travel
secondary waves
liquids and gases do not transmit
S waves
Two types of surface waves
rayleigh waves
love waves
causes earth’s surface and anything resting on it to move up and down much as ocean swells toss a ship
rayleigh waves
causes earth’s surface to move from side to side
love waves
this motion is particularly damaging to the foundation of structures
love waves
p waves are the first to arrive at a recording station, the S waves, and finally surface waves
s waves have slightly greater amplitudes than p waves, and surface waves exhibit even greater amplitudes
Seismologists use a variety of methods to determine two fundamentally different measures that describe the size of an earthquake:
intensity
magnitude
scale that uses observed property damage to estimate the amount of ground shaking at a particular location
intensity
scale that uses data from seismographs to estimate the amount of energy released at an earthquake’s source.
magnitude
A measure of how an earthquake was felt in a certain locality area
PEIS
phivolcs earthquake intensity scale
developed the first magnitude scale to use seismic records
Charles richter
is calculated by measuring the amplitude of the largest seismic wave recorded on a sesimogram
richter scale - richter magnitude
seismologists now favor this newer scale for measuring medium and large earthquakes
moment magnitude
is calculated by determining the average amount of slip on the fault, the area of the fault surface slipped, and the strength of the faulted rock
moment magnitude
the phenomenon of transforming a somewhat stable soil into mobile material capable of rising towards earth’s surface
liquefaction
major undersea earthquakes may set in motion a series of large ocean waves
tsunami
processes that deform Earth’s crust to create major structural features, such as mountains, continents, and ocean basins.
tectonic processes
continents were once united into a single supercontinent
continental drift hypothesis
single supercontinent named
Pangaea
He suggested that Pangaea broke up long ago and that the continents then moved to their current positions.
alfred wegener
evidences of the continental drift hypothesis
- the continental jigsaw puzzle
- fossils matching across the seas
- rock types and geologic features
- ancient climates
Constructed a map that pieced together the edges of the continental shelves of South America and Africa at a depth of about 900 meters (3000 feet).
SIr Edward Bullard
A small aquatic freshwater reptile whose fossil remains are limited to rocks of Permian age (about 260 million years ago) in eastern South America and southwestern Africa.
mesosaurus
seed fern
glossopteris
Includes the crust and the uppermost, and therefore coolest, part of the mantle
lithosphere
Earth’s strong outer layer
lithosphere
stone
lithos
is a hotter, weaker region in the mantle that lies below the lithosphere
asthenosphere
weak
asthenos
The lithosphere is broken into about two dozen segments of irregular size and shape called
lithospheric plate
plates
Seven major lithospheric plates are recognized and account for 94 percent of Earth’s surface area:
- North American Plate
- South American Plate
- Pacific Plate
- African Plate
- Eurasian Plate
- Australian- Indian Plate
- Antarctic Plate
Intermediate-sized plates include:
- Caribbean Plate
- Nazca Plate
- Philippine Plate
- Arabian Plate
- Cocos Plate
- Scotia Plate
- Juan de Fuca Plate
One of the main tenets of the plate tectonics theory is that plates move as somewhat rigid units relative to all other plates.
plate movement
Three types of plate boundaries:
divergent plate boundaries
convergent plate boundaries
transform plate boundaries
where two plates move apart, resulting in upwelling and partial melting of hot material from the mantle to create new seafloor
divergent plate boundaries
is the longest topographic feature on Earth’s
surface, exceeding 70,000 kilometers (43,000 miles) in length.
oceanic ridge system
Longest mountain range in the world which is underwater.
mid-atlantic ridge
along the crest of some ridge segments is a deep canyon like structure
rift valley
The mechanism that operates along the oceanic ridge system to create new seafloor
seafloor spreading
As the tectonic forces continue to pull apart the crust, the broken crustal fragments sink, generating an elongated depression
continental rift
where two plates move toward each other and the leading edge of one is bent downward as it slides beneath the other.
convergent plate boundaries
Convergent boundaries are also called
subduction zones
Located along the west coast of South America.
peru-chile trench
It is more than 4500 kilometers (3000 miles) long, and its floor is as much as 8 kilometers (5 miles) below sea level.
peru-chile trench
located in the western pacific
mariana trench
the deepest part of the ocean
challenger deep
Trenches in the Philippines:
- Philippine Trench
- Manila Trench
- Negros Trench
- Cotabato Trench
Three types of convergent plate boundary:
- Ocean-continent convergence
- Oceanic-oceanic convergence
- Continental-continental convergence
the wedge of mantle rock is sufficiently hot that the introduction of water from the slab below leads to some melting.
partial melting
Mountain systems like the Andes, which are produced in part by volcanic activity associated with the subduction of oceanic lithosphere,
continental volcanic arcs
The newly formed land, consisting of an arc-shaped chain of volcanic islands,
volcanic island arc
island arc
plates slide horizontally past one another without the production or destruction of lithosphere.
transform plate boundary
transform fault
The most common and abundant material on Earth.
rock
Composed of smaller crystals called minerals
rock
The grains or crystals may be microscopically small or easily seen with the unaided eye.
rock
two basic characteristics of rocks
texture
mineral composition
latin word for fire
“ignis”
form when molten rock solidifies at the surface or beneath the surface
igneous rocks
molten rock that is underground
Magma
molten rock that breaks through the Earth’s surface
Lava
latin word for settling
sedimentum
consists of particles derived from the weathering of other rocks
sedimentary rocks
composed of a clasts of minerals and rock fragments
Detrital sedimentary rocks
precipitation from solution waters
Chemical sedimentary rocks
best example is coal
Organic sedimentary rock
Greek word for after
meta
Greek word for form
morph
known as the Vishnu schist, it formed deep below earth’s surface where temperatures and pressures are high and in association with mountain-building episodes in precambrian time
metamorphic rock
A process that transforms the mineralogy, texture and sometimes chemical composition of the parent rock (original rock).
Metamorphism
due to high pressure and temperature
metamorphism
Refers to any planar (nearly flat) arrangement of mineral grains or crystals within a rock
Foliation
Are usually layered or banded
Foliated metamorphic rocks
allows us to view many of the interrelationships among different parts of the Earth system.
rock cycle
It helps us understand the origin of igneous, sedimentary, and metamorphic rocks and to see that each type is linked to the others by external and internal processes that act upon and within the planet.
rock cycle
molten rock that forms deep beneath Earth’s surface.
Magma
Over time, magma cools and
solidifies.
crystallization
the resulting rocks
igneous rocks
these particles and dissolved substances
sediment
a term meaning “conversion into rock.”
lithification
The sedimentary rock reacts to the
changing environment and turns into the
third rock type,
metamorphic rocks
the study of the solid Earth, the rocks which comprises it, and the processes
geology
Why study geology?
supplying things we need
avoiding geologic hazards
protecting the environment
understanding our surroundings
what are the earth systems?
atmosphere
hydrosphere
biosphere
geosphere
Earth as a giant machine driven by two heat engines:
internal heat engine and external heat engine
Earth’s interior:
crust, mantle, core
rigid
lithosphere
weak
asthenosphere
is broken into plates that are in motion
lithosphere
how old is earth by the use of radiometric dating?
4.6 billion years old
Geology as a discipline
The earth is our laboratory
timing is also important in geology
scale of rock features
main branches of geology
physical geology and historical geology
composition, processes beneath and on the surface
physical geology
origin and development through time
historical geology
main branches of physical geology
Physical Geology
* Volcanology
* Seismology
* Environmental Geology
* Engineering Geology
* Economic Geology
* Mineralogy
* Petrology
* Geochemistry
* Geophysics
* Geomorphology
Historical Geology
* Paleontology
* Stratigraphy
* Geochronology
monitoring, volcanic processes, hazards
volcanology
earthquake and seismic waves, hazards
seismology
interaction between humans and geologic environment
environmental geology
application of geologic information
engineering geology
metalliferous and non-metalliferous
economic geology
minerals
mineralogy
rocks
petrology
chemical composition
geochemistry
physical properties of rocks
geophysics
landforms and landform evolution
geomorphology
ancient life (fossils)
paleontology
succession of strata (layers)
stratigraphy
age of earth materials to provide a temporal framework
geochronology
Earth’s landscapes shaped by sudden and often worldwide great catastrophes (Earth is young)
catastrophism
catastrophism is proposed by
baron georges cuvier
Physical, chemical and biological laws that operate today also operated in the geologic past
uniformitarianism
uniformitarianism is proposed by
james hutton
Branch of Geology that studies the composition, properties, and genesis of minerals
mineralogy
building blocks of rocks
minerals
minerals NIDOH meaning
N – Naturally occurring
I – Inorganic
D – Definite chemical composition
O – Orderly crystalline structure
H – Homogenously solid
the smallest particle that cannot be chemically split
atom
It is a positively charged particles
proton
A particle with no charge
neutron
The central part of an atom composed of neutrons and electrons
nucleus
It is a negatively charged particle surrounding the nucleus
electron
Refers to the number of protons in an atom
atomic numbers
Refers to the group of atoms of the same number of protons
element
Mass of a particular atom
atomic mass number
Atoms of the same element with different atomic mass number
isotope
contain nuclei that do not tend to change spontaneously
stable isotope
have a potential to undergo radioactive decay
unstable isotope
A region where electrons move
electron cloud
A principal orbit where an electron revolves around the nucleus
principal shells
Refers to the electron/s on the outermost shell
valence electron
Refers to the force or mechanism that holds two or more atoms together to form crystals, then minerals, and then rocks.
chemical bond
Refers to the results of bonding two or more atoms.
chemical compund
Atoms tend to gain, lose, or share electrons until they are surrounded by eight valence electrons.
oclet rule
formed by the attraction of two atoms with opposite charges
ionic bonding
formed by equal sharing of electrons from both participating atoms
covalent bonding
refers to the collective sharing of the sea of valence electrons between several positively charged metal ions
metallic bonding
types of bonding
ionic, covalent
metallic bonding
Most conspicuous characteristics of a mineral
color
refers to the elements that are not part of the original compound of the mineral
impurities
The appearance of quality of light reflected from the surface of a mineral.
luster
minerals that have the appearance of a metal
metallic
minerals with metallic appearance but develop a dull coating or tarnish
submetallic
glassy appearance
vitreous
have an appearance like a pearl or inside a clamshell
pearly
have an appearance like satin cloth
silky
have an appearance as though coated in oil
greasy
Color of a mineral in powdered form. It can also help distinguish between minerals with metallic and nonmetallic luster
streak
when no light is transmitted
opaque
when light, but not an image is transmitted
translucent
When both light and image are visible
transparent
optical properties
color
luster
streak
diaphaneity
Refers to the common characteristic shape of a crystal or aggregate of crystals
habit
Refers to the strength of a mineral or its resistance to breaking or deforming
tenacity
Minerals that can be shatter into small pieces when struck
brittle
Minerals that can be easily hammered into different shapes
malleable
Minerals that can be cut into thin shavings
sectile
Minerals that can bend and snap back into its original shape after the stress is being released.
elastic
Measures the resistance of a mineral to abrasion or scratching
hardness
A relative hardness scale which consists of 10 minerals arranged in order from softest (1) to hardest (10).
mohs hardness scale
Refers to the tendency of a mineral to break along planes of weak bonding
cleavage
Defines the mass per unit volume of a mineral
density
Describes the density of a mineral
specific gravity
Ability of the mineral to be attracted in a magnet
magnetism
taste, feel, smell
sensory properties
Ability of a mineral to produce double image when light is transmitted
double refraction
Ability of a mineral to fizz when an acid is placed
effervescence
Rock-forming minerals. composed of Silicon and Oxygen
silicates
economic minerals. minerals used for construction
non-silicates
a pyramid shape with four identical faces
tetrahedron-shaped bond
physical properties of minerals
optical properties
crystal shape
mineral strength
mineral mass
other physical properties
