MIDTERM Flashcards
Sustainability is engineering that meets the ______ __ ___ _______ without compromising the ________ __ ___ ________
needs of the present
viability of the future
What is the triple bottom line
balance btw social, environmental and financial impacts
explain physical geology
study of materials, processes on and below the Earth
explain historical geology
origin of the Earth and development
explain engineering geology
analysis of Earth history, processes and impact on human history
what are the 4 spheres?
geosphere
hydrosphere
atmosphere
biosphere
Ground water makes up ___% of all fresh water
31
what is hydrology?
how water flows across the surface: water balance, flow channel systems
who came up with catastrophism
James Usher
what is catastrophism
the Earth’s landscapes (mountains, canyons) had been shaped primarily by great catastrophes
who came up with uniformitatianism
James Hutton
explain uniformitarianism
physical, chemical, biological laws that operate today here also operated in the geological past
THE PRESENT IS THE KEY TO THE PAST
“forces that appear small could have great impact over longer periods of time”
catastrophism or uniformitarianism?
uniformitarianism
how old is the earth approximately
4.6 million years old
what is relative dating?
events are placed in proper sequence or order w/o knowing their age in years
what is the law of superposition?
in layers of sedimentary rocks/lava flows, the youngest layer is on top and the oldest is on the bottom
when did the Big Bang happen
approx 13.7 million years ago
what is continental drift
who proposed it?
the continents moved about the face of the planet
Alfred Wegner
example of continental drift
pangea
the lithosphere consists of:
the crust and the upper most (brittle) part of the mantle, broken into smaller units called plates
what is thin, rocky, oceanic or continental, made of granite and basalt?
crust
mantle is:
solid, rocky shell that extends to a depth of 2900 km
what is made of an iron-nickel alloy w minor amounts of oxygen, silicon and sulphur? It is also very dense
core
the hydrosphere is a dynamic mass of _______, continually on the move, ___________, precipitating on the ______ and returning to the ocean again
water
evaporating
land
the atmosphere is a
life-giving, gaseous envelope surrounding the Earth, produces weather/climate
thin and tenuous is describing the:
atmosphere
biosphere?
all life on Earth
geosphere?
beneath the atmosphere and oceans
continents w mountains and shields, directly reflect tectonic processes
what is paleomagnetism?
rocks that formed thousand/millions of years ago and recorded the location of the magnetic poles at that time, and are said to possess fossil magnetism
explain polar wandering?
the idea that the magnetic poles had migrated through time
magnetic poles have gradually wandered due to continental drift
explain the sea floor spreading
- deep-ocean trenches are sites at which ocean crust is drawn back to the planet
- the older portions of the sea floor are gradually consumed as they descend into the mantle
due to sea floor spreading, continents have:
wandered
lithosphere is broken into how many plates?
7
divergent plate boundaries:
this plate boundary occurs where 2 plates move away from one another another at oceanic ridges where continents split, upwelling material
what do divergent plate boundaries create?
new ocean basins
convergent plate boundaries?
2 plates move together with descent of oceanic crust into mantle or collision of 2 continental plates
transform fault boundaries
where plates slip past each other, typically between 2 oceanic ridge segments
list proof that supports plate tectonic theory:
- continental rifts
- magnetic polar wandering paths
- mid-ocean ridges
- volcanic arcs
- ocean trenches
- volcanic islands associated w hot spot tracks
- increasing sediment age
- symmetrical pattern of magnetic intensities recorded in ocean floor rock
the tunnel boring machine Earth Pressure Balance is designed for :
clay but not for running sand
oceans accounts for what % of the earths water?
71%
how is earths system powered?
energy from the sun and from the heat from the earths core
explain the big bang theory
large explosion that sent all matter in the universe flying outwards at incredible speeds
what is the nebular hypothesis?
bodies in solar system evolved from solar nebula
the crust solid/rigid solid is composed of
silica materials
the mantle/plastic solid is composed of
magnesium/iron minerals
what are the 2 types of seismic waves
body
surface
body wave
travel through earth’s interior
p and s
surface wave
travel on the earths surface
difference between a p and s wave
p: faster, travel through every material
s: can’t travel through water
what is the rock cycle?
the loop that involves the processes by which one rock type changes to another
go through the rock cycle (5 steps):
- molten magma becomes igneous rock
- weathering creates sediments
- sediments lithify to sedimentary rocks
- burial and heat produce metamorphic rock
- add more heat and it repeats
greatest expanse of time
eon
phanerozoic
visible life
the most recent eon, began just over 540 million years ago
a subdivision of an eon is:
an era
what are the eras of the phanerozoic eon
cenzoic (recent)
mesozoic (middle)
paleozoic (ancient)
eon–>era–>_______–>______
period
enoch
how and why is isotope analysis and decay used?
igneous rocks contain uranium
uranium decays to lead at a defined rate
relative ratio of lead to uranium gives age of rock
radioactive decay
breakdown of an isotope
radiometric dating
calculate ages of rocks and minerals that contain particular isotopes
half-life
time required for half the parent radioactive nuclei in a sample to decay to daughter products
what is relative dating?
events are placed in their proper sequence or order w/o knowing their age in years
law of superposition
younger rocks are deposited over older rock layers
principle of fossil succession
fossil organisms success each other in a determinable order
principles of horizontality
layers of sediment originally horizontal
flat rock layers have not been disturbed
principle of cross cutting relations
younger features cut across older features
what is an unconformity
break or gap in the rock record caused by erosion or nondeposition
index fossils
widespread geology and limited to a short span of geologic time
continents
prominent features are linear mountain belts
shields
ocean basins
ocean ridge system
deep ocean trenches
what is our current detailed understanding of the continents?
plate tectonics
what is a geomagnetic reversal?
earths magnetic field periodically reverses polarity
the magnetic field is preserved in?
cooling lava
dates when the polarity of the earths magnetism changes was determined by:
lava flows
the lithosphere consists of _________ mantle and overlying _______
it is broken into _______ ______
uppermost
crust
moving plates
what are the main methods for measuring plate motion used today?
- GPS tracking
- hot spots trace movement of Pacific plate relative to mantle
- average rate of motion calculated by the time interval between oldest and youngest volcanic structures
what drives the movement of the plates?
convection in the mantle
_________ plates move relative to one another at very _____ rates (plate tectonics)
lithospheric
slow
where do divergent boundaries occur
mid-ocean ridges
underneath rift valleys
subduction zone
consumption of crust into mantle
Isostasy is why the earth isn’t _______
smooth
For any earth material to be considered a mineral it must exhibit the following characteristics (5):
- occur naturally
- solid at surface temperatures and pressure
- possess an orderly internal structure, atoms must be arranged in a definite pattern
- definite chemical composition, can vary w/in specific limits
- USUALLY inorganic
Atoms are bonded to form a particular _________
structure
polymorphism is
when elements are able to join together in more than one type of geometric arrangement
ex. graphite and diamond
explain crystal habit:
shape
external expression reflecting orderly internal arrangement of atoms
explain lustre:
quality of light reflected from the surface of a mineral crystal
metallic/non metallic
explain colour:
the colour lol
obvious, but not always diagnostic due to alterations from impurities
explain streak:
colour of a mineral in its’ powdered form
obtained by rubbing mineral across piece of unglazed porcelin
explain hardness:
measure of minerals resistance to abrasion or scratching
explain cleavage:
tendency of a mineral to break along planes of weak bonding
explain fracture:
depending on the chemical structure of a mineral and the balance of strength in the bonds, it may break or fracture in a distinctive matter
explain specific gravity:
numbers representing the ratio of the weight of a mineral to the weight of an equal volume of water
define a rock:
a solid mass of minerals
define an element:
basic building blocks of minerals
atomic number
number of protons in an atom
atomic weight
approx. the total number of protons and neutrons in nucleus
list the other properties of minerals (3):
malleability, elasticity, striations
describe the silicates
most common mineral group
Si-O tetrahedron
list some of the non silicates
oxides hydroxides sulphides sulphates halides carbonates phosphates
2 oxides include:
magnetite
hematite
2 hydroxides include:
limonite
bauxite
2 sulphides include:
galena
sphalerite
2 sulphates include:
gypsum
anhydrite
2 native elements include:
gold
copper
2 halites include:
halite
fluorite
2 carbonates include:
calcite
dolomite
2 phosphates include:
turquoise
apatite
how and what are igneous rocks made from?
the cooling of molten lava
what does magma form from?
the partial melting of rocks inside the earth
lava is magma that:
reaches the surface of the earth
another word for extrusive is
volcanic
another word for intrusive is
plutonic
extrusive igneous rocks are rocks that
form when magma solidifies AT THE SURFACE
intrusive igenous rocks are rocks that
FORM AT DEPTH from magma that crystallizes slowly
what is a body of plutonic rock called?
a pluton
what are extrusive igneous features (3):
- lava flows
- fissure eruptions
- volcanoes
what are intrusive igenous features (5):
- batholiths
- laccolith
- sills
- dykes
- volcanic necks
what are the 3 components of magma?
melt, solids, volatiles
what is in the melt?
liquid portion of magma composed of mobile ions
what is in the solids?
silicate minerals that have already crystallized from the melt
what are the volatiles?
gases dissolved in the melt, water, carbon dioxide, sulphr dioxide which are confined by immense pressure exerted by the overlying rocks
make magma lighter so it rides
explain texture:
describes the overall appearance of a rock based on the size, shape and arrangement of its interlocking crystals
what are the 3 contributing factors to the texture of igneous rocks:
- rate of cooling of magma
- amount of silica present
- amount of volatiles in the magma
geothermal gradient:
T increase in the Earth’s upper crust, increasing with the depth
melting beings if:
CONFINING PRESSURE drops slightly
TEMP increases slightly
VOLATILES are introduced
what occurs when confining pressure drops?
decompression melting
cooling magma resulting in the systematic arrangement of ions into crystal structures is:
crystallization
magmatic differentiation:
formation of one or more secondary magmas from one parent
primary mafic magmas:
also what is another name for them
originate from direct melting of mantle
periodite
Andesitic and felsic rocks
found only w/in continents
mixing of mafic magma and melted continental crust
felsic: _________ composition
granitic
mafic: _________ composition
basaltic
intermediate: _________ composition
andesitic
Ultramafic composition:
composed entirely of ferromagnesian silicates
glassy texture:
very rapid cooling of molten rock
obsidian
aphanitic texture:
fine grained
rapid rate of cooling or magma
microscopic crystals
phaneritic texture:
coarse grained texture
slow cooling
larger crystals
pegmatitic texture:
very coarse grained texture
very slow cooling
forms in late stages of crystallization
poryphitic texture:
minerals form at different temperatures and rates
large and small crystals intermixed
pyroclastic texture:
ejected during a violent volcanic eruption
factors that impact viscosity of magma:
- dissolved gas increases fluidity
- viscosity (silica content)/composition
- temperature
eruption volumes
jets of hot ash-laden gases that evolve into buoyant plumes
Nuee ardente
fiery pyroclastic flow made of hot gases infused with ash and debris
race down the slopes of volcanos at up to 200 km/h
lahar
debris flow composed of mostly wet volcanic materials off steep sided/ flanks of volcanoes
fluid _______ lavas generally produce quiet eruptions, allowing the gases to _______ upwards and _______ with ease
mafic
migrate
escape
highly ________ lavas, also known as _________ or __________ produce more explosive eruptions
viscous
rhyolite
andesite
Shield volcano
produced by the accumulation of fluid mafic lavas
broad, slightly domed (caldera)
Cinder Cones
ejected lava fragments that harden while in flight
Calderas
large collapse depressions having a more or less circular form
Fissure Eruptions
lead to immense buildups of basalt
Lava Domes
as thick silica-rich lavas flow/squeeze through the vent, might produce a steep-sided dome-shaped mass of congealed lava
weathering
breakdown of a rock at or near the Earths surface
mass wasting
transfer of rock and soil down slope by gravity
erosion
physical removal of material by water, wind, ice, etc.
mechanical weathering
breaking of rocks into smaller pieces by physical forces
chem comp of rock stays same
increases surface area
chemical weathering
chemical transformation of rock into one or more new compounds
breaks down components and internal structures of minerals
frost wedging
water in cracks freezes, expands and breaks the rock
creates large piles of talus slopes
unloading (2 types)
sheeting: concentric slabs coming loose
exfoliation dome
what causes unloading?
temperature cycling and stress relief
biologic activity (mech)
disintegration resulting from plants (roots), burrowing animals and humans
dissolution (chem)
soluble ions released from rock, aided by acidity
oxidation
chemical reaction in which an element loses electrons
rusting
hydrolosis
H+ ion from water attacks and replaces other positive ions in the mineral, causing the crystal structure to collapse
rocks containing calcite or halite dissolve ________
readily
rocks containing silicate minerals are relatively _________
resistant
Differential weathering
since masses of rock do not weather uniformly, this results in many unusual and spectacular rock formations
what are the controls of soil formation?
parent material time climate drainage plants and animals topography
pedalfer is a type of soil that is
accumulation of oxides and clays
organic-rich soil
temperate climates
pedocal is a type of soil that is
high accumulations of calcium carbonate
temperate grassland
low clay
laterite is a type of soild that is
wet and tropical climates
concentrates iron and aluminum
clay as foundation is:
unpredictable
sensitive to disturbance
can fail catastrophically
silt as foundation is:
sensitive to frost and variations
sand as foundation is:
good
good drainage
sensitive to water content and density
gravel as foundation is:
rough and angular
or rounded
talus slopes:
sections of rock that are wedged loose and may tumble into large piles
base of steep rock outcrops
infiltration capacity is controlled by:
intensity and duration of rainfall slope of the land soil texture nature of the vegetative cover prior wetness of the soil
what are the 2 types of water flow?
laminar
turbulent
laminar flow is
slow, smooth channel
turbulent flow is
fast, rough channel
what are the 4 methods of flood control?
- artificial levees
- flood-control dams
- channelization
- floodplain management
waves derive ______ and __________ from wind
energy
motion
wave height
distance btw trough and crest
wavelength
horizontal distance between crests
wave base is approx
1/2 wavelength
surf is
turbulent water created by breaking waves
tides are:
daily elevation of ocean surface
an incoming tidal current is known as a _______ current
flood
a seaward-moving tidal current is known as a _______ current
ebb
areas affected by tidal currents are called
tidal flats
an estuary is
an inlet of the sea formed at the mouths of streams
sedimentary rocks form from:
precipitation, sedimentation and accumulation of weathered rock material
diagenesis
all of the chemical, physical and biological changes that take place after sediments are deposited, but PRIOR TO METAMORPHISM
recrystallization and lithification
recrystallization
development or replacement of more stable minerals with less stable ones
lithification
when sediments are transferred into solid sedimentary rock by compaction and cementation
list the 5 types of sedimentary environments:
- continental
- transitional
- marine
- deep
- sedimentary facies
continental sedimentary environment:
rivers and streams
glacial
wind
transitional sedimentary environment:
- Tidal flats
- Beaches
- Lagoons
- Deltas
marine sedimentary environment:
Shallow (to about 200 metres);
deep sedimentary environment:
Deeper than 200 m
sedimentary facies sedimentary environment:
each unit has characteristics reflecting a particular environment
different sediments often accumulate adjacent to one another at the same time
detrital sedimentary rocks
sediment transported as solid particles
chemical sedimentary rocks
chemical sediment that was in solution
organic rocks
from carbon rich tissues of once living things
strata or beds are
layers
bedding planes are
flat surfaces that separate strata
cross-bedding are
inclined layers
mudcracks are
shrinkage on exposure to air
ripple marks are
small waves of sand formed by moving water
remains or traces of prehistoric life preserved in sediment/sedimentary rock are known as
fossils
the 2 types of fossils are:
body
trace
the three types of preservation fossils are:
Recrystallization
Petrification or Replacement
Mould – internal and external impressions
fissility means the rock splits into ….
what rock does this? what rock doesn’t?
thin layers
shale does
siltstone does not
describe sandstone
cement, sand sized particles
transported by wind and water
types of sandstone (3)
quartz, arkose, wacke
conglomerate consist of ________ gravel
rounded
breccia is composed of large _______ particles
angular
evaporites:
rock salt
rock gypsum
potash
salt flats
dissolved material precipitated as
white crust on ground
describe limestone
most abundant chemical rock
composed mainly of calcite
metamorphism
changes in solid rock when a rock
is subjected to temperatures or pressures very
different from where they formed
true or false: for metamorphic rock, the parent rock can be any type?
true
the most important metamorphic agent is ______
heat
what do chemically active fluids do?
- Enhance migration of ions; act as catalysts
- Aid in re-crystallization of existing minerals
- Hydrated minerals lose water during heating
Uniform Confining pressure
applies forces equally in all
directions;
=denser metamorphic rocks
Directed pressure
which is unequal in different
directions,
=results in distortion
foliation
preferred orientation of platy minerals in a metamorphic rock
what are the three factors that influence foliation?
- Rotation of platy and/or elongate mineral grains into a
new orientation - Changing the shape of equidimensional grains into elongate shapes aligned in the preferred orientation
- Re-crystallization of minerals to form new grains growing in direction of preferred orientation
Contact metamorphism occurs when
rocks around an igneous body are cooked as magma invades the host
regional metamorphism
develops metamorphic rocks
describe slate
v. low grade
Very fine-grained
originally mudrocks and volcanic ash
flat, slaty, rock cleavage
Phyllite
Glossy sheen and wavy surfaces, wavy cleavage
Platy minerals not large enough to be identified with the
unaided eye
fine crystals of muscovite and chlorite
schist
medium to coarse grained
platy minerals dominate
schistosity
gneiss
Medium- to coarse-grained Banded appearance High-grade metamorphism composed of light feldspar-rich bands with layers of dark ferromagnesian minerals (gneiss texture)
greenschist
low grade
ferromagnesian minerals
foliation
green colour
amphibolite
higher grade than greenschist
chlorite converted to amphibole
less distinct foliation
granulite
very high grade
amphiboles converted to pyroxene and garnets
rocks begin to melt at the ________ zone
transititon
what is a glacier
thick mass of ice that originates on land from the accumulation, compaction and recrystallization of snow
how does glacial ice form?
- snowflakes become granular snow
- air is forced out
- recrystallized into a denser mass, called a firn
- at 50m depth, firn fuses into a solid mass of interlocking crystals
internal deformation
occurs within ice
under pressure, ice is plastic
basal slip
entire ice mass slipping along ground
meltwater
acts like a hydraulic jack, lifting ice to move over rocks
Soft bed deformation
Water-saturated sediment deform under glacier
Zone of fracture
-Upper 50 metres
-Tension causes crevasses
to form in brittle ice
rapid movements of a glacier called a
surge
Ice advances if accumulation _______ loss
exceeds
ice front “retreats” if ablation _______ or accumulation _________
increases
decreases
a glacier forms in the:
zone of accumulation
there is a net loss to the glacier at:
zone of ablation
lower limit of the glacier is the:
equilibrium line
calving is the
breaking off of large pieces of ice into water
plucking
• Lifting and transport of rock
blocks (Erratics) at the base of
the glacier
abrasion
Rocks in ice acting like
sandpaper
Produces rock flour and glacial
striations
glacial trough
u shaped
Transformed by deepening, widening & straightening
hanging valley
Former tributary valleys above the glacier
cirque
head of a glacier
tarn
lake in a cirque
arete
sharp ridge
horn
pyramid mountain
spur
triangular cliff
Roche moutonnées
asymmetric bedrock knobs with steep
sides indicating direction of ice movement
fjord
water-filled glacial trough along a coast
Glacial drift
refers to all sediments of glacial origin
Till
Material deposited directly by glacial ice
Stratified drift
Sediments laid down by meltwater
what is a lateral moraine
ridges along the sides glaciers
what is a medial moraine
form where two glaciers merge
end moraine marks limit of ________
advance
Ground moraine
spreading under overriding ice
Deformation
changes in the original form and/or size of a rock body
force puts ___________ objects in motion or ________ the motions of moving bodeis
stationary
changes
stress
force applied to a given area
strain
changes in the shape or size of a rock body caused by stress
what type of stress?
-applied unequally from different directions
differential
what type of stress?
-shortens a rock body
compressional
what type of stress?
-elongates a rock body
tensional
what type of stress?
-changes the shape of a rock body
shear
brittle fracture
low temps and pressures near the surface
ductile fracture
high temps and pressures deep: solid state flow
joints are fractures that
result from brittle deformation –typically no displacement
during crustal deformation, rocks are often bent into a series of wave-like undulations
this is called a
fold
what are the 4 parts of a fold?
and describe
limbs - 2 sides of a fold
axis - crest of a fold
plunge - inclined axis
axial plane - divides a fold as symmetrically as possible
what are the 3 types of folds?
and describe
Anticline–up-warped or arched rock layers
Syncline–down-warped or troughs of layers
domes and basins - 3D anticlines and synclines
what is a fault?
fractures in rocks along which appreciable displacement has taken place
hanging wall block moves down relative to the footwall Accommodate lengthening (extension) of the crust what type of fault?
normal
Graben is where
central block drops as plates separate
Horst are
raised blocks between graben
Dip-slip faults:
Reverse(thrust) faults are:
hanging wall block moves up relative to footwall
accommodate shortening of crust
dominant displacement is horizontal and parallel to the strike of the fault
what type of fault?
strike slip
stress =
force/area
linear strain=
change in length/ original length
elastic stiffness/elastic (Young’s) Modulus, E:
Resistance (Reaction Force) to Deformation BEFORE yield or failure
stress= __________ x strain
modulus
Shear Strength NOT dependent on normal pressure means:
cohesion
shear Strength FULLY dependent on normal pressure
friction
strength (in terms of failure)
Stress Level WHEN Failure or Yield Occurs
stiffness (in terms of failure)
Relationship between Stress & Strain BEFORE Yield
ductility (in terms of failure)
Relationship between Stress & Strain AFTER Yield
porosity is the
• Volume of Void Space Divided by the Total Volume
permeability is the
ability of fluid to flow through a porous solid
what are 4 ways to mitigate landslides?
Removal of Water
Movement of Slope Material
Restraints
Protection
removal of water means adding ________ __________
surface drainage
Lower Water Pressure= _________ in Effective Normal Stress = Greater ______ Strength
increase
shear
mass wasting is
the downslope movement of rock and soil under the direct influence of gravity
what is the role of mass wasting?
geologic process that often follows weathering
Combined effects of mass wasting and running water (erosion) produce stream
Gravity is the __________ force
controlling
what are other contributing factors to mass wasting? (4)
saturation of the material with water
Over-steepened slopes -unstable
Loss of anchoring vegetation
Earthquake ground vibration
explain the role of water in mass wasting (4)
saturation of the material with water
Water pressure reduces frictional resistance
Water interaction reduces particle cohesion
Water adds weigh
the stable slope angle is the
angle of repose
list and describe the 4 controls and triggers of mass wasting
over-steepened slopes: slope too steep for that type of material
removal of vegetation: root systems bind soil and regolith; leaves protect slope surface from raindrop
earthquakes as triggers: an dislodge large volumes of rock and unconsolidated material
liquefaction: water saturated surface materials behave as fluid-like masses that flow
explain the 3 types of motion in the mass wasting process
fall: detaches, forms talus slope
slide: material moves along a surface as a coherent mass)
flow: material viscously deforms
rockslides are when:
blocks of bedrock slide down a slope
a slump is a ___________ slide and is when
rotational
downward sliding of a mass of rock or unconsolidated material as a unit along a curved surface
a debris flow is a
rapid event that involves a flow of soil and regolith with large amount of water
slow viscous movement on hillsides means (3)
waster saturates the soil and regolith
Prone to viscous (slow) flow but can be fast
Materials often rich in clay and silt
underwater “_________” are common and widespread geographically
landslides
earthquake is
the vibration of Earth produced by the rapid release of energy
what is the focus of an earthquake?
point of energy release -radiates in all directions from its source
Earthquakes generate _________ ______ that radiate throughout the earth
seismic waves
Following an earthquake, adjustments along a fault generate a series of smaller earthquakes referred to as ____________
aftershocks
small earthquakes often precede a major earthquake by days or even by as much as several years referred to as __________
foreshocks
seismology is the:
study of earthquake waves
seismographs are instruments that:
record seismic waves
travel through Earth’s interior (P and S)
what kind of wave?
body
travel on the Earth’s surface
what kind of wave
surface
what is the epicentre?
location on the surface above the focus
intensity:
measure of the degree of earthquake shaking at a given location
magnitude:
estimates the amount of energy released at the source of the earthquake
