Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
284 Cards in this Set
- Front
- Back
|
igneous
|
material cooled and solidified from a melted condition
|
|
|
sedimentary
|
material transported and deposited by wind, moving water, or glacier ice
|
|
|
metamorphic
|
igneous or sedimentary rock whose character has been changed, typically under conditions of deep burial
*solid state transformation. bulk chemical composition typically does not change, except with presence of h2o |
|
|
rock cycle
|
any one of the rock types may be converted
|
|
|
definition of rock
|
any coherent, naturally occurring substance, generally composed of minerals.
|
|
|
criteria to be a mineral:
|
a rock must be...
1. naturally occurring (cannot be man-made) 2. Inorganic (are not and never were living) 3. definite chemical makeup (each mineral contains specific elements in definite proportions) 4. crystalline (Component atoms are arranged in an orderly network at specific distances and angles to one another) |
|
|
hardness
|
Measure of resistance of a mineral to scratching, evaluated on a relative scale of 1 to 10.
|
|
|
luster
|
appearance of a mineral's surface in reflected light.
|
|
|
color
|
does not work well for mineral identification
|
|
|
streak
|
The color of a mineral when powdered
|
|
|
cleavage
|
the tendency of a mineral to split along certain planes determined by internal atomic arrangement and bonding strength
|
|
|
fracture
|
The non-planar breakage of minerals - no well-defined cleavage
|
|
|
ore
|
an earth material in which a metal resource is sufficiently concentrated to be of economic value
|
|
|
oxide
|
metal atoms bonded with oxygen
|
|
|
sulfide
|
metal atoms bonded with sulfur
|
|
|
native element
|
free, uncombined mineral atoms (ex: native copper, gold)
|
|
|
silicates
|
minerals based upon a structure in which a silicon atom is surrounded by four oxygen atoms that occupy the corners of a tetrahedron
|
|
|
ferromagnesian
|
rich in iron and magnesium
|
|
|
magma
|
melted rock inside earth's surface
|
|
|
lava
|
magma that has flowed out of earth's surface
|
|
|
mafic/ultramafic
|
igneous rock that is dark, dense, and ferromagnesian
|
|
|
felsic
|
igneous rock that is rich in feldspar and silica mineral
|
|
|
plutonic
|
igneous rocks that have cooled intrusively. crystals are large - large enough to see with the unaided eye. coarse texture
|
|
|
pegmatite
|
plutonic igneous rock with huge crystals
|
|
|
volcanic
|
igneous rock that has solidified at the surface. smaller, finer crystals.
|
|
|
tuff
|
fine-grained product of explosive volcanism. rock material has shattered.
|
|
|
porphyry
|
igneous texture in which a few larger crystals are set in a matrix of small crystals.
created in two stages: first at depth (large crystals formed), and then with a quick ascent to the surface - remaining magma solidifies |
|
|
phenocrysts
|
large crystals in a porphyry
|
|
|
batholith
|
igneous formation. large irregular granite deposits with no known bottom.
|
|
|
stock
|
small batholith
|
|
|
dike
|
tabular (sheet-like) igneous formation that cuts across structure of country rock. (cuts across layers)
|
|
|
sill
|
tabular igneous formation that is mostly parallel to structure of country rock
|
|
|
laccolith
|
igneous sill with a domed upper surface that has deformed the overlying rock.
|
|
|
pyroclastic
|
magmatic materials that have been explosively ejected from a vent, and are partially or totally solidified before hitting the ground.
associated with felsic magmas with considerable water content where continental lithosphere melts. form composite volcanoes. (tall, cone-shaped) |
|
|
fissure flows/plateau basalts
|
nearly horizontal flows of magma
|
|
|
volatiles
|
substances (chiefly h2o) that are gases at low temperatures
|
|
|
viscosity
|
resistance of a substance to flow. viscosity increases as lava cools. more complex the silicates in the magma, the higher the viscosity.
|
|
|
SiO tetrahedron
|
one silicon bound to 4 oxygen in a tetrahedral formation
|
|
|
vesicles
|
cavities in volcanic rocks once occupied by gas bubbles.
|
|
|
stratification
|
prominent layering of rocks
|
|
|
clastic sediment
|
source rock is weathered, eroded, and transported to point of deposition.
|
|
|
mechanical weathering
|
breaking larger pieces into smaller ones.
|
|
|
chemical weathering
|
partially dissolves original materials, or transforms them into new minerals `
|
|
|
chemical/biochemical sediment
|
dissolved ions that are precipitated as non-clastic material
|
|
|
diagenesis
|
sediment dissolves and re-precipitates
|
|
|
signs of sedimentary maturity
|
well-rounded, well-sorted (particles all of a similar size), reduced particle size
|
|
|
factors essential to metamorphism
|
high pressure and high temperature
also: water can help along metamorphism - water dissolves in rock |
|
|
shear stress
|
force applied to a rock along only certain directions
|
|
|
dynamic metamorphism
|
rocks on either side of a fault are forced past one another for great distances. mechanical, radically changes texture
|
|
|
contact metamorphism
|
heat and fluids (h2o) escape from hot magma intrusion cause metamorphism.
original form may be preserved while changing the content of the minerals |
|
|
regional metamorphism
|
most common type.
shear stress, pressure, and high temps are all factors. affects very large areas in which rocks that formed near the surface have been brought down to great depths where they recrystallize. |
|
|
metamorphic foliation
|
parallel layering of crystal faces
|
|
|
parent rock
|
original rock
|
|
|
low-grade metamorphism
|
does not completely obliterate all features of parent rock
|
|
|
high-grade metamorphism
|
well-developed foliation, much of the original rock's identity has been erased
|
|
|
fossil
|
any evidence of past life
|
|
|
paleontology
|
the study of fossils
|
|
|
clade
|
all the members of a group of descendant organisms extending back through geologic time to their earliest common ancestor
|
|
|
cladistics
|
a procedure based upon comparisons of living and fossil organisms to interpret the relationship of their lines of descent (clades) through time
|
|
|
speciation
|
split of a clade into two or more lineages
|
|
|
cladogram
|
diagram representing lines of descent dividing in a branching pattern
|
|
|
bilateral symmetry
|
a central plane divides right and left halves which are mirror images of each other
bivalves: plane of symmetry passes between the valves brachiopods: plane of symmetry passes through the center of each valve |
|
|
radial symmetry
|
organisms whose bodies are evenly distributed uniformly around a central point
|
|
|
law of superposition
|
in an undisturbed sequence of strata, younger strata overlie older strata
|
|
|
principle of original horizontality
|
sediments are initially deposited in horizontal strata
|
|
|
law of cross-cutting relationships
|
faults and igneous intrusions must be younger than the rocks that they cut
|
|
|
principle of faunal succession
|
there is a regular, definite progression of fossil forms in going from lower (older) to higher (younger) strata. This fossil succession is unique, and cannot be repeated in the same manner during another episode of geologic time
|
|
|
index fossils
|
abundant, geographically wide-ranging, readily preserved
identifiable with a specific interval of geologic time useful in estimating relative age of rocks bearing the fossils, helpful in correlating rocks bearing similar fossils |
|
|
when was the extinction of non-bird dinosaurs
|
end of the Cretaceous
|
|
|
when was the largest of all mass extinctions
|
end of the Permian
|
|
|
when did plants move to land
|
Silurian
|
|
|
by when were all major animal phyla present
|
Cambrian
|
|
|
mnemonic for remembering geologic time scale periods
|
Quit Telling Crazy Jack That Peter Paul Mary Died Slowly Over Coals
Quaternary Tertiary Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian Precambrian |
|
|
Phylum Protozoa
|
one-celled aquatic organisms. most common fossil phylum.
|
|
|
Phylum Porifera
|
Sponges.
|
|
|
Phylum Cnidaria
|
Animals having a hollow body with tentacles surrounding mouth, ex: sea anemones, jellyfish, corals
|
|
|
Phylum brachiopoda
|
Marine mammals with calcium carbonate shells. bilaterally symmetrical valves.
|
|
|
Phylum Mollusca
|
Most common macroscopic phylum. Ex: calms, snails, octopus, squid
|
|
|
Phylum Anthropoda
|
Insects and crustaceans
|
|
|
Phylum Echinodermata
|
Starfish, sea urchins, sand dollars, etc
five-sided radial symmetry |
|
|
Phylum chordata
|
Mobile animals with a dorsal nervous system and a notochord or vertebral column
|
|
|
fossils without alteration
|
preserved in young sediments. ex: frozen of mummified carcass, insects trapped in amber.
|
|
|
fossils preserved with alteration
|
have experienced some chemical or physical change.
|
|
|
replacement fossilization
|
original material is replaced atom-by-atom by minerals and carried to the site and precipitated by groundwater.
|
|
|
preservation by permineralization
|
partial if not total replacement. groundwater has deposited mineral matter into the pore spaces, but much of the original hard-part material is also preserved.
|
|
|
compression
|
forms when soft parts are pressed into a fine-grained sediment. a thin film of carbon is left behind.
|
|
|
molds and casts
|
sediment has surrounded or infiltrated the hard part, and has lithified (hardened).
|
|
|
trace fossils
|
preserve signs of the organisms activity, not a part of the organism itself
ex: gastroliths (pebbles swallowed by reptiles to aid digestion), burrows, tracks, prints, and coprolite (fossilized dung) |
|
|
preservation bias
|
some organisms are more readily fossilized than others.
|
|
|
collector's bias
|
some fossils are more sought after for collection
|
|
|
principle of uniformitarianism
|
the present is a result of the past, and geologic processes have remained essentially the same throughout geologic time.
|
|
|
linnean classification system
|
organisms are classified in a hierarchy according to their degrees of similarity
|
|
|
planimetric map
|
locations of cultural and natural features
|
|
|
topographic map
|
uses contour lines to convey information about elevation
|
|
|
Mercator projection
|
assumes that lines of latitude and longitude are perpendicular and uniformly spaced.
distortion greatest at the poles |
|
|
map grids
|
coordinates of latitude and longitude for each location are unique, no two locations having the same pair of coordinates
|
|
|
topographic contour line
|
imaginary line that connects all points of equal elevation on the land surface
|
|
|
contour interval
|
the difference in elevation between adjacent contour lines
|
|
|
contour line rules
|
cannot intersect
closed loops (not always shown within the map) cannot intersect a body of water V up a stream valley more closely spaced - the steeper the slope hatched lines in a closed depression |
|
|
relief
|
difference in elevation between local elevation highs and lows
|
|
|
gradient
|
relief / path distance
|
|
|
slope
|
relief / shortest, straight-line distance
|
|
|
joint
|
fracture with no offsetting motion
|
|
|
fault
|
fracture with offsetting motion
|
|
|
unconformity
|
buried surface of erosion
|
|
|
map view
|
pattern created by the intersection of rock units with the earth's surface.
|
|
|
cross section
|
pattern created by the intersection of rock units with a vertical plane
|
|
|
strike
|
the compass direction of a horizontal line on the dipping plane
|
|
|
dip
|
the downward angle between the horizontal and the dipping plane.
dip direction is perpendicular to strike direction |
|
|
stress
|
force per unit area
causes strain (deformation) |
|
|
tensional strain
|
pulling apart, extension, stretching.
causes normal fault, rift |
|
|
compressional stress
|
rocks pressing together
causes folds, reverse faults, thrust faults (=reverse fault with a low-angle fault plane) |
|
|
shear stress
|
tangential
strike-slip faults |
|
|
vertically directed stress
|
stress up or down
uplifts = dome subsidence = basin |
|
|
dip-slip fault
|
displacement is parallel to the dip of the fault plane
|
|
|
strike-slip fault
|
displacement is parallel to the strike of the fault plane.
|
|
|
footwall
|
an old miner's term - describes the side of the fault that one could stand on
|
|
|
hanging wall
|
the wall that hangs above the footwall
|
|
|
normal fault
|
created by tension. the hanging wall moves DOWN relative to the footwall.
|
|
|
reverse fault.
|
created by compression. hanging wall moves UP relative to the footwall.
|
|
|
fault slickensides
|
grooves on the fault face that indicate the general direction of movement
|
|
|
disconformity
|
surface of erosion between parallel strata
|
|
|
angular unconformity
|
surface of erosion between non-parallel strata
|
|
|
nonconformity
|
surface of erosion between sedimentary strata above, and metamorphic or intrusive igneous rock below.
|
|
|
dome
|
results from uplift
limbs dip away from the center in all directions |
|
|
basin
|
results from subsidence
limbs dip toward the center in all directions. |
|
|
OLDER BEDS TILT TOWARD YOUNGER BEDS
|
OKAY?
|
|
|
syncline
|
U-shaped - youngest beds are in the center of the outcrop pattern
|
|
|
anticline
|
oldest beds in the center of the outcrop pattern
|
|
|
focus
|
the exact place withing the crust of the earth where an earthquake occurs
|
|
|
epicenter
|
the spot on the earth's surface directly above the focus
|
|
|
P waves
|
compressional waves which travel the fastest
|
|
|
S waves
|
more slowly traveling seismic shear waves
|
|
|
L waves
|
effects confined to near earth's surface and which travel the most slowly of the three types
|
|
|
aquifer
|
a rock body that has the capacity to transmit "usable" quantities of water to a well
rock types that make a good aquifer: sandstone, conglomerate, fractured limestone |
|
|
aquitard
|
a rock body that does not transmit usable quantities of water over a reasonable short period of time
ex: shale |
|
|
water table
|
a level below which the ground is saturated with water, and above which it is not saturated (although moisture may be present)
|
|
|
porosity (primary and secondary)
|
fraction of a rock body consisting of void spaces
primary: present when the rock body was created secondary: created later by fracturing or dissolution |
|
|
permeability
|
a measure of how well interconnected the pores are, hence how easily the material can transmit fluids
|
|
|
alluvial aquifer
|
high primary porosity and permeability
diffuse (slow) flow, providing time for breakdown of contaminants a natural filter ex: Ogallala Aquifer |
|
|
karst aquifer
|
fractured limestone
may have low porosity or permeability, but can be created by fracturing or dissolution discrete (rapid) flow - little or no filtering |
|
|
recharge
|
the process of surface water entering an aquifer
|
|
|
discharge
|
groundwater exits an aquifer and enters a body of surface water
|
|
|
problems with increased impervious cover
|
concentrated pollutants on top cover
increases the rate of runoff and worsens floods inhibits recharge |
|
|
differentiation
|
During crystallization, as a body of magma separates into various compositions
|
|
|
"living" molecules
|
atoms arranged in long chains
chiefly C,H, N, and O abundant atoms in atmosphere, hydrosphere |
|
|
atoms in crystals of minerals
|
3-dimensional repeating patterns
chiefly Si, O, Al, Fe, K, etc. abundant atoms in rocks |
|
|
gneiss
|
high-grade metamorphic rock
|
|
|
ex of evaporate sedimentary rocks
|
gypsum, rock salt, limestone
|
|
|
ex of intrusive igneous rocks
|
gabbro and granite
|
|
|
Prokaryotes
|
relatively small, single-celled organisms
no nucleus appeared before eukaryotes |
|
|
basalt
|
igneous
mafic Ca plagioclase feldspar, pyroxene, olivine abundant in oceanic crust smaller crystals |
|
|
How are Si-O tetrehedrons arranged in clay minerals?
|
linked together in sheets
|
|
|
constituents of soil
|
water
atmospheric gases organic material chemically weathered rock material |
|
|
Where did the hydropsphere mostly come from?
|
Volanic eruptions delivering water up from the earth's deep interior.
|
|
|
processes that can occur during metamorphism
|
minerals dehydrate
existing minerals recrystallize new minerals grow in preferred directions under the influence of shear stress |
|
|
ionic bonds only
|
halite
|
|
|
x-ray diffraction
|
analyzes the structure of atoms in a mineral
|
|
|
What did the Miller-Urey pioneering experiment to simulate early earth conditions synthesize?
|
relatively simple organic compounds (amino acids, etc)
|
|
|
2 most abundant elements in earth's crust
|
oxygen and silicon
|
|
|
most explosive volcanism can build...
|
a stratovolcano
|
|
|
example of chemical weathering
|
acid rain attacks mafic minerals, partially dissolving them.
|
|
|
scientists classify pyroclastic material by:
|
its size and condition when ejected (molten or solid, hot or cold)
|
|
|
mineral consisting of only si-o tetrahedrons, in which the atom at every corner is shared with an adjacent identical structure, forming a framework silicate
|
quartz
|
|
|
how is net negative charge neutralized in a crystal?
|
Adding positive ions to the structure
By sharing corner atoms |
|
|
sequence of events re: origin of life on earth
|
1. Amino acid molecules originate
2. DNA molecules originate 3. Prokaryotes originate. 4. Eukaryotes originate |
|
|
If the earth's earliest atmosphere was of volcanic origin, what constituent did it lack?
|
O2 - oxygen gas
|
|
|
mineral for which color is an unreliable property for identification
|
quartz
|
|
|
About how much sediment does the Miss river deliver to the Gulf of Mexico each day?
|
about 1 million metric tons
|
|
|
seismic P waves
|
fastest
particles travel parallel to wave travel |
|
|
Can be used to trace evolutionary relationships among organisms
|
sequences of genetic coding
sequences in embryonic developmental stages comparisons of fossil skeletal structures |
|
|
Why is there a P wave shadow between the 103 degree and 142 degree distant from an earthquake focus?
|
P waves experience refraction as they travel faster in the mantle but slower in the core
|
|
|
Animal fossils in the Middle Cambrian Burgess Shale, western Canada, are important because:
|
fossilize animals with "hard parts" and ones consisting of only soft tissue (a very rare situation) are both preserved
|
|
|
in what ways did early synapsids (ancestors of mammals) differ from early diapsids (ancestors of reptiles)?
|
synapsids: one opening behind each robit
diapsids: two openings behind each orbit |
|
|
What happened to Texas streams and the coast when sea level fell during the Pleistocene Ice Age, and then rose again?
|
During low sea level, streams eroded deep valleys that were flooded by rising sea level, creating bays
Increased erosion cased accumulation of large sand deposits offshore, which are the source material for today's barrier islands |
|
|
As P, S, and L waves travel farther from an earth quake focus:
|
body waves accelerate
surface waves stay constant |
|
|
What evidence for organic evolution by natural selection did Charles Darwin observe?
|
Some fossil species appear to be ancestral to multiple present-day species
present-day species can be classified intuitively by a branching system ie Linnean classification Breeding of pigeons or dogs can create rapid modification of populations |
|
|
Why does the Nile delta have a classic delta shape, while the Mississippi delta has a birdfoot shape?
|
The Miss delivers sediment to the Gulf of Mexico much faster than it is removed by subsidence or longshore drift, whereas delivery and removal in the nile delta are in balance.
|
|
|
The more steeply a burst of earthquake energy enters the earth, the...
|
farther away from the earthquake it emerges to the surface of the earth
|
|
|
homology
|
paleontologists correlate human bones with bones of another animal
|
|
|
continental crust
|
less dense, thicker, generally granite
|
|
|
oceanic crust
|
more dense, thinner, generally basalt
|
|
|
which land-dwelling vertebrate group has the most present-day diversity?
|
Birds
|
|
|
methods to correlate sedimentary strata
|
direct tracing by "walking out" a bed from one locality to another
matching on the basis of similar fossils matching on the basis of similar sequence of strata |
|
|
Modifications allowing lobe-finned fish to move onto land and become amphibians
|
development of...
robust rib cage sturdier shoulder and pelvic girdles lungs |
|
|
Governs the travel speeds of P and S waves
|
Incompressibility, rigidity, and the density of the transmitting material
|
|
|
What are prominent feature of north american delta deposits of the pennsylvanian age?
|
extensive coal deposits
indicators that streams in central Texas flowed from east to west, away from present-day Gulf of Mexico |
|
|
Which is the most important factor in the process of evolution through natural selection
|
the ability of an organism to attract a mate and produce viable offspring
|
|
|
Mohorovicic discontinuity (Moho)
|
Present worldwide
p waves slower above moho, faster below boundary between crust and mantle |
|
|
What type of stream sediment load is deposited in natural levees? Chiefly:
|
suspended load
|
|
|
Mantle is composed chiefly of:
|
ultramafic rock, mostly olivine and pyroxene
|
|
|
Why are may petroleum deposits associated with salt deposits?
|
Because salt in nonporous, with makes an excellent seal or trap of oil accumulated below the salt
|
|
|
the first vertebrates to appear in the fossil record lacked:
|
jaws
|
|
|
a typical sediment sequence from a deltaic environment will consist of:
|
a hodge-podge of coarse channel sediments, fine and organic-rich inter-channel sediments, and shallow marine carbonate sediments
|
|
|
Most recent period of the Mesozoic era
|
Cretaceous period
|
|
|
What function or behavior distinguishes among the three groups of mammals
|
how they bear and nourish their young
|
|
|
why can't s waves travel though the earth's outer core?
|
the outer core is liquid
|
|
|
Iceland
|
constructed of basalt volcanoes and flood basalt flows
sits astride Mid-atlantic ridge prone to shallow earthquakes |
|
|
fracture zones
|
offset mid-ocean ridges laterally
|
|
|
Mid-Atlantic Ridge
|
Maintains precise midway position between continents
Offset by fracture zones Where the ridge swings sharply through a bend, individual segments are offset along fracture zones Topographically high occupies central 1/3 of the atlantic basin Deep rift occupies the crest of the ridge Splits in the Indian ocean |
|
|
most ocean trenches associated with...
|
Pacific Ocean (Pacific Ring of Fire)
|
|
|
Major mountain belts originate by forces of...
|
compression exerted laterally
|
|
|
rate of deposition in oceans
|
very slow, away from coasts
|
|
|
No oceanic fossils older than...
|
late Jurassic
|
|
|
continental shelf
|
zone of hsallow water bordering world's land masses
vast region continental crust extends offshore beneath the shallow waters of the shelf |
|
|
continental slope
|
area that continental shelf slopes off into at around a a depth of 130 meters
|
|
|
continental rise
|
thick sediment wedge banked against continental slope
fan shaped masses accumulate to create |
|
|
ocean ridge system
|
continuous system
medial valley in between crest bounded by normal faults - ridge is in tension - being pulled part offest by strike-slip fracture zomes |
|
|
black smokers
|
underwater hot springs
|
|
|
East African Rift Valleys
|
Fault-bounded valleys containing active volcanoes and a series of lakes
Dropped-down along faults |
|
|
ocean trenches
|
deepest places on earth
nearly all border the perimeter of the pacific volcanoes associates with trenches generally erupt adesite (midway between basalt and rhyolite) associated with violent earthquakes |
|
|
volcanic arcs
|
volcanic island chains (Aleutian Islands in Alaska)
|
|
|
abyssal hills
|
relatively small topographic highs underwater
|
|
|
seamounts
|
slightly larger than abyssal hills, mostly of volcanic origin
|
|
|
atolls
|
rise steeply from ocean floor. culminating at sea level in a broad, shallow lagoon hemmed in by a reefy barrier
Darwin proposed they are subsided volcanic islands |
|
|
guyots
|
seamounts whose flat tops lie as much as 2 meters below sea level
|
|
|
2 main mountain belts
|
one nearly circling the pacific (includes Andes)
one extending eastward from southern europe (includes Alps) |
|
|
evidence for continental drift
|
evidence in ancient rocks that local climate differed from today's climate
distributions of fossils - widespread dispersal of fossils of animals that could not have traveled great distances distribution of ancient mountain belts and zones of regional metamorphism apparent polar wandering curves |
|
|
plate tectonics
|
earth's surface us composed of a small number of tectonic plates that are in motion (mostly horizontally)
belts of earthquake epicenters and volcanoes mark the margins, where plates are interacting |
|
|
asthenosphere
|
compeeting high pressure and high temps are almost in balance - mantle is softened
becomes magma upon reaching surface lubricating layer over which plates move |
|
|
plates pulling apart
|
mid-ocean ridge system, where oceanic crust is being created
continental rift valleys |
|
|
plates colliding
|
ocean trench system - crust being consumed
compressional continental mountain ranges (Himalayas) |
|
|
plates slipping past one another
|
oceanic fracture zones
strike-slip faults transform fault motion crust conserved - neither created not consumed |
|
|
failed arm
|
rift that failed to become a sea
ex East African Rift Valley |
|
|
positive magnetic anomaly
|
place where earth's magnetic field is stronger than regional average
|
|
|
magnetic field reversals
|
recorded by rocks created in seafloor spreading
creates "stripes" of alternately normal and reversely magnetized basalt can determine rate of seafloor spreading by dividing distance/time |
|
|
negative magnetic anomaly
|
magnetic field is weaker than regional average
|
|
|
oceanic and continental plates collide
|
oceanic plate subducts - it is more dense
|
|
|
hot spots
|
ascending hear is concentrated into relatively small area
plate rides over stationary hot spot and creates a linear chain of islands |
|
|
"icehouse" earth
|
major ice sheets in the polar regions
|
|
|
"greenhouse" earth
|
time when there was no glaciation at all on earth
ex Mesozoic era |
|
|
"snowball" earth
|
entire planet covered in ice
|
|
|
"hothouse" earth
|
time of intensely hot worldwide climate
|
|
|
when vast amounts of ice are stored on the continents...
|
sea level drops
|
|
|
Milankovitch cycles
|
describe motion of the earth's orbit around the sun and the earth's orientation with respect to the plane of the orbit
depends on variation of: eccentricity of earth's orbit angle of tilt precession - axis wobbling |
|
|
what drives the tectonic plates?
|
convection in the mantle
rising - ocean ridges sinking- ocean trenches |
|
|
where waves travel through the earth faster, that part of the earth is...
|
cooler
slower = hotter |
|
|
dip-fed
|
streams
flowing downslope under influence of gravity |
|
|
tributary network
|
tributaries join together, finally joining one master stream
|
|
|
distributary network
|
master stream breaks off into distributaries
|
|
|
dissolved load
|
dissolves ions in a stream
|
|
|
suspended load
|
tiny particles so light they are kept up by the stream's turbulence
|
|
|
bedload
|
load that rolls, hops, or slides along the base of the channel
|
|
|
meanders
|
sinuous loops that form when a stream flows through alluvial plains consisting of unlithifiesd sand and mud
|
|
|
outer bank of a meander
|
erosive - turbulence and velocity
asymmetrical creates a steep undercut bank |
|
|
point bar
|
inner bank of a meander
shallower less velocity and turbulence sediment is deposited - sand or gravel |
|
|
natural levees
|
deposited when rivers overflow their banks
|
|
|
progradation of a delta
|
builds land surface forward into what was formerly the sea
river must flow farther and farther to reach the mouth |
|
|
why deltas subside (sink)
|
1) mud gets compacted and water squeezed out *most important factor
2) isostatic adjustment - sinks under its own weight (iceburg) |
|
|
delta lobe
|
local area where delta is currently depositing sediment
|
|
|
prodelta
|
offshore deposit in front of the delta plain
|
|
|
strike-fed depositional system
|
horizontal deposition
coastal systems wave action distributes sediment laterally along a coast |
|
|
motion of water molecules in open water
|
circular
circles get smaller closer to wave base (deeper) become ellipses as they approach shore |
|
|
longshore drift
|
waves, driven by wind and entraining sand, slosh obliquely up a beach
the sand "walks" in a sawtooth manner along the beach |
|
|
salt (depositionally speaking)
|
relatively low density
incompressible mechanically weak and easy to deform unstable - terrigenous rock over salt deposits |
|
|
salt domes located
|
Northeast texas and the Gulf of Mexico
|
|
|
growth fault
|
fault in sedimentary rock that forms at the same time that the sediment is deposited
no earthquakes - constant slow creep |
|
|
barrier islands
|
formed by fluctuations in sea level
inner coastline deeply indented by bays outer coastline fronted by long, narrow, sandy barrier islands |
|
|
glacier ice
|
metamorphic rock
as snow is deposited, snowflackes become compacted into old snow or firn. trapped air becomes isolated, forming bubbles ice crystals coarsen and interlock |
|
|
zones of net accumulation and wastage
|
in glaciers
accumulation - ideally steady state, maintains constant size and shape wastage - where ice eventually is melted or discharged |
|
|
internal flow of glaciers
|
streamline - paths of individual water molecules is parallel
|
|
|
ice under short and long-term stress
|
short - brittle, forms crevasses
long - ductile, flows |
|
|
deformation of glacier ice
|
deep ice deforms by flowing
internal deformation - upper part flows more rapidly while base is retarded by friction |
|
|
polar ice sheet
|
surface temp is below freezing, internally even colder
temp increases toward base due to geothermal heat |
|
|
"temperate" glacier
|
about 0 degrees (melting/freezing point) at surface
slightly colder at base to keep the glacier solid |
|
|
river valley profile
|
v-shaped cross section
river does not fill the entire valley |
|
|
glacial valley profile
|
u-shaped cross section
glacier fills entire valley builds steep bowl-shaped walls at the head of the valley (cirque) |
|
|
hanging valleys
|
left after a glacial tributary has melted
|
|
|
till
|
deposited by glaciers
unsorted sediment |
|
|
moraine
(ground, end lateral, medial) |
landform consisting of glacial sediment (till)
may be deposited beneath the ice sheet as a ground moraine may heap up at the end of the glacier as an end moraine lateral moraines are on the sides of the valley medial moraines are where later moraines merger |
|
|
how an ice age results
|
polar region occupied by a continent or an ocean with restricted interchange with the world ocean, the polar regions become thermally isolated and an ice age results.
|
|
|
Gondwana
|
southern supercontinent
floated over south pole before breakup |
|
|
isotope fractionation
|
heavy stable O isotope is precipitated more effectively than light isotope.
|
|
|
meteoric water
|
water precipitated from the atmosphere
|
|
|
eccentricity
|
change of earth's orbit
~100 thousand year cycle |
|
|
precession
|
wobble of earth's axis
~23 thousand year cycle) |
|
|
tilt of earth's axis
|
~41 thousand year cycle
|
|
|
hydrocarbons
|
organic chain molecules that make up petroleum
carbon atoms linked into a chain short chains are volatile. long chains are more viscous deposits form in sedimentary rocks/sedimentary basins |
|
|
kerogen
|
giant complex organic molecules
start out as decayed organic matter, changing with burial and heating later cracked into shorter molecules, including hydrocarbons and methane (shortest, natural gas) |
|
|
requirements for creation of an oil or gas deposit
|
1. source rock rick in organic constituents
2. porous and permeable reservoir rock for hydrocarbons to be stored in (sandstone, fractured limestone) 3. trap or seal on the reservoir ex: anticlines, unconformity with impermeable overlying strata |
|
|
stratigraphic trap
|
buried fluvial system:
point bar sand - reservoir floodplain mustones (source and seal) fault plane can be a trap |
|
|
salt structures as a petroleum trap
|
rising masses of salt are highly impermeable, trap oil and gas underneath
|
|
|
Mathusian theory
|
Population grows geometrically, while food supply only grows arithmetically
Insufficient food supply will eventually limit the growth of human population - occuring in limited parts of the world |
|
|
non-renewable resources
|
sporadic distribution
exhaustibility increasing rate and extent of usage |
