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OH MY GOD WHERE IS IT
caroline schaff
181
Geology
Undergraduate 2
11/01/2012

Additional Geology Flashcards

 


 

Cards

Term

 

 

Process that raises surface of the crust

Definition
uplift
Term

 

 

process by which rocks bend or break in response to compression, tension, or shearing

Definition
deformation
Term
Process by which one kind of rock transforms into a different kind of rock
Definition
metamorphism
Term

 

 

Mountains are constructed by tectonic plate interactions in a process called...

Definition
orogenesis
Term

 

 

Mountains frequently occur in... 

Definition
elongate, linear belts.
Term
constructive processes ______, while destructive processes ________.
Definition
build mountains up, tear them back down again
Term

 

 

Young mountains are (1)

 

 

Middle-aged mountains are (2)

 

Old-age mountains are (3)

Definition

1) high, steep and growing upward.

2) dissected by erosion.

3) deeply eroded and often buried.

 

 

Term

 

 

Change in shape via deformation is called

Definition
strain.
Term

 

 

_____ is the study of rock deformation.

Definition
Structural geology
Term

 

 

Fractures that have no offset.

Definition
joints
Term

 

 

Layers that are bent by slow plastic flow.

Definition
folds
Term

 

 

Fractures that are offset.

Definition
faults
Term

 

 

Planar metamorphic fabric.

Definition
foliation
Term
Undeformed terrain
Definition
aka unstrained/ horizontal beds, spherical sand grains, no folds or faults
Term
deformed terrain
Definition
tilted beds, metamorphic alteration, folding and faulting
Term
translation
Definition
change in location
Term
rotation
Definition
change in orientation
Term
distortion
Definition
change in shape
Term
stretching
Definition
pulling apart
Term
shortening
Definition
squeezing together
Term
shear
Definition
sliding past
Term
brittle and ductile
Definition
two major deformation types
Term
temperature and pressure
Definition
deformation type depends on...
Term
brittle deformation
Definition
rocks break by fracturing
Term
shallow crust.
Definition
brittle deformation occurs in...
Term
ductile deformation
Definition
rocks deform by flow and folding
Term
deeper crust
Definition
ductile deformation occurs in...
Term
10 to 15 km
Definition
a transition between brittle and ductile deformation occurs at...
Term
caused by force acting on rock, known as stress
Definition
what is the cause of deformation?
Term
stress
Definition
the force applied per unit area across an area
Term
much deformation
Definition
a large force per area results in...
Term
little deformation
Definition
a small force per unit area results in...
Term
compressional
Definition
squeezing
Term
tensional
Definition
pulling apart
Term
shear
Definition
sliding past
Term
horizontal compression
Definition
tectonic collision produces...
Term
most common
Definition
tectonic collision is the ____ form of deformation
Term
thicken
Definition
compression tends to ____ material. greater stress in one direction.
Term
thin
Definition
extension tends to ____ material.
Term
pressure
Definition
an object feels the same stress on all sides
Term
strike and dip
Definition
3-d structural orientation is described by...
Term
strike
Definition
horizontal intersection with a tilted surface
Term
dip
Definition
angle of surface down from the horizontal
Term
perpendicular to strike, measured downslope
Definition
dip is aways...
Term
linear structures
Definition
line rather than plane such as scratches on rock
Term
bearing
Definition
compass direction
Term
plunge
Definition
angle from horizontal
Term
joints
Definition
planar rock fractures without offset, result from tensional tectonic stresses
Term
veins
Definition
minerals can fill joints to form...
Term
weathering
Definition
joints control _____ of rock.
Term
parallel sets
Definition
systematic joints form in...
Term
faults
Definition
planar fractures offset by movement cross the break
Term
active or inactive
Definition
faults may be ___ or ____.
Term
earthquakes
Definition
sudden movement along faults cause...
Term
displacement
Definition
faults may offset large blocks of earth. the amount of offset is a measure called _____.
Term
the dominant type of crustal stress and defines the fault.
Definition
the direction of relative block motion reflects... (2)
Term
hanging wall block (above the fault), and the footwall block (below the fault).
Definition
on a dipping fault, the blocks are classified as the...
Term
your head is near the hanging wall block, and you are standing on the footwall block.
Definition
standing in a tunnel excavated along the fault... where are your head and feet?
Term
dip-slip
Definition
blocks move parallel to fault-plane dip.
Term
strike-slip
Definition
blocks move parallel to fault-plane strike
Term
oblique-slip
Definition
combination of dip-slip and strike-slip
Term
parallel
Definition
In a dip-slip fault, sliding is ____ to fault-plane dip, thus blocks move up or down the slope of the fault.
Term
reverse fault and normal fault
Definition
Two kinds of dip-slip faults depend on relative motion...
Term
hanging wall moves up
Definition
reverse fault
Term
normal fault
Definition
hanging wall moves down
Term
reverse fault
Definition
fault dip is steeper than 35 degrees.
Term
thrust faults
Definition
fault dip is less than 35 degrees.
Term
right lateral
Definition
opposite block moves to observer's right.
Term
left lateral
Definition
opposite block moves to observer's left
Term
strike-slip fault
Definition
in a ____, fault motion is parallel to the strike of the fault. 
Term
Shattered fault breccias
Definition
...are preferentially eroded.
Term
slickensides lineations
Definition
fault motion creates...
Term
fluid flow
Definition
minerals may grow on fault surfaces due to
Term
folds
Definition
layered rocks may be deformed into curves called 
Term
hinge
Definition
portion of maximum curvature on a fold.
Term
limb
Definition
less curved "sides" of a fold
Term
axial plane
Definition
imaginary surface defined by connecting hinges of successively nested folds
Term
folded rock
Definition
orogenic settings produce large volumes of...
Term
series
Definition
folds may often occur in a...
Term
anticline
Definition
arch-like fold; limbs dip away from the hinge
Term
syncline
Definition
trough-like fold; limbs dip toward the hinge
Term
monocline
Definition
a fold like a carpet draped over a stairstep
Term
blind faults
Definition
monocline is generated by _______ in the basement rock.
Term
plunging fold
Definition
has a hinge that is tilted
Term
non-plunging fold
Definition
has a horizontal hinge
Term
sheep mountain
Definition
____, Wyoming, is a plunging fold.
Term
dome
Definition
fold with appearance of an overturned bowl, erode to expose old rocks in center and younger rocks outside
Term
basin
Definition
fold shaped like a bowl, erode to expose young rocks in center and older outside
Term
vertical crustal motions
Definition
Domes and basins result from...
Term
flexural folds
Definition
layers slip as stratified rocks are bent.
Term
flow folds
Definition
Form by ductile flow of hot, soft rock
Term
buckle
Definition
horizontal compression causes rocks to...
Term
smear out.
Definition
shear causes rocks to...
Term
compressional deformation
Definition
Foliation develops via...
Term
flattening
Definition
Develops perpendicular to shortening strain.
Term
uplift
Definition
Construction of mountains requires substantial...
Term
marine sediments
Definition
Mt Everest is comprised of ____ (formed below sea level).
Term
thickened crust
Definition
Lofty mountains are supported by a thickened crust.
Term
thickened lithosphere
Definition
High muntains are supported by...
Term
collisional orogenesis
Definition
Thickening is caused by...
Term
35 to 40 km thick
Definition
Average continental crust
Term
50 to 70 km thick
Definition
Beneath orogenic belts (how thick?)
Term
buoy the mountains upward.
Definition
This thickened crust helps...
Term
balance
Definition
Surface elevation represents a ____ between forces.
Term
gravitational attraction
Definition
Pulls plates into the mantle.
Term
Buoyancy
Definition
Floats plates on top of the mantle
Term
isostatic equilibrium
Definition
The term ____ describes a balance between forces.
Term
Isostasy
Definition
_______ is compensated after a disturbance.
Term
the lithosphere down.
Definition
Adding weight pushes the...
Term
isostatic rebound
Definition
Removing weight causes...
Term
uplift and erosion
Definition
Mountains refelct a balance between...
Term
steep and jagged
Definition
Mountains are _____ due to erosion.
Term
accelerates
Definition
Erosion _____ with height.
Term
rock strength
Definition
Weight of high mountains overwhelms...
Term
geological time
Definition
the span of time since Earth's formation
Term
4.57 billion years
Definition
How old is earth?
Term
principle of uniformitarianism
Definition
Physical processes we observe today also operated in the past at roughly the same rates and were responsible for the formation of geologic features observed in outcrops.
Term
James Hutton
Definition
first to articulate the idea of uniformitarianism
Term
relative ages
Definition
based upon order of formation. qualitative method developed hundreds of years ago.
Term
numerical ages
Definition
actual number of years since an event, quantitative method, developed more recently, age is assigned a number
Term
horizontality and continuity
Definition
strata often form laterally extensive horizontal sheets, subsequent erosion dissects once continuous layers, flat-lying rock layers are unlikely to have been disturbed
Term
each bed is older than the one above and younger than the one below
Definition
(super position)in an undeformed sequence of layered rocks...
Term
truncate
Definition
younger features _____ (cut across) older features.
Term
younger
Definition
faults, dikes, erosion, etc., must be _____ than the material that is faulted, intruded, or eroded.
Term
inclusions
Definition
a rock fragment within another
Term
igneous zenoliths
Definition
country rock that fell into magma
Term
weathering rubble
Definition
debris from preexisting rocks
Term
plutonic igneous intrusion
Definition
(baked contacts) thermal metamorphism occurs when country rock is invaded by ...
Term
sedimentary rocks
Definition
fossil remnants or traces of once-living organisms are often preserved in ________.
Term
appearance, range, and extinction/ fossil content
Definition
3 things used for dating/ a time period is recognized by its
Term
fossil range
Definition
first and last appearance
Term
locally, regionally, globally
Definition
fossil succession permit correlation of strata
Term
numerical age/relative age
Definition
age of a geological feature in years/whether one geological feature is older or younger than another
Term
unconformity
Definition
a time gap in the rock record due to non-deposition or erosion
Term
angular unconformity, nonconformity, disconformity
Definition
3 types of unconformity
Term
angular unconformity
Definition

rocks below an angular unconformity were tilted or folded before the unconformity developed.

cuts across the underlying layers - and the layers below have a different orientation from the layers above.

from where rocks were tilted by either folding or faulting, before being exposed at the Earth's surface.

Term
angular unconformity
Definition

Horizontal marine sediments deformed by orogenesis. High mountains are eroded away to below sea level. Sediments deposited horizontally on the erosion surface.

Term
nonconformity
Definition
metamorphic or igneous rocks overlain by sedimentary strata
Term
cooled, uplifted, exposed, eroded... sediment is then deposited on eroded surface and lithified
Definition
ig/met rocks must have (4 things)
Term
disconformity
Definition
parallel strata bracketing non-deposition... due to an interruption in sedimentation
Term
sedimentary record
Definition
Earth history is recorded in strata...
Term
stratigraphic column
Definition
summary of geologic information at a particular location (region) depicted as a sequence of sedimentary strata
Term
correlation
Definition
age relationship between the strata at one locality and the strata at another
Term
lithologic
Definition
_____ correlation is based on rock type.
Term
sequence
Definition
the relative order in which the rocks occur
Term
geologic column
Definition
a composite stratigraphic column can be constructed, assembled from incomplete sections across the globe, it brackets almost the entirety of earth's history
Term
eons
Definition
the largest subdivision of time (100s to 1000s Ma)
Term
eras
Definition
subdivisions of an eon (65 to 100s Ma)
Term
period
Definition
subdivision of an era (2 to 70 Ma)
Term
Epochs
Definition
Subdivisions of a period (.011 to 22 Ma)
Term
3.8 Ga (ga - billion years)
Definition
life first appears on earth when
Term
anaerobic single-celled organisms
Definition
early life consisted of...
Term
numerical age
Definition
many relative ages can now be assigned actual dates
Term
geochronology
Definition
numerical dating is also called
Term
numerical age
Definition
based on radioactive decay of atoms in minerals... radioactive decay proceeds at a known, fixed rate. radioactive elements act as internal clocks.
Term
radioactive decay
Definition
when an element changes to a different element
Term
isotopes
Definition
elements that have varying #s of neutrons (always same # of protons)
Term
stable
Definition
isotopes that never change
Term
radioactive
Definition
isotopes that spontaneously decay
Term
radioactive decay
Definition
progresses along a decay chain. decay creates new unstable elements that also decay. decay proceeds to a stable element endpoint.
Term
parent isotope
Definition
the isotope that undergoes decay
Term
daughter isotope
Definition
the product of this decay
Term
half-life
Definition
time for 1/2 unstable nuclei to decay.
Term
one half of the original parent remains.
Definition
after one t1/2..
Term
one eighth of the original parent remains
Definition
after 3 t1/2
Term
measuring the ratio of parent isotopes to daughter isotopes and calculating the amount of time by using the known t1/2.
Definition
The age of a mineral can be determined by...
Term
closure temperature
Definition
temperature below which isotopes are no longer free to move (in a mineral)
Term
a specific mineral in the rock cooled below the closure temperature.
Definition
Isotopic dates specify the time at which...
Term
reset
Definition
if rock is reheated, the radiometric clock is...
Term
meta
Definition
when rock cooled from the high T down to a low T
Term
growth rings
Definition
annual layers from trees or shells
Term
rhythmic layering
Definition
annual layers in sediment or ice
Term
visible life
Definition
phanerozoic
Term
before life
Definition
proterozoic
Term
ancient
Definition
archean
Term
hell
Definition
hadean
Term
recent life
Definition
cenozoic
Term
middle life
Definition
mesozoic
Term
ancient life
Definition
paleozoic
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