Term
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Definition
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Term
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Definition
made of preexisting rocks
classified based in composition, grain size, texture |
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Term
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Definition
made of organisms
organisms made shells from dissolved componets |
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Term
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Definition
preciptated inorganically from water
evaporates, limestone |
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Term
| biogenetic and chemical sedi rocks classified based on 2 |
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Definition
mineroligy
orecipitatin mechanism |
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Term
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Definition
| bio activity alters water so minerals DIRECTLY precipitate |
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Term
| organic rock production mechanism |
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Definition
| deposits very full if organic matter such as coal |
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Term
what does the age of a rock tell you 3
2 eg of specific helpful sediments |
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Definition
geoloic history and relationships
aids in relativ age dating
BIOSTRATIGRAPHY
interbedded ash and volcanic units
detriatal zircons - radioisotpes |
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Term
provenace of rocks 3
2 eg to use |
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Definition
the source of sediment
geologic history
sediment basins can record the erooded rock;s history
detrital zircons
paleocurrent indicators |
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Term
environment of deposition can tell you 3
3 eg to look for |
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Definition
paleogeography
paleoclimate
paleobiogeography
sediment textures
minerology
fossils |
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Term
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Definition
physical and chemical changes that change sediment into a sedi rock
occurs after deposition |
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Term
geochem of rocks can tell us 4
2 eg of tools to use |
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Definition
correlation of strats
paleoclimate interpretations
record poist deposition diagenisis
record of bioactivity in the environment |
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Term
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Definition
| allignment of sedimentatry rocks with the flow diorection of a current passing over it |
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Term
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Definition
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Term
| 5 steps for forming sedi rocks |
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Definition
begin with source rock
weathering - loss of chemically unustale species
transpo - increases rounding, loss of mech unstable species
deposition - produeces stratification, sorts by size, density, often addds chemical species
diagenisis - authigenisis, cementation, compaction |
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Term
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Definition
| process whereby a mineral or sedimentary rock deposit is generated where it is found or observed. |
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Term
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Definition
physical - mech breakdown
chemical - rxns change rock composition
bio - with aid by/ perpretraited by organisms, bio acids, root wedging |
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Term
| physical weathering 4 examples |
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Definition
by wind water ice
thermal stress - alternating hot/ cold
frost wedging
unloading |
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Term
| chem weathering 3 expamples |
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Definition
rain dissolution by H2CO3 (chem weathering in this way is earth';s thermostat - increased sedi of rocks = lower T)
hydrolysis - can turn fspar to clay
oxidation - controls oxygen concentration |
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Term
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Definition
o horizon - loose decaying org matter
a - minerals and humus
e - eluvation zone (transpo of dissolved species by rain water), leeching
b - clays
c - partially altered parent material
unweahered parent material |
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Term
soil layers - depend on ______
2 other points |
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Definition
depends of precipitaion
dry = clasys
wet = thick and well devoloped with saprolite
bacterial and org breakdown of rocks for increased nutrients
paleosoils |
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Term
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Definition
| ancient soil used ot reconstruct surrface |
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Term
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Definition
| removal of weathered material |
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Term
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Definition
dimensionless
large Re = turbulent
small Re = laminar |
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Term
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Definition
mue (crazy u) - viscocity
v - velocity of fluid
r constant
p = density |
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Term
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Definition
V=Cd^2
v = settling veloc
c = drag coeffient
d = particle diameter |
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Term
| 2 ways sedi moves in river |
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Definition
suspension
saltation - bouncing along floor |
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Term
sedi gravity flows 3
2 types with exaples |
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Definition
very rapid transpo
very large quantities of sedi
very coasrse sedi
subarial - debis flows
subaquesous - turbidity currents |
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Term
| 6 types of sedi gravity flows |
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Definition
grain flow
fluidization
liqifaction
debris/ mud flow
debis avalanche
turbidite |
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Term
| 4 most imprtnat gravity flows |
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Definition
grian glow
fluidization
debris flow
turbidite |
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Term
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Definition
mass of dry cohesionless sedi
by gravity
no water needed |
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Term
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Definition
grains supported by water
upward motion of escaping fluid |
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Term
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Definition
sedi looses strength and cohesion due to appleied stress like and EQ
behaves like a liquid |
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Term
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Definition
supported by cohesive mud matris
poorly sorted mis of sedi and water
steep slopes needed
fast flow |
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Term
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Definition
grain suport mechanism is turbylence
more fluid flow than grain flows
decrese in slope stops the flow
gravity driven |
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Term
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Definition
| processes occuring now over extrmeely ,ong time period explain the geologic record |
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Term
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Definition
| short term violent massive global scale events shaped geologic record |
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Term
| primary sedi structures 2 |
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Definition
physically created during transpo and deposition
define environments |
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Term
| secndary sedi structures 5 |
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Definition
physical or bio created
occur after initail deposition of sedi
sometimes diagnostoc
soft sedi deformation
post depositional |
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Term
| unideriectional currents 2 |
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Definition
water flows one way making diagnostic features
man generate x beds (sediment is pushed up hill and down into valley filling the valley) |
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Term
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Definition
occur in specific tidal areas
herringbone x strat - equal power water flows |
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Term
| secondary sedi structures examples 3 |
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Definition
ball and pillows
flame strucutres
cokvulte bedding - complex folding of laminations |
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Term
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Definition
paleoenvironmental interpretations
define inchnofacies |
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Term
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Definition
| assembly of fossils that gives conditions an organism may have inhabited |
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Term
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Definition
sandst formed from resistant rock
area of heavy decomposition (river channel, warm wet environ)
often thin deposits |
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Term
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Definition
made up of many types of rokcs
thick deposits
erroded from high relief sources |
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Term
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Definition
qtz arentite
fspar areneite
lithic arentie
wacke |
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Term
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Definition
most common sandst
not evenly distributed in time
formed from intense weatherinf of stable cratons |
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Term
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Definition
low sorting and less mature
common at continental normal faults
formed from less intense weathering than qtz areneite |
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Term
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Definition
| common in orogonic wedges |
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Term
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Definition
common in turbidity flows
dominant sandst of the archean |
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Term
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Definition
| area of increasseing mountain height over subducting crust |
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Term
clays 2
2 types
2 common names |
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Definition
phylo silicates with tetra and octa layers
aqueous environs
type 1 - ot-ot layers
typer 2 - tot-tot layers with interlayers cations tha tattract water (more charge = more water)
monmorillinite - swells
illite - no swelling |
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Term
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Definition
abundant in reored
anoxic coniditions
high concntrations of organic matter |
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Term
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Definition
| anoxic fossil beds that limiy decomp of organisms "storage place" exceptional fossil preservation |
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Term
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Definition
everything after dep and before metam
chem phys, bio proccessing
compaction 0 reorganize grains to more compact structure
lithification |
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Term
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Definition
gaps with no matris
interconnectedness of pores |
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Term
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Definition
compaction - clast deformation and distorotion
decrease permiability and porosity
caused by increased p due to burial
pressure dissolution |
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Term
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Definition
precipitate form in cracks, proes around grain edges
styolites |
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Term
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Definition
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Term
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Definition
minerials precipitate from pore fluiods
variable formation times
effects - lithification - binds clasts
large decrease in porpsity |
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Term
| common cements in sand stones 3 |
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Definition
calcite - very soluble and very common
- near surface where small changes in pH hav large impact on doissolution
qtz - less soluble but increases with increasing T
Iron oxides - red
- dissolves in reducing environs (low O)
- quick precip in oxic environs |
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Term
carbinate cememts 2
3 eg and locations |
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Definition
readily occurs in deposition and burial
depth and water composition has large impact on type of cement
arag/ calcit
dolomite at depth |
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Term
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Definition
new minerals created from recycled elements and minerals
alteration of clays
hematite forms from FeO minerals |
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Term
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Definition
diff mineral preipitates in previuosly occupied space
needs dissolution of orginal precip of new
petrified wood - replaced by chert |
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Term
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Definition
existing minerals grow larger
very common in carbonates (may obscure orginal texture) |
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Term
| deporitional environ sequence 4 |
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Definition
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Term
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Definition
fan shaped
coarse with poor sorting
formed at sharp topgraphic boundries
has b riv channels throughout it |
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Term
a fan
formation caused by
located at
how thick |
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Definition
majoir change of slope causes hydraulic pressure to decrese
rift valleys, grabens, fareland basins
km thick |
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Term
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Definition
streams, floods b riv
gravity, debris, mud
plants may occupy space increasing stability |
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Term
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Definition
coasre up
distal x beds
unsorted debris
immature sedi |
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Term
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Definition
| stream discharge cant carry all sedi in it |
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Term
| favour b riv over m riv when 3 |
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Definition
high errosion
coarse sedi
low or varied discharge |
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Term
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Definition
associated with fast up life/ down dropping basins
fine upwards
low mud, high sand and cobble cincentratins
l and t bars |
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Term
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Definition
further from the source
energy goes to cutting laterally not into bedrock bc of flat topography
long ribbon sands
entranched m riv from uplift |
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Term
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Definition
floodplain
point bar
channel |
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Term
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Definition
lake
fine sedi
fine laminations often with seasonal bio sedi
fresh water may have wierd chem
organic rich |
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Term
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Definition
river spreads at sea, bars form, river splits
fining away from river mouth
sheltered locals
at river dominated - more side than errosion
at wave dominated - sedi moves parallel to shore
tends to prpograde - coasrse up |
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Term
sequence strat
untip -
downdip - |
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Definition
link sedi packs that are bound by correlative conformities and unconformities
to source
to basin |
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Term
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Definition
relate time of dep
similar rock types
they are used in tandem |
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Term
sequnnce boundry cause =
2 types |
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Definition
sea level fall
below slope = shelf break
no shift in relative shoreline position |
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Term
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Definition
set of beds bound by marine flooding surface
causeed by sea level rise (eusatic)
coarsen up with abrupt shoft to fine grain
facies depositedin lateral continuity |
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Term
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Definition
vertical succession of sedi units caused by lateral change in depositional environ
lateral change in lithology in correltave units reflect horizontal change in dep environ |
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Term
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Definition
Highland sys tract
sedi accumulation faster than accomodation |
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Term
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Definition
transgressive system tract
onset of coastal transgression |
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Term
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Definition
lowland system tract
after sea level rise |
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Term
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Definition
separates TST from Hst
Deepest water facies in unit |
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Term
| Marine dep environs near and far shore |
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Definition
n - coarse, turbidites (buoma sequences)
f - finer dominated by bio sedi and marine snow |
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Term
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Definition
silicious ooze - bio orgs that make shells of silica
calacreous sedi |
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Term
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Definition
connect 2 larger water bodies as elongate passages
amplify currents bc of constriction
only small sea surface elevations needed for storng surrents
flow modified by channel obstructions |
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Term
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Definition
large scale x beds
sandstx bedding without mud drapes (Mud drapes are found in deltas)
trace fossils shoould refelct marine salinity levels |
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Term
| how does sea level influence velocity |
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Definition
hoigh sea level
decrsae constriction
decrease v
increase sedi accomodationm space
may cause low e deposits over high e |
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Term
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Definition
| use fossils for age dating |
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Term
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Definition
rock at bc latitudes originally formed in baja CA?
paleomag data suggests low lat formation
lack of large scale geo evidence for transpo however |
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Term
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Definition
1 rocks formed at current lat, no need for long transpo
2 paleomag data suggest soem rokcs have paleomag data for low lat. need to travell long distance in short time |
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Term
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Definition
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Term
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Definition
| zone just above high tide to just bellow low tide |
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Term
3 main carb dep environ
dimensions of deposits |
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Definition
bahamas
arabian peninsula
warmer = higher dep
laterally extnsive, not thick |
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Term
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Definition
normal salinity
well mixed (oxygenated)
bioturbation common
bioherm in high e environ |
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Term
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Definition
| ancient reef made of organic structures |
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Term
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Definition
form at the edge of carbonate platform
record the chem of the ocean |
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Term
record ocean chem by
what 4 things cna you nmeasure |
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Definition
analzing the precipitates form the ocean like carbonates
O and C isotopes
T
Atmos CO2 |
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Term
stable isotopes
may cause____ which may depends on______ |
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Definition
diff in mass cases diifferent behavior
frctionation
temperature, easy of uptake into bio proceesses |
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Term
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Definition
| relative abundance of an isotope compared to a standard |
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Term
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Definition
| photosyth preferentially uptakes 12C over 13C leavign ocean high in 13C |
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Term
boron isotopes 2
absundance of isotopes based on |
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Definition
B(OH)3 as boric acid
B(OH)- as borate same size and charge as carbononate minerals. can easilt substitute
contoilled by pH and fractionations |
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Term
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Definition
thin
isochronus - laid down at same time
conspicuos
wide spread
volc ash, fossils of massive die off |
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Term
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Definition
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Term
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Definition
1 major eustatic cycles caused by super cintentnt breakup/ formation
2 eustatic cycles induced by volume changes in MOR systems
3 crustural flexures
4 rapid eustatic fluctuations bc ice cheet growth/ decay and delta growth/ decay |
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Term
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Definition
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Term
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Definition
| pump enmergy into ground, diff ltih units have diffeernt seismic v so can map the refractions |
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Term
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Definition
| conformabel succession of related strata bound by conformitoes and unconformities |
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Term
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Definition
| conformable successions of beds bound by marine flooding surfaces |
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Term
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Definition
| accomodation space is grater than sedi supply |
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Term
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Definition
| sedi supply greater than accomodation space |
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Term
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Definition
| sedi supply is about equal to accomodation space |
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Term
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Definition
accumulation of km of thick sedi
long livede
need lonng term subsidence to create accomodation space |
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Term
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Definition
| topography is a function of litho density |
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Term
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Definition
| topography a function of litho thickness |
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Term
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Definition
ridgid astheno can act as an elastic plate
flaxes when loaded |
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Term
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Definition
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Term
| extensional boundry basins |
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Definition
rift basins
ultimately passive margins
driven by crustal thinning and heat flow of astheno sphere beneath it |
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Term
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Definition
| ocean contacting contintal litho that is not active |
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Term
convergen boundry basins 3
eg |
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Definition
flexure of underlying plate by weight of overriding plate
deepest at mountain fronts
most accomodation space
forarc basins |
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Term
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Definition
pull apart basins
heat lost thru walls so rapid fault controlled subsidence
rapid lateral facies variations |
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Term
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Definition
1 continental rift at spreading centre
2 new oceanic crust at seaflor spreading centre
3 ocean basin with MOR and passive margins
4 passive margin becomes active, oc subd under cont
5 continued subd, MOR closes
6 cont crust from either side of MOR colides |
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Term
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Definition
sedi packages and mountain beslts the vesult of vertical motion
now we know horizontal techtonics dominate |
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Term
| geocynclinal theory past view |
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Definition
| sedi accumulation occured in lond troughs |
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Term
| geocynclinal theory presnt wiew 5 |
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Definition
sedi weighs down crust increasing subsidence and sedimentation
folds and faulting
mnts where thick sedi deposited
uplift from contraction of cooling earth and sedimentation shifting to oceans |
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Term
accomadation space created at tech spreading centers how?
conv 2
div 2
transform 1 |
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Definition
c - crustal flexing and faulting
d - faulting, thermal subsidence
t - faulting |
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Term
| intracratonal basons cause of subsidence 3 |
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Definition
underlysing rifts
cooling after intrusions of dense material
downwelling from cold spots |
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Term
| edvidence for the appearance of Oxygen 4 |
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Definition
dissapearnace of detrital pyrites, BIFs, Sulfur MIF
appearance of redbeds |
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Term
| grain flow rock record evidence 3 |
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Definition
no grading
massive deposits
grain orientation parallel to flow |
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Term
| fluidized flow rock record evidence 4 |
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Definition
convolute laminations on top
fluid escape structures like pipes, flames
poor grading
flame and loading structures |
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Term
| debris flow rock record evidence 4 |
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Definition
irregular top with grains projecting
poor sorting
poor grading
scours at base |
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Term
| turbidity current rock record evidence 3 |
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Definition
micro cross laminations
good grading
laminated |
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Term
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Definition
| failed rift valley (3rd leg) |
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Term
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Definition
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Term
| what age with a detrial zircon give you? |
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Definition
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Term
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Definition
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Term
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Definition
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Term
| thin sedi packages found in what basin |
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Definition
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Term
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Definition
| an abundant and characteristic fossil |
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Term
| sequences that represents a rapid deepening of water deoth |
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Definition
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Term
| zachos oxy isotope curve records |
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Definition
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Term
| change in abundance of carbon isotopes in carbonates represents |
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Definition
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Term
| most common mineral in sandstone |
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Definition
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Term
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Definition
|
|
Term
| why are black shales black? |
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Definition
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Term
|
Definition
| ratio of inertial force to gravatational force |
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Term
characteristics of primary sedi structure 3
and ine that is not |
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Definition
occur in clastic rocks
porodiced by currents
reflect transpo and depo features
not bio activity |
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Term
| do trace fossil assemblages give the organism that made the fossil? |
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Definition
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Term
| thickness of a lamination |
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Definition
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Term
| most preserved volume of sedi found in what eon |
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Definition
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Term
| fast chem weathering by 2 |
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Definition
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Term
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Definition
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Term
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Definition
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