EOS 201 MT

sedimentology: processes that erode, transport, and deposit sediments

petrology: charectoristics and origins of sed rocks

• sedimentology=process
• petrology=products

facies refers to spefic charectoristics of a rock as a product of its depositional enviornment

Deep ocean basins, due to the low oxygen content and low energy.

anything above sea level is being eroded and moved to below sea level.

that the processes that have shaped earth in th epast will exist in the future thus we can use events in the past to predict the future.

effect of amalgamated physical weathering is that it increases the surface area of existing rock.

Products: clasts and matrix material

• +freeze thaw (water vol inc/dec)
• +insolation (thermal exp/dec)
• +orogenic or glacial rebound
• +organic activity (roots/burrows)

from organisms, works as both chemical and physical weathering

• effect: breakdown into alteration materials
• product: cements

• Dissolution (cal, hal)
• oxidation (olv, pyx)
• hydrolosis (silicates)
• hydration/dehydration (anhydrite, gyp)

A dissolution reaction (new ions in solution in products)

this particular rxn is the dissolution of calcium carbonate with carbonic acid to produce calcium ions in solution

A oxidation or redux reaction (notice how the oxydation number of Fe has changed)

specifically this reaction is the oxidation of pyroxene  to limonite

This is a hydration/dehydration (the forward is dehydration) Note the solid product with water a s a by product

this specific rxn is that of anyhrite dehydration to gypsum

This is a hydrolysis reaxtion not the H+ in the reactants side of the rxn

this specific rxn is feldspare to kaolinite with k ions in sol and silic acid as by product

physical weathering

they are hydrous aluminum phyllosillicates which are the proucts of 

Hydrolosis reaxiotns

these are all products of precipitations from dissolution rxns

because of the transport in fresh and the holding tank that is marine. all due to residency times and and solubility

High solubility=low evaportaion

C>G>H

calcium precips before gypsum then halite

∴halite is at the center of a closed basin and the landward edge of a restricted basin

oxidation does not dpepend on rain, in diffrent ways you could argue the others, hydration, dissolution hydrolosis

trick question, it will make ions in solution not soil

mostly physical (although lichens do play a bio and chem role) 

primarily freeze thaw lithic frags

primarily physical due to insolation flds may be present as lithics as no water for ions in sol.

oxidation makes iron oxides

fine sediment may bel blow all the way around the world

includes all types and proccesses, typically a lot of lithics, larger grain saize a younger soil

includes all types but chemical weathering is highest due to high Temp making rxns faster/easier.

lots of thick clays (think jungle quicksand) lots of hematite and kaolinite

• clast framework differs from matrix
• clast and 2^ndry provenace is outside of depositionl basin 

seds typ: qtz,flds,msk,clays, Fe³⁺

• conglomerates>2mm
• sandstones 2-1/16^thmm
• mudstone < 1/16^thmm
•      *siltstone=gritty
•      * claystone=smoth

originate within the depositional basin  from dissolved constituients

chemical-evaporites and Iron formations

biochem/biogen/organic- carbonates, cherts, phosphates, carbonacious

refers to the the grains size of a sample

• unimodal-one size typical of delta or deep sea
• bimodal- 2 sizes- typical of river
• polymodal- several sizes typical of glacier

carbonate (limestone) grains that form intrabasinally

• peloids- poop
• ooids- coated grains (skelatal or lithic)

coarse crystaline cement that fills the pore spaces of carbonate rocks

carbonate mud acts as a cement in carbonate rocks

can begin to crystalize at which point it is called micro-spar

(spar is the crystal)

black shales are often common of phospherites

the black coming from the high amount of organic rich undecayed carbon material they posses

Humic materials are those derived from plants, they are a major source of carbon in sed rocks

primarily humic materials are responsible for coal deposits

sapropelic materials are decomposed marine organisms (phyto/zoo plankton) they are major contributors to oil resivors anre are what commonloy give phospherites their dark-black color

most common during anoxic (without oxygen) periods in earth history due to high levels of CO2

• peat
• lignite
• bitumasious coal
• anthracticite

another name for oil shale. kerogen bearing mudstones have ~25% carbon matter.

kerogen is microbially altered plant and animal mater

petroleum is the end product that is derived through the maturation of kerogen to hydrocarbon polymers

the older of the two iron rich ssed rocks

laminations a/o beeding of iron rich material (hematite magnetite) between marine muds/shales/cherts

phanerozoic iron stones newer then bifs

not laminated/intrabedded the way BiFS are

from errosion of latericit (fe or al rich) soil

1- intrabasinally as ions in solution producing crystaline chem or biochem rock

2- extrabasinaly as clasts produce clastic sed rocks

• F_G-gravity- holds grain to btm
• F_D-drag force or shear force
• F_L-Lift force- Bernoulli effect

• F_G>F_D+F_L sed remains on bed or settles out
• F_G<F_D+F_L sed will be entrained in current

basically as current velocity changes above and below a sediment an area of low pressure above and downstream of a sediment which helps it to become entrained in the current flow

a graph showing the relationship between stream velocity and the ability to entrain varrying sized sediments

• 1- reynolds number
• 2- froudes number

ratio of inertia to viscosity

determines whether a flow is laminated or turbulent

• reynolds low= laminar
• reynolds high= turbulent

laminar is smooth, sub parellel sheets flowing slowly, mostly viscous fluids

turbulent is rough, irregular flow, eddies, lower viscosity fluids

ratio of inertia to gravity

fr<1=tranquil flow, small quantity sediment transport. ripples, sandwaves and dunes

fr>1= rapid flow, large quantity sediment transported, plane beds, antidunes, chutes and pools

sediment moves along bedding surfaces through

traction- rolling sliding creeping

slatation- intermittent contact with the bed due to eddies...think of it bouncing down the bed form

when sediment is entrianed in the current flow

usually smaller grains

turbulence is needed to keep grains entrained

• Fr<1= lower flow regime
• irregular water surface
• small sed transport

creates ripples sandwaves and dunes

Fr>1= upper flow regime

• glassy streaked out water
• large quantity of sed transport

creates plane beds, antidunes, chutes and pools

reynolds number tells us the type of flow laminar or turbulent

frueds tells us bedforms (low fr= ripples, dunes, sandwaves...hig= planebeds, antidunes chutes and poools

water tends to have a much shalllower x-beeding in the area of 15°

air tends to be steepper around 30°

x bedding will be indicitive of the lee (steeper)side ∴ the cross bedding tends to dip in the dirrection of flow

cross bedding is indicitive of the lee (stepper side) of the dune/ripple there for it basicly will appear to dip down stream

cross beding will have a ntangential base which tells us which is the top/btm side of the bed

cross stratification is created by asymetrical ripples showing unidirectional motion, thus the lee side of the ripples is presserved in a parrellel planar fashion

hearing bone is from bi directional symetrical ripples/dunes

lenticular, wavy and flaser beding strucutres

appear as wavy lines of mud inbetween beeding lenticular is thickes flaser thinest

created from tidal currents where there is more force in one direction

it is a product of ocean storm systmes

hummocks are the high swales are the low

• 1- rockfall (rock must go through the air)
• 2-rockslide
• 3-slump

these have little internal deformation of the material

• 1- grain flow
• 2- debris flow
• 3-turbidity current
• 4- fluidised flow

• slope > 30°
•  support by grain interactions= dispersive pressure
• typical of aeolian sand slidding down face of dune

• same thing as liquifaction
• support by rising fluid through medium
• can flow on slope of 3°

• support by cohesive mud matrix
• slope ~10°
• huge variation in grain size

think of lahahrs volcanic mudflow

turbulence is the grain support mechanism

like an underwater debris flow but more fluid = higher reynolds number

its a series of layers a-e (e on top) as the result of a turbidy current loosing its velocity

•                   low velocity
• E- fine mud with possible bioturbation (often not preserved)
• D- suspension settling of fine material may display lenticular to flaser laminations
• C- low flow regime seetling indicated by ripples a/o climbing ripples
• B- high flow regime planar beddng of coarser material
• A- more massive bed of coarsest sediments
•                 highest velocity

a feature on the btm side of bedding where a more dense material has overrode a lighter matierial. the lighter material is pulled up into the upper layer

when a suspended sediment is pulled downward by gravity into the underlying still soft bed.

liquifaction of a less dense layer below a more dense layer allows the more dense amterial to be completyl pulled into it or something like that

trace fossils...fossils of marine organism tracks that help to determine things like water temp, depth salinity etc.

• 1-skolith-vertical tubes burrows
• 2-cruziana- horizontal u shaped troughs
• 3-zoophycos-arcuarate(bow shaped) feeding traces
• 4-nereites-meandering feading trials

al lthe changes that occur after deposition that turn it into a sed rock

maybe biological, physical or chemical

creates tighter grain packing thus a reduction in porosity

mud compacts the most 70% porosity to 20%

deals with the bioturbation and microbal activity. typically effeyts sediment size and chemistry of pore fluids.

helps to create kerogen and thus HC resivoirs

• 1-cementation
• 2-authigenisis
• 3-replacemet
• 4-recrystilization
• 5- dissoulution

serrated surfaces where mineral material has been removed by pressure dissolution

• 1-liesegangen bands (rings of alterations material)
• 2-concretions or nodules (hard percipates of mineral cement)
• 3- sand xstals (large diagenitc calcite xstals)
• 4-geodes- void in rock with diagentic minerals growing in it

It coarsens upwards

no you still need something to bind the rock we need chemical diagenisis

turns the sediments into rock by binding the partilcles i.e. LITHIFASACTION

cement fills almost all reming pore space significantly reducing porosity

calcite and qtz, and iron oxide (1-2% will make it red)

calcite, aragonite and dolomite

• sandstone 
• mosiac- between clasts
• overgrowths- around clasts

• cabonates
• drusy
• blocky
• rimcement

authigenisis is the creations of new minerals in-situ

• 1- clay minerals kaolonite to illite or chlorite
• 2-feldspar-->clay--> sericite
• 3- hematite and pyrite from fe bearing

• chemical diagenisis refering to the replacement of one mineral to another 
• for example petrifid wood all organic carbon is replaced by chert

existing clasts retain their chemistry but grain size gets larger

such as micrite turing in into spar

important process tha tincrease 2nd degree porosity in rocks by removing solubale minerals

• braided have tranverse and longitudal bars
• tranverse-sndier cross bedded
• longitudal- massive planar bed forms, imbricated pebbles x bedding at down stream side

meandering have point bars- epsilon cross bedding from the lateral movement of the point bar and cut bank

• 1- total lack of absence of MARINE fosils
• 2-relitivly poor sorting
• 3- red color common of oxidation
• 4- unidirectional patterns
• 5- downstream decrease in grain size
• 6- fining upwards

easy to mistake with glacial outwash and delta plain deposits

finning upward at a point bar or delta

coarsening upward in aluvial fans and progradtions

imature, compositionaly mature is an extremly high level of only qtz. in aeolian there is still abundant feld and others that have not been removed due to the lack of water

• high angle 30deg (compared to 10-15 in water)
• thick tabular cross bedding
• no typical vertical sequencing
• rare fossils