Sed/Strat 1

2.58Ma

2.58-23.03 Ma

23.03-66Ma

End 66 Ma (Quaternary, Neogene, Paleogene)

66-145Ma

145-201.3 Ma

201.3-251.9Ma

66-251Ma (Cretaceous, Jurassic, Triassic

251-541Ma (COSDMPP)

443.8-485.4Ma

485.4-541Ma

541-4600Ma (Proterozoic, Archean, Hadean)

541-2500Ma

4000-4600Ma

Process oriented

Spatial and Temporal variations

Steno

1. Superposition

2. Original Horizontality

3. Original Lateral Continuity

in anysequence of undisturbed strata, oldest layer at bottom, and successively younger layers are successively higher

states that sedimentary layers were deposited nearly horizontal and parallel to Earth’s surface

At the time of depotion, strata extened cont in all directions until they termintated by thinning at the edge of the basin, ended abruptly at a barrier to sedimentation, or graded laterally into a different sediment type

Principle that processes acting upon Earth today have also operated in the geologic past

principle that body fossils occur in strata in a definite determinable order

states that a rock unit, sediment body, or fault that cuts another geologic unit is younger than the unit it was cut

facies that are found today in vertical sequence are the product of a series of depositional environments which lay laterally adjacent to eachother

Tectonics(internal)

Climate(external)

tectonics+climate=erosions+deposition

abrasion

insolition(thermal fatigue) and exfoliation

frost wedging and exfoliation

root-wedging

salt-wedging

transport

dissolution

hydrolysis

oxidation and reduction

amount of material available (erosion)

space available (accommodation space)

preservation potential

host most natural resources (oil,gas,water)

preserve Earth’s geological history

significant for energy resources, environment, economy

70%

Subcritical

Supercritical

Turbulent

Laminar

Function of viscosity, size, shape and density of particles

a single solide sphere settling in a fluid has a terminal settling velocity which is uniquely related to the diameter

high density minerals settle more rapidly than low density minerals

slow moving, high viscous fluids can transport courser grained materials more easily than less viscous materials

texture

composition

sed structures

classified according to grain size and composition

classified according to clast size and composition

composed of ^{>30% of clasts}

4-64mm

64-264mm

264+mm

2-4mm

flows smooth and streamlined

flows irregular and chaotically

phi=-log2(d)

fine size: positive

course size : negative

form

roundness( angularity)

surface texture

measure of the range of grain sizes presnt and the magnitude of the spread around the mean size

Give us info on physical processes and depositional environments

control oil and gas resivior quality (porosity and permeability)

control groundwater reservior volume

orthoconglomerate

when clasts are in contact with eachother and matrix is <20%

paraconglomerate

when matrix is >20%

made of clasts of different compositions

made of clasts of the same composition

support+clast type+avg size of clasts+conglomerate

relative proportion of quartz, feldspars and lithics/rock fragments

primary depositional fabric

l=lithics (<62micrometers

R=rock fragments include all polycrystalline lithic fragments (size bias)

sediment transported by the effect of gravity acting directly on the sediment or rock

highly cohesice sediment water mixture drived by its own weight

initiate on slopes >10, flow on slopes <5

poorly sorted

large range of grain size

mud matrix

lack internal layering

base may show evidence of shearing or scouring

either no grading, normal or reverse grading

subaqueous

triggers: earthquake, storm, sediment failure, alignment slopes

turbulence causes sediment to become suspened

creates desnity contrast with surrounding water

flows stop when density contrast is reduced by settling

head: concentration of courser particles, most intense turbulance, overhanging, velocity slower than body

body: uniform, steady velocity, velocity > haed velocity, feeds head, near uniform thickness, can be area of erosion or deposition

tail: thins rapidly away from body, becomes more dilute, area of deposition

desnity contrast

Massive Ungraded mudstone, possibel bioturbation, pelagic seds

Lower flow regimes planar laminated siltstone

Ripple laminated fine-grained sandstone, flame/convolute lamination

Uper flow regime planar laminated medium grained sandstone

Normally garded sandstone, course grains or rip-up clasts at the base scoured base

concentarted dispersions of grains in which sedimenrt is supported by upward escape of flow of pore water or by injection of water from below

thick, poorly sorted sand

identified by fluid escape structures

occur on steep surfaces near angle of repose (30)

cohesion often causes cohesionless sediment to be piled up beyond angle of repose

grain-to-grain contact supports flow

most commonly observed in aeolian environments

deposits difficult to preserve

almost like billiards balls

material for carbonate sediments is extracted from the dissovled load of the sea or other body of water

light, pH, temperature and nutrients

carbonate platforms (non-reefs)

organic reef env

slope basin carbonates or carbonate ramps

mixed carbonate siliciclastic systems (non-reef)

most important control on skeletal carbonate precipitation because of the dominance of photo-autotrophic arganisms in carbonate productions

the water depth at which the rate of supply of calcium carbonate from the surface is equal to the rate of dissolution

solubility of calcium carbonate is determined by temperature, pressure and dissolved CO2 in the water

in areas of high productivity, greater rates of supply makes the CCD deeper

decrease CaCO3 solubility, deeper CCD, higher T, lower P

The CCD gets deeper

Deeper

biogenic

non-biogenic

carbonate minerals (micrite and sparite)

calcite, aragonite, dolomite

molluscs, stromatolites, nanoplanktos, cephalopods, corals, crinoids, coccoliths, oncoids

ooids( speherical bodies of CaCO3 less than 2mm

poloids (fecal pellets) no cocentric structure

intraclasts- fragments of calcium carbonate material that has been partially lithified and then broken up and reworked to form clasts

made of fine-grained calcium carbonate less then 4 micrometers across

they form by chemical precipitation of CaCO2 out of saturated wtaer

course-grained calcite crystals that appear clear to translucent in plane light

relative abundance of 1. carbonate grains or allochems, 2. microcrystallline carbonate mud (micrite) and sparry calcite cement

relative abundance of allochems and micrites or sparite, but does not consider ID of grain

increase temp

decrease pressure

increase CO2 and lower solubility of CO2

photosynthetic organisms

preference for calcite vs aragonite seas

Mg2+ rich seas favor aragonite