Term
| What are the 3 succesions in Werner's neptuneism (formed in H2O) theory? |
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Definition
tertiary (post flood)
secondary(fossils w/flood)
primary (no fossils) |
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Term
| What is the GSSP and what do they do? |
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Definition
They define a geological location where you can physicaly see a boundary specific to a rock succession.
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Term
| What are the sources of sed rocks? |
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Definition
a)transported by weathered rock (erosion).
b)biological (animal plants, bacteria)
c)seawater precipitation (evaporites)
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Term
| What conditions does an evaporite form under? |
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Definition
| The mineral needs to be supersaturated in a body of water with an excess of ions or salinity. Needs heat to evoporite water and needs a certain shallow depth. |
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Term
| How does dolomite precipitate? |
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Definition
| It tends to form in small quantities in arid coastal settings related to microbial activity. |
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Term
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Definition
| It is the level to which fluids will move and it is the global sea level. |
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Term
| What 3 factors can cause a change in base level elevation? |
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Definition
1. plate tectonics-ocean floor cools and sinks and this can change via sea floor spreading or subduction.
2.eustatic-sea level controlled by climate and rate of glaciation.
3.sediment supply-if more sediment has been deposited into shelf, the base level will decrease. |
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Term
| what are the 3 types of weathering? |
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Definition
| Mechanical, biological and chemical weathering. |
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Term
| Describe mechanical weathering? |
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Definition
| rocks are broken off and broken into smaller clasts. Freezing and thawing is a major primary source as water gets into the cracks at high altitudes, freezes and the ice expands. |
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Term
| Describe biological weathering? |
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Definition
| Life forms will break material by animals burrowing or tree roots cracking into rocks. |
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Term
| Describe chemical weathering. |
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Definition
| A change in mineralogy will cause a change in hardness which leads to mechanical alteration. |
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Term
| What are the different processes of chemical weathering? |
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Definition
1. Hydrolysis- alteration of silica via an acid reaction in an acidic solution.
2.hydration/dehydration-water is added/removed . hydration causes rust.
3.oxidation/reduction-exchange of electron
4.disolution/precipitation-controlled by solubillity of pore space |
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Term
| How is Bowen's reaction relevant in a rocks ability to weather? |
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Definition
| Minerals that form at high temperatures are more susceptible to weathering as there are not as stable at earth's surface. Quartz is most resistants. |
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Term
| What is submarine weathering? |
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Definition
| Fresh seawater can be brought into subsurface and can chemicaly alter sea water via thermal vents. Basalt introduces Ca, Sr, K and Si into sea water. |
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Term
| What are the characteristics of an immature rock? |
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Definition
| there will be a wider range of source, will have angular clasts and will have more Fe and Mg. |
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Term
| What are characteristics of a mature rock? |
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Definition
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Term
| What is typical of a mature rock? |
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Definition
| There will be fine well sorted well rounded grains with an increase in porosity and permeability. More minerals present in lower Bowens reaction series. |
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Term
| What are the main factors behind seds transport? |
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Definition
| Medium(H2O, Ice, wind) and independant (gravity). |
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Term
| What are the 2 types of movement dependant on change of pressure? |
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Definition
Static, body force gravity (dependant on elevation).
dynamic-pressure created by a lateral gradient (high to low P). |
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Term
| What are the 2 methods of eroding sediment? |
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Definition
| Lateral and vertical pressure gradient. |
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Term
| What Is Bernouli's Equation and how does it operate? |
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Definition
Ps=Po+1/2Pvsq.
As velocity goes up, potential energy will stay the same and it will override the pressure energy and create uplift. |
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Term
| What force causes material to move in H2O? |
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Definition
Pressure gradient creates a shear stress that creates a movement. influenced by density(p)
pbulk=psedC+pFluid (i-c)
C=concentration of solid in mixture. |
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Term
| What effect does viscosity have on sediments? |
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Definition
| With a higher viscosity, rate of sediment settling and erosion decrease as well as reduced turbulence. |
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Term
| Why effect does friction have on water? |
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Definition
| It slows the velocity down at the edge and near the bottom of the river until it reaches zero at sea floor. |
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Term
| What are the two types of flow and describe them? |
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Definition
Laminar-all flow lines are parrallel and horizontal.
Turbulent- flow moves in all directions (eddies) in a net direction of flow.(responsible for sed transport). |
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Term
| What is kinematic and dynamic viscosities and what are there relationships to each other? |
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Definition
Kinematic vis. measure rate at which momentum of eddies disappear.
Dynamic viscosity measures the horizontal distance a fluid moves and its increasing velocity the shallower it gets.
v=u/p. v=kinematic, u=dynamic. |
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Term
| How do eddies effect flow? |
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Definition
| Eddies have mass, volume and velocity and when the eddies interact with eachother, they empede flow. |
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Term
| What factor in eddies causes increase in viscosity? |
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Definition
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Term
| What is the equation for laminar and turbulent flow? |
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Definition
laminar- L=udv/dy
turbulent- T=udv/dy+ndu/dy, where n=number of eddies. |
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Term
| What is Reynolds number and what does it signify? |
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Definition
It is a unitless value that determines the difference b/w laminar (under500) and turbulent (over 2000) flow
RE=ul/v
where u=velocity, l=length of pipe and v=viscosity. |
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Term
| what governs turbulent flow? |
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Definition
| eddie viscosity and the potential for that is superimposed by dynamic viscosity. |
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Term
| what is boundary shearing? |
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Definition
| transition from laminar to turbulent flow. as water moves over seafloor, bottom layer does not move, change in grain size or water flow, when the floor is smooth, the eddies will not catch on the grains. |
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Term
| discuss separation of flow |
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Definition
| This occurs when there is an unmoveable object and there exist a separation bubble before and after the obstacle. This is a break in communication with flow. There is also a boundary (shear zone) with fast and slow moving water. |
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Term
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Definition
friction created by drag
fd=3piDuv |
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Term
| discuss sediment fallout and its equations. |
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Definition
force of rock
=4/3pi(Prock-Pfluid)g(D/2)cu
fdrag=3piDvu
this determines wether rock settles
fluid drag=force of rock
settling V
V=(dP)gDsq/18u=stokes law, limited to med sand. |
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Term
| [image]Discuss Hjulstroms equation. |
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Definition
it is the inertial force that exceeds h20's ability to carry a grain. The grain can be eroded, transported or deposited based on grain size and velocity |
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Term
| What are the real world effects on grain transportation? |
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Definition
1medium dependant - bedload, saltation suspension loads
2grain size variation, due to change in energy results in grading
3unidirectional flow-change bedform type w/ change in energy. this can cause dunes or ripples which are in equib with water. 3d sinuosity-allow particle to move at different lines. |
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Term
| what is an oscillation flow? |
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Definition
| related to waves, periodic |
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Term
| how does burial chert form? |
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Definition
beds of chert are formed by burial diagenesis or primary sediments.
on sea floors-form from silicious ooze (diatoms and radiallarian)
opal Si of the diatoms form clalcadoy or microquartz. |
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Term
| How are diagenetic cherts formed? |
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Definition
replacement of CaCO3 by water rich in Si
formation by opals of silicious creatures being redistributed(diatoms, sponges)
forms nodules in rocks.
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Term
| how are phosphites formed? |
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Definition
in general, phosphites our found in fluids that have been washed through soils or absorbed in plant or flow to marine settings and are absorbed by animals.
associate with shallow marine continental shelves.
high organic productivity-low O2 |
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Term
| In what order to evaporites form? |
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Definition
| Least soluble compounds are precipitated first. calcium carbonate, dolomite, gypsum, halite and sulfides. |
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Term
| How do CaSo3 form (evaporites)? |
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Definition
| gypsum or anhydrite forms when precipitation of seawater once concentration is 19%. it precipitates under all but the most arid conditions. Anhydrite forms from burial of gypsum w/no water or direct precipitation in arid shorelines |
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Term
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Definition
| may have formed on widespread shelves or shallow basins with the iron originating in muddy deposits. source of Fe-hydrothermal or weathering. required anoxic water for transport. |
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Term
| what is required for a rock to be carbanaceous (organic) deposit? |
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Definition
| requires greater than 2% organic matter. requires limited or anaerobic conditions. this could happen in water logged swamps, bogs, stratified lakes, and lagoons (marine w/restricted circulation). |
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Term
| Discuss supratidal zones. |
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Definition
| lies above high water mark and undated by seawater during very high tides and storms. can be a marshy shore where microbial matts form. |
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Term
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Definition
| they are coastlines with low relief and poorly defined beach. wetted by very high tides and storms. groundwater comes from seepage from the sea. Water rises and the salts become concentrated to form a brine and gypsum and anhydrite form. gypsum crystals form in the shore whereas the anhydrite forms further up in the supratidal. |
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