EOS 120 Mid-Final

• * great majority inorganicly derived
• *naturally occuring
• *have a distinct internal structure (bond lattice)
• *maintain a fixed chemical composition
• *homogenous mixture

Yes

its fits all the criteria, its main difference from sugar is that it is inorganic.

NO

It breaks a couple of the rules. it is organic, and it must be produced/synthesized (nbot natuarlly occuring)

In general NO....some may answer that in its solid form ice it could be considered so.

some are some arent. they must fit the criteria....mostly due to naturally occuring

in some minerals ions w/ simialar charge and radius may be substituted for one another.

• ex. feldspare (NaAlSi₃O₈) subs the Na⁺ for K⁺
•       Quartz SiO₂ is very pure because the Si & O are not easily substituted.

ions try to fill their valence shells to gain stability

Ionic=transfer= weak

covelaent = sharing=strong

only about 20 minerals that make up earths crust.

most common are silicates made of Si & O

remainder are Al,Mg,Na,K, Fe

minerals become unstable with changes in heat and pressure.

In a subduction zone hydrous minerals sink with the crust

pressure becomes to great

they become unstable and form new minerals a/o rocks

• basalt/gabro------>eclogite
• plagioclase----------> pyroxene/garnet

due to mineral stability relating to pressure graphite turns to diamond

pressure only found below 140km deep

kimberliite magma

so how do diamonds exist on surface? surface conditions are not enough to break the covelant bonds.

• 1. rounded structures
• 2. losse debris (regolith)
• 3. secondary minerals (ions in solution)
• 4. creating landforms

• Physical - mechanical breakage
•                no change in chemistry
•                **increases surface area

• Chemical - decomposition
•                  weakening of chemical bonds
•                  reactions work to 'stabalize' minerals

Biological-combo roots wedge and also produce hemic acid

• **often work together
• **water usually required

1. ice wedging - water in craks freezes-->expands=broken rock

2.pressure unloading- rock formed at high heat pressure relaxs at surface and breaks along prefered orientation

1. dissolution - everything disolved no by product (halite/calcite)

2. hydrolosis - clay minerals left behind (feldspare to claymineral-kaolinite and disolved minerals)

3. oxidations -with atmospheric or hydrous oxygen (iron oxides)

Clastic - made of other rocks (brecia, conglomerate, sand stone, mud stone etc.)

Chemical - evaporites (rock salt)

Biological - from plants/animals (coal)

• *downslope movement of earth materials
• * when driving force (down slope) > resisting (retaining) force

* either slope increases OR cohesion(friction) decreases

• material strenght - weathering = less cohesion (strenght)  
•                             weathering = more mass=more force

• water content - high = additional mass = more force
•                         high= less cohesion= less resistence

over steepening - i.e. undercutting - a slope will try to achieve equilibrium

Creep - gradual down slope movement - very slow

Slump - movement of a choherent mass along a curve - slow to moderate

Flows - material is in a viscous flowing state, mudflows earth flows & debris flows - rapid movement

slides - total failure along a determined plain (slipage plain) - rapid to moderate

falls - material movement through the air

1. creation of new or altered landscapes

2. alteration of procesess.

however rivers are the single biggest factor to errosion!

• 1. stream competence - ability to transport sediments by size/density
• 2. Stream capacity - ability to transport volume of sediment

• 3. suspeneded load - fine sediment in suspension (clays etc)
• 4. bedload - rolling sliding coarse particle
• 5. dissolution - disolved sediments

• * most frequent of all natural disaters
• *when Q/driving force/shearstress exceeds channel capacity
• recurence i.e. 100yr flood is not how often but how likelky i.e. a probability
• *100yr flood = 1% chance, 2year flood = 50%

• *it is encouraged by human activity
• paved surface= less ground saturation=more run off
• bridges restrict river flow
• changing the base level and slope of profiles

• water in pore spaces in the ground
• percalation zone = water travels throuhgh
• saturation zone = all pores are 'full'

the line between the two is the water table - it generally follows the topography.

recycletime= residencetime/rate of exchange  (~280 yrs)

by H isotopes in the water

• H¹ most common
• H³ or trintium is radioactive

• porosity = % volume of por space in sediment
• common soil is 30-50%

permiability= ability of water to move through substrate determined by pore size (not pore %)

aquifers = permiable regions transmit water freely (san, gravel)

aquitards = impermiable layers that hinder prevent mobility (clay)

excessive use of ground water lowers the localized water table and can leave neighbooring wells dry.

ireversible loss of aquifers

reduced structure of soils (leaning tower piza) 

contamination , leaching through permiable layers into ground water

they hold about 3% of total water and 95%of fresh water

• snowflake--->granular snow-------->firm---------->glacial ice
•             lose struc.                packing         formation

they flow under their own weight in an almost plastic like way

creep - rotating grains underneath act as rollers

basal slip - water lubricant underneath

points on the outside have more drag the in the middle so the middle moves downslope faster

1. valley glaciecer - like frozen rivers

2. ice sheets - huge regardless of topography

the result of glacial errosion and transportation. a poorly sorted mixture of shit

• river
• rounded peaks, overlaping spurs, V shapped valleys

• glacial
• horns(sharp peaks) cirques, morains

• after glaciation
• horns, truncated spurs, hanging valleys, U shapped valleys

• lateral - along sides
• medial - down the middle -when two ice flows come together 
• terminal - marks the furthest advance
• recesional- built as the glacier receeds.

caused by malakovitch cycles

• 1. earths orbit is eccentric (sometimes closer or further from sun)
• 2.obliquity or axis tilt ( which parts of earth face the sun at what angle)
• 3.percision or the wooble on the obliquity

• cool planet - thus eccentric orbit
• percipitation - high seasonability due to high obliguity

• 1.weathering and eroision creates detritus
• 2. detritus transported to basin
• 3. deposition of detritus in basin
• 4. lithifacation

terrigenous sediments are sediments eroded on land and transported to sea by rivers, 

turbidity current is like an underwater river, water more dense from above sediments moves downward

these two factors create the continetal shelf

as a pile of sediments grows, pressure forces water out of and compacts the pore space, minerals percipitate out of the water and creates cements

comon cements are carbonates, clays, silica

a reef island in the middle of the ocean

a reef grows alongside a hotspot volcano, as the plate moves the volcano cools and supsides, reef continues to grow upward

• created from > 30% biogenic material
• calcareous ouze - Ca rich
• silicieous ouze SiO₂ rich

• transgression - sea moves onto land
• regression - the opposite

sediments and deposition occur in different locations (finer sediment further from shore line) therefore we can see a 'barcode' of the changing sea level by overlying layers of sand and clay

a-pro-phan = archean , proterozoic, phanerozoic

• archean = 3800-2500 mya
• proterozoic = 2500-570mya
• phanerozoic = 570mya - pres

Zircon grains from metamorphosed sediments U-Pb radiometric ages 4.4 billion years old

• Age of Solar System 4.567 Ga
• • Oldest detrital zircons ~ 4.4 Ga Western Australia: implication of oceans
• • Oldest Rocks 4 Ga, Acasta Gneisses, NWT Canada
• • Oldest Supracrustal volcanics and seds 3.8 Ga, Isua, Greenland
• • Oldest well preserved terrane, fossils 3.5 Ga, W. Australia

pillow lavals from the archean period.

BIF formations, the oxidation of Fe⁺² to Fe⁺³

also cyanobacteria (use Co2 and produce O2)

a sedimentary deposit when stones drop from ice flows into underlying mud (ice flow over deep water) 

key element 'drop stones'

they are found near the equator proving the ice at equator snowball earth.