Geology Exam #1

stream discharge

(Q) m^3/s Q= cross sectional area x velocity of channel

Infiltration

- surface water gets transferred to ground water.

Small grains

Deposited— low energy

Floodplain-

Flat area formed by flooding (fine sediment)

Water scarcity (economic)

Infrastructure, poor management, climate events.

Chemical

Minerals produced by chem reaction (precipitates) ex. Evaporates- halite calcite- travertine *hotsprings *caves SiO2- precipitate- chert *petrified wood

Continued..

- root wedging -honeycomb weathering (salt wedge)

Sediments

-clastic sediments: weathered rock and minerals. (Sand, gravel, clay) -shells, teeth, bones -plants -minerals formed by precipitation (minerals that form from a solution *water)ex. Evaporation produces salt.

Formation of Earth

-collision +accretion through gravity

Lithification

-compaction -cementation -dissolved ions (GW) -precipitates mineral

Dissolution

-dissolved -calcite CaCo3

Transfer Processes

-evaporation: water-gas -condensation gas-water -precipitation -transportation-atoms movement from ocean to land -infiltration

Frost wedging/ Freeze thaw

-expansion of water when it freezes -frequency of freeze thaw cycle -humid ,temperate climate -high elevations - talus slopes (products at base of slope)

Solar System

-formed by nebulae: clouds of dust and gas *gravitational attraction (larger objects have a greater gravitational attraction) densest area collapses- sun *dust + gas rotate around sun

Environment of deposition

-grain size- energy -sorting: distribution of grain size -shape- rounding- water. Angular-ice, landslide

Reduce storm water runoff-

-green infrastructure- build back natural systems -rain gardens,rainwater harvesting, bioswales.

Contour lines

-lines of equal elevation -never cross or intersect(can't have two elevations at same location) *Shape of lines tells you about topography

O-2

-most abundant -all other common elements are cations (ionic bonding)

Properties of minerals:

-naturally occurring -inorganic -solid at Earths surface -internal structure (crystal lattice) -definable chemical composition *building block of rock.

Sources of heat?

-object colliding and accelerating had heat. -collisions-friction- heat -compression of material -radioactive decay

2 factors drive groundwater flow?

-permeability and water table slope

Sectors of water use (how we use water)

-public supply -Domestic: water use in home -irrigation:crops -thermoelectric power:electricity -industrial -mining -livestock -aquaculture- fish farming

Early Earth

-temps were hot- 200 c *molten

Tropical areas

-warm + wet have the highest rates of chemical weathering. -deserts- very low rates of chemical weathering and minimal physical weathering. Humid temps— high rates physical weathering.

Rate of GW flow

1. Permeability material 2. Slope of water table Slope WT= 100-50/2000 *Water table and HH are the same in an unconfined aquifer.

Annual Probability-

100% chance of 100 yr flooding any given year.

Big Bang

13.77 billion years ago. 1. Cosmic microwave background (afterglow of Big Bang) 2.expanding red shift

Silicates

90% siO4 an ionic group

Hydrolysis

Alteration of groups of minerals to clay mineral. Ex. Feldspar—kadinite *weakening of mineral

Stream-

Any body of flowing water. -channel

Reservoirs

Anywhere water is stored . -atmosphere -ice/ snow (glaciers) -oceans (97%) -lakes/streams -ground water -biosphere

Increase in Q

Are and velocity will increase. 1. Depth 2. Increase width through erosion. 3.Flood- flows outside of channel (decreases valley)

Drainage basin/ water shed

Area from which water in a stream comes from.

Ripples

Asymmetric -1 direction of flow (river) Symmetric - 2 directional flow (beach)

Unconfined aquifer

At surface

index countours

Bold lines, coarser scale

1. Physical

Breaking of rocks and minerals into smaller pieces.

2. Chemical

Chemical alternation of minerals.

Chemical Weathering

Chemical weathering *rain is naturally acidic

EX:

Cross sectional area of. Channel: 5ft^2. area of velocity: 5ft/sec Q= 5(5) = 25ft^3/sec

Decrease in Q

Decrease in velocity and channel area 1. Depth 2. Width 3. Deposition

Water scarcity (physical)

Demand is greater than available resource (supply)

Hydrologic Cycle

Describes storage + movement of water on earth

Groundwater Depletion

Discharge extraction>recharge of aquifer 1. Lowering of after table 2. Pore collapse- subsidence(when you replace water with air) 3. Saline intrusion- saltwater contamination of freshwater aquifer. (Costal regions)

Sorting

Distribution of grain sizes. Well sorted: all the same (high porosity) poorly sorted: all different sizes (low)

Permeability

Ease of flow

Base level-

Elevation that which stream cannot erode below. (Lowest point on the stream profile) Determined by its mouth. -Changes with climate and flow

Hydraulic head

Energy available at any given location to drive ground water flow. -unconfined hydraulic head = water table elevation.

Velocity of Stream

Energy cm/sec (determines the process) *velocity is controlled by slope (gradient) also by the amount of water

Flood recurrence interval-

Ex. 100 yr flood. A flood of given size occurs on ave. Once/100yrs.

Local base level-

Ex. Resistant rock, a damn

Weathering

Exposure of rocks and minerals to surface conditions- (weather, rain, atmosphere) (lower pressure then formation + more variable temperatures.

Straight channel

Fastest flow in center just below surface. Least amount of friction.

Oxidation

Fe, Mn, Ms -Reacts with oxygen -physical weathering increase exposed surface area— which in turn increases chemical weathering.

Clastic Sed Rocks

Formation: 1. Weathering 2. Erosion- removal from source 3. Transportation (water wind ice)

Large Grains

High energy deposited (because all fine + medium grains are being eroded + transported)

Unconsolidated sediments

High porosity

Grain size of sediment

Large- low porosity small- high porosity

Bedding bed

Layers of sediment- mostly horizontal (refer to notes)

Water table

Loosely mimics topography/ surface of earth - goes up and down with weather

Meanders-

Low gradient, near mouth, sediment channel.

Aquitard

Low permeability- un fractured rock, clay

Un fractured bedrock

Low porosity

Leeve-

Low ridge made up of (coarse sediment) (gravels)

Pressure Release

Lower pressure-rock expands-cracks

Aquifer

Material that can transmit water easily.

1. Deposition

Material that settles out of water flow.

Bank full stage-

Maximum water flowing in a channel.

Porosity

Measure of the percent of open space (pores) in a material. Volume pores —————————- X100 volume materials

Stream discharge

Measure of volume of water passing a given location in given amount of time.

Deposition

Medium loses ability to carry seds.

Biological

Minerals produced by life. -shells, other skeletal parts -CoCo3-Calcite-limestone (warm shallow ocean) -plankton -corals -SiO2(quarts from plankton) -diatoms- algae (cold, deep oceans) = chert

Non clastic sedimentary rocks

Non clastic sedimentary rocks

Urban areas-

Not as much can be absorbed into ground. Water doesn't infiltrate when there is pavement. (More runoff) -lag time shorter because we have drainage systems designed to move water.

Crystal-

Orderly arrangement of atoms. Graphite- soft diamond- hard *carbon based

Physical weathering processes

Physical weathering processes

Organic

Plants- coals

Primary porosity

Porosity of unaltered materials

3. Erosion

Removal of material by the stream

Water Withdrawl

Removed from hydrologic cycle but may be returned. ex. Thermoelectric

Secondary porosity-

Rocks are fractured or dissolved.

Ultimate base level

Sea level

Confined aquifer

Separated from surface by aquitard.

Covalent-

Shared electron

Flash Floods

Short duration with heavy rainfall.

Hydrograph-

Shows discharge through time.

Grain size

Size of particles in stream. *boulders > 256mm—- clay .002mm

Stream profile

Slope of the stream ^elecation/ distance - stream gradient

Tributary

Small river flows into a bigger one

Stream Processes

Stream Processes

Groundwater-

Subsurface water that resides in open space. (Pores) (within rocks or sediment)

Sheet wash

Surface runoff not in a stream *surface runoff collects in low areas to form streams.

2. Transportation

Transport of material by stream.

Contour interval

Vertical distance between contour lines.

Flux

Volume of water/ year *cubic km or miles

Consumption:

Water not returned to hydrologic cycle. *largest consumption- agriculture

Flooding

When Q is greater than channel can accommodate.

Abrasion:

Wind or water with fine particles wearing down rock. "Sandpaper"

Polymorph

same chemical composition, different structure