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