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97 Cards in this Set
- Front
- Back
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Relative geological time |
The order in which events occurred |
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Principle of original horizontality |
Sediment is usually deposited in horizontal layers
If sedimentary rocks are at angles they were affected by tectonic forces after they formed |
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Principle of superposition |
Oldest layers are at bottom; younger layers on top |
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Principle of crosscutting relationships |
If igneous rock cuts across existing rock, it must be younger than the existing rock |
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Principle of faunal succession |
If a rock contains old fossils it must be older than a rock containing younger fossils
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Index fossils |
Numerous, widespread, short-lived, easily identified fossils for age reference
The rock must be older than the extinction date of the organism |
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Key beds |
Thin, widespread sedimentary layer that was deposited rapidly and at the same time over a wide area; often due to a volcano or a meteor |
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Radiometric dating |
Looking at the decay and half life of the radioactive isotopes to see how old something is |
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Half-Life |
The amount of time it takes half of radioactive isotopes to turn into its daughter isotope
Referenced in radiometric dating Half life of Uranium is 710 million years |
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Parent isotope |
The radioactive isotope that eventually decays into a daughter isotope
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Child isotope |
An isotope that has decayed from a radioactive parent isotope
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Carbon-14 dating (radiometric dating) |
Comparing the ratio of C-14 to C-12 in an item to the atmosphere Can only be used for things under 50,000 years older C-14 decays and is not replaced when something dies |
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Pre-Cambrian Eons |
Hadean, Archean, and Proterozoic 540 million years ago or earlier |
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Phanerozoic Eon |
Paleozoic (544-248 mya)
Mesozoic (248-65 mya) Cenozoic (65 mya - present) |
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Paleozoic Era |
Development of shelled organisms and later animals with bones, spines, etc.
Cambrian Explosion Permian Extinction of marine and land life 544-248 mya |
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Mesozoic Era |
Break-up of Pangaea Dinosaurs (KT extinction) & mammals emerge, phytoplankton & flowering plants Asteroid left iridium-ash layer 248-65 mya |
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Cenozoic Era |
Humans evolve Grass and birds proliferate Continents are in current position 65 mya - present |
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Evaporation |
Liquid water becomes a gas (vapor) & enters the atmosphere Usually over oceans or other large bodies Can occur anywhere though |
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Transpiration |
The process by which plants release water into the atmosphere |
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Condensation |
Water vapor becomes liquid water Cloud creation, opposite of evaportation |
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Precipitation |
Rain, snow, sleet, hail, freezing rain All forms usually start as liquid water and then some free and become solid or semi-solid |
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Sublimation |
Direct conversion of ice & snow to water vapor in the atmosphere
Often happens on the east edge of the Rockies |
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Deposition |
Vapor turns directly into ice Opposite of sublimation |
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Infiltration |
Surface water seeps into the ground |
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Porosity |
The capacity to hold water; the amount of water the rock or soil can hold The volume of space (pores) in which water can seep Mud is high, sand is high, shale is low |
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Permeability |
The ability of rock or soil to transmit water
How easily water can pass through a given rock or soil Increasing depth decreases permeability |
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Zone of saturation |
Completely wet layer of soil and bedrock above the impermeable rock
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Zone of aeration |
Above the water table Rock/soil may be wet but not saturated |
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Aquifer |
An area that has a significant quantity of groundwater Must be porous and permeable so it can be pumped and replenished |
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Unconfined aquifer |
An aquifer that is open to the zone of aeration |
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Confined aquifer |
An aquifer that has impermeable layers above and below it
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Artesian well |
A well that has been tapped into an artesian aquifer so it's under pressure |
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Spring |
Where the water table naturally intersects the land Often can happen along a hillside if there is a perched water table in the hill |
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Caverns |
Ground water dissolves limestone to create caverns
Most caverns are flooded |
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Sinkholes |
When cavern roofs collapse or if limestone is dissolved at the surface downward
Pumping water out of aquifers can accelerate and exacerbate sinkholes |
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Karst Topography |
Landscapes of underground water, caverns, and sinkholes |
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Kettle lake |
A lake created when a glacier left behind a large chunk of ice as it receded |
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Crater lake |
Water that accumulated in a volcanic crater |
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Oxbow lake |
Cut-off part of a river meander When a river erodes and creates a new path, the other path becomes a weird-shaped lake |
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Oligotrophic |
Poorly nourished lakes Deep, cold (often mountain lakes) Nutrients sink to the bottom where sun can't penetrate and aren't available to life near surface |
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Eutrophic |
Well nourished
Plants growth and plankton Sunlight reaches bottom of lake Lakes become more eutrophic with time |
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Drift |
All rock or sediment transported & deposited by a glacier All different sizes of particles: fine silt up to large boulders Drift can be classified into till and stratified till |
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Unsorted till |
Till deposited directly by glacier
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Sorted (stratified) till |
Carried by a glacier then a stream Sediment is sorted because it is deposited in water |
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Moraine |
Mound or ridge of till |
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Kame |
An irregularly shaped hill or mound that accumulates sorted till on top of a glacier, when the glacier melts away it goes onto land |
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Esker |
A long winding ride of stratified sand and gravel Formed by streams flowing under the glacier Leaves winding ridges when glacier melts |
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Drumlin |
Whale shaped hill formed by glacial ice on top of ground moraine or unsorted till
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U-Shaped valley |
U-shaped valleys are scoured out by glaciers |
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Hanging valley |
V-shaped valley formed by streams or rivers |
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Gradient |
Steepness of the stream bed Steeper stream = faster flowing stream |
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Discharge |
Amount of water flowing in the stream Measured in cubic meters per second More water = faster flow |
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Channel |
Shape of the stream channel and the amount of friction between the bed and banks Streams flow faster in the middle Smoother channel = faster |
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Bed |
The floor of the stream |
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Banks |
The sides of the stream |
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Capacity |
The total amount of sediment a stream can carry The amount of sediment the stream can carry past a given point in a given amount of time Fast moving streams can carry more sediment |
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Competence |
The largest particle a stream can carry Fast moving streams can carry larger particles |
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Load |
Types of sediment |
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Dissolved load |
Ions dissolved in the water (individual, charged molecules and atoms) |
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Suspended load |
Small particles of clay and silt Usually the largest quantity of sediment Cloudy, muddy water |
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Bed load |
Rocks, cobbles, pebbles, etc. moved along the bottom of the channel |
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Downcutting (Vertical erosion) |
Erosion downward into the stream bed |
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Lateral erosion |
Erosion against the banks Forms meanders (multiple bends) as they flow Meandering rivers cause lots of lateral erosion along outside edges and deposition along inside edges |
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Base level |
The deepest a stream can erode its bed The lowest-most base level is sea level, it can't erode after that |
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Comets |
Where Earth got all of its water during Big Bang Comets were sent to outer solar system via solar winds, then knocked out of their orbit and sent towards us |
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Neap tide |
Smallest range of tides When the Moon and Sun are perpendicular to each other |
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Spring tide |
Largest range of tides
Moon and Sun are lined up with another |
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Wavelength |
Distance between successive crests or troughs |
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Crest |
Highest part of the wave |
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Wave height |
Distance from trough to crest |
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Ocean currents |
Like rivers within the oceans Brings water from one part of ocean to another |
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Surface currents |
Move water in the upper 400 meters of the ocean Driven by surface wind patterns |
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Deep sea currents |
Move water below 400 meters Driven by gravity Colder, saltier water |
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Gulf Stream |
Brings warm water from the equator up to the East Coast and over to Europe One of the most important currents for the northern hemisphere is the Gulf Stream |
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California Current |
Canadian water comes down causes upwelling of water from deep in the ocean Keeps California coast cold down to Santa Barbara |
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Oxygen |
21% of the atmosphere |
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Nitrogen |
78% of the atmosphere |
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Pressure |
Pressure in a fluid increases the deeper down you go Pressure = force/area Pressure is greater at the bottom of our atmosphere Measured with a barometer |
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Trophosphere |
The layer we live in Weather, clouds & water vapor Trophosphere gets cooler as you go up |
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Stratosphere |
Temperature increases up to 50 km Ozone forms here |
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Mesophere |
Thin air, very cold, up to 80 km Above 55 km: Temps fall again through region |
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Thermosphere |
Temperatures rise rapidly to about freezing High energy environment |
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Electromagnetic radiation (light) |
Energy in the form of light |
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Albedo |
The amount of a surface reflects Mirrors, glaciers, snowfields are high Water is low |
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Scattering |
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Greenhouse effect |
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Angle of incidence |
The angle that sunlight hits the Earth When angle is small, it's more intense When is large, its spread out Latitude depends on time of year |
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Length of day |
Over the year, the angle of incidence changes and shortens or increases daylight Equator always has 12 hours of light and 12 hours of darkness North & South trade off with 6 months of darkness |
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Seasons |
Two effects on the seasons: Change in the intensity of light hitting the Earth's surface Change in the length of days |
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Tropic of Cancer |
Summer Solstice occurs here June 21
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Tropic of Capricorn |
Sun shines over 23.5 on December 21st for the winter solstice
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Convection |
Warm air rising above the denser air |
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Evaporation |
A change of state from liquid to gas
More rapid the evaporation, the faster the cooling |
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Condensation |
A change of state from gas to liquid |
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Absolute humidity |
The total amount of water vapor in the air (mass of water vapor)
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Relative humidity |
The amount of water vapor relative to the maximum amount possible
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Dew point |
The temperature at which, for a given amount of water vapor, the air will become saturated The temperature it takes water vapor to turn into rain |
