Term
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Definition
a fossil that is useful for dating and correlating the strata in which it is found. |
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Term
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Definition
A stratigraphic column is a representation used in geology and its subfield of stratigraphy to describe the vertical location of rock units in a particular area. A typical stratigraphic column shows a sequence of sedimentary rocks, with the oldest rocks on the bottom and the youngest on top. |
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Term
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Definition
The geological time scale (GTS) is a system of chronological measurement that relates stratigraphy to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred throughout Earth's history. |
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Term
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Definition
eons- are the largest ssubdivision of time (hundreds to thousands of Million years).
eons names are as follows
- Hadean-"hell" (4.6-3.8 ga)
- Archean- "ancient" (3.8- 2.5)
- Proterozoic- "before life" (2.5-0.542)
- Phanerozoic- "visible life" (542- 0)
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Term
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Definition
eras- subdivisions of an eon (65- to hundreds MA)
-divided in to periods based on fossil succession
Cenzoic- "recent life"
Mesozoic- "middle life"
Paleozoic- "ancient life"
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Term
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Definition
In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age and shorter than a period. We are currently living in the Holocene Epoch of the Quaternary Period. Rock layers deposited during an epoch are called a series. |
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Term
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Definition
Radioactive decay is the spontaneous breakdown of an atomic nucleus resulting in the release of energy and matter from the nucleus. Remember that a radioisotope has unstable nuclei that does not have enough binding energy to hold the nucleus together. |
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Term
| parent and daughter isotope |
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Definition
parent isotope is radio active which in oart is unstable.
daughter is stable.
The radioactive isotope is called the parent, and the isotope formed by the decay is called the daughter. A radioactive isotope decays at a constant rate proportional to the number of radioactive atoms remaining. |
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Term
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Definition
half life takes parent isotope to decay in to the daugher.
Not only does it decay by giving off energy and matter, but it also decays at a rate that is characteristic to itself. The rate at which a radioactive isotope decays is measured in half-life. The term half-life is defined as the time it takes for one-half of the atoms of a radioactive material to disintegrate. |
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| how can half lives be used to absolutley date a rock sample |
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Definition
p=d
16=0 decay hasnt startted yet
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8=8 (1 1/2 half way time started)
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4=12 ( 2 1/2 half life)
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2=14
age of rock= half life x duration |
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Term
| basic parts of the water cycle. |
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Definition
Evaporation -When water is heated by radiant energy it turns into water vapor
Transpiration- Evaporation from plants.
Condensation-When water vapor cools, molecules join together and form clouds.
Precipitation -When clouds get heavy the waters falls as rain, sleet, hail, or snow
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Term
| where is most of the water |
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Definition
ocean, glacier, groudwater, surface water.
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Term
| where is most of the fresh water? |
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Definition
Over 68 percent of the fresh water on Earth is found in icecaps and glaciers, and just over 30 percent is found in ground water. |
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Term
| why are we interested in stream run off when they are such a small part of the water budget? |
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Definition
| its the way they are able to measure how much water has fallen. etc |
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Term
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Definition
A drainage basin or catchment basin is an extent or an area of land where all surface water from rain, melting snow, or ice converges to a single point at a lower elevation, usually the exit of the basin, where the waters join another body of water, such as a river, lake, reservoir, estuary, wetland, sea, or ocean. |
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Term
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Definition
the watershed of a continent, esp (often caps.) the principal watershed of North America, formed by the Rocky Mountains. continental divide in Science Expand. continental divide. A region of high ground, from each side of which the river systems of a continent flow into different continental-scale drainage basins. |
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Definition
a stream or river that flows into a larger river |
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Term
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Definition
it is between the zones of erosion and deposition and serves to transport sediments. |
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Term
| what are the factors that determine the velocity of a stream? |
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Definition
The first is flow velocity, and the second is the volume of water in the stream. Flow velocity is influenced by the slope of the surrounding terrain, the depth of the stream, the width of the stream, and the roughness of the substrate or stream bottom.
gradient/ slope shape size roughness stc.
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Term
| how do they affect the velocity? |
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Definition
| it determines of flow will be slower or faster? |
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Term
what is discharge and how is it calculated?
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Definition
the amount of water flowing through a specific point in a channel over time.
velocity= volume of water passing a point per unitof time
multiply cross sectional area x average water velocity.
D (q)= Ac x V |
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Term
how do stream characreristics change from headwaters to mouth
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Definition
Bedrock channels- cut into solid rock, form in the headwaters
Alluvial channels- form in sediment that was previously deposited in the valley, near the mouth |
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Term
types of loads transported by streams?
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Definition
Sediment load- material moved by running water load.
dissolved load- ions from chemical weathering
suspended load- fine particles (silt and clay) in the water.
bed load- larger pareticles roll, slide and bounce along the bottom. |
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Term
what is a base level?
what is a local base level? |
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Definition
The base level of a river or stream is the lowest point to which it can flow, often referred to as the 'mouth of the river'. For large rivers, sea level is usually the base level, but a large river or lake is likewise the base level for tributary streams. |
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Term
where do they usually find straight streams?
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Definition
always near the headwarters (source) of the stream.
gradient is steep
discharge is low
competene is high
sediments are course (small
channels are straight
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Term
| what are the different features of a meandering stream? (point bars, cut banks, oxbow lakes, floodplanis, natural leeve) how do they form? |
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Definition
meandering stream have continuous looping curves (meanders). they form where the stream gradeitn is low.
the substrate is osft and easily eroded. the stream exists within a broad floodpain.
oxbow lake is fromed from cutoff meander.
flood pplains are often bounde by bluffs.
natural leeves form ridges parallel to the channel. |
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Term
how do incised rivers form?
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Definition
| with extreme rapid uplift the meadering stream can become incised. |
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Term
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Definition
porosity- controlled by the grain size, packing and amoutn of sediemnt
pores are open spaces within sediment or rock.
the volume of open space is termed porosity
Permeability- a measure of the ability of a fluid to flow through rock. water can not flow through impermeable material. |
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Term
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Definition
2/3 comes from groundwater fresh weater.
ground water is trappe dunder ground that has been purified through rock minerals. |
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Term
| high porosity & Permeability |
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Definition
| congromerate/ sand stone. |
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Term
| what are saturated and unsatruated zones? |
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Definition
saturated zone is which pores are completley filled with water. next to water table.
unsaturated zone is interval of soil and rock near the surface in whcih pores are filled primarily with air and some water. |
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Term
| where is the water table? |
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Definition
water table is a subsurface boundary between the 2 zones.
in humid settings the water table is closer to the surface.
in arid settings itmay be tens to hundreds of meters down.
the water table is the tops of the zone of saturation.
the water table position changes with rainfall. |
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Term
| how might the water table change over time? |
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Definition
changes with rainfall.
during seasonally rainy periods the water table rises
during prolonged droughts the water table falls. |
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Term
aquifiers
aquitards
aquicludes
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Definition
aquifiers- rock that store and transmit groundwater in suffieicent qunatities to supply wells and springs. they have a high porosity and high permeability.
examples are sandstone and clastic sedimentary.
Aquitards/ aquicludes- rocks that slow/ prevent flow of water to or from an adjacent aquifer.
low permeability
barrrier to flow.
examples - granite gneissic, shale |
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Term
what are gaining and losing streams
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Definition
In this classification system, streams are either "gaining" or "losing" streams (Figure 1-4). A gaining stream is one in which the channel bottom is lower than the level of the surrounding groundwater table. Through the course of the summer, water moves from the ground into the channel. |
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Term
| what are recharge and discharge. |
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Definition
recharge- water coming in to the surface.
refilling it uop.
discharge- removing water form furface for exapmple wells. |
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Term
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Definition
spacial change in hydraulic head
the height change over a horizontal distance nad steeper - faster flow, and steepness of the land.
steeper - faster flow.
less steep- slower flow. |
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Term
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Definition
| water table collapses from over pumping. |
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Term
| what are unconfined, confined and perched aquifiers? |
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Definition
CONFINED AQUIFER
A confined aquifer is one in which the water is being held under pressure which is greater than the atmospheric pressure. The water is between two confining layers. This forces the water to rise.
UNCONFINED AQUIFER
An unconfined aquifer is one in which the water is under atmospheric pressure and only partially filled. Here the only confining layer is on the bottom.
PERCHED AQUIFER
A perched aquifer is one where a small body of groundwater is separated from the main aquifer by a confining layer.
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Term
| how does water move through an aquifer |
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Definition
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Term
| the type of aquifer affect water quality |
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Definition
| springs are always the best wya and cleanest way of fresh water. |
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Term
| overpumping of wells risks what |
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Definition
| sink holes, cone of depressions, land resifdensce, sinkage of deserts. etc; |
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Term
| different types of global changes |
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Definition
physical vs biological
: population, climate, the economy, resource use, energy development, transport, communication, land use and land cover, urbanization, globalization, atmospheric circulation, ocean circulation, the carbon cycle, the nitrogen cycle, the water cycle and other cycles, sea ice loss, sea-level rise, food webs, biological diversity, pollution, health, over fishing, and more.[2 |
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Term
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Definition
super continent cycle- plate tectonics, ocean basins open and close, continetla land masses collidea dn rift apart super continets form several times.
sea level has risen and fallen many times. the rock cycle. |
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Term
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Definition
chemical fluxes between liveing and non living. the hydrologic cysle, water moves between reservoirs on or near earths surface.
regualtes climate.
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Term
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Definition
carbon returned to atmosphere.
Biochemistry
the series of processes by which carbon compounds are interconverted in the environment, chiefly involving the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels
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Term
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Definition
long term climate change, short term climate change.
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Term
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Definition
long term climate change, short term climate change.
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Term
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Definition
paleoclimates- investigations of past climatic variation.
computer simulations- modeling past and futuer changes. |
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Term
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Definition
past climates are interpreted by datable earth materials that are climate sensitive.
oxygen isotopes ratios are preserved in carbinate shells of organisms. growth rings- tree rings can easily be dated. ring thickness reflects climatic changes. |
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Term
| know the green house effect |
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Definition
the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface. |
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Term
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Definition
a gas that contributes to the greenhouse effect by absorbing infrared radiation, e.g., carbon dioxide and chlorofluorocarbons.
carbon methane, nitros acid etc
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