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Geology 103 3rd test
Mass Wasting, Paleontology, Water, Energy and Climate Change
72
Geology
Undergraduate 1
12/15/2009

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Term
What are the factors that influence mass wasting events?
Definition
Angle of Repose, Saturated vs Unsaturated (Wetter is more unstable), "over steepening" of slopes, is the supportive vegetative cover,
Term
What are the causes of mass wasting events:
Definition
Natural: Earthquakes and liquefaction, water(rain and snow melt), weathering, geological over-steepening.
Human: over-steepening by construction projects, road-cuts, and quarries.
Term
How do we classify mass wasting events?
Definition
by Material, speed, type of movement (Laminar or turbulent), location (submarine or terrestrial)
Term
Laminar vs turbulent
Definition
All in one direction vs all different directions.
Term
What are the 4 types of Mass Wasting events?
Definition
Creep, Slump, Rockfall, Rockslides, Debris Flow, Mudflow, and Lahar
Term
Creep
Definition
Slow (mm/yr), too slow to see. caused by unconsolidated material moving down the slope via gravity.
Vertical objects slope over time.
Term
Slump
Definition
Rapid slide (m/s) however you can still run away from it. caused by rocks slipping down a curved surface.
Term
Rockfall
Definition
Rapid (m/s) from steep or vertical angles.
Term
Rock slides
Definition
Rapid (m/s). Caused by rock or sediment moving rapidly along a plane of weakness such as bedding or foliation.
Term
Earth flow
Definition
sediment
Term
mudflow
Definition
super wet sediment (flows like a liquid)
Term
debris flow
Definition
big chunks
Term
Lahars
Definition
volcanic mudflows
Term
Angle of repose
Definition
It is the maximum angle of a stable slope determined by friction, cohesion and the shapes of the particles.
Term
What's special about submarine landslides?
Definition
They are much larger than land-based ones and can create catastrophic tsunamis.
Term
What are the four largest reservoirs of water on the earth?
Definition
Oceans (97.2%), Glaciers (2.15%), Groundwater (0.62%), Freshwater lakes (.009%)
Term
What are the 6 processes involved in the Hydrologic cycle?
Definition
Precipitation, Evaporation, Infiltration, Runoff, Transpiration, Storage in Lakes and Underground.
Term
Young River vs old river
Definition
straight,steep and fast. usually in the highlands. vs winding, flat and slow and usually in the lowlands.
Term
What is river maturity?
Definition
Matures as the river down-cut into the ground overtime.
Term
Discharge
Definition
the volume of water flowing through a give cross section during a given time.
Term
Drainage basin
Definition
Fundamental geographic unit or track of land that contributes water to a stream or stream system
Term
Trunk streams vs Tributaries
Definition
Primary river in a watershed vs streams that feed into it.
Term
Velocity
Definition
determines the size of particles the stream can move.
Term
Gradient
Definition
vertical drop over horizontal flowing distance. Same a slope!
Term
Meander
Definition
a sinuous, S-shaped curve that forms in a mature river system.
Term
Oxbow lake
Definition
Forms when erosion cuts off the neck of a tight-meander loop.
Term
Name the two bank of a curved river:
Definition
The deposition bank (point bar) on the inside and the cut bank of the outside.
Term
How does an oxbow lake-
Definition
forms when erosion cuts off the neck of a tight-meander loop.
Term
Channel
Definition
Where the stream usually runs.
Term
Alluvial fans
Definition
build at the base of a mountain in an arid semiarid region. Usually occurs where a significant break in slope.
Term
Delta
Definition
Forms where a sediment-laden stream flows into standing water.
Term
Floodplain
Definition
Low flat area adjacent to a stream that is subject to periodic flooding & sedimentation usually dry. becomes submerged when it floods. Is formed by the meandering of a river.
Term
Terraces
Definition
Mark previous levels of a floodplain.
Term
Flood
Definition
when a river channel goes over it's max discharge.
Term
Primary impacts of a flood
Definition
Death, Injury, Damage to property, landscape changes.
Term
Secondary
Definition
Water pollution, fire, disease, disruption of social and economic activities.
Term
Recurrence Interval
Definition
The average time between two floods of a given time. There is an inverse relationship between interval and intensity.
Term
Effects of urbanization?
Definition
Can significantly enhance flood events, paving increases flood height, the probability, flood will weak sooner during a storm and their will be more runoff.
Term
Why live in a floodplain?
Definition
Good soil for farms, easy access to river transportation, and flat ground to build on.
Term
Groundwater
Definition
Water stored within pores, cracks & fissures in the ground, water that infiltrates the ground.
Term
water table
Definition
the upper limit of water in an unconfined aquifer.
Term
Aquiclude
Definition
An impermeable layer along an aquifer.
Term
Porosity
Definition
The volume of pore (void) space in a sediment or rock.
Term
Permeability
Definition
the east with which fluids flow through geologic materials.
Term
Cone of depression
Definition
forms when discharge is greater than recharge.
Term
When does subsidence occur?
Definition
When discharge is greater than recharge
Term
saltwater intrusion
Definition
too much overdrafting causes salt water to get in and pollute ground water.
Term
Karst
Definition
Acid dissolves limestone, creating a network of caves & sinks. Can form sink holes on the surface!
Term
What is hydrothermal activity?
Definition
Any process associated with igneous activity involving the action of very hot waters. The waters involved can be derived directly from an igneous intrusion (i.e. juvenile water) as a residual fluid formed during the late stages of crystallization of the body, or can be external groundwater heated during crystallization of the intrusion. The hydrothermal fluids can react with and alter the rocks through which they pass, or can deposit minerals from solution.
Term
Who deals with water purity?
Definition
Water purity is established by the U.S. Public Health Service. It is controlled and monitored by the EPA and FDA.
Term
What are fossils?
Definition
evidence of past life in the geological record.
Term
Paleontology
Definition
the study of past life
Term
What are the three main disciplines of paleontology?
Definition
Paleobotany- study of plants. invertebrate paleontology and vertebrate paleontogy
Term
Paleobotany
Definition
Study of ancient flora which is important for reconstructing ancient climates and ecosystems. Works with coal and mold fossils.
Term
3 types of fossils
Definition
Replacement fossils- bone replaced by minerals though it maybe still look like bones. Mold- set in the rock, decays away, mold is left. Icnofossils- evidence of behavior an organism was engaged in
Term
Invertebrate paleontology
Definition
allows us to reconstruct environments, to define geological ages and date rocks with index fossils.
Term
Vertebrate paleontology
Definition
We are organism oriented trying to figure out how they lived. Either studying evolution or biography.
Term
What makes a good index fossil?
Definition
used to date rocks. best are geographically widespread, easily identifiable and evolve quickly.
Term
Cladograms
Definition
how related they are depends on how close they are (distance)
Term
When was the age of the dinosaurs?
Definition
Mesozoic Era which was from cretaceous to triassic.
Term
Where do fossil fuels usually come from?
Definition
Phytoplankton
Term
Coalification
Definition
results in different grades of coal. From Peat, lignite, bituminous and Antarctic.
Term
Coal
Definition
Formation: from altered plant matter
Extraction: open pit, strip mining.
Uses: electricity
Consequences: land disturbances, acid mine drainage, subsidence, water pollution, air pollution, fly ash, ecosystem degradation.
Term
Petroleum
Definition
Formation: Requires organic matter in an marine anaerobic environment.In order for oil to collect in concentrated area the earth must enclose the porous rocks containing the oil with non-porous rock through which the oil does not pass
Extraction: from anticline, fault and unconformity traps
Uses: internal combustion
Consequences:
Term
Crude oil
Definition
unprocessed petroleum before it is refined into different grades.
Term
Natural Gases:
Definition
Formation: Trapped in the crust. Methane Gas Hydrates are formed on the sea floor.
Extraction:
Uses: For heating

Consequences:
Term
Quaternary
Definition
was the most recent geological time scale started about 1.6 million years ago.
Term
When was the last ice age?
Definition
max was 20,000 years ago. Glaciers started retreating 12,000 years ago.
Term
What are short-term causes of ice ages?
Definition
Milankovitch Cycles
Term
What are the 3 variations in the Milankovitch Cycle?
Definition
Eccentricity or orbit, tilt and wobble or precession.
Term
earth's orbit
Definition
goes form oval to almost round
Term
Precession
Definition
axis wobble
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