43 Cards in this Set
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The largest expanse of time on the geologic time scale is the
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eon
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What is the smallest division in the Geologic Time Scale?
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Epochs
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Types of Uncomformities
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angular
discomformity
nonconformity
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inclusions
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rocks containing inclusions of another rock are younger than the rock from which the inclusion came
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Relative Time
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The determination of the sequence in which evens occurred, relative to each other.
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Absolute time
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absolute units (years, hours, minutes) to describe the occurrence of an event
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Eons
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geologist now recognize four eons: Hadeon, Archeon, Protezoic and Phanezoic
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eras
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4 major divisions of Earth's history in which particular plants and animals were dominant or in great abundance
Precambrian
Paleozoic
Mesozoic
Cenozoic (now)
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What period contains the lifespans of most dinosaur species?
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Mesozoic
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Which is the earliest (oldest) period of the Mesozoic?
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Triassic
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What period do we live in today?
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Quaternary
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_______ is the single most important geologic agent modifying Earth's land surface.
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Running water
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Hydrologic Cycle
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the circular pathway of water on Earth from the atmosphere,to the surface, below ground, and back
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Four Drainage Patterns
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Dendritic (Tree Branches), Radial (starts at a point e.g mountain), Rectangular (creates district changes), and Trellis (long lines with little rivers)
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Factors that control stream erosion and deposition
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Velocity, gradient, channel shape and roughness, and discharge
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Meandering Streams
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channels that are very curved, commonly formingtight loops. Such streams have high sinuosity and this type of bend is ameander
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Meandering Cutoffs
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Meanders develop and work their way downstream
Landforms - meander scars, oxbow lakes
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How does flooding occur?
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When water level rises and over tops the bank of the river.
EX. flash floods
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downcutting
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process in which water flowing through a channel cuts into the substrate and deepens the channel relative to its surroundings
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Porosity
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The amount of pore spaces present in a rock
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permeability
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the ease with which water can travel through a rock.
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What is the saturated zone?
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the area where all pore spaces are filled with water
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Flow velocity of groundwater depends on what two factors?
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Slope of the water table
Permeability of the rock or sediment
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What is the difference between an aquifer and an aquitard?
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An aquifer has extremely good porosity whereas an aquitard is not porous whatsoever and is completely lacking in permeability and porosity.
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What are the differences between an unconfined and confined aquifer?
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Unconfined- Has a water table, and is only partly filled with water Rapidly recharged by precipitation infiltrating down to the saturated zone
Confined-Completely filled with water under pressure. Separated from surface by impermeable confining layer. Very slow recharge
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how can groundwater be contaminated?
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Pesticides, Fertilizers, feed lots, landfills pollutants
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What are caves, sinkholes, and karst?
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Caves- naturally-formed underground chambers
Sinkholes- where the ground collapse
Karst- an area with many sinkholes with cave system beneath the land surface
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What are speleothems?
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Various intricately shaped formations the grow in caves by the accumulation of dripstone
ex. dripstone
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effects of groundwater
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caves/caverns
petrified wood
concretions
geodes
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What is Coastal Waters?
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Indeterminate region of the ocean extending seaward from the shoreline.
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what are estuaries?
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-area where freshwater form a river mixes with sea water
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How are estuaries classified? what types?
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Classifying by origin
ex. Coastal plain, Fjord. Bar-built, Tectonic
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What are pelagic sediments?
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fine-grained sediment that accumulates as the result of the settling of particles to the floor of the open ocean, far from land
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What are the three major, general provinces of the ocean floor?
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Continental shelf, continental slope, continental rise
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Difference between a seamount and guyot.
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seamounts = submerged basaltic volcanoes
guyots = large extinct volcanoes with flat submerged top
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What is the longest mountain range in the world?
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Andes mountain
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coriolis effect: what and how does it work
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objects move in nonlinear way, cause earth moving faster at equator; Nhemi=goes right Shemi=goes left
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What is thermohaline circulation?
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the vertical movement of ocean water driven by density differences resulting from the combined effects of variations in temperature and salinity; produces deep currents
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How are tides generated?
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Primarily generated by the moon's gravitational pull on the Earth, also the sun's gravitational pull and centrifugal force of rotation
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What are Abyssal Plains?
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Flat area of seafloor that makes up most ocean basins
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What is deflation and blowout?
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Deflation—the process of removing sediment by wind erosion
Blowout—area deflated by wind
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What are some characteristics of deserts?
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Streambeds flow intermittently, typically during/after heavy rain
Most of the time, steambeds are dry
Most deserts lack through-flowing streams
Many desert regions have internal drainage, such that steam drain into landlocked basin
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what are ventifacts
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rocks that have been eroded to have a flat surface, happens through abrasion
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GEOL 1040: Exam 3