GEOG101-Exam 3 Review
Absolute age
An age that is specified in years (given in actual numbers of years)
continental crust and oceanic crust
2 types of lithospheric crust
lower mantle (solid rock that is plastic), asthenosphere (solid state but nearer melting and easily deformed), lithospheric mantle (rigid and relatively brittle)
3 layers of the mantle
divergent, convergent, transform
3 types of plate boundaries
sedimentary, metamorphic, and igneous
3 types of rocks
dissolved load, suspended load, bed load
3 types of stream load
Stream
A channel in which water flows downhill by the force of gravity
Plate tectonics
A theory that describes the origin, movement and recycling of lithospheric plates and the resulting landforms
Oceanic crust
Beneath the oceans, composed mainly of basalt (formed from lava)
Trellis drainage pattern
Common in areas with tilted layers of sedimentary rock and synclines and anticline keep streams running along parallel valleys
Relative age
Compares age of one object or event with age of another without specifying how old either is and accounts for order of event
An overlying plate moves over a stationary hot spot and it creates a chain of volcanoes (Hawaiian Islands were formed by a stationary hot spot)
Describe hot spot island formation
slope stability depends on relationship between resistance force (keeps material in place) and downslope force or gravitational force (induces material to slip downhill); mass movements can be caused by an factor that increases downslope force or decreases resistance force
Describe the relationship between mass wasting resistance and gravitational force
streams in urbanized areas experience sudden spikes in discharge during heavy precipitation events and discharge quickly drops after the storm; underdeveloped areas do not peak as high and is spread out over a 20-hour period
Difference between urban areas and underdeveloped area with stream discharge
Wegner's Continental Drift Theory
Earth had one ocean and one supercontinent called Pangaea and this drifts as a result of convection in the asthenosphere beneath it. Theory states that continents move slowly across Earth's surface
crust (lithosphere), mantle, core
Earth's three major layers
Teton Range, Wyoming
Fault block system location formed when long fault block was lowered and erosion by streams and glaciers subsequently cut into the higher block, removing most of the overlying rocks and creating the jagged mountain topography seen today
contaminates groundwater and can cause earthquakes
Fracking cons
Natural gas is somewhat cleaner than coal, no international dependency for fuel
Fracking pros
ridge push, mantle drag, and slab pull
How do plates move?
1. Igneous rocks can be subject to weathering resulting in fragments deposited as sediment and can form sedimentary rock, 2. then this sedimentary rock can be buried deep in crust and compressed and heated under enormous pressure to form metamorphic rock; 3. and then metamorphic rock can be heated enough to melt into magma
How do rocks go from one family to another in the rock cycle?
With absolute age and relative age
How do scientists date materials?
Earthquake activity reveals plate boundary locations
How do we know where plate boundaries are?
Rocks first form when magma cools and hardens into rock from molten state, either deep within Earth's crust or at a volcanic vent (igneous rocks)
How does the rock cycle start?
Produced by circulating liquid metal in outer core generates electrical currents
How is Earth's magnetic field generated?
No, they are different and the magnetic field moves (one day magnetic north and south will be completely swapped)
Is the geographic north pole the same as the magnetic north pole?
Hot spot
Location at base of lithosphere where high temperatures cause the overlying crust to melt; Results form a mantle plume
Bed load
Material in stream channel that is too heavy to become suspended in the current
Dendrochronology-tree ring analysis and radiometric dating-assigning ages to materials based on radioactive decay of unstable elements in those materials
Method(s) of absolute age dating
Principle of Superposition-oldest rocks at the bottom and youngest rocks on the top
Method(s) of relative age dating uses...
Mineral
Naturally occurring, crystalline, solid chemical elements or compounds with a uniform chemical composition
They believed continents were fixed and immovable
People did not accept Wegner's theory because...
seafloor bathymetry, rock sample ages, patterns of magnetization
Plate tectonics evidence
Landslide
Rapid movement of rock or debris down a steep slope
Slumps
Regolith detaches and slides downslope along spoon-shaped failure surface and comes to rest more of less as a unit
Continental Divide
Ridge or highland that separates drainage systems that empty into different ocean basins
Yellowstone hot spot
Southwestern plate movement has transported McDermitt Caldera which was located over the hot spot. Hot springs and geysers are result of the active magma body that resides beneath the park
Principle of Uniformitarianism
The principle asserting that the processes now operating to modify the earth's surface are the same processes that operated long ago in the geological past and physical systems operate under gradual changes
Lithification
The process that converts sediments into solid rock by compaction or cementation.
Carbonation
The process when CO2 dissolves in water forming carbonic acid and reacts with carbonate rocks
Slab pull
The weight of a subducting portion of plate accelerates movement by pulling plate deeper into mantle
Soil creeps, slumps, flows and landslides, avalanches, and rockfall
Types of mass movements
Fracking (hydraulic fracturing)
Using pressurized fluid composed of water and chemicals to create fractures in rock and release natural gas or petroleum
jigsaw-puzzle fit between east coast of South America and west coast of Africa; he supported his theory using evidence from matching rock types on separated continents, deposits of glacial gravels, and fossils of organisms
Wegner's Continental Drift Theory evidence
Topography and the type of surface over which the streams flow
What do drainage patterns depend on?
earthquakes, rivers and roadcuts, ground saturation, removal of vegetation and weathering
What factors cause mass movements?
Trunk stream and tributaries form these patterns
What forms different types of drainage patterns?
solid inner core (dense elements mainly Fe and Ni) and liquid outer core (liquid alloy of Fe and Ni)
What parts of Earth's core is solid and liquid?
at high elevations and high latitudes (where temperatures routinely drop below freezing)
Where does physical weathering have the greatest effect?
dominant where temperatures are above freezing and there is ample moisture
Where is chemical weathering prevalent?
Transform plate boundary
Where one plate slips laterally past another
Drainage basin (watershed)
a geographic region drained by a single trunk stream and smaller tributaries that flow into it
Trunk stream
a single large stream into which smaller tributaries merge
Rocks
a solid mass composed of minerals or volcanic glass; most are composed of one or more minerals
Ephemeral stream
a stream that flows briefly after heavy rainstorms-most common in arid regions
Tributary
a stream that joins with other streams to form a larger stream
Limestone bedrock
areas that form most widespread type of karst topography (forms fastest in warm tropical regions)
Physical weathering
breakdown of rocks into smaller pieces (clasts) without altering the chemical make-up of the rock
Mantle drag
caused by lateral flow of asthenosphere beneath plates
Sinkhole
depression in Earth's surface resulting from weathering of carbonate rock underground
Anthropogenic intermittent streams
diversions of water from streams by people have made many formerly permanent streams run low or run dry
Stream gradient
drop in elevation of the stream channel in the downstream direction
Fluvial erosion
erosion by running water; streams transport broken and dissolved material downstream
Mudflows
fast-moving flow composed mostly of mud
synclines
fold in crust with U-shaped dip
anticlines
fold in crust with an arch-like ridge
Hydraulic action
force of flowing water; it frees rock fragments and sets them in motion
Metamorphic rock
formed by heat and pressure applied to preexisting rocks
Sedimentary rocks
formed through cementation and compaction of sediments
Igneous rocks
formed when magma or lava cools and hardens
Faulting
fracture in crust where movement and earthquakes occur
Soil creep
imperceptible downslope movement of soil and regolith as their volume changes in seasonal expansion-contraction cycles (slowest form)
Mantle
layer of heated, slowly deforming solid rock that lies between base of crust and outer core
Disappearing stream
leaves ground surface and flows into subterranean channels
Denudation
lowering and wearing away of Earth's surface
Base level
lowest level a stream can reach (usually sea level)
Ridge push
magma rising along a mid-ocean ridge lifts oceanic lithosphere and forces it apart
Continental crust
makes up continents, composed mainly of granite (forms from magma)
Stream load
material that moves with stream channel
carbonates
minerals composed of carbon that combines with other elements (like oxygen); carbonate minerals often cement particles of sediment together to form sedimentary rock (like limestone)
silicates
minerals composed of silicon and oxygen that combine with each other elements to form these minerals; rocks formed from this are structurally strong and relatively resistant to weathering
Mass wasting
movement of rock, soil, snow, or ice downslope by gravity
Dissolution
occurs through carbonation when acidic water reacts with calcite in limestone
Frost wedging
one kind of physical weathering in which water trapped in openings in rock freezes and expands (water->ice expands by ~10%), causing openings to grow; occurs where temps routinely drop below freezing
Oxidation
oxygen atoms combine with minerals in rocks and weaken them
Weathering
process by which solid rock is dissolved and broken apart into smaller fragments; cracks in rock (joints) provide surface area on which physical weathering can act
Chemical weathering
process that changes minerals in a rock through chemical reactions involving water
Karst
refers to an area dominated by the weathering of carbonate rocks, usually limestone
Dendritic drainage pattern
resembles tree branches and it the most common drainage pattern; forms when rivers cut into a geologically uniform surface
Rockfalls
rock tumbles off a vertical or nearly vertical cliff face
Asthenosphere
solid state, but nearer melting and weak and easily deformed part of the mantle
Dissolved load
soluble minerals that are carried in solution by a stream
Permanent stream
stream that flows all year
Anthropocene (Age of Humans)
the age of human transformation of Earth's physical systems (beginning around Industrial Revolution ~1800)
Holocene Epoch
the current epoch of geologic time which began 10,000 years ago, nested in Quaternary period in the Cenozoic era of the Phanerozoic eon
Stream discharge
the volume of water flowing past a fixed point within a stream channel
Differential weathering
unequal weathering across a rock surface
Divergent plate boundary
where two plates more apart as new crust is formed
Convergent plate boundary
where two plates move toward each other
Folding
wrinkle in crust from deformation caused by geologic stress (most often where plates converge in regions of subduction and collision) (ex. Appalachian Mountains)