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)