Science - Earth/Geology Flashcards

Terms Definitions
ridges
underwater mountaintops
continents
the seven great landmasses
Fall Solstice (Equinox)
September 22-23
convergent plate boundary
1.compressional stresses
-associated with trenches. crust consumed (subducted) back into mantle. relieves the pressure of divergent plate boundaries.
normal faults indicate compressional forces are at work while reverse faults result from tensional forcesT or F
F
Moraine
Marginal glacial deposits (lateral, medial, terminal, ground) of unsorted and unstratified material.
geologists
Study the processes that create Earth's features and search for clues about Earth's history.
earthquake
sudden release of slowly accumulated energy
Submarine canyons on continental shelves and slopes are cut by
turbidity currents.
volcano
mountain that contains magma and explodes cinders or lava
Scarification
Human-induced mass movements of Earth materials, such as large scale open pit mining and strip mining.
Magma
Molten rock from beneath Earth's surface; fluid, gaseous, under tremendous pressure, and either intruded into existing country rock or extruded onto the surface as lava.
Rock
An assemblage of minerals bound together, or sometimes a mass of a single mineral.
Wash
An intermittently dry steambed that fills with torrents of water after rare precipitation events in arid lands.
seismic wave
a wave produced by an earthquake
richter scale
measure energy released in an earthquake
new oceanic crust forms at
divergent plate boundaries
Boulders, cobbles, and sand are carried by a stream as
bed load
obsidian
igneous rock; smooth texture; used for making sharp weapons
Epicenter
Point on the surface that lies directly above the focus or hypocenter
Yardang
A streamlined rock structure formed by deflation and abrasion; appears elongated and aligned with the most effective wind direction.
Batholith
The largest plutonic form exposed at the surface; an irregular intrusive mass; it invades crustal rocks, cooling slowly so that large crystals develop.
Paleolake
An ancient lake, such as Lake Bonneville or Lake Lahonton, associated with former wet periods when the lake basins were filled to higher levels than today.
Erosion
Denudation by wind, water or ice, which dislodges, dissolves, or removes surface materials.
Frost Action
A powerful mechanical force produced as water expands up to 9% of its volume as it freezes. Water freezing in a cavity in a rock can break the rock if it exceeds the rock's tensional strength.
Carbonation
A chemical weathering process in which weak carbonic acid (water and carbon dioxide) reacts with many minerals that contain calcium, magnesium, potassium, and sodium (especially limestone), transforming them into carbonates.
basalt
a dark, dense rock with a fine texture
S waves (3)
-slower wave
-sine wave forms (matter displaced perpendicular)
-travels only through solids
lahar
one of the two most lethal hazards near a volcano; like a concrete river made from dirt or ash and snowmelt or rain
The Great Rift Valley of East Africa is an excellent example of
grabens
fissure
a large crack in the earth through which lava can flow
Prince William Sound Earthquake
1964 Earthquake, m9.2, Subduction Zone
Anti-Cyclones
High Pressure at the Center (Cool Air) High's
Mangrove Swamp
A wetland ecosystem between 30 degrees North or South and the equator; tends to form a distinctive community of mangrove plants.
Syncline
A trough in folded strata, with beds that slope toward the axis of the downfold.
Continental Divide
A ridge or elevated area that separates drainage on a continental scale; specifically, that ridge in North America that separates drainage into the Pacific on the west side from drainage to the Atlantic and Gulf on the east side and to Hudson Bay and the Arctic Ocean in the north.
Law of Cross-Cutting Relationships
Faults or Intrusions and Extrusions are always younger than the rock they cut through.
the process of metamorphism involves
the transformation of pre-existing rock
transform fault boundary
boundary where plates grind past each other
Reverse Faults
Hanging wall moves up relative to the foot wall (high angle fault, greater than or equal to 45 degrees) (Compression)
Mid Latitude Cyclones
Primary weather producer of lower 48 states. Move eastward across US
Ice Field
The least extensive form of a glacier, with mountain ridges and peaks visible above the ice; less than an ice cap or ice sheet.
Cascade Mountains
Volcanic range in NW US (WA, OR, CA) and includes Mt. St Helens, Mt. Rainier, Mt. Hood, Mt. Baker and many others
Samples can be taken from the deep sea floor by
coring devices
Indian Ocean Tsunami Warning System (Prior to 2004)
No, installed 18 months later
Natural Levee
A long, low ridge that forms on both sides of a stream in a developed floodplain; they are depositional products (coarse gravels and sand) of river flooding.
Remote sensing devices used to study the ocean floor are
magnetometers, echo sounders, seismic profilers, microwave radar instruments.
the amount of destruction caused by earthquake vibrations is affected by:
the design of structuresthe intensity and duration of the vibrationsthe nature of the surface material
The Mid-Oceanic Ridge rises high above the surrounding sea floor because
new lithosphere forming at the ridge axis is hot and of relatively low density.
how do we know how old the ocean floor is?
parent-daughter ratio in rock. as rocks are being fored, they are being pushed outward along ridges
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