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Geology111
I HATE GEOLOGY
63
Geology
Undergraduate 1
05/05/2009

Additional Geology Flashcards

 


 

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Term
Sediments: Clastic
Definition
Physically transported rock fragments produced by the weathering of preexisting rocks (gravel, sands and muds)
Term
Sediments: Chemical
Definition
A rock formed by the precipitation of minerals from solution either by inorganic chemical processes or extracted from solutions by organisms.
Term
Poorly Sorted
Definition
Gravel, Sand and Mud
Term
Better Sorted
Definition
Sand and Mud
Term
Well Sorted
Definition
Mud
Term
Degree of roundness
Definition
The further the rock travels, the more rounded the corners are
Term
Sediment to Sedimentary rock:First Step
Definition
Weathering
Term
Sediment to Sedimentary rock: second step
Definition
Transportation:  By Wind, Water, Ice
Term
Sediment to Sedimentary rock: Third Step
Definition
Deposition
Term
Sediment to Sedimentary rock: Fourth Step
Definition
Burial
Term
xSediment to Sedimentary rock: fifth step
Definition
Diagenesis: compaction/cementation
Term
Sediment to Sedimentary rock: Sixth step
Definition
Formation
Term
Grain Size Options
Definition
coarse, medium, fine
Term
Litification
Definition
Process after Digenesis
Term
Cementation
Definition
Chemical precipitation of mineral material between grains binds sediment into hark rock
Term
compaction
Definition
grains squeezed by the weight of overlying sediments.  Reduces pore space
Term
conglomerate
Definition
coarse particles anywhere from about 1 in-10 in pebbles, boulders
Term
sandstone
Definition
medium sized particles anywhere from 1-.062 mm Sand
Term
shale
Definition
fine sized.  .062-.0039 mm mud, silt, clay
Term
Chemical sedimentary rocks: Limestone
Definition
CaCO3, forms inorganically through precipitation from water or through other chemical reactions.  Also forms from calcium carbonate debris of animals. 
Term
Chemical sedimentary rocks: Coal
Definition
peat that has been buried, compacted, and heather, losting most of its water and oxygen in the process.  Depending on the amount of heat and pressure, coal can be soft and dull or hard and shiny.
Term
Chemical sedimentary rocks: Chert
Definition
a silica rich rock that forms in several ways.  Ones way chert forms is in layers from the accumulation and compaction of tiny, silica rich plankton shells that fall to the ocean floor
Term
Chemical Sedimentary Rocks: Evaporites (salts)
Definition
a rock composed primarily of halite,  salt forms as water in lakes and seas evaporates
Term
Continental Environments
Definition
beach, sand, shells, gravels SANDSTONE
Term
Shoreline Environments
Definition
lagoon, sand and mud derived from land, or calcite sand eroded from a freef, the tranquil water accumulates mud, overlain by limestone SHALE
Term
Marine Environments
Definition
Reef, the area becomes far away from the shore line to develop the coral LIMESTONE
Term
Transgression
Definition
The advance of the sea over a region. Associated with erosion then deposition of sediments more typical of deep water over the region
Term

Regression

 

Definition
retreat of the sea from a region.  Associated with erosion and then deposition of sediments more typical of deep water over the region. 
Term
Sedimentary Rock Structures
Definition

Mudcracks

Bedding

Ripple Marks

Fossils

Term
Principle of Original Horizontality
Definition
Layered strata are deposited horizontal or nearly horizontal to the Earth’s surface
Term
Principle of Superposition
Definition
in a sequence of undisturbed layered rocks, the oldest rocks are on the bottom
Term
Unconformity
Definition
 a surface between two layers that were not laid down in an unbroken sequence
Term
Disconformity
Definition
An unconformity in which the upper set of layers overies an erosional surface developed on an undeformed, stil horizontal lower set of beds
Term
Nonconformity
Definition
an unconformity in which the upper beds of sedimentary rocks overlie metamorphic or igneous rocks. 
Term
Angular Unconformity
Definition
an unconformity in which the upper beds overlie lower beds that have been folded and then eroded to a more or less even plane
Term
Geologic Time Scale:
Definition

Eon-Era-Periods-Epochs

 

(Largest-Smallest)

Term
Order of Eons
Definition

Hadean Eon

Archean Eon

Proterozoic Eon

Phanerozoic Eon*

 

Term
Order of Eras within Phanerozoic Eon
Definition

Palezoic Era (sealife, plantlife, etc and 70% extinct)

Mesozoic Era (Dinosaurs)

Cenozoic Era (Present)

Term
Isotopic Dating
Definition
radioactive elements decay to stable, non-radioactive elements.  The rate at which this decay occurs is constant. If we know the rate of decay and the amount present of both parent and daughter, we can calculate how long this reaction has been occurring. 
Term
Half-life
Definition
the time required for half of it to decay
Term
Glacier
Definition
Large masses of ice on land that move under their own weight
Term
Valley Glacier
Definition
Glacier that forms in the cole heights of mountains ranges where snow accumulates, usually in pre-existing valleys, and flows down the valley.  Can terminate on land or water.
Term
Continental Glacier
Definition
Slow moving, thick sheet of ice that cover large parts of a continent.  Modern example are Greenland and Antarctica ice sheets.
Term
Albation
Definition
total amount of ice that a glacier loses each year
Term
Accumulation
Definition
total amount of snow added to the glacier each year
Term
Plastic Flow
Definition
total of all the small movements of the ice crystals that make up a glacier, resulting in a large movement of the whole masses of ice.  Dominant process in polar/cold regions.
Term
 Basal Slip
Definition
At the base of the glacier, the ice is under tremendous pressure from the weight of the overlying ice.  Freezing point of water decreases as pressure increases.  Ice at the base of the glacier melts before ice at the surface of the glacier.  It is the movement of a rigid ice slab along a base lubricated by water.  Continental glaciers move mainly by basal slip, dominates in more temperature regions. 
Term
Pleistocene
Definition
a division of the quaternary period.  The Pleistocene began about 1.8 million years ago and ended roughly 10,000 years ago.  It was the last great ice age. 
Term
Holocene
Definition
current geologic epoch… The end of the last iceage marks the beginning
Term
Erosional Features: Striations
Definition
gouges or scratches cut into bedrock by the process of glacial abrasion.  They are usually parallel grooves representing  the movement of the sediment-loaded base of the glacier. 
Term
Erosional Features: Kettle Ponds
Definition
occur as a result of blocks of ice calving from the front of a receding glacier and becoming buried partially to wholly by glacial outwash.
Term
Depositional Features: Till
Definition
Sediment transported on, within, and at the bottom of a glacier.  As the glacier melts these sediments are deposited across the landscape forming distinct ridges, piles, or sheets.
Term
Depositional Features: Erratics
Definition
Rock transported on top, within, or below a glacier from one location to another location far from where the rock was originally located
Term
Depositional Features: Moraine
Definition
When till accumulates in sheets, piles and ridges forming landforms.
Term

Depositional Features: Moraine

 

Terminal Moraine

Definition
represents sediment deposited along the front of the glacier when it had reached its maximum extent.  It has the same shape and character as a recessional moraine.  Areas between a terminal moraine and present-day glacier were once covered with ice
Term

Depositional Features: Moraine

 

Lateral Moraine

Definition
Parallel ridges of debris deposited along the sides of a glacier
Term

Depositional Features: Moraine

 

Medial Moraine

Definition
ridge of a moraine that runs down the center of a valley floor.  Formed when two glaciers meet. 
Term
Possible Causes of Ice Ages
Definition
Plate Tectonics, Eccentricity, Tilt, Precession, Deep Ocean (Thermohaline) Circulation
Term
Eccentricity
Definition
Of the earth's orbit around the sun
Term
Tilt
Definition
Of the earth rotation access
Term
Precession
Definition
Rotation Wobble
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