Geology Test 4

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Geology Test 4

Flashcards Made For Test Four.  Chapters 12, 16, 17, And 18 

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Most Dry lands (low latitude deserts) are located in the vicinity of ____degrees north and south latitude of the equator.
are volcanoes that form on the ocean floor. 
The East coast of North America considered a _____ Continental Margin?
The San Andreas Fault in California is the boundary between the North American and Pacific plates is a transform fault, however, when we think of the sense (direction) of the movement it is called a ______.
Strike-Slip fault
Submarine canyons found on the continental slope and rise are believed to have been created____.
by turbidity currents. 
Which of the following is not true about deep ocean trenches: They are long and narrow depressionsThey are sites where plates plunge back into the mantle They are geologically very stable.
They are geologically very stable
_____continental margins typically exhibit wide, extensive, continental shelves. 
The _____lies at the base of the continental slope. 
Continental rise
Geologically, what is the best way to explain accumulations coral limestone beneath most atolls? 
The volcano never reached, but came close to the sea level surface, allowing for the coral to accumulate.
The term ____refers specifically to geologic mountain building.
An erosion removed the tops of mountain ranges, the crust will buoy (float) upward (like an iceberg would) causing fault movement.  This is an example of____.
Determine the type of geological structure.
Normal fault 
Determine the type of geological structure.
Reverse fault 
An unconformity is a buried _____.
Surface of erosion separating younger strata above from older strata below. 
A linear down folded structure with the youngest strata in the center is termed____.
Large circular down warped structures, like those found in Michigan and Illinois, are referred to as _____.
A "Andean" type plate boundary is a classic demonstration of how the mountain building process works at an ocean to continent plate boundary.
At a subduction zone
Guyots are_____
Underwater flat-topped seamounts
Which of the following best characterizes an angular unconformity
Tilted strata lie below the unconformity, and bedding in younger strata above is parallel to the unconformity.
In mountain regions, the Earth's crust is_____
thicker than average
Which of the following geologic observations would not bear directly on working out the sequence of geologic events in an area? inclusions of sandstone in a granite plutona dike of basalt running through a sandstone The mineral content of granitean unconformity between granite and sandstone.
The mineral content of granite
What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it? 
Law of superposition
What of the following refers to the investigative process by which geologists identify and math sedimentary strata and other rocks of the same ages in different geographic areas?
Does unconformity come before intrusion?
Which one of the following represents the greatest expanse of time in the Geologic Time Scale
The half-life of a radioactive element is 6000 years.  A sample of rock is 12,000 years old.  How much of the original radioactive element (parent product) would remain today?
Define nonconformity
an unconformity that separates crystalline rocks,either igneous or metamorphic, from sedimentary rocks.
The mountains on the Western North American Continent (Alaska in particular) were produced in part by the addition of small crustal block to the margin of the continent.  THese crustal fragments having distinct geologic histories are known as____.
What is the age of the Earth accepted by most scientists today?
4.5 billion years
What is an essential characteristic of an index fossil?
The organism only lived for a short period of geologic time.  
What combination favors folding rather than faulting?
High temperature and high confining pressure
____is the process (question 28) that occurs at active continental margins where sediments and older rocks are scraped off a descending plate and piled against the edge of the overriding plate.
Four factors  that influence the strength of rock and how it will deform
temperature, confining pressure, rock type, and time.
What is the one best measure of the wetness or dryness of a desert region?
Difference between annual precipitation and evaporation potential.
Look at the map view.
Desert pavement is the result of ______
Deflation from wind.
_____are not associated with a mid ocean ridge
deep ocean trenches.
How does wind transport sand grains?
by saltation as part of the suspended load.
T/F the predominant particle size in loess deposits is gravel and boulders.
T/F a playa is a dry, flat lake bed on the floor of a desert basin.
Desert definition____
Despite infrequent rainfalls, erosional and depositional features of running water are important in desert landscapes. 
A worm would stand a poor chance of being fossilized because_____
worms have no hard parts
The ____ is the idea or concept that ancient life forms succeeded each other in definite, evolutionary, pattern and that the contained assemblage of fossils can determine geologic ages of strata
Principle of fossil succession
An echo sounder operates by measuring the time required for a______
sound pulse travels from a ship to the seafloor and back.
Look at map view.
Long sand dunes that are oriented more or less parallel  to the prevailing wind with limited supplies of sand are called ______ dunes.
Solitary dunes who tips point downwind are_____dunes.
T/F abyssal plains owe their relatively featureless topography to thick accumulations of sediments that have buried an otherwise rugged ocean floor.
There is a considerable span of time for which there is no deposition and/or erosion between two of the sedimentary layers.  What was discovered?
Sandstone strata and a mass of granite are observed to be in contact.  What statement can be made?
The granite is older if the sandstone contains inclusions of the granite.
Deposits that form as a result of dense-sediment-laden water running down submarine canyons are called_____
____bedding occurs in the sedimentary deposits formed in question 51.  This type of bedding shows fine grained sediments at the top and coarser sediment on the bottom of the layer.
Streams in desert regions that flow intermittently are referred to as______.
Deserts have discontinuous drainage pattern of intermittent streams that do not eventually flow to the ocean.  THey are said to have ____drainage.
T/F trenches form the deepest parts of the ocean basins.
T/F Steppes are the driest of the true desert lands
Interestingly shaped stones produced by wind abrasion are called_____
Dip faults have mainly ____ movement
Left lateral____
road moves left 
T/F fractures in rock  that have not involved any fault slippage are called joints
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