Geology Exam 3 Material
Which of the following is an example of how rocks will respond to compressional stress?
-Folding -Reverse Faulting
When was the last glacial maximum in North America?
18,000 years ago
In order to determine the age of a rock, we need to know all of these with the exception of:
Amount of parent at the time of the formation of the rock
A fold with the oldest rocks in its core is a(an):
Anticline
Which type of fold has rocks folding up in the middle?
Anticline
What type of magma is produced at the highest temperatures?
Basaltic
The lowest elevation that a river can erode is its:
Base level
Where are the younger rocks in a basin?
Basins have the youngest rocks in the center and the oldest on the outside.
Which of the following scenarios best describes the deformation that will occur in different parts of the crust?
Brittle deformation is dominant in the shallow crust; ductile deformation is dominant in the deep crust.
Joints
Brittle deformations (fractures) in a rock along which there has been no movement
Faults
Brittle deformations (fractures) in a rock mass along which movement has occurred
During deformation of sedimentary rocks, which type of stress produces folds?
Compressional
Which type of stress on rock is uniform in all directions?
Confining pressure
In which tectonic setting would you expect to observe overthrust faults?
Convergent Boundaries
What as the name of the ice sheet that covered North America west of the Canadian Rockies?
Cordilleran Ice Sheet
The age of the oceanic crust _____ with decreasing distance from the Middle Ocean Ridge.
Decreases
Where do most metamorphic rocks form?
Deep within the Earth's crust
Which type of stress produces most crustal deformation?
Differential Stress
If strike and dips symbols were placed on a map of a basin, which way would the dips point?
Dips point down toward the center.
Folded rocks are uncommon in which tectonic setting?
Divergent Boundaries
The Black Hills of South Dakota are a good example of which feature?
Dome
Folds exhibit which type of deformation?
Ductile
A rock resulting from contact metamorphism will not have:
Foliation
Tensional Stress
Forces pull a body of rock outward, resulting in elongation of the body.
Compressional Stress
Forces push a body of rock inward, resulting in compression of the body.
What is not a principle used for relative age dating?
Gravity
Meandering streams:
Have a sinuous channel
What is the orientation of a fold's hinge line with respect to the orientation of plunge?
Hinge line is in the direction of plunge.
Which of the following is not an example of alpine glaciation?
Ice Sheet
The Himalayas mark the continent-continent collision between:
India and Asia
What bodies of water are formed when a stagnant block of glacial ice becomes partly or completely buried in glacial sediments, eventually melting?
Kettle Lake
________ is fine silt generated by glaciers that can be carried for long distances by the wind.
Loess
Could metamorphic rocks reach the surface of a planet without rock-uplifting processes?
No, metamorphic rocks must be uplifted and exposed by erosion.
Which type of fault is found in the Great Rift Valley of East Africa?
Normal
Which fault will see the hanging wall move down relative to the footwall?
Normal Fault
A fault formed by tensile stress is called:
Normal fault
__________ faults combine elements of strike-slip and dip-slip motions.
Oblique-slips
Shear Stress
Opposing forces push different ends of a body of rock in opposite directions, resulting in displacement of one end of the body with respect to the other. (Transform boundaries)
Which term is used to describe a fold in which one limb has been tilted far beyond the vertical?
Overturned
What type of magma has the highest viscosity?
Rhyolytic
Which of the following statements best describes the orientation of rock layers for a structural dome or structural basin?
Rock layers wrap around a single point.
Which of these rocks is not metamorphic?
Shale
Which type of stress would you expect to find at a transform boundary?
Shear
________ is an elevation point above which snow remains throughout the year.
Snowline
Mt. St. Helens is an example of a:
Statovolcano
Which tectonic stress will result in a lengthening of the crust?
Tension
Which type of stress would you expect to find at a divergent boundary?
Tension
Which type of stress has produced the fault-block mountains in the Basin and Range Province?
Tensional
Which moraine marks the furthest extent of glacial ice?
Terminal Moraine
In a normal dip-slip fault, which of the following statements describes the movement of the hanging wall relative to the footwall?
The hanging wall moves down relative to the footwall.
Elastic Deformation
The rock will return to nearly its original size and shape when the stress is removed.
After the occurrence of a normal dip-slip fault in flat-lying sedimentary rocks, the fault scarp produced is eliminated by erosion. What is the age of the rocks on the surface of the footwall side of the fault relative to those on the hanging wall?
The rocks on the footwall side of the fault would be older than those on the hanging wall side.
How will the orientation of a plunging anticline's limbs change in the direction the fold is plunging?
They will close to a point.
Brittle Deformation
This involves the fracturing of rock, and is associated with rocks near the surface.
Ductile Deformation
This is a type of solid state flow that produces a change in the size and shape of a rock body without fracturing. It occurs at depths where temperatures and confining pressures are high.
How do metamorphic rocks reach Earth's surface?
Through removal of overlying rocks.
________ is unsorted, unstratified, bimodal sediment directly deposited by the glacial ice.
Till
The continental shelf would have been exposed to the atmosphere during glaciations because sea level would have been dozens of meters lower at that time.
True
The only continental ice sheets left on Earth today are in Greenland and Antarctica.
True
In the deep crust, what happens to the rock under shear stress?
When the rocks are at depth, the rocks will distort, but not fracture
An active margin is:
a continental coastline that coincides with a plate boundary
Which feature is not considered a rock structure?
aa
What is the hinge line of a fold?
line of maximum inflection that layers wrap around
Which two rock types would you expect to see sitting next to each other after a very long period characterized by only uplift and erosion?
metamorphic and sedimentary rocks.
Synclines
where the rocks are curved downward into a trough
Anticlines
where the rocks create an upward arch
