Chapter 10 Geology
What kind of structure is present in Figure 2?
dome
Which type of force is responsible for normal strike-slip formation?
shear force
Choose the correct definition of a monocline:
A large steplike fold in otherwise flat-lying sedimentary rocks
Alluvial fans are composed of material built up from sediment from the foot of the mountains to the valley floor. They are evidence that __________.
Death Valley is a tectonically active region
What is rock deformation, and how might a rock body change during deformation?
Deformation is a rock's reaction to stress, which can cause a rock to change its shape or position.
The Basin and Range consists of north-south trending mountain ranges separated by basins. What causes this distinct topography?
Extension due to normal faulting causes valley floors to sink.
Based on what you learned in the video, which of the following statements regarding joints is true?
Joints are fractures in rocks where very little to no movement has occurred.
How do monoclines form?
Movement along a steep fault in basement rock pushes up a portion of the ductile rock layers above it.
Which of the following is required for a monocline to form?
Reactivation of steeply-dipping faults in basement rocks
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. Domes and basins are round and will fold in all directions around a central point.
Imagine a syncline has been eroded to a flat surface. How would the rock age change as you walked across that flat surface?
Rocks would be oldest on the edges and youngest in the middle.
Imagine an anticline has been eroded to a flat surface. How would the rock age change as you walked across that flat surface?
Rocks would be youngest on the edges and oldest in the middle.
The cracks in the sedimentary rocks are joints.The fractures are a result of brittle deformation.
false No cracks exist in this outcrop.The sedimentary rock shown here has been significantly displaced.
_____ are shown in the photo above. They are characterized by _____ sedimentary rock layers.
faults, discontinuous
A monocline is a type of a(n) ____
fold
Which of the following is an example of how rocks will respond to compressional stress? (Note: there may be more than one correct answer.) transform faulting folding reverse faulting normal faulting elongation
folding reverse faulting
What is a fault?
fractures along which rocks move
Which type of fault has NO vertical motion of rocks associated with it?
strike-slip fault
which tectonic stress will result in a lengthening of the crust?
tension
Which type of force is responsible for normal fault formation?
tensional force
The split cinder cone along the Southern Death Valley Fault is evidence that __________.
the Pacific and North American plates are moving alongside each other along strike-slip faults
What are rocks below and above a fault called?
the footwall below and the hanging wall above
What is a scarp?
the trace of a fracture called a normal fault, where a portion of crust slides down the fault surface
Which statement(s) correctly describe(s) brittle deformation and ductile deformation? SELECT ALL THAT APPLY. - Both types of deformation are reversible. - Brittle deformation describes a rock breaking as a result of stress, whereas ductile deformation describes a rock bending or folding as a result of stress. - Brittle deformation is permanent, whereas ductile deformation is reversible. - Brittle deformation describes a rock bending or folding as a result of stress, whereas ductile deformation describes a rock breaking as a result of stress. - Both types of deformation are permanent.
-Both types of deformation are permanent. -Brittle deformation describes a rock breaking as a result of stress, whereas ductile deformation describes a rock bending or folding as a result of stress.
How do geologists infer the orientation of rock structures that are mainly below Earth's surface?
After measuring the strike and dip of several outcrops within an area, geologists graphically present these data in the form of geologic maps.
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.
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.
Imagine a fold has been eroded to a flat surface. In general, how would you know whether this fold is plunging?
Nonplunging folds look like straight lines at the surface, and plunging folds look like wavy lines.
What is elastic deformation?
The temporary and reversible deformation of a rock caused by the gradual application of stress. During elastic deformation, the chemical bonds within the rock do not break.
What produces plunging folds?
a combination of folding and tilting
what is a syncline?
a fold shaped like an right side-up U
What is an anticline?
a fold shaped like an upside-down U
What does the term plunging fold mean?
a fold that is tilted down into Earth
Based on the ages of the rock layers in the cross-section, what kind of fold is in Figure 1? (Note: In map view, this feature would have a bull's-eye pattern.)
basin
Which type of force causes folding?
compressional force
Which type of force is responsible for reverse fault formation?
compressional force
Rank the following events in order from OLDEST to YOUNGEST in age.
oldest -Sediments are deposited in a horizontal orientation. -The sediments are buried and lithified into sedimentary rock. -Compressional forces cause the sedimentary rocks to bend into an anticline. -Processes of weathering and erosion expose the interior of the anticline.
