Geology chapter 10
What is a scarp?
the trace of a fracture called a normal fault, where a portion of crust slides down the fault surface
Which type of force causes folding?
compressional force
What are rocks below and above a fault called?
the footwall below and the hanging wall above
What statement regarding joints is true?
Joints are fractures in rocks where very little to no movement has occurred.
Which best describes the orientation of rock layers for a structural dome or structural basin?
Rock layers wrap around a single point.
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.
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
Which statement(s) correctly describe(s) brittle deformation and ductile deformation?
-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. -Both types of deformation are permanent.
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.
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.
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.
How do monoclines form?
Movement along a steep fault in basement rock pushes up a portion of the ductile rock layers above it.
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.
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.
What produces plunging folds?
a combination of folding and tilting
What is a syncline?
a fold shaped like a 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
Alluvial fans
are composed of material built up from sediment from the foot of the mountains to the valley floor
Which type of force is responsible for reverse fault formation?
compressional force
What is a fault?
fractures along which rocks move
Which type of force is responsible for normal strike-slip formation?
shear force
Which type of fault has NO vertical motion of rocks associated with it?
strike-slip fault
Which type of force is responsible for normal fault formation?
tensional force
