2 ch10

A)
Rupture and plastic deformation occur when stresses exceed the elastic limit of a material.

Which one of the following statements regarding rock deformation and strength is correct?

A)
horizontally directed; compressive stresses

Which one of the following stress situations results in folding of flat-lying, sedimentary strata?

A)
Horizontal distance is shortened perpendicular to fold axes.

Which one of the following is consistent with deformation by folding?

C)
The deeper strata are buckled upward along the fold axis.

Which one of the following is true for anticlines but not for synclines?

B)
strata oriented in roughly circular, outcrop patterns

A deeply eroded, structural basin would exhibit ________.

C)
strike slip

A ________ fault has little or no vertical movements of the two blocks.

B. reverse

In a ________ fault, the hanging wall block move up with respect to the footwall block.

B)
the crust is shortened and thickened

In thrust faulting, ________.

A)
steep, near vertical, dip-slip, fault scarps

Which one of the following would not be a characteristic of the San Andreas fault zone?

C)
a hanging wall block that has moved down between two normal faults

A graben is characterized by ________.

C)
tensional stresses and normal-fault movements

The mountains and valleys of the Basin and Range Province of the western United States formed in response to ________.

B)
Mesozoic, sedimentary rock formations in Utah, Colorado, and neighboring states

The Navajo and Dakota Sandstones are ________.

C)
formation

A ________ is a defined, recognizable, mappable, rock unit with a known age.

C)
the hanging wall block above an inclined fault plane moves downward relative to the other block

In a normal fault ________.

A)
the hanging wall block has moved up relative to the footwall block along an inclined fault

A reverse fault is one in which ________.

D)
roughly parallel fractures separating blocks that show no displacement

Jointing in rocks is characterized by ________.

A)
Normal faults

________ are the products of horizontally directed, tensional stresses.

D)
Tight folds

________ in layered sedimentary rocks are evidence for horizontal compression and shortening.

A)
a strike-slip fault that forms the boundary between tectonic plates

A transform fault is ________.

B)
San Andreas strike-slip fault

The ________ in California is the boundary between the North American and Pacific plates.

C)
cooler temperatures

Brittle deformation would be favored over plastic deformation in which of the following conditions?

B)
a low-angle, reverse fault

A thrust fault is best described as ________.

C)
hogback

A ________ is a prominent ridge formed by differential erosion of tilted, alternating hard and soft strata.

A)
an uplifted block bounded by two normal faults

A horst is ________.

D)
an elongate dome cored by Proterozoic igneous and metamorphic rocks

Which one of the following best describes the geology of the Black Hills region in South Dakota?

C)
mainly normal faulting as East Africa begins to fragment

The Great Rift Valley of East Africa is characterized by ________.

D)
basin

The Michigan geologic map shows older, Paleozoic strata (in roughly circular patterns) surrounding a core area of Pennsylvanian rocks. What is this structure?

C)
dip slip

Normal and reverse faults are characterized mainly by ________.

C)
a fold in which the strata dip toward the axis

A syncline is ________.

True

Normal faults form in response to horizontal, tensional stresses that stretch or elongate the rocks.

True

In a reverse fault, the hanging wall block moves up relative to the footwall block.

True

The oldest, sedimentary rock strata are exposed along the axial parts of deeply eroded anticlines.

True

Horizontal, compressive deformation involves shortening and thickening of the crust.

True

Along oblique-slip faults, both blocks have horizontal and vertical components of movement.

False

Basin and range topography, like that in the western and southwestern United States, indicates that compressive folding is active today or was active very recently, geologically speaking.

True

Plastic deformation occurs more readily in warm rock than in cool rock.

False

A graben is an upraised block bounded by two reverse faults.

True

Fractures in rock that have not involved any fault slippage are called joints.