Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
67 Cards in this Set
- Front
- Back
|
The line formed by the intersection of an inclined sedimentary layer and a horizontal plane is called the _ |
Strike |
|
|
The dip of a unit represents the _ |
Angle at which the bed inclines from the horizontal |
|
|
Which type of tectonic forces tends to squeeze and shorten a rock body? |
Compressive force |
|
|
Which type of tectonic force tends to push two sides of a body in opposite directions so that they slide horizontally past one another? |
Shearing forces |
|
What type of fault is depicted? |
Normal fault |
|
|
What best describes the behavior of rocks during deformation regarding brittle and ductile materials? |
Brittle materials deform by faulting, whereas ductile materials deform by folding |
|
|
What type of material undergoes smooth, continuous plastic deformation?
|
Ductile |
|
|
What types of forces dominate at convergent plate margins? |
Compressive forces |
|
|
The San Andreas fault is a result of what type of forces? |
Shearing forces |
|
|
Confining pressure is pressure applied _ |
In all directions |
|
|
Which statement about rock deformation is false? 1) Deep crustal rocks are more likely to deform ductilely than shallow crustal rocks 2) Hotter rocks are more likely to deform ductilely than cooler rocks 3) most sedimentary rocks are more deformable tha igneous rocks 4) Rocks under low surrounding pressure are more likely to deform ductilely than rocks under high surrounding pressure |
4) Rocks under low surrounding pressure are more likely to deform ductilely than rocks under high surrounding pressure |
|
|
What determines wheter a rock deforms in a brittle fashion versus a ductile fashion? |
Temperature Rock type Rate of deformation |
|
|
If a basalt unit near the surface of the Earth underwent compressive deformation, the result would most likely be _ |
Faulting |
|
|
A sample of marble has deformed brittlely during a laboratory experiment. If we wish our next sample of marble to deform plastically rather than brittlely, we should conduct the next experiment at _ |
Higher temperatrue and higher confining pressure |
|
|
Which condition of natural deformation is the most difficult to simulate in a laboratory experiment? |
The duration of the deformation event |
|
|
What is the scientific term for a crack along which no appreciable movement has occurred? |
Joint |
|
|
The difference between a fault and a joint is that _ |
Rocks on either side of a fault have moved, whereas rocks on either side of a joint have remained stationary |
|
|
Which deformation texture forms deep in the Earth's crust? |
Mylonites |
|
|
The San Andreas fault is an example of a _ fault |
Right-lateral strike-slip |
|
|
Which is not a dip-slip fault? 1) Normal fault 2) Reverse fault 3) Right-lateral fault 4) Thrust fault |
3) A right-lateral fault |
|
|
Reverse faults form in response to _ forces |
Compressive |
|
|
What type of fault is characterized by the rocks above the fault plane moving downward, relative to the rocks below the fault plane? |
A normal fault |
|
|
A fault plane strikes north-south and dips steeply to the west. Geologic observations indiacte that most of the fault movement was a dip-slip and that Mesozoic rocks occur east of the fault and Paleozoic rocks occur west of the fault. What type of fault is this? |
A reverse fault |
|
|
An oblique-slip fault suggests _ |
Shear forces combined with compressive or tensional forces |
|
|
What is a thrust fault? |
A low-angle reverse fault |
|
|
Which correctly links the tectonic force with the exprected type of faulting? 1) Compression = Normal faulting 2) Shear = Strike-slip faulting 3) Tension = Reverse faulting 4) Tension + compression = Oblique-slip faulting |
2) Shear = Strike-slip faulting |
|
|
The total amount of shortennig in an overthrust may exceed several _ |
Kilometers |
|
|
Which type of tectonic forces causes faulting? |
Compressive forces Shear forces Tensional forces |
|
|
What two measurements describe the orientation of a fault plane at a given location? |
Dip and strike |
|
|
A rift valley is _ |
A downfaulted block |
|
|
Which geologic feature is commonly formed in a region deformed by tensional tectonic forces? |
A rift valley |
|
|
In an anticline, _ |
The oldest rocks occur in the center and the limbs dip away from the center |
|
|
The surface that divides a fold into two symmetrical halves is called the _ |
Axial plane |
|
|
Upfolds, or arches, of layered rock are called _ |
Anticlines |
|
|
What is true about synclines regarding rocks and dip? |
The youngest rocks occur in the center and the limbs dip toward the center |
|
What type of structure is shown? (A is the oldest sedimentary rock, C the youngest) |
A faulted anticline |
|
Which way do the sedimentary layers dip? (A is the oldest sedimentary rock, C the youngest) |
Toward the east and west |
|
Why is unit A wider north of the fault than it is south of the fault? (A is the oldest sedimentary rock, C the youngest) |
Deeper levels of the structure are exposed on the north side of the fault |
|
What type of fault is depectied on the geologic map? |
A reverse fault |
|
|
An overturned fold is characterized by two limbs _ |
Dipping in the same direction, with one limb tilted beyond vertical |
|
|
Cataclastic textures form in association with what types of geologic structures? |
Faults |
|
|
What type of structure is characterized by rock layers that dip radially toward a central point? |
A basin |
|
|
Older rocks crop out in the core of which of the structures listed below? 1) Anticline 2) Syncline 3) Dome 4) Basin |
1) Anticline and 3) Dome |
|
|
Oil is commonly trapped in _ |
Structural domes |
|
The structure shown is a(n) |
Anticline |
|
The structure shown in the diagram above is a _ |
Plunging, assymetric fold |
|
|
Oil can be trapped at the top of a dome if _ |
There is an impermeable layer at the top of the dome |
|
|
Where do basins form? |
Where a part of the crust has been heated and subsequently cools and contracts Where tensional forces stretch the crust Where thick sequences of sediments are deposited |
|
|
If erosion stripped the top off a dome, one would find _ |
The oldest rocks exposed in the center |
|
|
Geologic maps are used to depict _ |
The strike and dip of the rock units at the Earth's surface The rock formations exposed on the Earth's surface The orientation of geologic structures that deform rocks exposed at the Earth's surface |
|
|
A diagram representing a vertical slice through the Earth's crust is called a _ |
Geologic cross section |
|
|
Which statement is false? 1) Asymmetrical folds have dipping axial planes 2) Synclines contain the youngest geologic units in the core 3) Symmetrical folds have dipping axial planess 4) Overturned folds have one limb that has rotated past vertical |
3) Symmetrical folds have dipping axial planes |
|
|
Development of mylonitic textures occurs with what other geologic process? |
Metamorphism |
|
|
The world's largest earthquakes occur along _ |
Megathrusts at subduction zones |
|
|
A fold that has a non-horizontal fold axis is called a(n) _ fold
|
Plunging |
|
|
The geologic history of an area is reconstructed using _
|
Geologic mapping |
|
|
A mass of rock exposed at the Earth's surface is called _ |
Outcrop |
|
|
Faults and folds can range in scale from centimeters to _ |
Tens of kilometers or more |
|
|
Whiat basic source reveals the geometry of rock formations? |
The outcrop |
|
|
On a map with a 1:2400 scale, what does 1cm represent on the map? |
2400cm |
|
|
What is the scale on a map where 1cm represents 1km? |
1:100'000 |
|
|
What sort of fault type is likely to form where shear forces combine with compressive or tensional forces? |
A thrust fault |
|
|
What does not affect rock behavior in regards to deformation? |
Temperature |
|
|
One of the most spectacular displacements observed along the San Andreas fault line involves _
|
Volcanic lava flows |
|
|
How do geologists recognize faults in the field? |
From scraps in the landscape |
|
|
Which geologic structure has a hanging wall? |
Anticline |
|
What name do geologists give to the rock block on the right? |
Hanging wall |
