Chapter 15 Flashcards
What is stress measured by?
Force per unit area
What is strain when referred to in the context of rocks
Change in size volume or shape of a body or rock unit in response to stress.
What are tensional stress
A stress due to a force pulling away on a body.
Elastic
Deformed material goes back to it’s original shape after being stretched.
Ductile
Capable of being molded and bent under stress.
What is a Geologic Map?
A map representing the geology of a given area.
What is a strike?
The compass direction of a line formed by the intersection of an inclined plane with a horizontal plane.
What is the angle of dip?
A vertical angle measured downward from the horizontal plane to an inclined plane.
What is the direction of dip?
The compass direction in which the angle of dip is measures. Usually the downhill direction.
What is included in a geologic map?
- Ore deposits
- Geologic structures
- Rock types
What are folds in the context of rocks?
Bend in layered bedrock.
What are the two types of rock folding?
Anticline
Syncline
What is unique about Anticline folding?
A fold shaped like an arch in simpiliar words if it was a radio wave it would be the peek.
What is unique about Syncline folding?
A fold shaped like a U or the trough of a radio wave.
what is a limb in a fold
Portion of a fold shared by an anticline and a syncline.
What is an axial plane?
A plane containing all of the hinge lines of a fold. Or a cross section of the peak and troph.
What is a source rock?
A rock containing organic matter that is converted to petroleum by burial and other post depositional changes.
What are Plunging Folds?
A fold in which the hinge line is not horizontal. It looks like a horseshoe
What is a structural dome?
A structure in which beds dip away from a central point aka a bosi pattern.
What is an asymmetric fold?
Any fold that is not vertical or tipped over.
What is an Recumbent fold?
Folds that are overturned to the point were they are basically horizontal.
What Is the difference between a structural basin and a structural dome?
in a structural dome the oldest rocks are in the middle while a structural basin has the youngest rocks exposed in the center.
What is an isoclinal forl(tight)
A fold were the folded limbs are nearly parallel to each other.
What is an isoclinal forl(tight)
A fold were the folded limbs are nearly parallel to each other.
What is a joint in bedrock
A fracture or crack in bedrock along which essentially no displacement has occurred.
What is a joint set in the bedrock?
Joints oriented in one direction approximately parallel to one another.
What is a fault in bedrock?
A fracture in bedrock along which movement has taken place.
What are the 4 types of faults?
- Reverse Fault
- Normal Fault
- Strike slip fault
- Oblique-Slip Fault
What is a thrust fault
A reverse fault in which the dip of the fault plane is at a low angle to horizontal. it faults at a very sharp angle that is almost horizontal.
What is a strike-Slip fault
A fault in which movement is parallel to the stricke of the fault surface.
What is a Graben when it comes to falts?
When a divergent plate plate boundery creates a trench at a falt
