Chapter 2 - Structural Geology Key Terms Flashcards
Accuracy
How close a measurement conforms with a standard or accepted value
Apparent Dip (α)
The inclination of a plane measured in a direction NOT perpendicular to strike
Apparent Dip Direction
The bearing of the vertical plane containing the apparent dip angle
Attitude
The orientation in space
ß
The angle between strike and the apparent dip direction
Bearing
The horizontal angle between a line and a specified coordinate direction, usually north or south
Depth (d)
The vertical distance from the ground surface downward to a feature of interest
Dip (δ)
The inclination of the line of greatest slope of an inclined plane, measured perpendicular to strike
Directed Line
A line described by its bearing and plunge
Fold Line
A hinge line along which a vertical cross section may be constructed and then flattened out to a horizontal or map view
Inclination
A general term for the vertical angle between the horizontal and a plane or line, measured downward
Outcrop Width (w)
The width of an outcrop, as measured on a map view, perpendicular to strike
Pole
A line perpendicular to a plane, and represented as a point on a stereographic projection
Plunge
The vertical angle between a line and horizontal
Precision
The degree of agreement or consistency of repeated measurements
Projection
The process by which points on one surface are transferred to another surface, such that in each view (map or cross section) the points correspond
Rake (Pitch)
The angle measured in a specified plane, between a line and the horizontal
Slope Angle (σ)
The angle from the horizontal down to the slope
Stereonet
A representation of angular relationships between planes and lines. In structural geology, a stereonet is synonymous with Wulff net, and equal angle stereographic projection
Strike
The bearing of a horizontal line in an inclined plane
Thickness (t)
The perpendicular distance between the top and bottom of a geologic unit
Trend
The bearing of the vertical plane containing a line
