Asbog Flash Cards
What is the apparent dip of a bed?
Apparent dip of a bed or plane is the incline of that bed or plane in a direction that is not perpendicular to the strike of the bed.
What is a fold line and how is it used?
The fold line is a hinge line along which a vertical cross section may be constructed and then flattened out to a horizontal or map view.
It is used to represent the subsurface along any given line in a map view. It does not need to be perpendicular to strike.
What is the angle and side relationships for the sin equation?
Sin a = opposite / hypotenuse
What is the angle and side relationships for the tangent equation?
Tan a = opposite / adjacent
If an attitude is given 35 degrees, S25 degrees E, what does that mean?
What is the general form of the thickness equation and why woulsnt you want to use it?
Thickness (t) = outcrop width perpendicular to strike (w) sin [ dip, slope]
Generally it je easier to solve a thickness peoblem graphically because you need to draw a diagram to scale anyway to get the slope angle and the perpendicular outcrop width.
If you have a flat surface and an outcrop width that is not perpendicular to strike, what equation would you use to calculate the thickness of the unit?
What is the general equation for calculating the apparent dip of a bed and when cant this equation be used?
What other methods can be used as an alternative?
What defines an index fossil?
An index fossil identifies and dates the strata in which it is found. It combines a wide geographic range with a narrow geographic occurrence.
What is net slip and where is it measured?
Net slip is the distance between two formerly adjacent points on either side of a fault, measured on the fault surface (in the plane of the fault).
What is an unconformity?
This is a gap in the geologic record that indicates an interruption in the depositional sequence occurred. This implies that lift and erosion have removed part of the geologic record or non-deposition has occurred.
What is the rule of Vs?
Rhe outcrop of a formation as it crosses a valley forms a V shape (as seen from map view). The V points in the direction that the formation underlies the valley.
What is a type locality?
A type locality is the place where a geologic feature (such as a fossil species or geologic formation or member) was first recognized and described. It contains the type section.
How does a reverse fault siffere from a normal fault? How are they the same?
A normal dault is a dip-slip dault in which the hanging wall has moved down relative to the footwall.
A reverse fault is a dip-slip fault in which the hanging wall has moved up relative to the footwall.
Both nronal and reverse faults have a dip between 45 and 90 degrees.
Define type section.
Type section is the originally described stratigraphic unit to which other parts of the unit in other locations may be compared.
It is preferable to describe the location where the units attain maximum thickness and where the top and bottom of the unit are exposed.
