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GEOL101 Lab 10
Structures, Maps, and Block Diagrams
25
Geology
Undergraduate 1
10/25/2010

Additional Geology Flashcards

 


 

Cards

Term
Geologic Map
Definition
Shows the distribution of rocks at Earth's surface. The rocks commonly are divided into mappable rock units that can be recognized and traced across the map area. This division is made on the basis of color, texture, or composition.
Term
Structural Geology
Definition
The study of how geologic units (bodies of rock or sediment) are arranged when first formed and how they are deformed afterward.
Term
Geologic cross section
Definition
A drawing of a vertical slice through Earth, with the material in front of it removed: a cutaway view.
Term
Block diagram
Definition
A combination of the geologic map and cross section. It looksl ike a solid block, with a geologic map on top and a geologic cross section on each of its visible sides.
Term
Attitude
Definition
The orientation of a rock unit or surface.
Term
Strike
Definition
The compass bearing (direction) of a line formed by the intersection of a horizontal plane (such as the surface of a lake) and an inclined layer (bed, stratum) of rock, fault, fracture, or other surface.
Term
Dip
Definition

The angle between a horizontal plane and the inclined (tilted) stratum, fault, or fracture.

 

Dip direction is always perpendicular to the line (bearing) of strike.

Term
Disconformity
Definition
An unconformity between relatively parallel strata.
Term
Angular unconformity
Definition
An unconformity between nonparalled strata.
Term
Nonconformity
Definition
An unconformity between sedimentary rock/sediment and non-sedimentary (igneous or metamorphic) rock.
Term
Faults
Definition
In rock units are breaks along which movement has occurred. Faults form when brittle rocks experience three kinds of severe stress: tension, compression, and shear.
Term
Tension
Definition

Pulls apart causing lenghtening.

Normal Fault

Term
Compression
Definition

Pushes together causing shortening.

Reverse Fault (High Angle)

Term
Shear
Definition

Rocks slide past each other causing tearing and smearing.

Strike-Slip Faults

Term
Antiforms
Definition
Are "upfolds" or "convex folds".
Term
Anticlines
Definition
If the oldest rocks are in the middle.
Term
Synforms
Definition
Are "downfolds" or "concave folds"
Term
Synclines
Definition
If the youngest rocks are in the middle.
Term
Plunging fold
Definition
The fold axis may not be horizontal, but rather it may plunge into the ground.
Term
Plunge
Definition
The angle between the fold axis and horizontal.
Term
Trend
Definition
The trend of a plunge is the bearing (compass direction), measured in the direction that the axis is inclined downward.
Term
Overturned fold
Definition
If a fold is tilted so that one limb is upside down, then the entire fold is called an overturn fold.
Term
Monoclines
Definition
Have two axial planes that separate two nearly horizontal limbs from a single, more steeply inclined limb.
Term
Domes and Basins
Definition
Are large, somewhat circular structures formed when strata are warped upward, like an upside-down bowl (dome) or downward, like a bowl (basin).
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