Prelab Exercise Name:______________________________________
Laboratory 10: Geologic Structures, Maps, and Block Diagrams
Please read pages 195-202 in your lab manual, then answer the following questions:
Please examine Figure 10.1. The 3-dimensional orientation of a planar feature (such as a tilted rock layer) can be described in terms of three components: (1) strike, (2) dip angle, and (3) dip direction.
The strike of a tilted layer is the direction of a horizontal _______________ drawn on the layer surface with respect to north.
The dip angle of the tilted layers is the angle of _________________ (tilting) of the layers, measured from the horizontal.
The dip direction of the tilted layers is the compass direction of downward tilt, measured perpendicular to the _____________ of the layer.
Faults are _____________________ along which movement has occurred.
_______________ faults are caused by tension (stress developed as the rock is pulled apart).
__________________ and _________________ faults are caused by _________________ (stress developed as the rock is squeezed together).
_________________________ faults involve horizontal motion and are caused by _____________ (sideways) stress.
Folds are __________________ or _________________ bends of rock layers.
Upfolds are called ________________________. If the oldest rock is found in the middle of an antiform, it's called an ______________________.
Downfolds are called ______________________. If the youngest rock is found in the middle of a synform, it's called a ______________________.
The imaginary line of symmetry that bisects a fold is called the ___________ (or hinge line). The imaginary plane of symmetry that bisects a fold is called the ________________________.
If the fold axis (hinge line) of an anticline or syncline is not horizontal, it's a __________________ fold.
The __________________ of a plunging fold axis is the compass bearing in which the axis plunges downward.