In the northeastern fault block of the Bree Creek Quadrangle there is a hill that is capped by Helm’s Deep Sandstone overlying Rohan Tuff. In Problem 3.1 you determined the attitudes of these two units at this locality. Use stereographic projection to determine the amount and direction of the tilting experienced by this fault block after deposition of the Rohan Tuff but before deposition of the Helm’s Deep Sandstone.

Problem 3.1

On the Bree Creek Quadrangle map determine the exact strike and dip of the Miocene and Pliocene units and label the map accordingly with the appropriate symbol. List each attitude in the space below as well as on your map. Use the lower contact of each unit, because the upper contact may have been eroded.

After determining the strike and dip of each formation, try to visualize the geology in three dimensions. Make sure that the attitude you determined is in agreement with the outcrop pattern. (A page for you to write your answers to Problems 3.1, 3.2, and 3.3 is provided on Fig. G-6, Appendix G.)

Transcribed Image Text:

Northeastern fault block Northern exposures Southern exposures Central fault block Northern area Galadriel's Ridge Southwestern area Western fault block Gandalf's Knob Southern exposures Thd Tr = Tg =