GEOLOGICAL STRUCTURES

Strike and Dip Strike = compass direction of the intersection line for an inclined plane (e.g., fault, or rock unit) with a horizontal plane. Dip = angle measured downward from the horizontal plane to an inclined plane and also the direction of the angle determined 90 degrees to the strike.

Fig. 15.7

Fig. 15.9

Fig. 15.6

Fig. 15.8

Fig. 15.2

Folds are classed as: 1. anticline

a. up fold b. limbs dip away from the nose

c. oldest rocks are exposed in the center of the fold.

2. syncline

a. down fold b. limb dips toward the nose

c. youngest rocks are exposed in the center of the fold

Fig. 15.17a

Fig. 15.11

Fig. 15.12

Fig. 15.1

CO 15

Fig. 15.10

Fig. 15.17b

Fig. 15.17c

Fig. 15.17d

Fig. 15.17e

Fig. 15.15

Fig. 15.13

Fig. 15.14

Fig. 15.16

Box 15.1.3

Box 15.2.1a

Fig. 15.18

Fig. 15.19

Fractures with differential movement. Movement is either- a. “horizontal”

1. right strike-slip or lateral

2. left strike-slip or lateral

b. “vertical”

1. normal 2. reverse

Fig. 15.5a

Fig. 15.5b

Fig. 15.28

Box 15.3.3

Box 15.3.4

Box 15.3.1

“Vertical” 1. Normal fault-hanging

wall moves down relative to the footwall.

a. Footwall is the block below the fault plane.

b. Hanging wall is the block above the fault plane.

2. Reverse fault – footwall moves down relative to the hanging wall.

a. Large reverse fault with shallow dip = thrust sheet or fault.

Fig. 15.22

Fig. 15.21

Fig. 15.25

Box 15.2.1b

Box 15.3.2

Fig. 15.24

Fig. 15.20

Fig. 15.26

Fig. 15.27b

Fig. 15.23

Types of Mountains 1. Fold Mountains

a. Alps, Andes, Rockies, Appalachian, Ouachita

2. Fault Block

a. Serria Nevada

3. Erosional Mountains (not true mountains) a. Ozark Mountains, Boston Mountains.

Box 15.2.2

Box 15.1.2

ADDITIONAL

PHOTOS

0142

0143

0145

0146

0147

0148

0150