sign in sign up
<<
Home , Anticline, Chevron (geology), Fault (geology), Fault block, Fold (geology), Horst (geology)

Structural

Rocks in the Are Bent, Stretched, and Broken … …by directed stresses that cause Deformation.

Types of Differential Tensional, Compressive, and

Strain is the change in shape and or volume of a caused by Stress. Joints, Folds, and Faults

Strain occurs in 3 stages: elastic deformation, ductile deformation, brittle deformation

1 Type of Strain Dependent on …

• Temperature

• Confining Pressure

• Rate of Strain

• Presence of

• Composition of the Rock Dip-Slip and Strike-Slip Faults Are the Most Common Types of Faults.

Major Types

2 and

BASIN AND Crustal Extension Formed the RANGE PROVINCE .

• Decompression melting and high heat developed above a subducted zone. • Former margin of Farallon and Pacific plates. • Thickening, uplift ,and tensional stress caused normal faults. • structures developed.

Fold Terminology

3 Open – convex upward arch with older rocks in the center of the (symmetrical)

Isoclinal

Asymmetrical

Overturned

Recumbent

Evolution Simple Folds of a fold into a reverse fault An eroded anticline will have older beds in the middle An eroded will have younger beds in middle

Outcrop patterns

4 • The Strike of a body of rock is a line representing the intersection of A layer of tilted that feature with the plane of the horizon (always measured perpendicular to the Dip). rock can be • Dip is the angle below the horizontal of a geologic feature. represented with a plane.

o 30 The orientation of that plane in space is defined with Strike-and- Dip notation.

Maps are two- Showing Topography, , and dimensional Age of Rock Units in “Map View”. representations of three- dimensional surfaces

• Geologic Structures are mapped to interpret stress history.

• Strike-and-Dip Symbols (among other geologic symbols and colors) are used to indicate, age, lithology, and structure.

“Law of V’s” - Plunging anticline points in direction of plunge Plunging syncline opens in direction of plunge

Geologic Map

5 Describe the structures and stress

Pay attention to age relationships and symbols

How does search for oil Draw the geologic map and natural gas? • http://www.youtube.com/watch?v=npPwVc dixRU

Three General Types of

• Fold and Thrust Belts Fold and Thrust Mountains • Fault Block Mountains • Volcanic Mountains

6 Fold and Thrust Mountains

Fault Block Mountains CASCADE MOUNTAINS

Volcanic Mountains So…how would you figure out the Appalachians?

7 APPALACHIAN FOLD BELT

Appalachian

8