Plane StructureLecture #15

IntroductionThe attitude of plane structure can be represented by number

There are two way to write the number:1. Strike and dip2. Dip and dip direction

Strike Plane Structure

Is a horizontal line on the planeIs a cross section of imaginary horizontal

plane to the plane structureThe cross section of two plane known as

line.

Strike of plane structure is an angle between the strike with the true north.

Strike is an angle of horizontal line on the plane with the true north

Two way to descript strike:1. Quadrant convention: N45E; S45W2. Azimuth convention (Clock wise): N135E; N225E

Quadrant Azimuth

Dip (True Dip)

An angle between plane structure with horizontal plane which measured from certain vertical plane

The certain vertical plane perpendicular with strike

On the plane structure, true dip always the biggest dip slope and the direction perpendicular to the strike, which is down slope.

Apparent dip is dip that measured on the vertical plane which is not perpendicular to strike

The magnitude of the apparent dip smaller compare to the true dip.

Dip Classification for BeddingShallow 0° – 20°

Moderate 20° – 50°

Steep 50° – 90°

An overturned bedding, the dip always descript as an angle that less than 90 degree (but the symbol of the dip on map will be different).

Common writing type for strike and dip direction on plane structure

Strike and dipDip and dip

directionQuadrant Azimuth

N0°E/80°E N360°E/80°E 80°/N90°E

Right Hand RuleAzimuth/bearing of strike is

the front visionDip is the right hand (90

degree from strike – clock wise rotation)

Strike and dip Symbol on Map

Strike and dip of bedding

Overturned bedding

Top vertical bedding

Horizontal Bedding

Foliation strike and dip

Vertical Foliation

Horizontal Foliation

Cleavage strike and dip

Vertical Cleavage

Horizontal Cleavage

Vein strike and dip

Vertical Vein

Horizontal Vein

Attitude N80°E/45° or S80°W/45°E or 45°, N170°E

Questions…