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Introduction to the Brunton Compass. Parts of the Compass Uses of the Brunton Compass - Bearing - Strike and Dip - Trend and Plunge Map Symbols. Text: Compton, p. 16-21; 34-39; Measurement of Attitude and Location; Lab 1 (website). Parts of the Compass. Compass Face
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Introduction to the Brunton Compass • Parts of the Compass • Uses of the Brunton Compass • - Bearing • - Strike and Dip • - Trend and Plunge • Map Symbols Text: Compton, p. 16-21; 34-39; Measurement of Attitude and Location; Lab 1 (website)
Parts of the Compass • Compass Face • - Arrow (white tip North) • - Directional Degrees (Quadrant or Azimuth) • Clinometer: Scales in Degrees and % Grade • Levels • - Bullseye Level • - Cylindrical Level • Mirror • Sighting Arm • Dampener • Magnetic Declination (~6.5° E of N)
Uses of the Brunton Compass • Locate North • Sight Angles • - measuring height / thickness of a feature • Bearing • Strike and Dip • Trend and Plunge
Bearing Bearing: direction from one point to another point. • 1-directional line • Quadrant Notation: N or S____° E or W • Azimuth Notation: _____° Note: With sighting arm pointing to object, always read the white tip of the needle.
Strike and Dip Strike: Direction of the line of intersection between a tilted plane and a horizontal plane. • 2-directional line • Azimuth Notation: _____ ° Note: Read the end of compass needle that makes dip direction to the right of the strike direction (Right-Hand-Rule).
Strike and Dip Dip: Angle between a tilted plane and a horizontal plane that is perpendicular to strike. • Maximum angle ( ≤ 90º ) • Notation: ____ ° N, S, E, W, NE, NW, SE, SW Note: If use Right-Hand-Rule, dip direction is implied.
W E Horizontal Dip Angle (E. McBride) Cross-Section: Dipping Strata
W E Horizontal Dip Angle (E. McBride) Cross-Section: Dipping Strata
Aerial View: Strike of Dipping Strata strike (E. McBride)
Trend and Plunge Trend: bearing of a linear feature. • 1-directional Line • Measured in Direction of Plunge • Azimuth Notation: _____° Plunge: angle between a tilted linear feature and a horizontal plane. • Notation: ____° Note: written as plunge, bearing
Trend and Plunge Linear Glacial Striations (Maine)
strike and dip strike and dip (vertical) strike and dip (horizontal) Map Symbols (map view) 45º
Bring to Lab • Course Packet • Brunton Compass • Field Notebook • Ruler (metric) • Protractor • Calculator (tangent) • Clipboard