The compass - clinometer is used to measure: (1) the orientation of geological planes and lineations with respect to north; and (2) the angle of dip of geological features with respect to the horizontal. This allows an accurate record of the geometry of the features to be constructed. The compass - clinometer can also be used in conjunction with a topographic map to accurately determine location.
There are two main types of compass - clinometer design on the market : the first type is made by Brunton, USA, the second type is made by Silva and Suunto, both based in Sweden. The Brunton - type compass-clinometer is a more sensitive device because of the in - built spirit levels and the graduation of the scales in 1 °rather than 2 °increments. The accuracy of the Silva - type compass- clinometer is suffi cient for most purposes and is much better designed for directly transferring compass directions to a map.
The compass - clinometer is both a magnetic compass and a device to measure the magnitude of the angle of dip of a surface from the horizontal. In order to do this it has two needles and two quite different scales (Figure 2.3 b and d). When the compass - clinometer is orientated with the compass window horizontal the magnetic needle will always point towards magnetic north – unless, that is, there is another magnetic body that is affecting it such as your hammer, a metal pen or a large magnetic body of rock. In addition if you are at very high latitudes compasses do not work well. Associated with the magnetic needle is a circular dial on the outside of the compass
Strike, Dip, and Structural Cross-Sections
Determination of the Orientation of a Dipping Plane by the the Compass - Clinometer
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