Geoscience Reference
In-Depth Information
Table 2.2
Typical sampling
equipment. See also Chapter 13.
the details within parts of an exposure that are impossible to
reach safely, or are simply better viewed from a distance (e.g.
geometry of features such as faults and river channel infi lls).
They are particularly useful for examining the detail of contacts
between different units in vertical sea cliffs and quarry faces. A
wide range of good quality lightweight binoculars is available
on the market.
Sampling equipment
Geological hammer
Sample bags
2
Paper, cling fi lm or bubble wrap to
wrap delicate samples
2.3 The compass-clinometer
Marker pens/tile scribe/correction
fl uid for labelling
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.
Chisels and other hammers
Trowel and/or spade for soft
sediments and pyroclastic deposits
Table 2.3
Optional and
specialist fi eld equipment.
There are two main types of compass-clinometer design on the
market (Figure 2.3, pp.
8
-
9): the fi rst type is made by Brunton,
USA, Freiberger, Germany and Breithaupt, Germany; 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
Brunton-type can also be used for more tasks (see below);
however, it is bulkier, more expensive and for some functions
more diffi cult to use. 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
(Section 2.3.3). Because the design of the two compass-
clinometers is different, their operation for some measurements
is also different. Instructions for both types of compass-
clinometer are provided in this section*.
Optional and specialist
equipment
Mapping pens/fi ne tipped pens
Relevant literature
Handheld GPS
Camera (Chapter 12)
Geophysical tools (Chapter 11)
Penknife
Weak hydrochloric acid (
c.
10%)
Clipboard or mapping case
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 2.3b 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
Rule and protractor
Mapping pens, coloured pencils
Binoculars
Scratch/streak plate
Pocket stereoscope
Geological Munsell colour chart
Jacob staff
*Apple have incorporated both a digital tilt meter (clinometer) and a compass
in their iPhone making it possible to measure dips and strikes of planes and
lineations. However, there is no sighting apparatus so it is not possible to do
everything you can with a compass-clinometer.
Hand brush to clean exposure
Hoe pick for cleaning sections
