Stepping into Field Geology

While Geology is a field of study that takes place both outdoors in the field and indoors in laboratories, Field Geology is a primary constituent of Geology. Most of the activities that are involved in Geology like sample collecting, mapping and recording takes place in the field. When moving into field geology for the first time, several important points need to be considered.

The first thing that needs to be considered is, Safety in the field. Mostly this means to be aware and protect one's self against threats from nature and wild animals. For this purpose a thorough knowledge about the surroundings, proper equipment and first aid facilities are essential. In the case of snake bites it is useful to know the closest hospital or medical center equipped with anti-venom serums. In addition to the above, proper usage of tools like the hammer and chisel will reduce the likelihood of an accident.

Once the safety is taken care of, the right tools and equipment related to field work must be made available. The common tools used in field geology are, Geological Compass(Brunton pocket transit or Silva compass), Hand lens(10X), Hammer and chisel, waterproof field book, mineral testing kit and sample bags. In addition to these basic tools, additional tools such as camera, GPS, binoculars  gold pans, metal detectors and Geiger  counters may be used for specific requirements.

The Geological Compass is arguably the most useful tool at the disposal at the Geologist or Engineer. In addition to the obvious purpose of locating the direction of north and calculating the bearing, a geological compass has the following functions.
- Finding the dip and Strike of geological features such  as foliation, joints bedding planes etc.
- Measuring slope angles
- approximating heights of objects
- a level
When using a compass, it is essential to keep away from vehicles, power lines and any other magnetized objects. This means that the Hammer and chisel also needs to be kept aside when using the compass. With the emergence of smartphones with magnetic sensors and accelorometers, applications that perform similar to a geological compass have been developed. One such application that can be used for traversing, calculating Dip and Strike along with a host of other useful functions is, Rocklogger which is available for the Android mobile platform.

Another important aspect of Field Geology is Sample Collection. When collecting rock samples, an approximate sample size of 3"x3"x3" or 4"x4"x4" is preferred. Weathered rock samples are generally avoided unless it is a specific requirement. Once collected, sharp edges should be trimmed off before bagging the sample to avoid tearing the bag. Cloth bags made out of a cotton fabric are usually used for this purpose. Samples should also be numbered systematically. While there is no hard and fast rule for this, a meaningful numbering system incorporating information such as collection year, area, and collectors initials is used to avoid confusion.

Field photography is also a requirement in certain cases. When taking a picture always a scale should be used. For small objects, a pen or another small object with a known size must be in the picture. In the case of photographing macro structures, wetting the surface of the rock helps to bring out the fine details on the surface. Care should be taken to avoid shadows to fall on a part of the rock when  photographing because it could lead to misinterpretation.

Brunton Compass - image from wikipedia