CARRYING OUT FIELD MAPPING IN EXPLORATION

Greetings everyone,

In our geological field, before we work on any area, we first explore the given locality also known as prospect. This gives us a fair idea about the nature of the area we are working on. During exploration, it is very important to first map out the area.

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_{Mapping Out An Area Within The Manso Nkran Area}

Field mapping is the starting of the entire exploration process. Mapping refers to the putting of various information of the earth on a sheet of paper with a scale. In other words, it is the act of projecting what is on the ground onto paper.

In order to kickstart our mapping journey, we need a base map showing the following; topography, landmarks, road networks, drainage pattern, etc.

We do this in order to get some sort of knowledge about what to expect to see even before we get to the field. That way, we can map the locality with relative ease and know when there are certain deviations to take note of.

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WHAT DO WE OBSERVE DURING FIELD MAPPING?

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There are certain key feature we keep an eye on while we are on the field. In order words, not everything out there is relevant to our field mapping process. Here are some key things we keep an eye on out there. We observe;

• The Various Rock Types/lithology (Shales, Sandstones, Siltstones, etc).
• Primary and Sedimentary Structures.
• Sedimentary Features (tool marks, ripple marks, etc).
• Composition: This includes lithic fragments or veins.
• Matrix: Whether or not there is presence of carbonates, silica or clay minerals.
• Measure the dip and strike (attitudes).
• Alterations

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_{Measuring Attitudes (Dip & Strike) On The Field}

Another thing we are keen to do during field mapping is to take the coordinates of the various places the outcrop is prominent. This ensures that we are able to readily identify the exact area we took our readings.

When we come across a previously drilled hole in the area, we take the attitudes there and mark the gps coordinates as well.

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MEASURING AND NOTING ATTITUDES IN THE FIELD

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In taking our attitudes at the field (dip and dip directions/strike), it is important that, we first orient ourselves. This means that we find our North using the sun. This is because, our readings need to be taken with respect to something (North) And preferably, make use of the dip direction instead of the strike because it is less confusing as opposed to the strike that requires that we use the Right-hand rule. Also, to properly write down the attitudes, we must follow this pattern;

Dip is strictly 2 digits. (62°)
Dip direction is 3 digits (086°)
Combined form becomes 62/ 086°

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_{Measuring the attitudes of a previously drilled hole in the field}

I hope we have all learnt something about field mapping today. I would be happy to receive any questions or contributions on this particular subject.

Thank you for your attention.

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All images were captured by me