Guide to field mapping (short and sweet). Broken into 2 parts, in the field and in the office. Mapping in the field First,
some notes for mapping in the field. Data is much more important than field interpretations. Take little stake in your
prior understanding of the stratigraphy/structures, and be as clear as you can with your notes. Take veeeerrry clear
geologic notes that you can understand. Every time you look at an outcrop, note the orientation of the structure (strike
and dip), any notable features (sedimentary, erosional, etc.), and give a rock description (as pure as possible). I say that
because prior understanding of the structure or stratigraphy of a region can sway your interpretation. Also, even noting
the look of an outcrop can give erosional cues (rounded are often limestones, flakey can be shale, etc.). An example of
why data is important: If you think you are in a unit because it is geologically logical, are you sure there is not a fault that
offsets your logic? Maybe a fold? Maybe that unit pinches out into an unconformity? Then what? Hence why I say data is
more important than interpretations. Those come later. My BEST recommendations while taking field notes is write
purely in data and have a very clearly defined section that includes your interpretations and what you think. Ok, now
that the background info is gone through. Lets talk about the steps at the outcrop. 1. First and foremost. Try your best to
make sure you are oriented relative to north. As a mapping geologist, it is imperative to know your orientation and your
location. Look at your map and your compass often. 2. PUT YOUR DATA ON YOUR MAP! When at an outcrop, please
please please record your orientation data site location on your field map. Trust me. 3. When you find an outcrop, again
remember your location before you take any data. Locate yourself on your map. Use GPS, use the bends in the road, use
elevation differences, all of those can help locate you on a map. 4. Now get on the rocks. Take the orientation of the
stratigraphy (strike and dip). I recommend taking a few and writing all of them down. 5. Make sure to look at the
structures. Any faults? What orientation? Faults can change a mapping area dramatically and are of the upmost
important to locate. If there are, record data from either side of the fault, with structural interpretations! 6. Now note if
there are any sedimentary structures, what kind? What orientation? 7. As best you can, write a rock description of all of
the units in the outcrop! Try to do so without the prior influence of a stratigraphic description of the region, those can
influence your interpretations later. 8. If there is more than one rock unit, NOTE THE CONTACT. This is really important
in mapping, even whether they are conformable (stratigraphic) or not (faulted or unconformity). Note the location and
orientation of the contact. It will help with making the final map. Making a geologic map 1. You have recorded all of your
data. Start compiling that onto a final map (in pencil). Start by placing your strike and dip symbols and adjacent, note the
structures you may have found (faults and folds etc.). They may influence your interpretation. 2. Then, start thinking
about the stratigraphy and how they make sense geologically. Was it a normal fault? Reverse? Does it make sense that
the older unit is below me elevation and stratigraphically? This is the part where your data and interpretations come
together. Make sure that you still have a raw version of your data though. 3. So, now you have locations on a map that
have an orientation, and hopefully you have a stratigraphic unit associated with that location. Best if that all makes
sense! 4. The next step is to fill in contacts. That is to draw a line of contact between two geologic units in a
REASONABLE location. That is, the contact has to be between two separate units, and should make geological sense
(likely is parallel to other contacts unless there is a major faultthere isn’t). 5. Finally, make sure all major structures are
outlined first (faults mostly because the can change a map). Make sure all contacts are drawn in, dashed where
interpretates, make sure all data is clear (strike an dip symbols, structures, etc.), and color in the units according to their
(or your) stratigraphic ideology!!! Good Luck.