joe nelson

General Equipment and Techniques Used on a Clastic Sedimentology Field Trip
Brought to you by UWM Geology Students Joe Nelson and James Gutoski


A Brunton Compass: The Brunton Compass is one of the most important tools used by a sedimentologist. The information one can gather using a Brunton is plentiful. The Brunton alone can give you strike and dip measurements. Information on Paleocurrents and changes in horizontally can be gathered.	The Jacob's Staff: When combined with a Brunton compass, a Jacob's staff can help you figure out deposit heights. The height that we have chosen to use is 1.5 meters. This allows us to get the maximum amount of information in the shortest amount of time. The Brunton can be set at numerous heights on the staff (increases in increments of 0.1 meters, notice the picture to the right).	A close up the Jacob's Staff


The Grain Size Comparitor - Mother Nature doesn't accept Visa, Master Card, or American Express. The comparitor is the cheat sheet of Clastic Sedimentologists. Information which was once scattered throughout numerous textbooks is now available on one credit card sized paper. Information on sorting, roundness, and particle size will allow you to determine information such as depositional environment, environment energy, transport distant, etc...	An Orientation Device (The Do-Hickey): A very useful invention of Dr. Isbell. This tool allows us to measure the apparent dips of bedforms within a deposit.
Other items not shown on this web site: -A ripple indices indicator (an Isbell Invention) -field notebook -rock hammer -hand lens -pen/pencil -inclinometer	Dr. Isbell, the Thomas Edison of geological inventions.

The Dummy Section (12 meters high)

The dummy section is an extremely simple breakdown of what an outcrop may look like. Each different color section equals a different rock type in an outcrop. Each section is 1.5 meters, the height of a Jacob's Staff.

Here Jim is measuring 1.5 meters on the chalk board. To do this he must first make the Brunton level, he does this by using the green bubble within compass. After this he looks through the hole in the Bruntons lid, while continuing to keep it level. Looking through, find an arbitrary point that lines up with the 1.5 meters. Remember that point, or have a friendly partner, such as Joe Nelson, mark it. That point will be ~1.5 meters above your starting point.

A More Complex Dummy Section

This dummy section shows in more detail the use of a Jacob's staff on a set of flat beds. Our miniature man, we will call him Norm for the lack of a better name, is holding a Jacob's staff. He has marked his arbitrary point of ~1.5 meters. He then places the Jacob's staff on the point that he just measured to be 1.5 meters. He repeats the same steps of leveling and looking through the lid. The point Norm sees now will be three meters above the original. Norm could continue to do this all day.

Dummies in a Real Section

This outcrop here is a perfect example of where you can use a Jacob's staff. The people within the photo are measuring 1.5 meters on the outcrop, marking that point, and then continuing to march up (1.5 meters at a time). During this march they also note physical features of the rock, such as grainsize, sorting, and roundness. They may also be stopped by Dr. Isbell for insightful, in-depth information about the outcrop. Why? because he knows a lot more than we do.

The USGS's Preferred Method of Measuring White Board Tilt

Here Jim is demonstrating how a geologist would use a Jacob's staff to measure tilted beds. First he places his Brunton on the tilted outcrop and measures the dip. He will set the level within the compass to the measured dip.
After this he must put the Brunton back onto the Jacob's staff. We will use the same methods on the tilted outcrop that he used on the level outcrop. The point he views will 1.5 meters above the previous point, at the time of deposition. Here one must be careful to repeatedly check the dip with the Brunton because it can vary within a tilted deposit. One must also be careful not to take measurements on apparent dips such as cross beds and accretionary features. You must use the master bedding surfaces.

Here is a great example of where you would have to use a tilted Jacob's staff to measure the height of an outcrop.
Notice the people for scale. You now know the 2 main uses of the Jacob's staff. Other uses include a walking stick, whacking down brush, hitting people, and defending your self against the arachnids of Kentucky.


An example of how to measure paleocurrent dips using an orientation device and a brunton compass.	The 'look' from Kim demanding more knowledge about the dip of this bed.

The studs who are bringing you this website

James Gutoski and Joe Nelson illustrate what UWM Geology is really about, looking good in the field!