FOSSIL Project Webinars: Field Notes 101, Excavating Fossils, and Basic Fossil Prep

by Joyce Drakeford, Special Friends of the Aurora Fossil Museum

On September 29, October 19, and November 30 I participated in the FOSSIL Project webinars. For each, I opted to connect on my Android phone via the AdobeConnect app.  If you missed any of the  webinars, please visit www.myFOSSIL.org and look for “videos” under the “resources” tab.

“Field Notes 101” with Bruce MacFadden

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Dr. Bruce MacFadden, distinguished professor and curator of vertebrate paleontology at the University of Florida / Florida Museum of Natural History, presented the second webinar in the FOSSIL series.  He discussed why, when, and how to take excellent paleontological field notes.

When collecting fossils, you want to have proper documentation for finds. That is where field notes come in. They help to document fossil discoveries, reflect your knowledge, and are a critical ‘best practice’ in paleontology. Lee Cone, amateur paleontologist and President of the Special Friends of the Aurora Fossil Museum, was quoted as saying, “Field notes are a very important part of an educational field trip, especially in regions that you may not be familiar with… In both [myFOSSIL] trips to Nebraska and Cincinnati I took a lot of pictures… When the picture is combined with field notes, all of the meaning of the picture comes to life.”

First, when going to a new fossil site you want to find out as much information as possible before going. This is the first step in your documentation. Reading previous reports about the site, looking at Google Earth and geological maps, and doing internet searches are all important for figuring out when and what you are collecting. When you are ready to visit the site, Dr. MacFadden recommends taking a waterproof notebook, heavy ballpoint pen or pencil, possibly a map, Garmin GPS, camera, and even your smart phone. He recommended phone applications such as ‘Mancos’ or ‘Where Am I’ to assist with your documentation collection. The ‘Mancos’ application will advise you of the rock formation (rock name), where you are (latitude & longitude), the rock group, and the stratigraphic member. The Apple iPhone also has a compass application that can be useful. Google Earth can also be used for GPS coordinates.

The essential information that you want to record during your trip include the date, who was collecting with you, locality/general location, latitude, longitude, rock name, published age of rock unit, other notes and observations, photos, and photo numbers. Include the kinds of fossils and what the rocks look like as part of your observations. Make a rough map and rock column sketch. Photos can include in-situ (in matrix) or float (out of the matrix/context). The latitude and longitude in the decimal convention are the most informative data set. The altitude is not always important, but would need to be included if collecting fossils from the top or bottom of a cliff.

When making on-site notations in your field book, reference the latitude, longitude, elevation, picture number, and diagrams for each collecting spot or find. When collecting fossil teeth, it is not important to document which tooth position it is. Multiple finds of the same item (like shark teeth) can be put together. This is known as cataloging by lot. When sharing on myFOSSIL.org geochronology and location would be great information to provide.

Thorough field notes give your finds scientific value. Museums DO care about all of this information and the overall intention is to give confidence in properly documenting your discoveries.

 “Excavating Fossils” with Dava Butler

The third webinar in the FOSSIL series was presented by Dava Butler, education coordinator at the Waco Mammoth National Monument and a science education graduate student at Montana State University.  She covered the basics of excavating vertebrate fossils and provided guidance regarding collection/excavation fossil laws.

Some people confuse the fields of paleontology and archaeology. Paleontology is the study of the history of life (fossils). Archaeology is the study of human history and culture (artifacts). The definition of a fossil is: evidence of life found in a geologic context. Fossils come in several forms.  Body fossils refer to the physical remains of an organism whether it be plant, animal, or bacteria. Body fossils also include molds, casts, and imprints of fossil shells. Trace fossils refer to the behavior of organisms such as burrows, tracks, and coprolites (feces). Another type of fossil is a chemical fossil. Chemical fossils are organic compounds created by the breakdown of organisms. This is where phosphate and petroleum come from.

When looking for fossils, keep in mind that every country, state, and county has different laws regarding collection. For example, in China it is illegal to export any fossil. When looking at private land rules, most fossils belong to the owner of the land where they are found. In addition to these rules and guidelines, many states have specific laws regarding the collection of vertebrate fossils. You are not allowed to take any fossils from a National Park. Dava recommends a good rule to remember: “If it has a spine, there might be a fine.” So please make sure you are knowledgeable about all rules and regulations in specific areas before collecting. Beyond laws, you should also incorporate ethics into your fossil collecting. The reason this is important is because every fossil is a unique piece of information and fossils cannot contribute to scientific knowledge without context.

You must protect yourself. Work with an ethical team like the Society of Vertebrate Paleontology, American Alliance of Museums, Paleontological Society, or Geoscientists in the Parks (National Park Service). To get in on excavation teams, check with museums, become an intern at a park, or join local paleontological societies or organizations looking for new team members. Dava was able to join The Mammoth Site dig through the Tate Geological Museum (Casper, WY). When looking for a team, you should examine their history of research and permits for excavation. Make sure the fossils are going to a public trust (for the benefit of science). If fossils are privately owned then the owner is the gatekeeper of who can study it. This, in turn, can cause negative effects in peer review studies. Something else to keep in mind when finding a project is that excavation can last from weeks to months.

Dava presented two “case studies” on vertebrate excavation.  Case Study 1 is the excavation of a Tyrannosaurid in sand. This includes trenching, pedestaling, stabilizing, and putting on a plaster jacket. A plaster jacket will last on a fossil indefinitely if needed. Vinac is often used in the field because it is easy to remove later. Occasionally, Butvar, an acryloid stabilizer, is used.

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Case Study 2 involved the excavation of a Ceratopsid in rock. The bones were covered with foil, tarp, and rocks since there were several days of wet weather. The best way to excavate from rock is with an awl or screwdriver and then lifting at the cracks in the rocks. When working on a site, Dava suggests keeping the matrix/sediment around the bones in order to collect microfossils which are then screened afterwards at the lab. If you find fragments of bone separate from the main fossil, put them in a ziploc bag and thoroughly document them so they can be studied at the lab. Since Casey Study 2 was on BLM (Bureau of Land Management) lands, remediation was required when the excavation was completed.

“Basic Fossil Prep” with Rachel Narducci

The final webinar in the FOSSIL series was a talk given by Rachel Narducci, who works as a fossil preparator and collections assistant at the Florida Museum of Natural History.  Rachel’s excellent presentation covered tons of information and resources for those interested in fossil preparation.

To start a preparation project, you must ask yourself the following questions: What is the desired outcome? Is the fossil just in need of stabilization? Is it for display only? Will it be used in research? How much time do you want to spend on the preparation? What condition is the fossil in? When considering preparation methods you will want to begin with the least invasive method and increase in strength as needed.

Scientific value of a specimen is based on a fossil having all of the associated field data. If field data is missing, most likely the fossil will not be prepared and instead will be put into a museum’s donation pile. Other things to do during preparation to maintain the scientific value of the fossil include: saving all of the matrix to be searched for microfossils, saving fragments that may fall off during the preparation process, and keeping track of any other special discoveries while completing the preparation task. Make sure all items are properly labeled!

Begin with tools such as a compressed air duster, soft brush, bristled paintbrushes, stiff-bristled paintbrushes for tougher matrix, your own finger nails, dental picks, and an air abrasion unit. Next, you can obtain carbide tools. They will need to be shaped into an elongated diamond shape with a rounded tip. Pneumatic tools will be the next step. These tools will need to be connected to an air compressor of at least 100 psi. These tools can be purchased on www.paleotools.com. With the pneumatic tool, you will need oil for internal lubrication and it is best used under a microscope. You may ask which tool you should buy – it all just depends on the project, but Rachel advises that the most common one used at FLMNH is the ‘Microjack 4.’

Magnification tools are the next item in the preparator’s toolbox. A headband magnifier is the easiest to use and cheapest option. Some of the models also have lights in them. Magnifying lamps are used the most by Rachel when prepping invertebrate fossils. They come in floor models and clamp models. Stereo dissecting microscopes on a boom arm are used for a lot of vertebrate fossil preparation. Finally, surgical microscopes are the biggest scopes and they are used to work on large specimens or at different angles (instead of just overhead like the stereo dissecting microscope).

Water is the basic cleansing liquid. It is easy to dispose of, has multiple uses, and is great for clay preparation. For fragile fossils or reversing/diluting glue, acetone and isopropyl alcohol would be appropriate. This requires proper disposal. Lastly, formic acid works best on fossils in limestone. This option is considered hazardous waste and requires regulated handling for disposal. Formic acid baths are commonly used to disintegrate matrix from fossils. To create a bath, a solution of 7% formic acid with water and tribasic calcium phosphate are placed in a plastic container. A loose lid is placed on top. When the mixture stops bubbling, it is finished. It may need to be repeated. It will need to be handled with rubber gloves. The rinse period is double the bath time. (For example: after being treated for 2 hours, a fossil would need a 4-hour rinse.)

There are several different glues, including Elmer’s wood glue (PVA), B72 paraloid, super glue, and sculpting/5 minute epoxies that have different uses in preparation. Elmer’s glue is commonly used after being mixed with acetate. For clay specimens it is mixed with water. B72 mixed with acetone dries very fast, but when mixed with isopropyl alcohol it reacts better to heat and humidity in the field. With either B72 mixture it needs to be thin for absorption into the fossil or thick to put pieces together. Painting this formula on will leave streaks, so it is better to pat it on slowly. With very porous bone, an eye dropper is suggested. Sculpting and 5 minute epoxy are used to fill large gaps.

In the field, plaster is commonly used to make casts for large fossils. For that you will need to have plaster of paris, water, and burlap strips. When prepping this in the lab, you will need sand bags to prop the jacket up, a spray bottle to apply water for softening the plaster, tin snips, and a box cutter. You will also want to cover it in plastic to trap moisture. After opening the jacket, take photos and label the pieces in Photoshop. Once the specimens have been removed, cleaned, and labeled, they should be entered into a spreadsheet. You can then label them with the matching spreadsheet entries. This way, when putting the specimen together, the spreadsheet and images can be used as a reference.

Rachel explained the process of making a mold for casting fossils. They can be used to make a full 3-D impression or can be used against a surface like external molds of invertebrates, called peels. Since FLMNH has 6.5 million invertebrate paleontology specimens, peels are used to separate them.

When labeling, pencils should be used because there are liquids in the lab that can make pens and markers bleed. Also, heavy paper like cardstock should be used for the same reason. When cataloging a fossil, it is recommended to use an archival ink. Writing should be in all capital letters. When writing on an irregular surface, a Radiograph pen should be used. For a small smooth area, a Micron pen can be used. In the case of a dark-colored fossil, a line of gesso can be applied before using the pens.

Acid-free paper labels and acid-free archival trays or boxes should be used when storing fossils. Other containers such as those comprised of cotton, bubble wrap, vials, gel caps, and ziploc bags are all acceptable. When storing in foam, ethafoam (a polyethylene foam) should be used. Fossils can be left in plaster bandages permanently if needed. Metal and glass cabinets can also be used to store fossils. Fossils are best kept in a low-humidly environment. High humidity can cause Pyrite disease. Never store fossils in wood containers. The wood, especially in combination with high humidity, can cause fossils to get Byne’s disease. Both diseases will lead to rapid decomposition of fossils. Specimens should also be kept away from Styrofoam, cardboard, and direct sunlight.

Overall, preparation is a constant experiment for the best techniques and most cost-effective ways to prep and store fossils. Trial and error are used for the most part! A book Rachel recommends is entitled “Vertebrate Paleontology Techniques, Volume One.” She also suggests two websites that help with amateur preparation (see slide from webinar below). Rachel answered quite a few questions during the webinar, and then researched many more and posted answers on the myFOSSIL site. If you have a question you would like answered about fossil preparation and storage, you can contact Rachel on the myFOSSIL site at @rnarducci.

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