Preparing a fossil requires a variety of tools, some of which are shown here. Top left to bottom right: spray water bottle, lubricating oil for airscribes, acetone, PVA, carbide picks, brushes, a PaleoAro and a microjack (airscribes of different sizes and strengths), dust mask, goggles, and ear muffs for noise protection.
The first project I got started on at FLMNH was preparing a fossil dugong from the Culebra formation of the Panama Canal. My main focus has been on a cluster of vertebrae that are held together by a carbonate and siltstone matrix. The process of preparing this fossil is rather slow going because the matrix is extremely hard and nearly the same color as the bone. To help distinguish them, the fossil is sprayed or brushed with water to remove dust and help bring out the color of the bone. While it is damp, I use carbide picks and airscribes (basically handheld jackhammers) to remove the matrix. The goal at this step of preparation is to remove as much matrix as possible while leaving a thin layer just above the bone and to leave any areas where it is too difficult to distinguish between bone and matrix. Next, a thin layer of PVA, a glue reversible with acetone, is added to protect the bone when it is placed in a diluted formic acid bath. The acid breaks down some matrix but does not damage the bone, although some etching can occur over time. The fossil is then soaked in running water to remove any remaining acid and the PVA is removed to begin the process of manually removing matrix over again. Broken pieces of bone often become loose after the bath and must be secured with glue before continuing.
The fossil lab station where Dawn prepares the dugong vertebrae. She uses a surgical microscope that can easily pivot to get multiple views of the fossil while she uses tools to remove matrix.
Preparing this fossil has taken a lot of time and the effort of many people, and it still requires much more before it is finished. But progress is being made; when I started I couldn’t see through the neural canal of one vertebra, but now I can! Once preparation is completed, this fossil promises to provide us with interesting new information on Miocene dugongs from the Panama Canal area.
Dawn at her prep station in the Sereno Fossil Lab. (Photo courtesy of Nicole Ridgwell)
Hi! My name is Dawn Mitchell and I am a museum intern working with PCP-PIRE here at FLMNH, which is a long way from my hometown of Chicago, Illinois. My interest in paleontology started early, and you could often find me traversing the halls of the Field Museum of Natural History, peering curiously through the glass windows of the McDonald’s Fossil Preparation Laboratory there. That prep lab became the subject of one of the admissions essays I submitted to the University of Chicago, where I graduated from last June with a B.S. in Geophysical Sciences. During my tenure at UChicago I learned basic fossil preparation techniques in Dr. Paul Sereno’s fossil lab and worked with 3D reconstruction and 3D printing of fossils for a senior project with Dr. Zhe-Xi Luo.
A 3D-printed model of the shoulder girdle and right humerus of the short-beaked echidna Tachyglossus aculeatus. The model was printed at twice the size of the original specimen. (Photo courtesy of Dawn Mitchell)
Dawn updating Field Museum catalogue records of Eocene mammals. (Photo courtesy of Susumu Tomiya)
Also during my senior year, I had the good fortune of having most of my Fridays free, giving me the opportunity to volunteer at the Field Museum and assist with the curation of Eocene fossil specimens from the Washakie Basin of Wyoming. Here at FLMNH, my duties so far have consisted of preparing parts of a fossil dugong from Panama and researching North American fossil mammal collections in the Paleobiology Database. I’ll post more details on these projects shortly, and I look forward to sharing my experiences here at FLMNH!
Sean Moran recently traveled to Santa Cruz, CA to work with high school teachers developing lesson plans incorporating paleontology. Read his post on GABI-RET’s blog!
Sean Moran shows off a geological sample taken at Capitola Beach. Photo by Rob Hoffman.
The 3-5 Ma (Pliocene) Purisima Formation, a marine sedimentary unit that is fossiliferous and interpreted to preserve marine shelf deposits, crops out at Capitola Beach as well as several other locations around Santa Cruz. The fact that it is close to many local schools and provides material for several type of geology lessons makes in an appealing place for class field trips. The hope is that these trips with teachers will catalyze the creation of lesson plans centered on Capitola Beach [read more on GABI-RET].
Wes von Dassow (back, left) spoke with students in the Santa Cruz schools during the last week of October. Photo by Laura Beach.
It’s already Thursday and I am just sitting down to write about the conversations I’ve been having with teachers and classrooms full of students since Monday. It’s been really interesting talking to and, most times, having back and forth conversations with these classes. I’ve been told how some classes can be more attentive or rambunctious based on class “personality”, the time of day, or the general malaise that seems to cloud kids natural curiosity throughout high school. But, who am I to complain about those few classes? I remember being the same way to some degree at their age, which was only 4 years ago for me! [read more on GABI RET]