Visitors to FossiLab may see volunteers working on several of these long term projects. Scroll down to read about them all, or click on a project in this list to jump directly to it.
One of the most impressive views in FossiLab right now is of a set of very large brown teeth emerging from a block of rock that rests on the table in the center of the room. The teeth belonged to a brontothere, a rhinoceros-like relative of horses and tapirs that became extinct about 35 million years ago. We are using an air scribe to remove the rock matrix from the teeth and the surrounding skull. The skull, shown below on the left, is upside down, so the teeth, which are attached to the upper jaw, are pointing upward.
Thousands of brontothere specimens have been collected in North America and Asia, allowing scientists to document the many ways that brontothere species changed during their 20 million years of evolutionary history. Reconstructions of some of the many species are shown in the historic drawing by Charles R. Knight shown below, right.
Watch a video that shows our progress removing matrix from the brontothere skull.
Follow this link to read. Learn why the brontothere is the "oldest" project in FossiLab: Dental Work, Anyone?
|Triassic Fossils from Arizona|
On recent field expeditions to Petrified Forest National Park in northern Arizona, Museum curator Dr. Anna K. Behrensmeyer collected fossil-rich matrix dating from the Late Triassic Period (about 200 million years ago). The tiny fossils that FossiLab volunteers are excavating from the small blocks of rock are shedding light on the ecosystem that existed there at that time.
More than 350 good-quality specimens have been recovered from the matrix so far. These are mostly small teeth, but we also have discovered the jaw of a small pterosaur (a flying reptile) - likely a new species. Other specimens include archosaurs (ancestors of crocs and birds), early theropod dinosaurs, amphibians, and fish. The search goes on. We hope to find fossil evidence of early mammals.
Because the fossils are so tiny, we use very small tools - visitors may even see us applying tiny bits of glue to broken fossils with a cat whisker!
Follow this link to learn more, including why these fossils started their trip to FossiLab on horseback: Tiny Fossils, Big Excitement
Follow this link to read about the field work in Zimbabwe: Fossil Hunting under the Watchful Eyes of Lions
Museum Curator Dr. Brian Huber studies fossil foraminifera to answer questions about ancient changes in climate.
Foraminifera are tiny ocean-dwelling single-celled organisms that construct shells. Different species, identified by their unique shapes and by other shell features, inhabit a wide range of ocean environments, from the intertidal zone to the deep sea. Benthic species live in sediments on the sea floor, while planktonic species live in the upper 300 feet or so of the ocean. The shells of dead foraminifera accumulate on the sea floor, where there may be tens of thousands of shells per cubic centimeter (about a fifth of a teaspoon).
The fossil record of foraminifera is ancient, going back more than 550 million years. They are valuable indicators of past climate change because their shells are sensitive to changes in environmental conditions. We measure oxygen isotope ratios in fossil shells recovered from ancient sea beds to determine the geologic history of seawater temperature change near the ocean surface and on the ocean floor.
Several FossiLab projects involve picking or sorting 90 million year old foraminifera cored from rock in Tanzania that formed as ocean sediments accumulated during the Cretaceous.
Visit the Fossil Preparation Page to see how FossiLab volunteers use small paint brushes to pick up and move the minute shells.
Dr. Scott Wing, Curator of Fossil Plants, has collected and studied thousands of fossil plants from Wyoming and South America for his research into the ecological responses to periods of climate change that occurred between about 70 and 40 million years ago. One period of rapid global warming, called the Paleocene-Eocene Thermal Maximum (PETM), provides the closest analog in earth history to current human-induced global warming.
The leaves sent to FossiLab are still partly covered by rock matrix that must be removed to reveal as much of the fossils as possible. Leaf preparation is complicated by the fact that a block of rock may contain multiple overlapping leaves, only some of which are of scientific interest. To guide our work, the scientists draw hash marks on the rock to tell us which leaves they need to see and which areas of rock (and, at times, other leaf fossils) must be removed. We use a microscope during preparation to help us see the delicate fossils and avoid damaging them with our tools. The block of rock shown below on the left has been marked for preparation. The fossil shown below on the right is completely uncovered and ready for study.
Read Dr. Wing's Summer 2011 Field Dispatches to Smithsonian Magazine.
Access a classroom activity based on Dr. Wing's work to learn how the PETM fossils help us understand global warming in the past.
|Making Fossil Replicas|
From the upper FossiLab window you can look down on a table where we are making replicas of the right foot bones from a Tyrannosaurus rex. These bones were collected by Museum staff in Montana in 2002 (read about the field work here) and were prepared for study by FossiLab volunteers. Now we are making several sets of plaster replicas, called casts.
First, we coat the fossils with silicon rubber to form a mold. The rubber follows every contour, nook and cranny of the bones, allowing the casts to replicate all the surface detail of the fossils. If the shape of a fossil is "simple," the mold is made in two halves. If it is more complex, the mold may be divided into three or more sections. Each section of silicon mold is reinforced with a plaster "mother mold" which helps maintain the proper shape shape. When the mold is completed, the fossil is removed and the inside of the mold is lined with fiberglass-reinforced plaster to form the cast.
We make casts for several reasons:
NMNH scientists frequently go on collecting expeditions to countries that require the return of any fossils found once they have been prepared and initial studies have been completed. Before we return the fossils, we make and retain exact replicas so that scientists here can continue to study them, and visitors can view them.
We make replicas of fossils in our collections that we wish to display but that are too fragile to withstand the vibrations and heat and humidity fluctuations they would experience on exhibit. Displaying a replica of the rarest and most delicate fossils allows us to show visitors what they look like without endangering the fossils themselves.
Another reason to make casts is that we sometimes exchange replicas with other museums. Trading allows us to assemble more complete collections, making it easier for scientists to compare fossils that are housed in different museums. It also makes it possible for rare fossils to be displayed in many museums at the same time.
|Several steps in the molding and casting of a fossil whale jaw bone are shown below.|
|Drawing Fossils with Camera Lucida|
Scientists include high quality photographs of fossils in the research papers they publish about their discoveries. This allows others to study them and decide if they agree with the scientist's interpretations. Sometimes, if critical features of a fossil are hard to see in photos, a scientific illustrator will be asked to create precise drawings of the fossil. The drawings make the photos easier to interpret by highlighting the important features.
Artists volunteering in FossiLab use a microscope with a camera lucida attachment to make scientific illustrations of small fossils for Museum scientists. With this setup, the artist simultaneously sees a magnified image of the fossil and an image of his or her drawing. The effect is that the artist can "trace" the outlines of the fossil and any critical features, creating drawings that retain very accurate proportions.
Visit the Paleo Art website to learn more about scientific illustration techniques.
|Building Storage Jackets|
Once excavated from the rock that has supported them for millions of years, the fragile, brittle fossils are susceptible to damage from vibration, gravity and improper handling. To protect them, we build form-fitted storage jackets with a soft inner layer of foam or felt and an outer layer of hard, fiberglass-reinforced plaster. Visitors to the lab can nearly always see storage jackets at some stage of construction. The work takes place in the large sandbox in the center of the room where sand supports the fossils during the early stages of jacket construction.
Visit another Department of Paleobiology website to read more and watch a video about building storage jackets.
[ TOP ]