Research on fossils brings light to Earth’s history
October 4, 2012
Dr. Tamera Schiappa, professor of Geology specializing in paleontology, is continuing her 20 year long research on 288 million year-old fossils.
The subject of her National Science Foundation (NSF) funded research was shelled arthropods known as ammonoids from the Permian period located in a marine basin in the west coast. The basin stretched from southern Arizona to northern Nevada and was filled with many different species of animals. By studying how the ammonoids changed, Schiappa hopes to better understand what the environment was like over 280 million years ago.
Although there are many different species of ammonoids, there are only two main types of them. The first type is called equatorial and they came from warm climates near the equator. The second type is known as boreal and they migrated from near the poles.
Because they are extremely sensitive to temperatures, Schiappa wanted to determine if they lived at the same time if there was a change in the climate, which caused one type of ammonoids to become extinct and become replaced by another. If they lived at the same time, then the warm water circulation patterns would have been one side of the basin, while cold-water circulation patterns would have been on the other side.
In order to figure out if the two types of ammonoids lived at the same time, Schiappa used a brand new technique that involved studying Strontium isotopes left from conodonts, which were small worm-like animals that were frequently eaten by ammonoids.
Traces of the conodonts can be found in the rock surrounding the ammonoids fossils. In order to study them, geologists must carefully separate the fossil from the rock by using a scalpel. After the rock is separated, it is dissolved in acid, and only traces of the conodonts will be left.
These isotopes are studied by using a machine called a mass spectrometer which is able to calculate the age of a sample with an accuracy of plus or minus one year. After dating the conodonts, Schiappa was able to figure out that the two types of ammonoids did not live at the same time.
By finding out that they lived during different periods of time, Schiappa determined that there must have been a noticeable climate or tectonic that altered the water circulation pattern from hot to cold. After water turned cold, the equatorial fauna died out and cold-water fauna migrated into the basin.
Schiappa said that because we know that the temperature of the basin has changed, we may be able deduce that the climate became colder as well. This is strange because most geological evidence suggests that the climate getting much warmer around the world during the Permian period.
“This has provided us with an understanding of the palaeogeographic and palaeoenvironmental evolution of the western margin of North America,” Schiappa explained. “To the broader scientific communities we have a better understanding of what was going on in the western margin at this time.”
Schiappa collected her own samples of ammonoids from North Eastern Nevada with groups of undergraduate students in the Department of Geography, Geology and the Environment.
“Nationally funded and state funded research has really benefited our students here at Slippery Rock because they have gotten to participate in the science,” Schiappa said. “I have had several students who have been able to use that experience to propel them into their next stage. Some students go into graduate school because of it, and others have been able to become successful in their careers. I think that there is a lot to say about undergraduate research because it benefits everybody.”
Dating the ammonoids for the NSF was just a small part of Schiappa’s research. That study was for a three year long grant that began in 2000, which funded a small group of scientists about a half a million dollars. Studying each different type of species of ammonoids was a large part of Schiappa’s research before she received her NSF grant. She is now using PASSHE and university grants to further research ammonoids and the Permian period.