Antonio Simonetti, a research associate professor in the Department of Civil Engineering and Geological Sciences at the University of Notre Dame, is the coauthor of an important new paper describing a novel method for age dating dinosaur fossils.
Simonetti and colleagues from the University of Alberta used a U-Pb (uranium-lead) dating technique to analyze a fossilized dinosaur bone discovered in New Mexico.
The atoms in some chemical elements have different forms, called isotopes.
These isotopes break down at a constant rate over time through radioactive decay.
And much of that dating work will be done in a new laboratory facility at Notre Dame. Neal, a professor of civil engineering and geological sciences, have received a National Science Foundation-MRI equipment grant to establish MITERAC the Midwest Isotope and Trace Element Research Analytic Center in Cushing Hall.If a radioactive isotope is said to have a half-life of 5,000 years that means after 5,000 years exactly half of it will have decayed from the parent isotope into the daughter isotopes.Then after another 5,000 years half of the remaining parent isotope will have decayed.However, the method used by Simonetti and his colleagues determined that the New Mexico plant eating dinosaur was alive roughly 700,000 years after the surmised giant extinction event.Although the challenge to the accepted dinosaur extinction model has received the most attention, Simonetti believes that the dating method described in the paper is especially significant.The majority of the time fossils are dated using relative dating techniques.Using relative dating the fossil is compared to something for which an age is already known.The current method paleontologists use to date dinosaur fossils is a technique called relative chronology.The method estimates a fossils age relative to the known age of deposits of sediment in which it was found.Index fossils are fossils that are known to only occur within a very specific age range.Typically commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites work best as index fossils.