Momentum

The Geologic Time Scale, a multivolume reference book updated every eight years, is known as one of the most essential texts for geoscientists worldwide. It is also one of professor Daniel Goldman’s highest professional achievements. 

The book reconstructs the Earth’s 4.6 billion-year history, dividing it into time intervals with boundaries marked by significant events, such as mass extinctions and the first appearance of certain types of animals — as discerned through the study of rocks, fossils and sediments.

“The Geologic Time Scale is the most fundamental of tools in the geosciences,” Goldman said. “It serves earth scientists across disciplines in most everything they do, particularly any research that involves calculating rates of change. Evolutionary rates — or rates of tectonic plate movement, for example — need precise time-calibrated data. Being chosen to work on this project is especially satisfying because it represents significant recognition of my research in paleontology.”

Goldman is lead author on the chapter on the Ordovician Period, which began about 488 million years ago and lasted nearly 45 million years — back when most of North America was south of the equator. The Ordovician Period is best known for encompassing a rapid radiation of marine life, called the Great Ordovician Biodiversity Event, and ending with the second biggest mass extinction in Earth’s history.

The chapter will cover new and improved quantitative methods of relating shallow- and deep-water fossil occurrences to time, which will allow scientists to more objectively determine whether fossils discovered at different locations around the globe existed at the same time.

Goldman’s chapter co-authors are Stephen Leslie, head of James Madison University’s Department of Geology and Environmental Science, and Peter Sadler, earth sciences professor at the University of California, Riverside. They spent the past two years preparing the chapter, working with a lot of new data, including methodological advances, better fossil information and many new radiometric dates.

“The result is better ways of integrating that data to construct a more precise time scale,” Goldman said.

Goldman’s contributions to the field led to his election as a Geological Society of America fellow in May 2019. Founded in 1888, the society is an international group of scientists in academia, government and business with more than 20,000 members in over 100 countries. It supports scientific discovery, application of geoscience knowledge, public dialogue on geoscience issues and earth-science education.

“Fellows are so named as a reflection of their important and sustained contribution to their field,” said Don Pair, College of Arts and Sciences associate dean for interdisciplinary research and experiential initiatives. 

Goldman, who joined the University faculty in 1997, is known for his research on a group of fossils called graptolites — ancient zooplankton that are useful in determining the relative age of rocks. Based on his research, Goldman in 2007 established a new subdivision of the Ordovician Period, called the Katian Stage. He also has produced more than 125 publications, abstracts and field guides.