Featured Research

from universities, journals, and other organizations

Largest North America Climate Change In 65 Million Years, Study Shows

Date:
February 8, 2007
Source:
University of Florida
Summary:
The largest climate change in central North America since the age of the dinosaurs 65 million years ago, a temperature drop of nearly 15 degrees Fahrenheit, is documented within the fossilized teeth of horses and other plant-eating mammals, a new study reveals.

University of Florida vertebrate paleontologist Bruce MacFadden examines a fossil oreodont jaw from Nebraska in the Florida Museum of Natural History collections in Gainesville, Fla., on Jan. 30, 2007. MacFadden is part of a team that is the first to use fossil teeth and bones to provide evidence of a dramatic climate change about 33.5 million years ago.
Credit: Photo by Jeff Gage/Florida Museum of Natural History

The largest climate change in central North America since the age of the dinosaurs 65 million years ago, a temperature drop of nearly 15 degrees Fahrenheit, is documented within the fossilized teeth of horses and other plant-eating mammals, a new study reveals.

The overwhelming majority of previous climate-change studies on the 400,000-year transition from the Eocene to the Oligocene epochs, about 33.5 million years ago, focus on marine environments, but University of Florida vertebrate paleontologist Bruce MacFadden and his colleagues turned their attention to fossils from the Great Plains.

The study will be published online Feb. 7 in the journal Nature and will appear in the Feb. 8 print edition.

"If a temperature change of this magnitude occurred today, Florida would have weather similar to Washington, D.C., or even farther north," said MacFadden, a curator at the Florida Museum of Natural History.

The Eocene-to-Oligocene transition is known in the fossil record as the Grande Coupure, the "Big Cut" in French, because it marks a massive extinction of life in both marine and land environments. Scientists believe the drop in temperature was likely due to changes in oceanic currents, MacFadden said.

"Fossil mammals are archives of ancient information," MacFadden said. "Their teeth are like little time capsules that allow us to analyze chemicals captured millions of years ago within the animals' skeletons."

MacFadden said 49 of the 68 fossil teeth analyzed came from the Florida Museum's vertebrate paleontology collection. Researchers analyzed oxygen and carbon isotopes in the preserved teeth and bones of primitive fossil horses and a primitive cloven-hoofed mammal called an oreodont. Isotopes are atoms of naturally occurring elements, characterized by varying numbers of neutrons but constant numbers of protons. Oxygen isotopes act as thermometers, telling scientists at what temperature they were formed; and carbon isotopes act as barometers, revealing relative humidity.

"A combined analysis of the isotope composition of bones and teeth is a new approach to studying this boundary in time," said Alessandro Zanazzi, a doctoral student in geology at the University of South Carolina and lead author of the paper. "Tooth enamel has very low porosity and low organic matter, so it maintains the isotopic composition of when it was formed."

Donald R. Prothero, a professor of geology at Occidental College and an expert on the Eocene-to-Oligocene transition, said, "We have long known that there were some dramatic climatic changes in the earliest Oligocene based on the record of marine plankton and isotopes. But we didn't know how much change there was in degrees, although the plant changes suggested it was indeed about 15 degrees."

Prothero also said gaps in the fossil record from Nebraska may have prevented researchers from obtaining detailed temperature data, and he hopes further studies will be completed at other sites such as Wyoming.

Additional co-authors include Matthew J. Kohn, associate professor of geology at the University of South Carolina and advisor to Zanazzi, and Dennis O. Terry Jr., assistant professor of geology at Temple University. The study was funded by a grant from the National Science Foundation.


Story Source:

The above story is based on materials provided by University of Florida. Note: Materials may be edited for content and length.


Cite This Page:

University of Florida. "Largest North America Climate Change In 65 Million Years, Study Shows." ScienceDaily. ScienceDaily, 8 February 2007. <www.sciencedaily.com/releases/2007/02/070207171908.htm>.
University of Florida. (2007, February 8). Largest North America Climate Change In 65 Million Years, Study Shows. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2007/02/070207171908.htm
University of Florida. "Largest North America Climate Change In 65 Million Years, Study Shows." ScienceDaily. www.sciencedaily.com/releases/2007/02/070207171908.htm (accessed October 20, 2014).

Share This



More Fossils & Ruins News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

So, Kangaroos Didn't Always Hop

So, Kangaroos Didn't Always Hop

Newsy (Oct. 16, 2014) Researchers believe an extinct kangaroo species weighed 500 pounds or more and couldn't hop. Video provided by Newsy
Powered by NewsLook.com
1000-Year-Old Viking Treasure Hoard Found in Scotland

1000-Year-Old Viking Treasure Hoard Found in Scotland

Reuters - Light News Video Online (Oct. 14, 2014) A hoard of Viking artifacts dating back over 1,000 years is discovered by a treasure hunter with a metal detector in Scotland. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Early Apple 1 Computer Set for Auction

Early Apple 1 Computer Set for Auction

AP (Oct. 10, 2014) A vintage Apple computer and a letter by Charles Darwin on the sex life of barnacles are among the unusual pieces of science history that go up for auction in New York later this month. (Oct. 10) Video provided by AP
Powered by NewsLook.com
Archaeologists Find 200,000-Year-Old Pre-Neanderthal Bones

Archaeologists Find 200,000-Year-Old Pre-Neanderthal Bones

Reuters - Light News Video Online (Oct. 9, 2014) French archaeologists say they have discovered historically significant pre-Neanderthal remains which give insight into the behavior of the extinct human species. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins