Featured Research

from universities, journals, and other organizations

Study Associates Asteroid Or Comet Impact With Extinctions In Argentina

Date:
December 14, 1998
Source:
Brown University
Summary:
A new study shows that a previously unknown impact from an asteroid or comet coincides with the disappearance of 35 different types of ancient mammals and a flightless bird 3.3 million years ago. The impact may have directly caused the regional extinctions or triggered a climate change that led to the disappearance of the animals in what is now southeastern Argentina.

PROVIDENCE, R.I. -- A new study shows that a previously unknown impact from an asteroid or comet coincides with the disappearance of 35 different types of ancient mammals and a flightless bird 3.3 million years ago. The impact may have directly caused the regional extinctions or triggered a climate change that led to the disappearance of the animals in what is now southeastern Argentina.

Related Articles


The findings may provide an opportunity for scientists to study the cause and effect of an event that wiped out animal life similar to species on Earth today.

"Unlike what impacts did to dinosaurs and other prehistoric creatures, this was not an event that led to global extinctions," said principal investigator Peter Schultz, professor of geological sciences at Brown University and an impact specialist. "We've found something linked to much more recent land history. The advantage to studying something this young is that you can really examine the forensics.

"This is a threshold event. It may have been just large enough to cause regional damage and extinctions and may have triggered a climate change. El Niño or a volcanic eruption produces small tweaks to the climate compared to what one of these impacts can do." The cyclical cooling of the Earth's temperatures that began soon after the impact 3.3 million years ago continues today, he said.

The study is published in this week's Science magazine. Its co-authors are Argentinean scientists Marcelo Zarate and Cecilia Camilion; Willis Hames, an Auburn University geologist; and John King, a researcher in the Graduate School of Oceanography at the University of Rhode Island. The team studied an 18-mile-long narrow layer of greenish glass and red brick-like materials found in the high ocean cliffs of southeastern Argentina. Called escoria, the glass had puzzled scientists since it was first described in 1865.

[Editors: A color image of the escoria is available at the News Bureau's web site.]

The glass and surrounding red-baked powder bear the signatures of a powerful ancient blast archived in the thick Argentine dust, say the researchers. They describe a half-dozen physical signs, from the twisted and folded shapes of the glass to its isolation from other potential sources such as volcanoes. Chemical analysis of the glass produces all the right impact signatures: unusually high levels of magnesium oxide and calcium oxide, significant amounts of iridium and chromium, and only the tiniest traces of water.

The study shows the glass occurs just below a layer of dusty deposits containing fossil evidence of a 3-million-year-old disappearance of 36 local types of animals. Extinct species include large armadillo-like creatures, ground sloths, hoofed groups of related mammals and a flightless carnivorous bird. Other fauna later appeared in their place.

By using a laser fusion technique to measure heavy to light argon atoms in the glass, and by comparing the magnetic readings of the glass layer to published records of magnetic-field changes over the eons, the researchers date the glass as 3.3 million years old, just prior to the extinctions.

Using research by other scientists that compared heavy to light oxygen isotopes in sediment cores from the nearby ocean floor, Schultz and colleagues offer evidence of a sudden drop in both atmospheric and water temperatures almost 3.3 million years ago. The finding indicates that a climate change occurred shortly after the glass appeared and just prior to the animal life turnover.

"This research is analogous to comparing several time clocks," said Schultz. "We compared a clock in the glass to a clock in the soil to a clock in the deep-sea cores. This told us the conditions at the time. We were surprised to find that the appearance of the glasses and the turnover of the fauna coincided with a temperature drop."

The research began as a simple project to determine the origin and age of the escorias. However, the work identified a series of coincidences that strongly suggest a major, ecosystem-altering event took place relatively recently, geologically speaking, he said.


Story Source:

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


Cite This Page:

Brown University. "Study Associates Asteroid Or Comet Impact With Extinctions In Argentina." ScienceDaily. ScienceDaily, 14 December 1998. <www.sciencedaily.com/releases/1998/12/981214075517.htm>.
Brown University. (1998, December 14). Study Associates Asteroid Or Comet Impact With Extinctions In Argentina. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/1998/12/981214075517.htm
Brown University. "Study Associates Asteroid Or Comet Impact With Extinctions In Argentina." ScienceDaily. www.sciencedaily.com/releases/1998/12/981214075517.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Fossils & Ruins News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Researchers Bring Player Pianos Back to Life

Researchers Bring Player Pianos Back to Life

AP (Dec. 17, 2014) — Stanford University wants to unlock the secrets of the player piano. Researchers are restoring and studying self-playing pianos and the music rolls that recorded major composers performing their own work. (Dec. 17) Video provided by AP
Powered by NewsLook.com
Domestication Might've Been Bad For Horses

Domestication Might've Been Bad For Horses

Newsy (Dec. 16, 2014) — A group of scientists looked at the genetics behind the domestication of the horse and showed how human manipulation changed horses' DNA. Video provided by Newsy
Powered by NewsLook.com
Mozart, Beethoven, Shubert and Bizet Manuscripts to Go on Sale

Mozart, Beethoven, Shubert and Bizet Manuscripts to Go on Sale

AFP (Dec. 16, 2014) — A collection of rare manuscripts by composers Mozart, Beethoven, Shubert and Bizet are due to go on sale at auction on December 17. Duration: 00:57 Video provided by AFP
Powered by NewsLook.com
Old Ship Records to Shed Light on Arctic Ice Loss

Old Ship Records to Shed Light on Arctic Ice Loss

Reuters - Innovations Video Online (Dec. 15, 2014) — Researchers are looking to the past to gain a clearer picture of what the future holds for ice in the Arctic. A project to analyse and digitize ship logs dating back to the 1850's aims to lengthen the timeline of recorded ice data. Ben Gruber 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