Featured Research

from universities, journals, and other organizations

Prolonged climatic stress main reason for mass extinction 65 million years ago, paleontologist says

Date:
March 27, 2010
Source:
Freie Universitaet Berlin
Summary:
Long-term climate fluctuations were probably the main reason for the extinction of the dinosaurs and other creatures 65 million years ago, according to new research from a German paleontologist. The results challenge the almost 30-year-old theory that a meteorite impact at the Mexican Yucatan peninsula was the single cause for one of the five largest mass extinctions in Earth history.

According to new research from a German paleontologist, long-term climate fluctuations -- not a giant meteorite impact -- were likely the main reason for the extinction of the dinosaurs and other creatures 65 million years ago.
Credit: iStockphoto/Adrian Chesterman

Long-term climate fluctuations were probably the main reason for the extinction of the dinosaurs and other creatures 65 million years ago. This conclusion was reached by PD Dr. Michael Prauss, paleontologist at Freie Universitaet Berlin, based on his latest research results.

Prauss thus challenges the almost 30-year-old theory that a meteorite impact at the Mexican Yucatan peninsula was the single cause for one of the five largest mass extinctions in Earth history, which has most recently been reiterated in a publication in the journal Science. According to Prauss, the impact was only one in a chain of catastrophic events that caused substantial environmental perturbations, probably largely controlled by the intermittent activity of the Deccan volcanism near the then-Indian continent, that continued over several million years and peaked at the Cretaceous-Paleogen boundary.

"The resulting chronic stress, to which of course the meteorite impact was a contributing factor, is likely to have been fundamental to the crisis in the biosphere and finally the mass extinction," says Michael Prauss. In a research project funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) and in collaboration with Prof. Dr. Gerta Keller, paleontologist at Princeton University, U.S.A., Prauss analyzed several drill cores and rock sections covering the extended Cretaceous-Paleogene boundary interval at Brazos River, Texas, USA. The investigated region is located about 1000 km northwest of the Chicxulub impact crater and is well known among geologic scientists for its exceptionally complete preservation of Upper Cretaceous sediments.

Based on an analysis of the appearance and distribution of organic-walled microfossils such as Algal cysts, pollen, and spores of terrestrial plants, Prauss shows that significant and persistent variations in the ecosystem of the Upper Cretaceous started long before the meteorite impact. Among others, these are reflected by fluctuations in sea-level and marine algae productivity.

Prauss also considers it highly problematic to equate the meteorite impact with the position of the Cretaceous-Paleogene boundary: "The actual impact took place well before the geochemically and micropaleontologically defined Cretaceous Paleogene boundary." He supports his assertion with the position of the so-called fern spike, an episodic, significant increase in the proportion of fern spores caused by the pioneering phase of ferns in repopulating landscapes of destroyed ecosystems. In all sections of the investigated area the fern spike occurs well before important stratigraphic evidence for the Paleogene.

The new results contradict a publication by Schulte et al. (2010) in the March 5 issue of Science. Schulte et al. summarize the Cretaceous-Paleogene issue only to arrive at the 30-year-old theory of the impact as the sole cause of mass extinction. The occurrence of substantial fluctuations within the ecosystem of the Upper Cretaceous before the impact is disputed and the impact event is equated in time with the biostratigraphic Cretaceous-Paleogene boundary. "In the light of the new data, both of these points have to be refuted," says Prauss.


Story Source:

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


Journal References:

  1. Michael L. Prauss. The K/Pg boundary at Brazos-River, Texas, USA -- An approach by marine palynology. Palaeogeography, Palaeoclimatology, Palaeoecology, 2009; 283 (3-4): 195 DOI: 10.1016/j.palaeo.2009.09.024
  2. Michael L. Prauss. Marine palynology of upper Maastrichtian to lowermost Danian strata from the Mullinax-1 core, Brazos River, Texas, USA -- evidence for palaeoenvironmental changes. Palaeogeography Palaeoclimatology Palaeoecology, 2010; DOI: 10.1016/j.palaeo.2010.03.035

Cite This Page:

Freie Universitaet Berlin. "Prolonged climatic stress main reason for mass extinction 65 million years ago, paleontologist says." ScienceDaily. ScienceDaily, 27 March 2010. <www.sciencedaily.com/releases/2010/03/100326124654.htm>.
Freie Universitaet Berlin. (2010, March 27). Prolonged climatic stress main reason for mass extinction 65 million years ago, paleontologist says. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2010/03/100326124654.htm
Freie Universitaet Berlin. "Prolonged climatic stress main reason for mass extinction 65 million years ago, paleontologist says." ScienceDaily. www.sciencedaily.com/releases/2010/03/100326124654.htm (accessed April 20, 2014).

Share This



More Earth & Climate News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. Video provided by Newsy
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:
from the past week

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