Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A cataclysmic event of a certain age

28.07.2015

Geologist James Kennett and an international team narrow the date of an anomalous cooling event most likely triggered by a cosmic impact

At the end of the Pleistocene period, approximately 12,800 years ago­ -- give or take a few centuries -- a cosmic impact triggered an abrupt cooling episode that earth scientists refer to as the Younger Dryas.


This map shows the Younger Dryas Boundary locations that provided data for the analysis.

Credit: UCSB

New research by UC Santa Barbara geologist James Kennett and an international group of investigators has narrowed the date to a 100-year range, sometime between 12,835 and 12,735 years ago. The team's findings appear today in the Proceedings of the National Academy of Sciences.

The researchers used Bayesian statistical analyses of 354 dates taken from 30 sites on more than four continents. By using Bayesian analysis, the researchers were able to calculate more robust age models through multiple, progressive statistical iterations that consider all related age data.

"This range overlaps with that of a platinum peak recorded in the Greenland ice sheet and of the onset of the Younger Dryas climate episode in six independent key records," explained Kennett, professor emeritus in UCSB's Department of Earth Science. "This suggests a causal connection between the impact event and the Younger Dryas cooling."

In a previous paper, Kennett and colleagues conclusively identified a thin layer called the Younger Dryas Boundary (YDB) that contains a rich assemblage of high-temperature spherules, melt-glass and nanodiamonds, the production of which can be explained only by cosmic impact. However, in order for the major impact theory to be possible, the YDB layer would have to be the same age globally, which is what this latest paper reports.

"We tested this to determine if the dates for the layer in all of these sites are in the same window and statistically whether they come from the same event," Kennett said. "Our analysis shows with 95 percent probability that the dates are consistent with a single cosmic impact event."

All together, the locations cover a huge range of distribution, reaching from northern Syria to California and from Venezuela to Canada. Two California sites are on the Channel Islands off Santa Barbara.

However, Kennett and his team didn't rely solely on their own data, which mostly used radiocarbon dating to determine date ranges for each site. They also examined six instances of independently derived age data that used other dating methods, in most cases counting annual layers in ice and lake sediments.

Two core studies taken from the Greenland ice sheet revealed an anomalous platinum layer, a marker for the YDB. A study of tree rings in Germany also showed evidence of the YDB, as did freshwater and marine varves, the annual laminations that occur in bodies of water. Even stalagmites in China displayed signs of abrupt climate change around the time of the Younger Dryas cooling event.

"The important takeaway is that these proxy records suggest a causal connection between the YDB cosmic impact event and the Younger Dryas cooling event," Kennett said. "In other words, the impact event triggered this abrupt cooling.

"The chronology is very important because there's been a long history of trying to figure out what caused this anomalous and enigmatic cooling," he added. "We suggest that this paper goes a long way to answering that question and hope that this study will inspire others to use Bayesian statistical analysis in similar kinds of studies because it's such a powerful tool."

Media Contact

Julie Cohen
julie.cohen@ucsb.edu
805-893-7220

 @ucsantabarbara

http://www.ucsb.edu 

Julie Cohen | EurekAlert!

More articles from Earth Sciences:

nachricht Sun's impact on climate change quantified for first time
27.03.2017 | Schweizerischer Nationalfonds SNF

nachricht NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Electrical 'switch' in brain's capillary network monitors activity and controls blood flow

27.03.2017 | Health and Medicine

Clock stars: Astrocytes keep time for brain, behavior

27.03.2017 | Life Sciences

Sun's impact on climate change quantified for first time

27.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>