Chemistry 2011.org
Chemistry2011.org
All About Chemistry... 2011 and beyond

Related Stories

Same forces as today caused climate changes 1.4 billion years ago

Natural forces have always caused the climate on Earth to fluctuate. Now researchers have found geological evidence that some of the same forces as today were at play 1.4 billion years ago.

Fluctuating climate is a hallmark of Earth, and the present greenhouse effect is by far the only force affecting today's climate. On a larger scale the Earth's climate is also strongly affected by how the Earth orbits around the sun; this is called orbital forcing of Climate-Change'>climate change. These changes happen over thousands of years and they bring ice ages and warming periods.

Now researchers from University of Southern Denmark, China National Petroleum Corporation and others have looked deep into Earth's history and can reveal that orbital forcing of Climate-Change'>climate change contributed to shaping the Earth's climate 1.4 billion years ago.

"This study helps us understand how past climate changes have affected Earth geologically and biologically," says Donald Canfield, principal investigator and professor at Nordic Center for Earth Evolution, University of Southern Denmark.

The evidence comes from analyses of sedimentary records from the approximately 1.4 billion-year-old and exceptionally well preserved Xiamaling Formation in China.

Changes in wind patterns and ocean circulations

The sediments in the Xiamaling Formation have preserved evidence of repeated climate fluctuations, reflecting apparent changes in wind patterns and ocean circulation that indicates orbital forcing of Climate-Change'>climate change.

Today Earth is affected by fluctuations called the Milankovich cycles. There are three different Milankovich cycles, and they occur each 20,000, 40,000 and 100,000 years. Over the last one million years these cycles have caused ice ages every 100,000 years, and right now we are in the middle of a warming period that has so far lasted 11,000 years.

"Earth's climate history is complex. With this research we can show that cycles like the Milankovich cycles were at play 1.4 billion years ago -- a period, we know only very little about," says Donald Canfield, adding:

"This research will also help us understand how Milankovitch cyclicity ultimately controls Climate-Change'>climate change on Earth."

In the new scientific paper in the journal PNAS, the researchers report both geochemical and sedimentological evidence for repeated, short-term climate fluctuations 1.4 billion years ago. For example the fossilized sediments show how layers of organic material differed over time, indicating cycle changes in wind patterns, rain fall and ocean circulations.

"These cycles were a little different than today's Milankovich cycles. They occurred every 12-16,000 years, 20-30,000 years and every 100,000 years. They were a little shorter -- probably because the Moon was closer to Earth 1.4 billion years ago," explains Donald Canfield.

Story Source:

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

Share this story with your friends!

Social Networking

Please recommend us on Facebook, Twitter and more:

Other social media tools

Global Partners
Feedback

Tell us what you think of Chemistry 2011 -- we welcome both positive and negative comments. Have any problems using the site? Questions?

About us

Chemistry2011 is an informational resource for students, educators and the self-taught in the field of chemistry. We offer resources such as course materials, chemistry department listings, activities, events, projects and more along with current news releases.

Events & Activities

Are you interested in listing an event or sharing an activity or idea? Perhaps you are coordinating an event and are in need of additional resources? Within our site you will find a variety of activities and projects your peers have previously submitted or which have been freely shared through creative commons licenses. Here are some highlights: Featured Idea 1, Featured Idea 2.

About you

Ready to get involved? The first step is to sign up by following the link: Join Here. Also don’t forget to fill out your profile including any professional designations.

Global Partners