. 24/7 Space News .
A Curve Ball into the Snowball Earth Hypothesis?

Kennedy and his colleagues' most recent research reveals that life in the oceans during the "snowball" event basically went on as usual. This new data is difficult to reconcile with the effects on life an entirely ice-covered ocean would have imposed, and this fundamentally challenges the Snowball hypothesis.

Boulder - Dec 3, 2001
The idea that the Earth was encased in ice some 650 million years ago has sparked much scientific debate in recent years. In the ongoing Snowball Earth "fight," scientists continually uncover and report new evidence that supports their respective views. Martin Kennedy, from the University of California, Riverside, has just tossed a curveball into the Snowball Earth theory with new data he reports in the December issue of Geology.

The Snowball Earth hypothesis proposes that during several profoundly cold periods of Earth's history that occurred from 750 to 600 million years ago, the ocean was covered by a thick sheet of ice. This would have had a huge impact on early life on Earth, and would have just about wiped it out entirely. Scientists generally agree that ice sheets reached low latitudes on the planet during severe glaciation, but the idea of a completely ice-covered ocean is what's being disputed.

Kennedy and his colleagues' most recent research reveals that life in the oceans during the "snowball" event basically went on as usual. This new data is difficult to reconcile with the effects on life an entirely ice-covered ocean would have imposed, and this fundamentally challenges the Snowball hypothesis.

This new evidence also supports alternative models, such as Kennedy's post-glacial release of methane from massive Clathrate destabilization that he proposed in last May's issue of Geology.

For the last six years, Kennedy has collected limestone and dolomite rocks from Precambrian glacial deposits to establish a record of carbon isotopic variation through the glacial interval. These data indicate consistent positive isotopic values from glacial rocks in northern Namibia, central Australia, and the North American Cordillera.

"The criteria was that they had to occur in a marine succession and they should not be detrital but precipitated in situ," Kennedy said. "I also wanted to have as many examples as possible to establish a global record and discount local effects or misinterpretation from a single locality. While one interval might be lacustrine, it is unlikely that all are, and since they all show roughly the same positive values then it is more likely to be a meaningful result."

His evidence shows that the carbon isotope 13C to 12C ratio was actually higher during the glaciation indicating the presence of a healthy and productive marine ecosystem. This ratio dropped only after the ice had melted and this suggests that other influences other than those proposed in the Snowball hypothesis must have been active.

"If there was no photosynthesis or life in the ocean, the carbon isotope values would be the same as the mantle," Kennedy said. "Only the presence of life causes a difference in those values. We did not find isotopic evidence that a global ice sheet impacted overall marine productivity. We would think that if an ice sheet covered the oceans, it would have had an impact on marine production or photosynthesis and we find no carbon isotopic evidence for this. The oceans just look normal."

Related Links
Geological Society of America
Geology Journal
Department of Earth Science at UCR
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


Ocean Circulation Shut Down by Melting Glaciers After Last Ice Age
Greenbelt - Nov 19, 2001
At the end of the last Ice Age 13 to 11.5 thousand years ago, the North Atlantic Deep Water circulation system that drives the Gulf Stream may have shut down because of melting glaciers that added freshwater into the North Atlantic Ocean over several hundred years, NASA and university researchers confirm. Since the Gulf Stream brings warm tropical waters north, Western Europe cooled.







  • Gender Issues Related To Spaceflight: A NASA Perspective
  • Bush Appoints Bean Counter In Bid To Salvage NASA From ISS Overruns
  • NASA Seeks Volunteers For Month-Long Bed Rest Study
  • World Space Week: A Celebration of Space Exploration

  • New Research From U.Colorado-Boulder Reveals Mars' Lumpy Magnetic Field
  • Nature's Flight System Could Be Key To Exploring Mars
  • Odyssey Down To 10 Hour Orbit
  • Can Biosensors Find Life On Mars?

  • Last Boeing Delta 2 For 2001 Will Launch An Argonaut
  • Canada's First Space Telescope to Ride a "Rockot"
  • Space Communications, Khrunichev To Cooperate
  • DirecTV Sat To Launch Monday

  • Envisat Set To Flood Earth With New Data
  • Envisat No. 1 -- Europe's Environment Satellite
  • New views of Earth
  • DigitalGlobe Successfully Launches QuickBird Imaging Satellite

  • Surviving Oblivion In Deep Space
  • Into The Deep Space Of Nowhere
  • Into The Deep Space Of Nowhere
  • Out To The Horizon Of Sol

  • Taking The Medium Class Route To Deep Space
  • No Bucks Without ET
  • Shuttle Ready To Collide With Some Dust
  • Into The Deep Space Of Nowhere

  • Moon and Earth Formed out of Identical Material
  • Lunar Soil Yields Evidence About Sun's Dynamic Workings
  • Unique tasks for SMART-1 in exploring the Moon
  • NASA Seeks Berth On India's Moon Mission

  • Paradigm Chosen to Provide GPS-based Tracking for Highly Sensitive Security Application
  • GPS Satellite Signals Help Drivers Save Fuel and Reduce Emissions
  • Galileo Development Forges Ahead Pending Ministerial Decisions
  • TeleType Unveils Multi Tracker Device

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement