New Data Kicks Up ’Snowball Earth’ Fight

In 1998, Paul F. Hoffman and Daniel P. Schrag at Harvard University put forth a chilling description of earth’s climate some 650 million years ago. Their theory, dubbed snowball earth, held that between 750 million and 580 million years ago, ice repeatedly enveloped our planet, coating the seas from pole to pole and killing off early life almost completely. During the past few years, the idea has stirred up a great deal of debate. And new data published in the December issue of Geology only further throws snowball earth into question.

Lead author Martin Kennedy at the University of California, Riverside, and colleagues collected limestone and dolomite rocks from Precambrain glacial deposits in northern Namibia, central Australia and the North American Cordillera. When they analyzed these samples, they discovered that the ratio of the carbon isotope 13C to 12C was higher during the glaciation than after the ice had melted. This pattern, they say, suggests that the oceans supported a healthy ecosystem at the time — which would be hard to do were they frozen over.

“If there was no photosynthesis or life in the ocean, the carbon isotope values would be the same as the mantle,” Kennedy says. “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.”

Media Contact

Kristin Leutwyler Scientific American

Alle Nachrichten aus der Kategorie: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Zurück zur Startseite

Kommentare (0)

Schreib Kommentar

Neueste Beiträge

High-thermoresistant biopolyimides become water-soluble like starch

This is the first report for the syntheses of water-soluble polyimides which are Interestingly derived from bio-based resources, showing high transparency, tunable mechanical strength and the highest thermoresistance in water-soluble…

Land management in forest and grasslands

How much can we intensify? A first assessment of the effects of land management on the links between biodiversity, ecosystem functions and ecosystem services. Ecosystem services are crucial for human…

A molecular break for root growth

The dynamic change in root growth of plants plays an important role in their adjustment to soil conditions. Depending on the location, nutrients or moisture can be found in higher…

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close