New Study confirms periods with extremely cold climate – Glaciers covered even equatorial regions
It is probable that for several times planet earth was completely covered by ice, geologists say. From a distance, it would have looked like a huge snowball.
A new study from the University of Göttingen now confirms that the Earth went through episodes of extremely cold climates millions and billions years ago.
In so-called “Snowball Earth” periods, glaciers even covered equatorial regions. Geologist Dr. Daniel Herwartz has reconstructed the oxygen isotopic compositions of ancient (sub) tropical glaciers.
“The oxygen isotope composition of the glaciers can provide information about the climate conditions on an earth totally covered by ice”, says Dr. Herwartz, who is the lead author of the study in Göttingen and who now works at the University of Cologne.
The results are published in Proceedings of the National Academy of Sciences of the USA (PNAS) on April 13, 2015.
The studied rocks, 2.4 billion and 700 million years old, were samples from north-western Russia and China. At the time, both regions were located close to the equator. There, the rocks interacted with melt water from (sub) tropical glaciers and stored the provided isotopic information for hundreds of millions years.
The reconstructed oxygen isotope composition for the glaciers of the 2.4 billion year event is similar to one that is nowadays only observed in the coldest place of our planet: in central Antarctica with mean annual temperatures of minus 40 degree Celsius. “To imagine places like Egypt or Florida with mean annual tem-peratures of minus 40 degree Celsius is just mind-boggling, but that is what the data suggests” says Dr. Herwartz.
The 700 million year old rocks from China conform to climates similar to southern Greenland today and suggest a much warmer climate than the 2.4 billion year old rocks from north-western Russia. The scientists were able to reconstruct the glacial water isotopic compositions by analysing the 17O isotope with a highly precise method.
The “Snowball Earth” hypothesis poses that the entire earth was frozen with all oceans covered under sev-eral hundred meter thick sea-ice. At low CO2 levels ice caps extend to lower latitudes and once, a critical part of the Earth’s surface is covered by ice, reflection of sunlight leads to a further decrease in temperature and ends in an entirely frozen planet.
Only the raise of atmospheric CO2 through continuing volcanic activity could enforce a competing greenhouse effect and released the Earth from it’s frozen state. “’Snowball Earth’ events are critical intervals in the evolution of life. While an entirely frozen planet restricts live to small enclaves like hot springs, the times after such events often show an unseen explosion of live.” says co-author Prof. Dr. Andreas Pack from the University of Göttingen.
Herwartz D., Pack A., Xiao Y., Muhlenbachs K., Sengupta S. and Di Rocco T.(2015): Revealing the climate of snowball Earth from Δ17O systematics of hydrothermal rocks. Proceedings of the National Academy of Sciences of the USA. Doi: 10.1073/pnas.1422887112
Dr. Daniel Herwartz
Universität zu Köln
Institut für Geologie und Mineralogie, Abteilung Umweltisotopengeologie
Phone: +49 221 4703240
Romas Bielke | idw - Informationsdienst Wissenschaft
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine