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
NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center
New research unlocks forests' potential in climate change mitigation
21.04.2017 | Clemson University
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy