 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
 by Staff Writers Gottingen, Germany (SPX) Dec 22, 2022
Several billion years ago, the oceans were probably not as hot as often assumed, but were instead at much more moderate temperatures. This is the conclusion of a research team from the University of Gottingen and the German Research Centre for Geosciences (GFZ), Potsdam. The scientists analysed "cherts" - sedimentary rocks that form from seawater and the remains of silica-secreting creatures. Using these "time capsules", the team showed that the oxygen isotope ratios are determined by the cooling of the solid Earth and depend less on the temperatures of seawater. The results were published in PNAS. How can it be that ancient cherts - between 3.85 and 2.5 billion years old - are so highly enriched with the lighter oxygen isotope (oxygen-16 or 16O)? What information do these valuable time capsules actually record about the history of our Earth? To investigate this decades-old mystery in the geosciences, the research team examined circa 550 million years old cherts from southeast China. These samples document that after the deposition of sedimentary mud, the amorphous precursors of cherts recrystallise hundreds of metres below the Earth's surface, recording temperatures at depth - and not the temperature of the ocean above them. This finding sparked the idea that oxygen isotope ratios could depend on the heat flow from the Earth's interior - a completely new angle on the old mystery. "Our calculations show that when the flow of heat is higher, the proportion of oxygen-16 becomes higher, because recrystallisation takes place at higher temperatures," says Junior Professor Michael Tatzel from the Geosciences Centre of the University of Gottingen. At the same time, seawater is enriched with oxygen-16 under these conditions. This solves the puzzle of why there is a large proportion of the lighter oxygen isotope in ancient cherts: heat flow on the early Earth was approximately double modern values. "Cherts are obviously no accurate recorders of seawater temperatures in the past. Our findings mean that we need to interpret oxygen isotopes in cherts in a whole new way," says Tatzel. Co-author Patrick Frings from GFZ Potsdam adds: "I think this work will open the door to some exciting new developments in the coming years, because our understanding of the heat flow effect will allow more accurate reconstructions of seawater temperatures in deep geological time. In addition, we will be able to decipher the thermal structure and tectonic history of ancient sedimentary basins." The calculated effect of heat flow on oxygen isotopes in cherts also means that the isotopically light Archean cherts are indicative of a temperate to warm climate on early Earth - hot oceans seem very unlikely. This conclusion is central to understanding the evolution of life on the young Earth.
Research Report:Chert oxygen isotope ratios are driven by Earth's thermal evolution
JAXA startup Tenchijin announces funding from JAXA Tokyo, Japan (SPX) Dec 18, 2022 Tenchijin is pleased to announce the investment from the Japan Aerospace Exploration Agency ("JAXA"). This is the first ever investment of JAXA's capital investment into business. This funding will enable Tenchijin to enhance its product capabilities and expand its usage to yield direct benefits for society and businesses on Earth. Since incorporation in 2019, Tenchijin has been developing business as a JAXA Startup. With this funding, Tenchijin will enhance its partnership with JAXA to expand its ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
