A new study by Jacobs University Bremen, in close cooperation with the University of Bonn and the University of Cologne, shows that 2,700 million years ago vast landmasses already existed on earth. The research results have now been published in science journal Geology. (DOI: 10.1130/G35014.1).
The Temagami Iron Formation: an archive of 2,700-million-year-old seawater
Copyright: M. Bau / Jacobs University Bremen
The question when vast landmasses rose above sea-level remains an issue of debate within the science community. Computer simulations, for example, suggested that 2,500 million years ago only 3% of the Earth’s surface area was dry.
A new geochemical approach to address this issue has now been developed by Michael Bau, Professor of Geosciences at Jacobs University Bremen, his Ph.D. student Sebastian Viehmann and collaborators Dr. Elis Hoffmann (University of Bonn) and Prof. Carsten Münker (University of Cologne), who studied the distribution of rare trace elements and the isotopic composition of hafnium (Hf) and neodymium (Nd) in ancient seawater.
Analyzing unusually pure iron-rich sedimentary rocks (banded iron-formation, BIF) from Temagami, Canada, which are an archive of 2,700-million-year-old seawater, the researchers were able to extend the Hf isotope record of seawater back in time to the Early Earth’s ocean.
The Temagami BIF shows that 2,700 million years ago, seawater was anomalously enriched in the radiogenic Hf-176 isotope, whereas its Nd isotopic composition was normal. This reveals that the same decoupling of Hf and Nd isotopes, which is observed in the modern ocean, did already persist 2,700 million years ago.
Prof. Bau explains: “Seawater that is enriched in Hf-176 is produced when rocks at the Earth’s surface are subjected to terrestrial erosion and weathering. The observed decoupling of Hf and Nd isotopes recorded in the Temagami BIF indicates that already 2,700 million years ago, large areas of dry land were emerged above sea-level and exposed to wind and rain.”
The results of this study are now published in scientific journal Geology.Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents
Authors: Sebastian Viehmann, J. Elis Hoffmann, Carsten Münker, Michael BauContact:
Andrea Daschner | idw
Scientists shed light on carbon's descent into the deep Earth
19.07.2017 | European Synchrotron Radiation Facility
Thawing permafrost releases old greenhouse gas
19.07.2017 | GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
19.07.2017 | Event News
12.07.2017 | Event News
12.07.2017 | Event News
20.07.2017 | Information Technology
20.07.2017 | Materials Sciences
20.07.2017 | Physics and Astronomy