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
Field widens for environments, microbes that produce toxic form of mercury
12.10.2015 | DOE/Oak Ridge National Laboratory
Unexpected information about Earth's climate history from Yellow River sediment
09.10.2015 | Uppsala University
Having a light touch can make a hefty difference in how well animals and robots move across challenging granular surfaces such as snow, sand and leaf litter. Research reported October 9 in the journal Bioinspiration & Biomimetics shows how the design of appendages – whether legs or wheels – affects the ability of both robots and animals to cross weak and flowing surfaces.
Using an air fluidized bed trackway filled with poppy seeds or glass spheres, researchers at the Georgia Institute of Technology systematically varied the...
Nondestructive material testing (NDT) is a fast and effective way to analyze the quality of a product during the manufacturing process. Because defective materials can lead to malfunctioning finished products, NDT is an essential quality assurance measure, especially in the manufacture of safety-critical components such as automotive B-pillars. NDT examines the quality without damaging the component or modifying the surface of the material. At this year's Blechexpo trade fair in Stuttgart, Fraunhofer IZFP will have an exhibit that demonstrates the nondestructive testing of high-strength automotive body parts using 3MA. The measurement results are available in a matter of seconds.
To minimize vehicle weight and fuel consumption while providing the highest level of crash safety, automotive bodies are reinforced with elements made from...
The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.
As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...
Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.
Inspired by insects
An interdisciplinary team of researchers has built the first prototype of a miniature particle accelerator that uses terahertz radiation instead of radio...
01.10.2015 | Event News
30.09.2015 | Event News
17.09.2015 | Event News
12.10.2015 | Press release
12.10.2015 | Press release
12.10.2015 | Physics and Astronomy