Thirty four million years ago, Antarctica was covered with temperate forests that included beech trees and cycads. Then, over a geologically short period of 200,000 years, global temperatures cooled and Antarctica became the frozen continent it is today. These pervasive climatic changes may be linked to weathering processes on the Antarctic continent.
Typical deep ocean sediment cores. Scientists use geochemical signals hidden in these sediments to reconstruct Earth’s climate history.
Dr. Chandranath Basak of the Max Planck Research Group Marine Isotope Geochemistry located at the University of Oldenburg, and his co-author Dr. Ellen Martin from the University of Florida found out that weathering of different types of rocks contributed towards the observed climate change at the Eocene/Oligocene boundary.
For this study they used deep-sea sediments obtained from the Integrated Ocean Drilling Program, a large-scale programme for scientific ocean drilling. In their publication in the scientific journal Nature Geoscience they suggest that weathering processes on the Antarctic continent may have been instrumental in lowering the carbon dioxide concentrations in the atmosphere, causing the observed climate cooling and subsequent ice growth.
When rocks are subjected to weathering, they can change the chemistry of the ocean, and the remnants sooner or later end up at the bottom of the ocean. Scientists can “read” such events in Earth’s history from these sediments, deposited over millions of years. They use characteristics in the composition of the sediment by which they can reconstruct processes in the past. Dr. Basak and Dr. Martin have analysed lead (Pb) isotopes in sediment samples and used a new approach to study weathering of the continents in the past.
“This method allows us to differentiate between chemical weathering, meaning alteration by chemical processes, and physical weathering, for example breakdown by glaciers”, says Dr. Basak. They could find evidence of carbonate rock weathering on Antarctica during ice growth, which may have contributed to chemical changes in the ocean that led to enhanced carbonate deposition, which is referred to as an ocean de-acidification event in contrast to modern ocean acidification.
Chandranath Basak says: “It is not easy to reconstruct the processes associated with climate change that occurred millions of years ago during the Eocene-Oligocene transition. Yet with our work we believe we could improve our understanding of this transitional period.”
University of Florida, Department of Geological Sciences, Gainsville, USAOriginal Publication:
Dr. Manfred Schloesser | Max-Planck-Institut
Volcanoes and glaciers combine as powerful methane producers
20.11.2018 | Lancaster University
Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen
Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.
Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...
Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.
Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...
Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.
Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...
Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.
In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...
On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.
19.11.2018 | Event News
09.11.2018 | Event News
06.11.2018 | Event News
20.11.2018 | Life Sciences
20.11.2018 | Life Sciences
20.11.2018 | Physics and Astronomy