This is a time of continents colliding, North America and Greenland hitting Europe, smashing together and making mountains. The planet’s land mass is mostly dusty and barren. Rivers were more like great expanses of water sliding into the ocean.
“You’d hardly know the place,” says Martin Gibling, professor with Dalhousie’s Department of Earth Sciences. “There was bare rock and sand, with crusts of bacteria and algae over the rock surfaces. And ancient rivers were very different, like big sheets of water carrying sand and gravel. They weren’t like channels whatsoever.”
Dr. Gibling and postdoctoral researcher Neil S. Davies wanted to find out more about those big rivers. What happened during the evolution of the Earth to throw them for a loop?
“If you think of a river, it’s wavy, it’s meandering,” explains Dr. Gibling. “A river has curves, eroding into its bank on one side, and depositing sediments on the other.”
For the answers to one of the most significant environmental changes in the Earth’s history, they turned to the fossil record using a literature compilation and fieldwork. Their research took them to 35 sites around the globe, including Port-au-port, Newfoundland, the Gaspé Peninsula of Quebec, the Channel Islands off the coast of France and Death Valley in California.
The difference, they discovered, was the earliest plants, stretching their roots down and stabilizing river banks. Instead of wide and sheet-like, rivers evolved to become more confined and narrower. Their research, highlighting the co-evolution of land plants and river landscapes, has just been published in the journals Geology and Earth-Science Reviews.
“Once the plants started to get a toehold, they sent spores into more inland areas,” says Dr. Davies, who hails from Birmingham, England. “The entire process took about 50 million years, with vegetation spreading until it dominated every landscape except total desert. The Earth could never be the same again.”
SEE: “Cambrian to Devonian evolution of alluvial systems: The sedimentological impact of the earliest land plants” in Earth-Science Reviews, February 2010
“Paleozoic vegetation and the Siluro-Devonian rise of fluvial lateral accretion sets” in Geology, January 2010
Charles Crosby | Newswise Science News
NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center
Steep rise of the Bernese Alps
24.03.2017 | Universität Bern
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy