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
Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute
Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Materials Sciences
08.12.2016 | Materials Sciences
08.12.2016 | Physics and Astronomy