Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017

Just as rivers move sediment across the land, turbidity currents are the dominant process carrying sediments and organic carbon from coastal areas into the deep sea. Turbidity currents can also destroy underwater cables, pipelines, and other human structures. Unlike rivers, however, turbidity currents are extremely difficult to study and measure.

At the Fall 2017 meeting of the American Geophysical Union, scientists from around the world will present 19 talks and posters about the Coordinated Canyon Experiment--the most extensive, long-term effort to monitor turbidity currents ever attempted. The results of this two-year project challenge existing paradigms about what causes turbidity currents, what they look like, and how they work.


This illustration shows some of the 16 sediment-flow events documented during the Coordinated Canyon Experiment. The arrows indicate minimum estimates of how far each event traveled down the floor of Monterey Canyon.

Credit: Image © 2017 MBARI

Usage Restrictions: May only be used in conjunction with an article about this research

The Coordinated Canyon Experiment (CCE) was conducted in Monterey Canyon, off the coast of Central California, over an 18-month period between October 2015 and April 2017. During this time, scientists observed and measured at least 16 turbidity currents using dozens of instruments at seven different locations in the canyon. These instruments allowed researchers to track sediment flows over a 50-kilometer stretch of canyon, from depths of about 250 to 1,850 meters.

Using a variety of new instruments and technologies, researchers collected data not just on the movement of water and sediment, but also on the evolution and shape of the seafloor. Physical processes within the flows were monitored at spatial scales ranging from centimeters to kilometers, and over time scales from seconds to months. The resulting data yielded a new and unexpectedly complicated view of a globally important phenomenon that has been studied and modeled for nearly 100 years.

During the experiment, an international team of researchers from the Monterey Bay Aquarium Research Institute, the U.S. Geological Survey, the University of Hull, the University of Southampton, the University of Durham, and the Ocean University of China combined their expertise and equipment. This allowed the team to monitor each turbidity current in unprecedented detail.

The experiment showed that sediment-transport events in Monterey Canyon are more common and much more complex than previously recognized. Rather than simply being flows of sediment-laden water, some turbidity currents also involved large-scale movements of the entire seafloor. Furthermore, many turbidity currents changed character as they moved down-canyon, suggesting that no single flow model can explain all the processes involved.

The researchers were particularly surprised to find that the timing of the 16 monitored turbidity currents did not coincide with commonly-proposed triggers, such as earthquakes or floods, and only a few coincided with extreme surf events. One possible explanation is that sediments build up gradually within and around the edges of Monterey Canyon until they reach some certain threshold, after which turbidity currents can be triggered by relatively small canyon-wall failures.

Of particular interest to geologists searching for oil and gas deposits, the quantitative sediment measurements and detailed seafloor and sub-bottom surveys used in this experiment gave geologists their first opportunity ever to correlate turbidity currents of known magnitude, extent, and duration with large- and small-scale sedimentary structures observed firsthand on the seafloor. After millions of years, these same sedimentary structures sometimes form conduits or traps for oil and gas in sedimentary rocks.

The Coordinated Canyon Experiment yielded many other firsts in the field of marine geology:

  • The highest velocity turbidity-current flow ever measured instrumentally (8.1 meters/second).
  • The first quantitative evidence that during some sediment events, movements in the seafloor propagated down canyon faster than measured currents.
  • The first measurements of changes in the internal velocity structure within a turbidity current as it progressed down canyon.
  • The first quantitative data showing that, in early stages of some events, entire sections of seafloor may move as a semi-fluidized mass--a process that has not been previously documented in the scientific literature.
  • The first data complete enough to allow marine geologists to correlate sediment-transport events of known extent, magnitude, and duration with specific marine sedimentary structures.

Kim Fulton-Bennett | EurekAlert!

More articles from Earth Sciences:

nachricht Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column
27.05.2020 | Leibniz-Institut für Ostseeforschung Warnemünde

nachricht An international team including scientists from MARUM discovered ongoing and future tropical diversity decline
26.05.2020 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New 5G switch provides 50 times more energy efficiency than currently exists

27.05.2020 | Information Technology

Return of the Blob: Surprise link found to edge turbulence in fusion plasma

27.05.2020 | Physics and Astronomy

Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column

27.05.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>