Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Columbia University researchers find key to the formation of new seafloor spreading centers

29.11.2002


A new model of mid-ocean ridge propagation: Introducing the process zone



The site of extensive volcanic activity and sea-floor spreading, the Galapagos Rise in the eastern equatorial Pacific Ocean has yielded groundbreaking research results for the field of plate tectonics. Jacqueline Floyd and her colleagues, all of Columbia University’s Lamont-Doherty Earth Observatory, are introducing a new model for the process of mid-ocean ridge propagation (lengthening), which is responsible for seafloor spreading and the consequent formation of ocean basins. Their study is featured as this week’s cover story in the scientific journal Science.

Using recently recorded earthquake data that had not been available to previous models, the researchers show that mid-ocean ridge propagation is preceded by a complex breakdown process and earthquake activity that allows the ridge to lengthen stably in the brittle crust of the ocean’s lithosphere, independent of the enormous resisting forces proposed by previous models.


"Previous investigators idealized mid-ocean ridges as perfect cracks in the oceanic crust, but our results show that the seismicity and crustal structure around the ridge tip is more complex. This has critical implications for our ideas of how the crust rifts apart to form a new seafloor spreading center," said Floyd. "The hydroacoustic seismicity data were critical for making these observations since the magnitudes of the earthquakes in Hess Deep lie below the magnitude threshold of global teleseismic networks. The earthquake data show a concentration of earthquake activity at the tip of the Galapagos rise in Hess Deep that we almost immediately recognized as being similar to acoustic emission patterns observed at the tips of propagating cracks in the laboratory. The strikingly similar seismicity and faulting patterns allowed us to apply principles from fracture mechanics studies in the lab, at scales of centimeters or less, to the problem of mid-ocean ridge propagation in the oceanic crust, at the scales of 10s of kilometers and more."

By examining earthquake data and the topography of the Hess Deep rift, an enormous underwater canyon at the western tip of the Galapagos Rise, the researchers found that what makes an underwater ridge lengthen is more complex in comparison to previous theories. The researchers observe that small-magnitude earthquakes and micro cracking in a region called the process zone precede propagation, and are followed by nucleation of the rift axis and upwelling of magma, which leads to seafloor spreading.

Computer modeling of the stress field at the Hess Deep rift supports the authors’ interpretation of the seismicity data as resulting from rifting at the tip of a crack-like mid-ocean ridge in the oceanic plate.

Hess Deep was an excellent place to test prevailing models of ridge propagation because it is a relatively simple structure, its tectonic history is well understood, it has minimal sediment cover, and a long-term record of seismicity was available.

This new understanding of mid-ocean ridge propagation in Hess Deep can now be applied to more complex rift settings in both the oceans and the continents.


###
To receive an abstract of this paper, please contact Science magazine at 202-326-6440.

Jacqueline Floyd is a Faculty Fellow and Ph.D. Candidate with the Department of Earth and Environmental Sciences and the Lamont-Doherty Earth Observatory, one of the world’s leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists continue to provide the basic knowledge of Earth systems that must inform the future health and habitability of our planet. Her co-authors on the study are Maya Tolstoy, John Mutter, and Christopher Scholz, all of Columbia’s Lamont-Doherty Earth Observatory.

The Lamont-Doherty Earth Observatory is a research unit of the Earth Institute at Columbia University, the world’s pioneer academic center for mobilizing the sciences and public policy in pursuit of a sustainable future, especially for the world’s poor. Its director is international economist Jeffrey D. Sachs. More than 800 scientists with strength in Earth science, ecology, health, social science or engineering are working together to reduce poverty, hunger, disease and environmental degradation. The Institute brings their creative knowledge to bear through teaching, research and outreach in dozens of countries around the world. In all it does, the Earth Institute remains mindful of the staggering disparities between rich and poor nations and the tremendous impact that global-scale problems – from the AIDS pandemic to climate change to extreme poverty in much of the developing world – will have on all nations.

Mary Tobin | EurekAlert!
Further information:
http://www.earth.columbia.edu

More articles from Earth Sciences:

nachricht More than 100 years of flooding and erosion in 1 event
28.03.2017 | Geological Society of America

nachricht Satellites reveal bird habitat loss in California
28.03.2017 | Duke University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

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...

Im Focus: Tracing down linear ubiquitination

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...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>