Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Findings by Scripps Scientists Cast New Light on Undersea Volcanoes

11.02.2005


Study in Science may help change the broad understanding of how they are formed


Hawaii-Emperor chain, the conventional theory holds.


A map of Beru Atoll, part of the Gilbert Ridge seamount chain in the Pacific Ocean



Researchers at Scripps Institution of Oceanography at the University of California, San Diego, have produced new findings that may help alter commonly held beliefs about how chains of undersea mountains formed by volcanoes, or "seamounts," are created. Such mountains can rise thousands of feet off the ocean floor in chains that span thousands of miles across the ocean.

Since the mid-20th century, the belief that the earth’s surface is covered by large, shifting plates--a concept known as plate tectonics--has shaped conventional thinking on how seamount chains develop. Textbooks have taught students that seamount patterns are shaped by changes in the direction and motion of the plates. As a plate moves, stationary "hot spots" below the plate produce magma that forms a series of volcanoes in the direction of the plate motion.


Now, Anthony Koppers and Hubert Staudigel of Scripps have published a study that counters the idea that hot spots exist in fixed positions. The paper in the Feb. 11 issue of Science shows that hot spot chains can change direction as a result of processes unrelated to plate motion. The new research adds further to current scientific debates on hot spots and provides information for a better understanding of the dynamics of the earth’s interior.

To investigate this phenomenon, Staudigel led a research cruise in 1999 aboard the Scripps research vessel Melville to the Pacific Ocean’s Gilbert Ridge and Tokelau Seamounts near the international date line, a few hundred miles north of American Samoa and just south of the Marshall Islands.

Gilbert and Tokelau are the only seamount trails in the Pacific that bend in sharp, 60-degree angles--comparable in appearance to hockey sticks--similar to the bending pattern of the Hawaii-Emperor seamount chain (which includes the Hawaiian Islands).

Assuming that these three chains were created by fixed hot spots, the bends in the Gilbert Ridge and Tokelau Seamounts should have been created at roughly the same time period as the bend in the Hawaii-Emperor chain, the conventional theory holds.

Koppers, Staudigel and a team of student researchers aboard Melville spent six weeks exploring the ocean floor at Gilbert and Tokelau. They used deep-sea dredges to collect volcanic rock samples from the area.

For the next several years, Koppers used laboratory instruments to analyze the composition of the rock samples and calculate their ages. "It was quite a surprise that we found the Gilbert and Tokelau seamount bends to have completely different ages than we expected," said Koppers, a researcher at the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps. "We certainly didn’t expect that they were 10 and 20 million years older than previously thought."

Instead of forming 47 million years ago, as did the Hawaiian-Emperor bend, the Gilbert chain was found to be 67 million years old and the Tokelau 57 million years old. "I think this really hammers it in that the origin of the alignment of these seamount chains may be much more complicated than we previously believed, or the alignment may not have anything to do with plate motion changes," said Staudigel.

Although they do not have positive proof as yet, Koppers and Staudigel speculate that local stretching of the plate may allow magma to rise to the surface or that hot spots themselves might move. Together with plate motion, these alternate processes may be responsible for the resulting pattern of seamounts.

Koppers and Staudigel will go to sea again next year to seek additional clues to the hot spot and seamount mysteries. "Seamount trails are thousands of kilometers long and even if we are out collecting for several weeks, we still only cover a limited area," said Koppers. "One of the things holding us back in developing a new theory is that the oceans are humongous and our database is currently very small we are trying to understand a very big concept."

The study was funded by the National Science Foundation.

Scripps Institution of Oceanography, at the University of California, San Diego, is one of the oldest, largest, and most important centers for global science research and graduate training in the world. The National Research Council has ranked Scripps first in faculty quality among oceanography programs nationwide. The scientific scope of the institution has grown since its founding in 1903 to include biological, physical, chemical, geological, geophysical, and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,300, and annual expenditures of approximately $140 million from federal, state, and private sources. Scripps operates one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration.

Mario Aguilera | EurekAlert!
Further information:
http://www.ucsd.edu

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>