Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Observations on Shape of Ocean Mountain Ranges Turn an Old Idea Upside Down

23.06.2004


Figure 1. Perspective view from the south of the mid-ocean ridge off the coast of Central America (far distance) showing how the morphology of this spreading ridge changes across transform faults and smaller ridge offsets. Note how the more westerly segments (offset in the direction of ridge migration) are shallower and broader than their neighbors. Image credit: Bill Haxby


Figure 2. Close-up perspective view from figure above showing how the shape and height of the ridge axis changes across a major transform fault. Image credit: Bill Haxby


New findings suggest that surface geometry determines volcanic activity

What causes the peaks and valleys of the world’s great mountains? For continental ranges like the Appalachians or the Northwest’s Cascades, the geological picture is clearer. Continents crash or volcanoes erupt, then glaciers erode away. Yet scientists are still puzzling out what makes the highs high and the lows low for the planet’s largest mountain chain, the 55,000-mile-long Mid-Ocean Ridge.

This week in the journal Nature, scientists at Columbia University’s Lamont Doherty Earth Observatory describe new findings that challenge current thinking about how the silhouette of the mile’s high deepwater ridge is formed.



The long string of mountains that zig-zags across the ocean floor define the boundaries of the crustal plates that make up the Earth’s surface. At the center of the Mid-Ocean Ridge is a continuous fissure in which hot magma bubbles up from below and cools to become new crust material added to the plates on either side. For decades, the most popular explanation for the ridge’s distinct undulating topography has been that magma flows upward from the mantle interior in directed streams of differing sizes. Larger magma flows lead to higher, broader peaks, while a magma trickle or drought is reflected in lower, more narrow valleys.

But after analyzing thousands of miles of the Mid-Ocean Ridge, Lamont marine geologist Suzanne Carbotte and co-authors Christopher Small and Katie Donnelly disagree. They discovered that the height and width of underwater mountains are highly correlated to the direction that the ridge and connecting plates move across the surface of the planet.

“Our observations indicate that these variations in ridge height reflect a top down rather than a bottom up process,” said Carbotte. “The motion of the plates seems to be the important factor, not the mantle.”

The twelve crustal plates that make up the surface of the Earth are constantly jostling each other as some grow in size and others shrink. In response, the Mid-Ocean Ridge migrates very slowly, moving at a rate of about an inch a decade in relation to fixed hot areas of the mantle below. Each underwater range in the mountain chain can be offset from the next by up to hundreds of miles, connected by a long perpendicular fault line. This geometry creates distinct ridge segments jutting back and forth.

Their results have implications for geologists concerned with crust and mantle structure, as well as for biologists interested in life around hydrothermal vents. Previously, many scientists believed that the structure of the upper mantle must be both physically and chemically diverse in order to explain the peaks and valleys along the Mid-Ocean Ridge. This implied that ridge segment would spend time above both high and low magma streams as it travels over the mantle.

“Our findings suggest that the upper mantle could be quite uniform and still produce a varied topography due solely to plate migration,” said Carbotte. “This has all sorts of implications. For example, if certain ridge segments are just more volcanically active than others due simply to their geometry, those locations may host hydrothermal communities over very long periods of time.”

This study was funded by The National Science Foundation.

The Lamont-Doherty Earth Observatory, a member of The Earth Institute at Columbia University, is 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 provide the basic knowledge of Earth systems needed to inform the future health and habitability of our planet. For more information, visit www.ldeo.columbia.edu.

The Earth Institute at Columbia University is among the world’s leading academic centers for the integrated study of Earth, its environment, and society. The Earth Institute builds upon excellence in the core disciplines—earth sciences, biological sciences, engineering sciences, social sciences and health sciences—and stresses cross-disciplinary approaches to complex problems. Through its research training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world’s poor.

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

Researchers devise microreactor to study formation of methane hydrate

23.08.2017 | Materials Sciences

ShAPEing the future of magnesium car parts

23.08.2017 | Automotive Engineering

New insights into the world of trypanosomes

23.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>