Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wax works: Wax proves a perfect model of the Earth’s crust

02.02.2005


Physicists in the US have proven that wax is a perfect model of the ocean floors. Using a tub of wax, geophysicists at Cornell and Columbia have produced a predictive model of tectonic microplates – one of the most important and poorly understood features of plate tectonics – for the first time. This research is reported today in the New Journal of Physics (www.njp.org) published jointly by the Institute of Physics and the German Physical Society (Deutsche Physikalische Gesellschaft).



This breakthrough gives scientists a clearer understanding of the mechanisms of plate tectonics: how the landmasses of the Earth shift and change over time, how earthquakes are generated, volcanoes erupt, and precious metals are concentrated in rich seams. Tectonic microplates could also help identify whether this process, which many scientists argue was a key factor in triggering the evolution of life on Earth, occurs on other bodies in the Solar System.

Richard Katz, now at Columbia University, and Eberhard Bodenschatz from Cornell University where the research was carried out, have produced the first mathematical model which successfully describes how ’tectonic microplates’ – dynamic whirlpools of ocean floor found at mid-ocean ridges - evolve and move over time. Writing in the New Journal of Physics, they announce their model which successfully predicts microplate behaviour as observed in a scale model of the ocean floor: a tank of wax heated from below. Scientists have been using wax to simulate the ocean floor since the 1970s. This research links these ingenious wax models with genuine patterns in the Earth’s crust for the first time.


Like ball-bearings trapped between two sheets of metal, tectonic microplates are rotating blocks of crust which are born where sections of mid-ocean ridge begin to overlap, then grow larger as they age, and gradually move away from the spreading ridge along with new ocean floor. They can reach sizes of up to 400km across, and rotate about 15 degrees every million years (fast by geological standards). Only 12 are known to exist, and they are one of the least well-understood features of plate tectonics.

The experiment began in 1998, deep in the basements of Cornell’s physics department. A large tank filled with wax had been set up by Professor Eberhard Bodenschatz to mimic spreading ridges on the ocean floor. The wax is heated from beneath, but cooled from above by air-conditioning units so that the surface becomes a rigid crust while the centre and base remain molten. A pair of long straight paddles move slowly away from the centre pulling the crust apart and causing new molten material to rise up and solidify at the surface, just like the creation of new ocean floor at mid-ocean ridges on the Earth.

Bodenschatz and his team of research students immediately began to notice features in the wax similar to a variety of geological features seen on Earth. They saw structures growing in the wax which were very similar to transform faults, like the San Andreas fault, rift valleys, and also the zig-zag rifts found on the surface of lava lakes in volcanic craters. They also found that when the paddles pull the surface apart at a certain rate, a rare spiral feature of mid-ocean ridges called microplates form and evolve, mimicking structures known to exist in the East-Pacific Rise such as the Easter microplate just off Easter Island in the Pacific.

Richard Katz from Columbia University said: "When I joined the research team at Cornell I became fascinated by the microplates which they could create in the wax and thought that we could use the model to begin to understand how real microplates on the earth come about and to accurately describe how they behave mathematically so we can predict their movement".

They made detailed observations of the formation of microplates using a video camera mounted above the tank, looking directly down onto the surface where they were forming. Lamps were mounted in the molten wax and directed upwards so that the pictures the camera took showed the thickness of the crust because of the difference in contrast.

Using these observations, Katz and his supervisor Eberhard Bodenschatz set out to write a mathematical expression based on existing assumptions about microplate behaviour. They found that their model predicts microplate evolution perfectly, and so can now predict how they’ll behave.

Katz said: "Microplates have a distinctive pattern on the sea-floor and in the wax tank. We can now use this model to predict how they’ll evolve over time, how plates near them will move and shift as they grow older and how microplates will affect the surrounding crust and the mid-ocean ridges which give birth to them. It should also help us identify very young microplates in the crust or very ancient ones. It might even help us identify plate tectonics on other bodies in the Solar System."

In their paper, Katz and Bodenschatz give an insight into why microplates form in the first place. It turns out that it might be because the crust around them is a strange chimera: neither transform fault nor spreading ridge but an unstable form in between. When the crust moves to become more stable, areas of crust overlap and might give birth to rotating microplates because of the forces opposing each other.

David Reid | EurekAlert!
Further information:
http://www.iop.org

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 >>>