Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research: Deep sea basalt may help reveal volcanoes’ impact on climate

04.10.2002


By examining volcanic rocks retrieved from deep in the ocean, scientists have found they can estimate the carbon dioxide stored beneath much of the earth’s surface – a development that could enhance understanding of how volcanoes affect climate. The research by University of Florida scientists and others will be reported this week in the journal Nature.



Scientists examined chunks of basalt, a type of volcanic rock formed when lava cools, from 12,000 feet below the Pacific along a massive geographical formation called the midocean ridge. The scientists discovered in these basalts traces of carbon dioxide and other compounds that originated deep within the Earth’s mantle, the source of most volcanic activity. Because compounds from this inaccessible region had never been found so well preserved, the rocks gave scientists a rare peek at what the mantle consists of – and what it might spew into the atmosphere through volcanoes.

"Most lava erupts at the surface and has lost its gases. From a geochemist’s point of view, you need to know what the composition of the mantle really is," said Mike Perfit, a UF geology professor and co-author of the Nature paper. "This kind of data might be useful in talking about the contribution of the mantle to the atmosphere and hydrosphere and how those concentrations might affect the climate."


Carbon dioxide is the leading "greenhouse gas" that traps heat and contributes to warming of the Earth. Scientists have long speculated volcanic eruptions can spew enough of this and other gases into the atmosphere to cause significant warming trends – changes so massive they may even spur mass extinctions. By giving scientists an idea of how much carbon dioxide lies under the Earth, the basalt may help answer this question, Perfit said.

When magma rises to the Earth’s surface and erupts as lava flows, Perfit said, it typically "de-gasses:" As the Earth’s pressure on the lava declines, the amount of volatile compounds that become gases at the surface rapidly decrease. It’s a bit like popping open a soft drink: The carbon dioxide bubbles off. As a result, carbon dioxide, water, sulfur dioxide, helium, chlorine and other "volatiles" are barely present in most basalt, making it difficult for geologists to figure out the amounts and proportions of these compounds in the mantle.

The deep ocean, however, is a unique environment. The water is so cold and the pressure so intense there it may keep the volatiles confined in the lava, known as magma when it first erupts and hardens. As a result, geologists have seen deep-sea geological formations such as so-called "pillow flows" as one of their best hopes for investigating the mantle question.

Perfit and colleague Dan Fornari, of the Woods Hole Oceanographic Institute, were among the scientists who dived in the manned deep-water submersible robot "Alvin" to probe a site a few hundred miles west of the Mexican coast. The area, known as the Siqueiros Transform fault, a deep part of the midocean ridge, was known to experience underwater eruptions, which is why the scientists chose it for their investigation. Perfit returned with a small load of golf ball- to basketball-sized pieces of basalt from the sea floor, where the water pressure was 350 times greater than at the surface.

This basalt not only had no bubbles, indicating that the volatile compounds remained in the lava, it also was very recently formed, making it an ideal study candidate. Scientists discovered that small crystals in the rock called olivines contained tiny bits of pure magma. Using newly developed technology that can analyze very small areas, researchers Alberto Saal and Eric Hauri, two of the other authors on the Nature paper from the Lamont-Doherty Earth Observatory of Columbia University, measured the volatiles in this magma.

Peter Michael, a professor of geosciences at The University of Tulsa familiar with the research, said other geologists have been able to measure some volatiles before, such as chlorine. But the Siqueiros Transform rocks provide a unique glimpse at carbon dioxide levels. This is important, because the midocean ridge is a mammoth, 40,000-mile long mountain where 85 percent of the world’s volcanic activity occurs. As a result, if the basalts Alvin returned to the surface are typical of other midocean ridge basalts, it could help determine the rate at which Earth’s below-ground carbon dioxide is supplied to the atmosphere through volcanoes, he said.

"What this work may allow us to do is actually compute the carbon dioxide not just for that magma, but for a lot of other midocean ridge basalt magmas," Michael said.

Writer: Aaron Hoover
ahoover@ufl.edu
Source: Mike Perfit
352-392-2128
perfit@geology.ufl.edu

Mike Perfit | EurekAlert!

More articles from Earth Sciences:

nachricht Climate satellite: Tracking methane with robust laser technology
22.06.2017 | Fraunhofer-Gesellschaft

nachricht How reliable are shells as climate archives?
21.06.2017 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>