Scientific Frontline® On-Site Search Engine by Google Co-op

Current UTC Time
 
News Home, where you will find the "Current Top Stories"The Communication Center contains current news briefs from major Universities, NASA, ESA, and the top three Aviation Mfg.Science section contains all the latest knowledge in Medical Research, Archeology, Biology, and other General Science NewsCurrent Earth Science and Environmental discoveries.The E.A.R., Environmental Awareness Report. E.A.R. will keep you advised of Environmental Alerts, Government, University, and public projects. All the current space discoveries from Hubble, Spitzer, Chandra X-Ray, ESO, Gemini, Subaru, ESA, NASA, and many more. The latest in space theories from leading astronomers and scientist from around the world.The Space Weather Forecast Center by Scientific Frontline, Current up-to-date space weather, forecasts, alerts and warnings. Images from SOHO, GOES, and STEREO. Plus solar observations from Erika RixCurrent space missions newsThe Cassini Main Page. Containing all the latest news from the Cassini Spacecraft around Saturn. Leading into Cassini status reports, The Cassini Gallery of all the latest images from Cassini. Seeing Saturn and all her moons like never before.Daily Sky maps, Celestial Events Calendar.Observatories Gallery, Images from the Great Observatories on Earth and Above. The Stellar Nights  Gallery, An amateur astronomical collection from John Crilly, Richard Handy, Erika Rix, and Paul RixCloudy Nights Telescope Reviews / An Atronomical Community.The latest in Computer, Nanotechnology, and General Technological advancements.The latest in Aviation achievements in civil, military, and space aviationThe World News Report,  news from the Voxant Viral Syndication, known as the Newsroom. Contains the latest videos from major news sources.The news archive from Scientific Frontline's past articles. A world of knowledge at your fingertips.Abstracts, Journals, and Technical papers maintained by Scientific Frontline. The Gateway to all the galleries in the Scientific Frontline collectionThe Scientific Frontline Discussion Rooms. Open to the public.upcoming events, seminars, and lectures from major universities, government, and privately sponsored programsSite Related links from major universities, government and private research labs.Assorted Downloads related to space, science, aviation, including screensavers and ASTROMONY SOFTWARE, and other endorsed programs.Words from Heidi-Ann Kennedy, Director Scientific FrontlineThe foundation of an online publication by SFL ORG. News Network called Scientific FrontlineContact page to Scientific Frontline / SFL ORG. News NetworkDisclaimer / Legal Notice for use of the SFL ORG. News Network's publication Scientific Frontline
an online publication of the SFL ORG. Educational News Network

News Brief Categories
Announcements | Aviation | Achievements & Awards | Boeing | ESA | Lockheed Martin | Medical | NASA | Northrop Grumman | Science | Space | Technology |
Univ. Announcements | Univ. Achievements & Awards | Univ. Grants & Funding | Univ. Medical | Univ. Science | Univ. Space | Univ. Technology | Womens Health

Study Provides Possible Explanation for Migration of Volcanic Activity on Mars

Sunday, December 14, 2008

Picture a ball. It's an ordinary ball in every way except that it is roughly 4,300 miles in diameter and is moving through the cold of space some 35 million miles from Earth, and hurtling around the sun in just less than two Earth years. This is Mars.

After a first glance at the Martian surface, one may quickly notice two striking global-scale features. The first is the three-mile elevation difference between the northern lowlands and southern highlands, known as the Crustal Dichotomy, which got the name because the highlands and lowlands are underlain by thick and thin crust, respectively. The second feature is the vast area of high elevation with numerous volcanoes near the equator covering a quarter of the Martian surface, known as the Tharsis Rise.

For a moment consider the tectonic plates that make up the crust of the Earth, including the way they move around the planet, rising from below as molten rock and dipping back down under the surface to melt and complete the chain. Earth is the only planet known to scientists that has this mechanism for moving huge sections of the planet's surface great distances. This movement accounts for, among other things, the chain of land masses that form the Hawaiian Islands. As the Pacific Plate moves over a plume of molten rock, the islands formed, one after another.

This is not the case on Mars, which appears to have a single plate that encapsulates the entire planet like the shell of an egg. But Shijie Zhong, associate professor of physics at the University of Colorado at Boulder, thinks this shell-like plate might be moving, driven by a powerful, single plume of hot material affecting the area of the thickened crust of the Crustal Dichotomy. This would explain the migration of volcanic activity in the Tharsis Rise region of the formation of Tharsis, he said.

The possibility of a large-scale, horizontal motion of the outer shell of Mars or similar terrestrial planets and moons has not been previously demonstrated, Zhong said. Using three-dimensional numerical models to simulate the slow churning of Mars' interior in response to the cooling of the planet, Zhong shows in the Dec. 14 issue of Nature Geoscience that a single plume of hot material rising through the planet's interior led to the earliest volcanism in the highlands region of the Crustal Dichotomy, simultaneously triggering rotation of the outer shell. As the shell moved southward over the stationary plume -- like a sheet of cardboard over a candle -- it shifted the location of the volcanism and created the Tharsis Rise.

Zhong said a very specific set of circumstances had to fall into place to get rotation of the outer shell to occur. First, he said an area of thickened crust needed to form on the planet's surface. "It is almost universally accepted that the Crustal Dichotomy with the thickened crust in the highlands formed in the first few hundred million years of Mars' existence, and the Tharsis Rise was only formed a few hundred million years later," said Zhong.

Scientists know this because the Tharsis region is nearly devoid of impact sites, unlike the pockmarked surface of the Crustal Dichotomy. "You don't see so many craters," said Zhong. "It's been resurfaced."

Within this smooth environment, obvious features pop from the surface. Volcanoes, in a straight line, mark the Tharsis Rise. One, Olympus Mons -- a still active volcano -- reaches 15 miles into the Martian sky.

"All the faulting, tectonics and volcanics on Mars in the last 4 billion years happen here, in the Tharsis Rise region," said Zhong.

The second condition is the one-plume convection in the mantle. For the last 10 years, Zhong and his collaborators have studied physical mechanisms for one-plume convection to explain hemispherically asymmetric structures known to have existed for terrestrial planets, including the Crustal Dichotomy and Tharsis Rise on Mars, Supercontinents Pangea and Rodinia on Earth, and mare basalts on the Moon.

Zhong's theory is that a single plume of hot material is jetting from the core of Mars out toward the surface. Where it breaks through, on the Tharsis Rise, it causes volcanoes. But it is the affect that the rising, super-heated material has on the neighboring Crustal Dichotomy's thickened shell that makes the shell of Mars move relative to the underlying mantle and the plume.

"The mechanism I'm describing here is a path to unify the two major features of Mars: the Tharsis Rise and the Crustal Dichotomy," said Zhong.

Source: University of Colorado at Boulder

Permalink: http://www.sflorg.com/comm_center/unv_space/p793_32.html

Time Stamp: 12/14/2008 at 6:28:44 PM UTC

Scientific Frontline®
RSS Feeds

Scientific Frontline®
The Comm Center
The E.A.R.®
World News Report
Stellar Nights®
Cassini Gallery
Mars Gallery
Missions Gallery
Observatories Gallery
Observatories Gallery
Space Weather Alerts
Events
Directors Chair

Scientific Frontline®
Is supported in part by “readers like you”
Jupiter's rocky core bigger and icier, model predicts
Researchers Interpret Asymmetry in Early Universe

Post 793 University Space News 032 Use navigation to scroll this category



Scientific Frontline®, Stellar Nights®, E.A.R.®, and Environmental Awareness Report®”
Are Registered Trademarks of the
Online Publication of the SFL ORG. Educational News Network
Oklahoma City, Oklahoma USA
A Not-for-Profit Educational News Service
© 2005 - 2009 All Rights Reserved



AddThis Social Bookmark Button
Home | Comm. Center | Science | Earth Science | Space | Space Weather Center | Aviation | Technology | Galleries | About Us | Contact Us | Site Map | FAQ