Featured Research

from universities, journals, and other organizations

Researchers Pinpoint Event That Led To Mars' Heyday

Date:
March 16, 2001
Source:
Washington University In St. Louis
Summary:
Planetary scientists at Washington University in St. Louis and various collaborators have concluded that the Tharsis rise in Mars' Western Hemisphere is key to many of the Red Planet's mysteries, including its large-scale shape and gravity field, and its early climate and water distribution.

Planetary scientists at Washington University in St. Louis and various collaborators have concluded that the Tharsis rise in Mars' Western Hemisphere is key to many of the Red Planet's mysteries, including its large-scale shape and gravity field, and its early climate and water distribution. Roger J. Phillips, Ph.D., Professor of Earth and Planetary Sciences, and Director of the McDonnell Center for the Space Sciences, and his colleagues suggest that an enormous load of volcanic material emplaced at the Tharsis rise caused global changes to the planet's outer strong layer, or lithosphere, creating many key features in the landscape. Two major ones, the Tharsis trough, surrounding Tharsis, and the Arabia bulge, on the planet's opposite side, are the result of this deformation. These features, in turn, are essential in the development of the Martian valley networks, the most common type of drainage system on Mars. Additionally, water and carbon dioxide released by Tharsis volcanism may have created an atmospheric greenhouse sufficient to warm the surface to above freezing, thus enabling running water to form the valleys.

The research was published as part of the March 16, 2001 issue of Science magazine.

The Tharsis rise dominates the western hemisphere of Mars. It is a broad, elevated region rising up to 10 kilometers above its surroundings and encompassing over 30 million square kilometers. The rise is the site of large-scale volcanism and extensive fracturing of the crust. Phillips and colleagues analyzed gravity and topography fields obtained from the Mars Global Surveyor spacecraft and compared them to a model of how these fields would behave when the heavy Tharsis volcanic load is dumped onto the spherical lithospheric shell.

"Imagine that Mars is a beach ball and that the Tharsis load is your fist," Phillips said. "As your fist pushes into the beach ball, there is a bulge created on the opposite side of the ball, and a depression or trough surrounds your fist. It is that simple."

The model correctly predicts many of Mars' broad-scale gravity and topography features. The researchers believe that these features were in place at the end of Mars' oldest time period, the Noachian epoch. This period extends back to near the planet's origin, estimated at about 4.6 billion years ago, and it ended between 3.8 and 3.5 billion years ago.

According to Phillips, the Tharsis magmas could have produced enough carbon dioxide and water to induce a climate that was sufficiently warm for liquid water to be stable on the planet's surface. "The total release of gases from Tharsis magmas could produce the integrated equivalent of a 1.5-bar carbon dioxide atmosphere and a global layer of water that is 120- meters thick," Phillips reported. "Much of the water would have been lost to space, but even so, these quantities of volatiles are sufficient to warm the atmosphere to the point at which the surface temperature is above freezing. The accumulation of atmospheric carbon dioxide from Tharsis may have made the latter part of the Noachian the most favorable time for this condition."

The researchers said that the development of the Tharsis trough and Arabia bulge was a major influence on the location and orientation of Martian valley networks and outflow channels. They pointed out that nearly all of the large Martian outflow channels originate in or flow into the Tharsis trough. The model tested the role of Tharsis loading in valley network orientations and the researchers concluded that many of these systems, similar to Earth's river systems, had to have formed after a "significant fraction" of the Tharsis load was in place. This is because the valleys follow the downhill direction of the topography induced by the deformation of Mars in response to the Tharsis load. As these valleys were formed near the end of the construction of Tharsis, in the latter part of the Noachian epoch, they may reflect the clement conditions induced by large amounts of atmospheric carbon dioxide that accumulated from the volcanism that developed Tharsis.

At the very end of the Noachian epoch, volcanism declined and carbon dioxide and water were removed from the atmosphere by a combination of factors, including stripping by the solar wind and thermal escape, among others. The removal of carbon dioxide and water would have driven surface temperatures below freezing, and Phillips estimates that this could have occurred in less than a few hundred million years. The preceding few hundred millions years, in the latter part of the Noachian, could well be considered Mars' "brief, shining moment."

"It is possible that during the Noachian Epoch, the structural and volcanic events associated with Tharsis evolution were the sine qua non that linked fluvial, geodynamical and climate activity on Mars, " Phillips concluded.


Story Source:

The above story is based on materials provided by Washington University In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University In St. Louis. "Researchers Pinpoint Event That Led To Mars' Heyday." ScienceDaily. ScienceDaily, 16 March 2001. <www.sciencedaily.com/releases/2001/03/010316073120.htm>.
Washington University In St. Louis. (2001, March 16). Researchers Pinpoint Event That Led To Mars' Heyday. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2001/03/010316073120.htm
Washington University In St. Louis. "Researchers Pinpoint Event That Led To Mars' Heyday." ScienceDaily. www.sciencedaily.com/releases/2001/03/010316073120.htm (accessed October 22, 2014).

Share This



More Space & Time News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com
Latin America Launches Communications Satellite

Latin America Launches Communications Satellite

AFP (Oct. 17, 2014) Argentina launches a home-built satellite, a first for Latin America. It will ride a French-made Ariane 5 rocket into orbit, and will provide cell phone, digital TV, Internet and data services to the lower half of South America. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
This Week @ NASA, October 17, 2014

This Week @ NASA, October 17, 2014

NASA (Oct. 17, 2014) Power spacewalk, MAVEN’s “First Light”, Hubble finds extremely distant galaxy and more... Video provided by NASA
Powered by NewsLook.com
Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Newsy (Oct. 17, 2014) The smallest of Saturn's main moons, Mimas, wobbles as it orbits. Research reveals it might be due to a global ocean underneath its icy surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins