[meteorite-list] Emerging Underground Aquifers Formed Martian Lakes, Seas

[Ron Baalke]

NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE

SENT: 
Oct. 18, 2010

FROM: 
Alan Fischer
Public Information Office
Planetary Science Institute
520-622-6300
520-885-5648
fischer at psi.edu


Emerging Underground Aquifers Formed Martian Lakes, Seas


Researchers at the Planetary Science Institute have found a 
new explanation for how seas and lakes may have once developed 
on Mars. 

J. Alexis Palmero Rodriguez, research scientist at PSI, has 
been studying the Martian northern lowlands region, which 
contains extensive sedimentary deposits that resemble the 
abyssal plains of Earth's ocean floors. It is also like the 
floors of other basins on Mars where oceans are thought to have 
developed.
 
The origin of these deposits and the formation of Martian lakes 
and seas are controversial. One theory is that there was a 
sudden release of large volumes of water and sediment from 
zones of apparent crustal collapse known as "chaotic terrains." 
However, these zones of collapse are on the whole rare on Mars, 
while the plains deposits are widespread and common within 
large basin settings, Rodriguez said. 

Citing evidence found in the planet's northern plains south of 
Gemini Scopuli in Planum Boreum, Rodriguez proposes in an 
article published in Icarus that groundwater emerged through 
extensive and widespread fractures forming the floors of 
ancient continental-scale basins on Mars. This led to the 
formation of river systems, large-scale regional erosion, 
sedimentary deposition and water ponding.
 
This model does not require sudden massive groundwater 
discharges, he said. Instead, it advocates for groundwater 
discharges being widespread, long-lived and common in the 
northern plains of Mars.
 
"With the loss over time of water from the subsurface aquifer, 
areas of the northern plains ultimately collapsed, creating 
the rough hilly surfaces we see today. Some plateaus may have 
avoided this fate and preserved sedimentary plains containing 
an immense record of hydrologic activity," he said. "The 
geologic record in the collapsed hilly regions would have been 
jumbled and largely lost.

"This model implies that groundwater discharges within basin 
settings on Mars may have been frequent and led to formation of 
mud pools, lakes and oceans. In addition, our model indicates 
this could have happened at any point in the planet's history," 
he said. "There could have been many oceans on Mars over time."

If life existed in Martian underground systems, life forms could 
have been brought up to the surface via the discharges of these 
deep-seated fluids. Organisms and their fossils may therefore 
be preserved within some of these sedimentary strata, Rodriguez 
said.


CONTACT:
J. Alexis Palmero Rodriguez
Research Scientist 
Planetary Science Institute                
520-622-6300 
alexis at psi.edu
 
 
PSI INFORMATION:
Mark V. Sykes
Director
520-622-6300
sykes at psi.edu

PSI HOMEPAGE:
http://www.psi.edu

PSI PRESS RELEASES:
http://www.psi.edu/press/