Mars rover sits on ancient beach

Dohm et.al. have proposed an ancient water filled basin in Arabia.
This is supported by the high hydrogen readings from GRS and by
geomorphology:

Did an impact basin make a water "reservoir" on Mars?
More evidence surfaces that the Red Planet has long been rich in
water.
by Robert Burnham
http://www.astronomy.com/Content/Dyn...1/685ysvia.asp

ANCIENT GIANT BASIN/AQUIFER SYSTEM IN THE ARABIA REGION, MARS: James
M. Dohm1, Nadine Barlow2, Jean-Pierre Williams3, Victor R. Baker1,4,
Robert C. Anderson5, William V. Boynton4; Alberto G. Fairén6, Trent M.
Hare7, 1Department of Hydrology and Water Resources, University of
Arizona, Tucson, AZ, 85721 ); 2Dept. Physics and
Astronomy, Northern Arizona University, Flagstaff, AZ, 86001; 3Dept.
of Earth and Space Sciences, Univ. of California, CA 90095, 4Lunar and
Planetary Laboratory, University of Arizona, Tucson, AZ; 5Jet
Propulsion Laboratory, Pasadena, CA; 6Centro de Biología Molecular,
Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain;
7U.S. Geological Survey, Flagstaff, AZ, 86001.
Lunar and Planetary Science XXXV (2004) 1209.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1209.pdf

They also suggest there may be a water aquifer there that may yet
persist that can be detected by ground-penetrating radar as on Mars
Express.


cf.
exoscientist
03/29/03 12:04 PM
"Mars Water, Odd Surface Features Tied to Life."
http://uplink.space.com/showthreaded...&Number=463425



Bob Clark


Garrison Hilliard wrote in message ...
Mars rover sits on ancient beach

The US space agency has announced that its robotic Mars rover Opportunity is
parked on what was once the shore of a salty Martian sea.
There is multiple evidence that the surface of Mars was awash with liquid water
at some time in its past.

But the latest findings from Nasa's robot explorers on the Red Planet are
fleshing out a picture of what Mars must have been like when it was wet.

Opportunity has been studying the rocks in a small crater since January.

Nasa scientists announced earlier this month that Opportunity's landing site at
Meridiani Planum was once "drenched" in water.

Wet environment
Tuesday's announcement is significant because it lends greater weight to the
hypothesis that Mars could have been a habitat for microbial life in the past.

But scientists agreed that only future sample return missions would be able to
resolve the question of whether life was once present on the planet.

The evidence comes from analysis of 30cm of a rocky outcrop in Eagle Crater,
Opportunity's landing site. Rocks in this outcrop are finely layered, one of the
key characteristics of sedimentary rocks.

"We're obviously dealing with a transiently wet, transiently dry environment,"
said mission scientist John Grotzinger.

"These findings prove that the spirit of exploration and discovery is alive and
well," said Nasa administrator Sean O'Keefe.

Prof Steve Squyres, principal scientific investigator for the rovers added that
evidence showing bromide salts in the rock pointed to evaporation.

This suggested a past environment where water came and went, which could have
been some kind of shore, he said.

However, it is not known for how long the region at Meridiani Planum was a wet
environment.

Water flow

"These types of rocks formed by water coming and going away again may be found
at other places on Mars," Prof Squyres told a news conference in Washington, US.

"If we find those places, we'll be able to find out how prevalent (water) had
been."

Layered rocks can be formed by volcanic activity. But Nasa scientists said the
presence of cross-bedding in the Martian outcrop, inclined discontinuities
between different layers of the rock, confirms that the Martian rocks are
sedimentary.

Sedimentary rocks can be formed through the action of wind. But scientists told
journalists that the form of the cross-bedding matched best with sediments laid
down in water.

The researchers said the water could have been flowing at a speed of 10 to 50cm
per second.

Scientists have found very high concentrations of sulphur salts in the outcrop.
On Earth, rocks with as much salt as these Mars rocks have either formed in
water or, after formation, have been highly altered by long exposure to water.

But scientists do not know how long the water was present at Meridiani Planum.
Neither do they know how deep the bodies of water were.


Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/h...re/3560867.stm

Published: 2004/03/23 19:20:40 GMT

© BBC MMIV

(Robert Clark) wrote in message om...
Dohm et.al. have proposed an ancient water filled basin in Arabia.
This is supported by the high hydrogen readings from GRS and by
geomorphology:

Did an impact basin make a water "reservoir" on Mars?
More evidence surfaces that the Red Planet has long been rich in
water.
by Robert Burnham
http://www.astronomy.com/Content/Dyn...1/685ysvia.asp

ANCIENT GIANT BASIN/AQUIFER SYSTEM IN THE ARABIA REGION, MARS: James
M. Dohm1, Nadine Barlow2, Jean-Pierre Williams3, Victor R. Baker1,4,
Robert C. Anderson5, William V. Boynton4; Alberto G. Fairén6, Trent M.
Hare7, 1Department of Hydrology and Water Resources, University of
Arizona, Tucson, AZ, 85721 ); 2Dept. Physics and
Astronomy, Northern Arizona University, Flagstaff, AZ, 86001; 3Dept.
of Earth and Space Sciences, Univ. of California, CA 90095, 4Lunar and
Planetary Laboratory, University of Arizona, Tucson, AZ; 5Jet
Propulsion Laboratory, Pasadena, CA; 6Centro de Biología Molecular,
Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain;
7U.S. Geological Survey, Flagstaff, AZ, 86001.
Lunar and Planetary Science XXXV (2004) 1209.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1209.pdf

They also suggest there may be a water aquifer there that may yet
persist that can be detected by ground-penetrating radar as on Mars
Express.

Big deal... You don't need to radiate Mars to know that...

I suggested that a few years ago, studying the beddings inside larger
craters and the several dark streaks coming from sedimentation
layerings. I can even say one thing. There is not an water aquifer but
remains of water aquifers. Most of them are going terminal.

How can one detect this. Just pick up Arabia's pics, follow a place
with those "wet" dark streaks and try to find zones of clear layering
and with a few good streaks. Better if they are located not on one
side of a hill but a little spread around. For example on a crater
with a good rim and with hills around. If you do so then you get many
intersting things. A few places still soak with water at certain
layers. However the water-rich layerings are usually getting quite
eroded, may due to internal movement of water. Sometimes, there are
signs of subsidiation. So, a few millions of years more and water is
mostly gone. Some may migrate over lower zones but it will be very
residual I think...

Then the partisans of Dead-Dried Mars will claim victory....

Janssen Crater is one of the places that is still highly rich in
water.


cf.
exoscientist
03/29/03 12:04 PM
"Mars Water, Odd Surface Features Tied to Life."
http://uplink.space.com/showthreaded...&Number=463425



Bob Clark


Garrison Hilliard wrote in message ...