Posted on 01/27/2004 10:39:22 AM PST by mjp
Nasa scientists have discovered what might be the most compelling evidence yet of rocks formed in water on Mars.
The Opportunity rover has sent back pictures of rock slabs that appear to contain thin layers, say researchers.
On Earth, this feature is suggestive of sedimentary rocks that are the product of material deposited by water or wind.
The layers are as thin as a centimetre in places which indicates they are unlikely to be old lava flows, but Nasa cautioned further analysis was needed.
Mission scientist Dr Andrew Knoll said that if the rocks were in fact sedimentary and not volcanic, they were probably formed by water and not by wind-borne sediments.
'Water-borne'
But the rover will need to drive up to the rocks to examine them closely with its science instruments to rule out a volcanic origin.
"It's going to be fascinating beyond words to get up close and personal with this thing," said payload lead scientist Steve Squyres.
When the rover gets close to the rocks it will be able to examine their microscopic structure.
Rock layers deposited by ash are usually laid down in parallel layers.
But if the rocks are sedimentary, there should be little imperfections and breaks between the layers. The rock particles should also be rounded.
Sedimentary rocks are often altered chemically by the water, but there are instances where this is not the case, scientists said.
The rover's alpha particle X-ray spectrometer should be able to examine the elemental chemistry of these rocks.
Dr Knoll suggested the rocks could be very old, possibly in the order of billions of years.
Power loss
Meanwhile, scientists said that Opportunity was losing some of its power.
Mission manager Jim Erickson said the likely cause was a thermostatically-controlled heater in the shoulder joint of the rover's arm, which is turning on automatically in response to drops in temperature.
"Normally, this is enabled by the ground and a thermostat on the side of the rover determines what the air temperature is, and if it is cold enough, it turns on the heater in this arm to keep it up to a temperature for operation," said Mr Erickson.
"Now, we don't normally always want it on because we aren't normally always operating the arm. Right now we're believing that it's going to be continuously on whenever it's cold enough."
LOL!!!!!!!!!!
Muleteam1
They're definitely sedentary rocks.
OK
Slate with fossils???
Agreed about this possibility. I was a geology major for a few years, and still sort of fancy myself as a casual authority on rocks. If a scene like this was in the Mojave desert I would expect to fine marine fossils in an outcrop like this. I would head straight over with my hammer and try to separate these slabs along their seems.
Imagine the hullabaloo if they send back a close-up later this month and there are little beasties fossilized in this rock!
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