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View Full Version : Lakebed on Mars Wasn't So Watery In the Past



Fraser
2005-Dec-23, 08:58 PM
SUMMARY: The Meridiani Planum region on Mars is currently the home of NASA's Opportunity Rover. But scientists believe that the entire region was covered with water millions of years ago, and could have been home to life. A new study is proposing that the area might have been much less wet than previously believed. A key element discovered by Opportunity could have been created by sulphur-bearing volcanic steam, and not water sediment layered down.

View full article (http://www.universetoday.com/am/publish/boulder_mars_less_watery.html)
What do you think about this story? post your comments below.

Greg
2005-Dec-24, 06:19 PM
I have had my reservations all along about large long standing bodies of water on Mars. It was as if all of the previous research and the direction it was headed was thrown out once the rovers started repoting back their data. It just doesn't make intuitive sense that a small, cold planet like Mars could hold onto bodies of water on its surface for so long. I have suspected all along that volcanic activity or large impacts could generate the conditions necessary for the complex chemistry we see the results of now. By the looks of this study it would be the former process that was responsible.

JESMKS
2005-Dec-24, 06:28 PM
I think the picture is misleading. It shows lava boulders who's origin are not related to the existance of water. Maybe this is a picture taken by Spirit and not Opportunity.
Jack

01101001
2005-Dec-24, 06:49 PM
I think the picture is misleading. It shows lava boulders who's origin are not related to the existance of water. Maybe this is a picture taken by Spirit and not Opportunity.
Jack
It's a Viking Lander 2 image. Notice the foot pad in the right foreground and the two marks of the trenching tool, center. The cylindrical shroud for the collector head lies on the surface right center.

NASA Viking Lander 2 image (http://pds.jpl.nasa.gov/planets/captions/mars/vlpan22.htm)

http://seds.lpl.arizona.edu/nineplanets/nineplanets/thumb/vlpan22.jpg (http://pds.jpl.nasa.gov/planets/captions/mars/vlpan22.htm)

A large version (http://pds.jpl.nasa.gov/planets/images/full/mars/vlpan22.jpg)

wayneee
2005-Dec-24, 11:54 PM
Mars is different now than it used to be(in my opinion) LOok at it, all that trenching, Oympus Mons . This place used to be Active Geologicaly. Something appened to Mars. Phobos and Deimos were once one, and impacted Mars splitting in two. the result killed Mars. Thankyou(bows)

GBendt
2005-Dec-25, 12:27 AM
Hi,

There have been large bodies of liquid water in the past of mars. Rivers flowed and dug out deep valleys and gorges. Later the water disappeared, and the surface turned into a dry and cold desert.
Nowadays, liquid water is widely available beyond the surface of mars and is splashing down slopes sometimes, there or there, leaving plenty of fresh cut gullies. The mars orbiters provided an overwhelming lot of evidence for that.

The climate of marsis not stable. There are glaciers on the martian surface, and fresh clear water ice. Even frozen lakes with icebergs were detected there. Under martian atmospheric conditions, ice will dissipate with time via a process of freeze drying. It should be gone after a while, thus the ice that is found on mars cannot be very old. It is most likely that there is water avaulable now and then to create ice. There must be times at which liquid water appears.

I read in papers that mars is currently undergoing a climatic change. Such changes may take place now and then, induced by changes of the orbit or by changes of inclination of the axis of mars.
Our moon stabilises the inclination of the axis of our earth. Mars does not have a moon of a mass to do that job for him.

I think that volcanic steams can produce sulphuric deposits in the martian soil. But we know that there are areas that were covered by water at times. We have pictures that give proof of heavy floodings.

But I recommend to spend a few dozen hours on examining the pictures of martian landscape we have rfom the orbiters, there are about 45000 made available to everybody by NASA...

Regards,

Günther

David Knisely
2005-Dec-25, 01:07 AM
SUMMARY: The Meridiani Planum region on Mars is currently the home of NASA's Opportunity Rover. But scientists believe that the entire region was covered with water millions of years ago, and could have been home to life. A new study is proposing that the area might have been much less wet than previously believed. A key element discovered by Opportunity could have been created by sulphur-bearing volcanic steam, and not water sediment layered down.

View full article (http://www.universetoday.com/am/publish/boulder_mars_less_watery.html)
What do you think about this story? post your comments below.

Well, whil the chemistry makes sense, things like the "blue berries" and the cross bedding in the rocks supports at least moderate amounts of liquid water existing for a period of time long enough to form these features. The study does not appear to address these facts. Clear skies to you.

Greg
2005-Dec-26, 05:48 AM
I do have some reservations about the cross-bedding and blueberries. I imagine that repeated volcanic events could result in layers of material. Repeated short-term volcanic events (or impacts) make more sense to me for the simple reason that I do not see how Mars could hold onto large bodies of water (of the liquid variety on the surface) for very long and this implies intermittent events that do not depend on water.
Steve Squyres has responded to this challenge by saying that the research was based on old rover data and that more recent data over the last year cements their theory of long-standing bodies of water. I posted a link to this below. Either way seeing publications from either group would be helpful in order to substantiate this discussion. Until then, I welcome the debate.

http://www.rockymountainnews.com/drmn/local/article/0,1299,DRMN_15_4334345,00.html

GBendt
2005-Dec-27, 11:22 AM
Hi.

A cross-bedding of sediment layers can be caused by desert winds or by short-time floodings, whenever a lot of sediment is transported and deposited at a time and the flow direction changed. Therefore cross bedded layers usually are no indication of standing bodies of water.
The blueberry-like iron-rich concretions found in rocks resemble very much concretions which can be found on earth in some lakebeds, and in dry sediment of that origin. Thus they may be seen as an indication of standing water bodies, e. g. lakes.
Such lakes do not need to be large, and do not need to exist for many years to develop these blueberries on their bottom, which form from iron ions, carbon dioxide, oxygen and water by a process of condensation. Bog iron ore is something similar. In Sweden this was gathered from the lakebeds where it forms, and the Swedish made a high-quality steel from it.

I have the impression that the effects of volcanism have a greater impact on martian landscape, because the martian weather does not create rainfloods to wear down the layers of the volcanic deposits. Instead, it creates winds. Thus, we can see many dunes on mars, but no rivers. The whole planet seems to be mainly covered by old thick packets of horizontal layers of volcanic origin.

Nevertheless, there are many valleys, and these must have been cut out somehow, and there are vast traces of really massive water floodings. The waether seems to have been a different one in the past of mars.

Today we find glaciers on mars, and meteor craters with blue ice on the bottom, and plenty of fresh gullies that run down various meteor crater slopes.
As liquid water surely exists below the martian surface, it may contain metal ions which can react with carbon acid and water. This way mineral deposits may be created, like those that were found by the rovers.

Regards,

GŁnther