Rounded Rocks in Gusev Crater

Just looking at the rocks on the floor of Gusev crater - they are rounded.
This implies water (or some other fluid) erosion.

I think from that first colour photo it is proven that Gusev indeed held
running water.

Nathan Rogers
Australia

"Blurrt" wrote in message
u...
Just looking at the rocks on the floor of Gusev crater - they are rounded.
This implies water (or some other fluid) erosion.

Or wind.

Doc

On Wed, 07 Jan 2004 00:07:01 GMT, "drdoody"
wrote:


"Blurrt" wrote in message
. au...
Just looking at the rocks on the floor of Gusev crater - they are rounded.
This implies water (or some other fluid) erosion.

Or wind.

Wind blown dust you mean.

January 6, 2004

Christopher wrote:

Or wind.

Wind blown dust you mean.

Sure, wind blown sub-micron dust in a 6 to 10 mbar atmosphere, dust which we know
is NOT composed of the same material as the rocks, erodes the rocks smooth. And
all that water, over millions of years, which just a few year ago didn't even
exist in the minds of many, erodes very little.

I don't think so.

Thomas Lee Elifritz
http://elifritz.members.atlantic.net

(Christopher) wrote in message ...
On Wed, 07 Jan 2004 00:07:01 GMT, "drdoody"
wrote:


"Blurrt" wrote in message
. au...
Just looking at the rocks on the floor of Gusev crater - they are rounded.
This implies water (or some other fluid) erosion.

Or wind.

Wind blown dust you mean.

Ventifacts can be produced by wind alone. This has been tested in
windtunnel tests. And we are talking a time frame approaching a
billion years not millions. This doesn't prevent water also being a
cause of the rounding but ventifacts have characteristics that should
clearly label them. Here are a few URL with images of ventifacts:

http://www.schweich.com/imagehtml/1440-20.html

http://www.lpl.arizona.edu/~planagan...y/0010028m.jpg

http://www.csun.edu/geology/Field_Tr...ifactridge.jpg

--Chris Vancil

"drdoody" wrote in message
y.com...

"Blurrt" wrote in message
u...
Just looking at the rocks on the floor of Gusev crater - they are
rounded.
This implies water (or some other fluid) erosion.

Or wind.

Doc

Yeah, I suppose. The NASA website states that too (which is where I suppose
you got the idea). It just seems to me that if we have an inflow channel
then there should be some signs of erosion associated with that inflow. I
guess the rocks need to be overturned by the rover to see if they are smooth
underneath as well. (Check out the airbag disturbed pics)

Nathan.

I think you guys are forgetting the time scale. The water
probably flowed 3 billion years ago. The rocks were deposited
by crater impacts later. A couple of billion years is plenty of
time for dust in the atmosphere to round the rocks.


Patrick

On 08 Jan 2004 04:28:15 GMT, (Patrick) wrote:

I think you guys are forgetting the time scale. The water
probably flowed 3 billion years ago. The rocks were deposited
by crater impacts later. A couple of billion years is plenty of
time for dust in the atmosphere to round the rocks.



It should be easy to tell the difference once the rover gets moving.
River-eroded rocks would tumble, and be eroded on all sides. Wind-eroded
rocks (above a certain size) would be more eroded on the side facing the
prevailing winds. Also, those embedded in the soil should not be much eroded
on the buried portions.

drdoody wrote:

"Blurrt" wrote in message
u...
Just looking at the rocks on the floor of Gusev crater - they are rounded.
This implies water (or some other fluid) erosion.

Or wind.

Doc

We have a lot of rocks here in Washington State, and such smooth,
rounded surfaces I've seen only on river rocks. Ditto for all the rocks
I've seen down in the deserts of Utah and Arizona.

Dick Morris wrote in
:

We have a lot of rocks here in Washington State, and such smooth,
rounded surfaces I've seen only on river rocks. Ditto for all the
rocks I've seen down in the deserts of Utah and Arizona.

You have an easy way of identifying earth rocks that have been exposed to
the surface for 2billion+ years? wow!

Get a clue please.. The earth surface is *active*. There are frequent(by
geological scales) glaciers marching past, lots of airborne stuff (dust,
sand, *rain*, *ice* , birds!, oxygen) that simply are not found in the same
form on Mars. Extrapolating your backyard-commonsense observations *will*
*not* *work* in an inherently foreign environment like Mars.