Spheres coming from bedrock?

Joe Knapp wrote:
JPL has posted new raw microscopic images of the spheres in situ, embedded
in the outcrop--pics taken 4am PST Sunday (sol 15):

http://tinyurl.com/2boql

http://tinyurl.com/2rtga


Joe

Every time a see a yet closer image of the outcrop at Meridiani Planum,
I hear this Krusty the Clown voice in my head saying: "What the hell was
that?!?!?"

I've just about given up speculation on the origin of this stuff. But
not quite...

Close-ups like this:

http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine and
sinter deposits. The first Navigation Camera images, while still on the
lander, looked like bedded clastic rocks (e.g. sandstone). As the rover
got closer, both the PanCam and NavCam images looked more like ratty
welded tuff (volcanic ash). Now, when the rover is right up against the
rock, it looks like a chemical precipitate! And the roundy things are
definitely a lag weathered out from whatever this stuff is.

It will be nice to get some close-up spectrometry for some idea of
composition. No one has said carbonate or silica out loud yet, but I
wonder...

If the spheres are the source of the hematite, what could the host rock
possibly be?
---
Tim Demko
http://www.d.umn.edu/~tdemko

"Timothy Demko" wrote in message
...
Joe Knapp wrote:
JPL has posted new raw microscopic images of the spheres in situ,
embedded
in the outcrop--pics taken 4am PST Sunday (sol 15):

http://tinyurl.com/2boql

http://tinyurl.com/2rtga


Joe

Every time a see a yet closer image of the outcrop at Meridiani Planum,
I hear this Krusty the Clown voice in my head saying: "What the hell was
that?!?!?"

I've just about given up speculation on the origin of this stuff. But
not quite...

Close-ups like this:


http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine and
sinter deposits. The first Navigation Camera images, while still on the
lander, looked like bedded clastic rocks (e.g. sandstone). As the rover
got closer, both the PanCam and NavCam images looked more like ratty
welded tuff (volcanic ash). Now, when the rover is right up against the
rock, it looks like a chemical precipitate! And the roundy things are
definitely a lag weathered out from whatever this stuff is.

It will be nice to get some close-up spectrometry for some idea of
composition. No one has said carbonate or silica out loud yet, but I
wonder...

If the spheres are the source of the hematite, what could the host rock
possibly be?
---
Tim Demko
http://www.d.umn.edu/~tdemko



In one of the briefings, I believe they said that mini-TES scans had
excluded such things as carbonates as the basis for the rock of the outcrop,
and that they showed that the outcrop did not contain appreciable hematite,
either.

In the closeup, the rock looks rotten and crumbly, made of sheets
alternating with porous layers. Whatever formed it has also captured some
of the spheroidal objects and some that even look disc-like. I thought the
pebbles in the soil samples might have been grains crumbled off the rocks,
but they seem to exist in pretty much that shape in the stone matrix. Could
there be any relationship between this cemented matrix and the bizarre
mechanics seen in the loose soil in the crater (and at Gusev)?

JJ Robinson II
Houston, TX
****************
* JOKE *
****************
* SERIOUS? *
****************
* SARCASTIC *
****************
* OTHER? *
****************

"Timothy Demko" wrote
Close-ups like this:


http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine and
sinter deposits.

Would sinter deposits be associated with hot springs such as in theis New
Zealand shot?

http://www.thenewzealandsite.com/photo/1413/

That "sinter terrace" does somewhat resemble the outcrop now that you
mention it. Found this definition:

Sinter: A type of fragile, commonly white or grey rock formed by
precipitation of silica from cooling hydrothermal solutions at or near a
hydrothermal vent. Precipitation of siliceous sinter (often with associated
sulfide minerals and precious metals) commonly occurs in neutral and acid
hydrothermal systems under the influence of biogenic agents such as algae
and bacteria (Cas and Wright, 1987, p. 316).


It will be nice to get some close-up spectrometry for some idea of
composition. No one has said carbonate or silica out loud yet, but I
wonder...

If the spheres are the source of the hematite, what could the host rock
possibly be?

Found this reference:

"EVIDENCE FOR AN 800 KM DIAMETER IMPACT STRUCTURE IN MERIDIANI PLANUM AND
ASSOCIATED CHANNELS AND BASINS: A CONNECTION WITH THE ORIGIN OF THE HEMATITE
DEPOSITS?"
http://www.lpi.usra.edu/meetings/lpsc2003/pdf/1414.pdf

"The connection between the impact structures and
the origin of the hematite could involve precipitation
from hydrothermal fluids associated with the heat from
the impact, either in lakes (e.g. like banded iron formation),
or directly in the observed layered deposits."

Joe

The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

That's pretty interesting, because if there were prolonged wet periods
on mars (ie before the atmosphere precipitated into icecaps) there was
probably time for such that sedimentary concretions could form,
rudimentary life could perhaps form too.

It would be interesting to give the rock a good whack though, and see
how solid it is.

Ross.


"Joe Knapp" wrote in message y.com...
"Timothy Demko" wrote
Close-ups like this:


http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine and
sinter deposits.

Would sinter deposits be associated with hot springs such as in theis New
Zealand shot?

"scrodchunk" wrote in message
om...
The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

That's pretty interesting, because if there were prolonged wet periods
on mars (ie before the atmosphere precipitated into icecaps) there was
probably time for such that sedimentary concretions could form,
rudimentary life could perhaps form too.

It would be interesting to give the rock a good whack though, and see
how solid it is.

Ross.

Unfortunately, the rovers left their rock hammers at home! And they call
these contraptions "geologists"? :-) I would add that the spherules in the
soil apparently originated from the bedrock, as it too contains the same
spherules.


"Joe Knapp" wrote in message
y.com...
"Timothy Demko" wrote
Close-ups like this:



http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine and
sinter deposits.

Would sinter deposits be associated with hot springs such as in theis
New
Zealand shot?

"scrodchunk" wrote in message
om...
The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

Wouldn't it be odd for the spherules to form in two completely different
environments? How about this alternative: we know (or at least Dr. Squyres
said) that the outcrop is just part of a vast sheet of the same material the
size of Oklahoma, just under the surface. Presumably that material is loaded
throughout with these spherules.

So that sheet is probably the source of all the spherules. You can even see
it in some of the rover photos, the spheres are concentrated where the
bedrock is below a thin layer of sand/dust:

http://www.copperas.com/astro/meridspheres.jpg

You can see the outcrop peeking through the sand in the back.

Since the bedrock is clearly being eroded away by coarse sand grains (such
grains clearly visible at work in http://tinyurl.com/2sxqk) the fine dust
in the soil is just pulverized bedrock (which has been said is very fine
grained "rock"). Since the outcrop doesn't show a hematite signature (the
spherules are invisible at TES scales to date), neither does the dust, nor
the sand. That leaves the spherules as the hematite carriers.

So across Meridiani there is a certain amount of sand that is continually
bouncing along the surface, scouring any outcrops, releasing the spherules.
Sand is much more easily lifted by the wind than is sub-micron dust,
particularly if the surface has pebbles. The pebbles tend to stagnate the
air near the surface. If an area of pebbles happens to get covered by sand
(say a dust devil rolls through), that might just tend to level out to the
pebble layer again, because that sand would be exposed to the laminar flow
of the wind. A table in "Mars," the compendium of Mars info put out in 1992
by JPL notes that about three times as much wind speed is needed to lift
("entrain") particles of a given size from a surface covered with cobbles
and small boulders vs. a "free stream" surface. So the pebbles more or less
stay exposed on top of the sand/dust such as we see. Just a guess!

It would be interesting to give the rock a good whack though, and see
how solid it is.

The RAT should give an estimate of that. Adirondack took a long time to RAT
(that's a verb I guess?)--this stuff might fly away in no time. That data's
going to be the key, along with a RAT/TES of the spherules. Pass the
popcorn.

Joe

I wrote JPl some of this yesterday. Base on what Dr. Squires has said, it
seems clear the spherules are being exhumed out of the matrix of the bed
rock. But notice they are relatively scarce in the bed rock. But on the
surface, epically outside of the crater, they are plentiful, virtually
covering the entire surface.

Thus it seems that the bedrock, thought to underlie the entire plain in
Meridiani, must be filled with these spherules that are eventually
"released" as the bedrock is eroded by wind. Perhaps the bedrock becomes
the dust and sand of Mars. The spherules are left behind, at least in this
area, to blanket the floor (or they may be blown and rolled from somewher
uphill).

And it seems likely the spherules are the source of the hematite. According
to the "mineral map", wherever the spherules are, the hematite signature is
strong (at the rim of the crater, outside the crater, some places inside.)
Conversely the signature is weak where there are few spherules (in the
bedrock, where the spectra of the soil was taken, and most significantly,
where the airbags of the Lander squashed them into the soil).

It seems to me the easiest explanation is fine volcanic ash (maybe cemented
with some water from snows when the orbital eccentricity changes)is the bed
rock and the spherules are hematite rich condensed globules. So any
geologist know of a plausable process by which a volanic eruption would make
both ash and hematite rich spherules?

Roy Clymer
" George" wrote in message
. ..

"scrodchunk" wrote in message
om...
The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

That's pretty interesting, because if there were prolonged wet periods
on mars (ie before the atmosphere precipitated into icecaps) there was
probably time for such that sedimentary concretions could form,
rudimentary life could perhaps form too.

It would be interesting to give the rock a good whack though, and see
how solid it is.

Ross.

Unfortunately, the rovers left their rock hammers at home! And they call
these contraptions "geologists"? :-) I would add that the spherules in
the
soil apparently originated from the bedrock, as it too contains the same
spherules.


"Joe Knapp" wrote in message
y.com...
"Timothy Demko" wrote
Close-ups like this:




http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine
and
sinter deposits.

Would sinter deposits be associated with hot springs such as in theis
New
Zealand shot?

OndaWeb wrote:

Thus it seems that the bedrock, thought to underlie the entire plain in
Meridiani, must be filled with these spherules that are eventually
"released" as the bedrock is eroded by wind. Perhaps the bedrock becomes
the dust and sand of Mars. The spherules are left behind, at least in this
area, to blanket the floor (or they may be blown and rolled from somewher
uphill).

And it seems likely the spherules are the source of the hematite. According
to the "mineral map", wherever the spherules are, the hematite signature is
strong (at the rim of the crater, outside the crater, some places inside.)
Conversely the signature is weak where there are few spherules (in the
bedrock, where the spectra of the soil was taken, and most significantly,
where the airbags of the Lander squashed them into the soil).

It seems to me the easiest explanation is fine volcanic ash (maybe cemented
with some water from snows when the orbital eccentricity changes)is the bed
rock and the spherules are hematite rich condensed globules. So any
geologist know of a plausable process by which a volanic eruption would make
both ash and hematite rich spherules?

I like most of this explanation, especially the origin of the hematite
concentration as a residual soil created by deflation (wind erosion) of
the light-colored bedrock and concentration of the denser spherules.
However, the origin(s) of the spherules and the bedrock are still open
questions.

I think that the spherules are diagenetic concretions or nodules
containing at least some hematite (and much more that the surrounding
bedrock). I think they formed sometime after deposition of the host
bedrock. The light color of the bedrock versus the dark spherules may
suggest that the diagenetic event that created the spherules leached the
bedrock of iron minerals and concentrated it in the spherules. If the
hematite is primary, then that tells us a lot about the oxidizing and
reducing conditions during emplacement. I think there is some textural
evidence that the lighter-colored matrix was at least partially
indurated (cemented or solidified) when the spherules were formed (some
of the MI pictures show grooves that may have been tightly cemented
bedding planes across which the spherules formed):

http://marsrovers.jpl.nasa.gov/galle...P2932M1M1.HTML

The interpretation of the bedrock as a volcanic ash, even an altered
ash, has not yet been supported. In fact, the presence of cross beds:

http://www.jpl.nasa.gov/mer2004/rove...s/image-1.html

suggests that even if it is an ash, it's been transported by some sort
of traction currents and is not a simple air fall.

I'd really like to know what mineral the sulfur is occuring in.

Similar hematite concretions in sandstones on the Colorado Plateau
(called "Moqui Marbles") may have formed due to hydrocarbon migration!

http://www.utahchronicle.com/news/20...d-580775.shtml

www.ugs.state.ut.us/online/pdf/pi-77.pdf

This story has a long way to go...
--
Tim Demko
http://www.d.umn.edu/~tdemko

"OndaWeb" wrote in message
...
I wrote JPl some of this yesterday. Base on what Dr. Squires has said, it
seems clear the spherules are being exhumed out of the matrix of the bed
rock. But notice they are relatively scarce in the bed rock. But on the
surface, epically outside of the crater, they are plentiful, virtually
covering the entire surface.

Thus it seems that the bedrock, thought to underlie the entire plain in
Meridiani, must be filled with these spherules that are eventually
"released" as the bedrock is eroded by wind. Perhaps the bedrock becomes
the dust and sand of Mars. The spherules are left behind, at least in
this
area, to blanket the floor (or they may be blown and rolled from somewher
uphill).

And it seems likely the spherules are the source of the hematite.
According
to the "mineral map", wherever the spherules are, the hematite signature
is
strong (at the rim of the crater, outside the crater, some places inside.)
Conversely the signature is weak where there are few spherules (in the
bedrock, where the spectra of the soil was taken, and most significantly,
where the airbags of the Lander squashed them into the soil).

It seems to me the easiest explanation is fine volcanic ash (maybe
cemented
with some water from snows when the orbital eccentricity changes)is the
bed
rock and the spherules are hematite rich condensed globules. So any
geologist know of a plausable process by which a volanic eruption would
make
both ash and hematite rich spherules?

I found an article pertaining to artificial spherical hematite. I have't
read it yet, so I can't comment on its contents, or relevance. But here is
the link:

http://www.ugr.es/~aquiran/ciencia/arti07.pdf

I have found nothing, nor seen anything about naturally occuring spherical
hematite, other than botryoidal hematite.

The MER web site has a video file that shows an expanded to zoom view of the
are where the spheres are located and the spheres themselves. What struck
me the most was the really tiny size of these spheres. It would have been
nice if they could have sent an intelligent monkey to hold a scale beside
them so we would know their exact size. :-) Note that nearly all naturally
occuring botryoidal hematite I've seen here on earth have a fibrous texture
when broken open (where else would I have seen it, right?). These Mars
spheres do not appear to have this fibrous texture to them. They appear to
be more granular and very fine grained at that, than anything else. So if
these spheres are pure hematite, someone is going to have a lot of fun
explaining how they were formed.

Roy Clymer
" George" wrote in message
. ..

"scrodchunk" wrote in message
om...
The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

That's pretty interesting, because if there were prolonged wet periods
on mars (ie before the atmosphere precipitated into icecaps) there was
probably time for such that sedimentary concretions could form,
rudimentary life could perhaps form too.

It would be interesting to give the rock a good whack though, and see
how solid it is.

Ross.

Unfortunately, the rovers left their rock hammers at home! And they
call
these contraptions "geologists"? :-) I would add that the spherules in
the
soil apparently originated from the bedrock, as it too contains the same
spherules.


"Joe Knapp" wrote in message
y.com...
"Timothy Demko" wrote
Close-ups like this:





http://marsrovers.jpl.nasa.gov/galle...2P2933M2M1.JPG

continue remind me of textures and fabrics I've seen in travertine
and
sinter deposits.

Would sinter deposits be associated with hot springs such as in
theis
New
Zealand shot?

"Joe Knapp" wrote in message
.com...

"scrodchunk" wrote in message
om...
The spheroid particles in the bedrock look a lot like those in the
surface 'gravel' To me this suggests two likely things.

a) the spheroids in the rock were formed in the same
manner as those in the gravel

and more interestingly

b) a period of change occured where the planet changed from
a state much like the current state (with spheroids in the
gravel) into a state where sedimentary rock could form (such
as a prolonged period of moisture, which has then returned
to the current state.

Wouldn't it be odd for the spherules to form in two completely different
environments? How about this alternative: we know (or at least Dr. Squyres
said) that the outcrop is just part of a vast sheet of the same material
the
size of Oklahoma, just under the surface. Presumably that material is
loaded
throughout with these spherules.

So that sheet is probably the source of all the spherules. You can even
see
it in some of the rover photos, the spheres are concentrated where the
bedrock is below a thin layer of sand/dust:

http://www.copperas.com/astro/meridspheres.jpg

You can see the outcrop peeking through the sand in the back.

Since the bedrock is clearly being eroded away by coarse sand grains (such
grains clearly visible at work in http://tinyurl.com/2sxqk) the fine dust
in the soil is just pulverized bedrock (which has been said is very fine
grained "rock"). Since the outcrop doesn't show a hematite signature (the
spherules are invisible at TES scales to date), neither does the dust, nor
the sand. That leaves the spherules as the hematite carriers.

Oh, if only they had send a hand holding a seive!

So across Meridiani there is a certain amount of sand that is continually
bouncing along the surface, scouring any outcrops, releasing the
spherules.
Sand is much more easily lifted by the wind than is sub-micron dust,
particularly if the surface has pebbles. The pebbles tend to stagnate the
air near the surface. If an area of pebbles happens to get covered by sand
(say a dust devil rolls through), that might just tend to level out to the
pebble layer again, because that sand would be exposed to the laminar flow
of the wind. A table in "Mars," the compendium of Mars info put out in
1992
by JPL notes that about three times as much wind speed is needed to lift
("entrain") particles of a given size from a surface covered with cobbles
and small boulders vs. a "free stream" surface. So the pebbles more or
less
stay exposed on top of the sand/dust such as we see. Just a guess!

It would be interesting to give the rock a good whack though, and see
how solid it is.

The RAT should give an estimate of that. Adirondack took a long time to
RAT
(that's a verb I guess?)--this stuff might fly away in no time. That
data's
going to be the key, along with a RAT/TES of the spherules. Pass the
popcorn.

Joe