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Spheres coming from bedrock?



 
 
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  #11  
Old February 13th 04, 07:13 AM
don findlay
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Default Spheres coming from bedrock?

"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?


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.



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?



  #12  
Old February 13th 04, 03:50 PM
Joe Knapp
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Default Spheres coming from bedrock?


"Timothy Demko" wrote

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.


Cross beds I take it simply means that the layers are not always
parallel--they diverge and converge sometimes? If so, how about this photo
of the effect of "volcanic bombs":
http://www.geo.hunter.cuny.edu/~cwang/impacts.jpg Wouldn't the layers in
that photo be a simple air fall?

It's interesting that last week Squyres said there were three main theories
for the origin of the spherules: lapilli, solidified volcanic material, or
concretions. He said the lapilli idea was "fading fast" on the logic that
they look to be of a different material than the matrix. There has not been
a word in the press conferences since about any progress along those lines.

However, an interview with Ronald Greeley, Ph.D., Regents Prof. of Geology,
Arizona State University Dept. of Geological Sciences, and one of the 7
Chairs of the Science Operations Working Group (SOWG) for Spirit and
Opportunity, Tempe, Arizona this Wednesday was a bit surprising. When asked
about the spherules, Prof. Greeley said:

"The general consensus seems to be centering around two possibilities:

"First, that they are what are called 'accretionary lapillae' * that is a
volcanic feature that forms in certain kinds of eruptions in which material
is added to a small nucleus like a little dust grain and these form these
spherule masses."

"Secondly, they could be some kind of precipitate * perhaps from water. In
additional findings, there are some minerals that have been identified in
the infrared that would suggest the presence of water since they form in
water. In particular, if this is a volcanic terrain that we are looking at,
the presence of these minerals might suggest this was a hydrothermal area."

What--lapilli are fading back in and the other two theories (magma &
concretions) are gone, to be replaced with "some kind of precipitate"?

Continuing:

IS THERE ANYTHING FROM ANY OF THE SPECTROMETERS OR ALPHA X-RAY THAT INDICATE
WHAT THE SPHERULES ARE MADE OUT OF?

"We can't measure the spherules individually * they are too small. We have
to get the chemical and mineralogical signatures for the whole mass and then
try to deduce what would be the composition of the spherules."

SO TODAY AS WE SPEAK ON FEBRUARY 11, IS IT STILL UNKNOWN WHAT THE SPHERULES
ARE MADE OUT OF?

"Yes * that's a work in progress."

....

AND ALL THIS IS ADDING UP TO A QUESTION ABOUT WHETHER THE PLACE WHERE
OPPORTUNITY CAME DOWN ORIGINALLY MIGHT HAVE BEEN HOT MAGMA COMING UP TO THE
SURFACE IN SOME KIND OF VOLCANIC ACTIVITY? OR AT LEAST HOT SPRINGS?

"Yes. The evidence is sort of pointing towards the presence of a hot
environment * hot for some reason and that's under debate right now.
Volcanic activity, magma close to the surface, is one possibility."

....

THE BIGGEST SURPRISE RIGHT NOW HAS BEEN THE HIGH AMOUNT OF SULFUR IN THE
BEDROCK?

"That was a surprise, yes. The measurements that have been made there
suggest there is a very high percentage of sulfur present in the material
and that there are these spherules that have been seen and reported earlier,
those are still very curious features."

"Such a high percentage of sulfur (in the bedrock) is unusual and this is
what leads some folks to consider the volcanic origin (at the Martian
bedrock), or at least volcanic processes to be involved. There are some
minerals that have been identified in the infrared that would suggest the
presence of water since they form in water. In particular, if this is a
volcanic terrain that we are looking at, the presence of these minerals
might suggest this was a hydrothermal area and sulfur is a component of such
environments."

SO THE BEDROCK MIGHT BE, IF WE WERE COMPARING IT TO THE EARTH, MIGHT HAVE
HAD AN ORIGIN SIMILAR TO SAY YELLOWSTONE NATIONAL PARK?

"Yes, to some parts of Yellowstone, that's right."

http://www.earthfiles.com/news/news....tegory=Science

Joe

  #13  
Old February 13th 04, 04:40 PM
don findlay
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?

(don findlay) wrote in message . com...
"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?


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.

______________________________

(PS. The spheres, maybe pyrite (altered to haematite))
  #14  
Old February 13th 04, 05:11 PM
George
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?


"don findlay" wrote in message
om...
"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?


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.



Can you post a link to some pictures or description of archaean rhyolitic
ignimbrites that look like what we are seeing on Mars? I don't doubt you
Don, but that kind of thing just isn't found in my neck of the woods, so I'd
like to see an example. TIA.

  #15  
Old February 13th 04, 05:13 PM
Jo Schaper
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?

don findlay wrote:




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?


If it is explosive, and high in Fe, the iron spherules could be formed
easily by spatter and air resistance. Ever notice what shape welding rod
spatter takes? Little balls.


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.


Not necessarily strange. 1.4Ga rhyolite ignimbrites and tuffs around
here here (Earth) are fairly high in Fe and Mg, AND amazingly enough
some of the crumbly stuff contains iron amygdules. I think I have piece
in the basement somewhere. Iron is a mix of magnetite and hematite.
Some seems to be primary, and some secondary deposits. Saw a paper at
GSA North Central last spring where people were debating biogenic or
abiogenic origins of iron spheres in this ore and possible bacterial
involvement in forming the spheres. Much of the SE Mo iron industry was
founded on rhyolitic Fe rich deposits. Even the granite around here is
magnetic.

On the other hand, maybe I have been teleported to Mars, and no one told me.




  #16  
Old February 14th 04, 12:48 AM
John
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Posts: n/a
Default Spheres coming from bedrock?

How about this. At one time the planet had rings. Rocks in the rings gently
collided with one another until they all reached a uniform size and
spherical shape. The rings' orbit gradually declined until the dust
dispersed over the whole planet and the heavier spherules fell along the
equator, here into a soft volcanic dust pillow.

Either that or Martians are deer.


  #17  
Old February 14th 04, 09:27 AM
George
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?


"don findlay" wrote in message
om...
(don findlay) wrote in message

. com...
"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?


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.

______________________________

(PS. The spheres, maybe pyrite (altered to haematite))


Based on what? They have yet to release any results on the TES analysis of
the spheres. If they are hematite, they are the lightest-colored specimens
of hematite I've ever seen. Oh well, I suppose we will have to wait and see
what NASA finds.

  #18  
Old February 14th 04, 09:29 AM
George
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?


"John" wrote in message
...
How about this. At one time the planet had rings. Rocks in the rings

gently
collided with one another until they all reached a uniform size and
spherical shape. The rings' orbit gradually declined until the dust
dispersed over the whole planet and the heavier spherules fell along the
equator, here into a soft volcanic dust pillow.


Surely you jest.

Either that or Martians are deer.


Surely you jest.

  #19  
Old February 14th 04, 08:16 PM
Nate Smith
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?

John wrote:
Either that or Martians are deer.


hey - the little critter with the rabbity ears!
he leaves his martain raisins in the sun.


- nate

  #20  
Old February 15th 04, 01:48 AM
don findlay
external usenet poster
 
Posts: n/a
Default Spheres coming from bedrock?

" George" wrote in message ...
"don findlay" wrote in message
om...
"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?


The rocks look for all the world like Archaean rhyolitic ignimbrites
(colour, platy parting and all). Spherules are characteristic;
coalesced pairs common.
http://users.indigo.net.au/don/pr/dogsballs.html (sometimes in
threes)
(The haematite would be unusual though. )

The spherules are a puzzle (to me). The spherule texture is little
different from that of the matrix.

df.



Can you post a link to some pictures or description of archaean rhyolitic
ignimbrites that look like what we are seeing on Mars? I don't doubt you
Don, but that kind of thing just isn't found in my neck of the woods, so I'd
like to see an example. TIA.


Link? No, unfortunately. They'd be just rhyolites to the survey.
Otherwise known as "ringing rock", which rhyolites generally are. You
can have great fun playing tunes on them, and cut slices ring like
tubular bells (glass).
Google up search terms "bipyramidal quartz" ignimbrite rhyolite flows
flow spheres spherical etc. Given the quartz, the whorly ignimbritic
texture, and the glass-like nature of the rock, the spheres seem to be
some sort of growth in an incandescent state (maybe it rained or
something, and caused nucleation (of what though?) , and the spheres
got entrained in what might have been some sort of gas flow). Because
they do occur in trains..

The spheres I'm thinking of (which are unusual in rhyolites generally,
but common in these particular units) are lithic. But having seen the
rhyolitic-looking rocks in the mars pics (long shot though and should
be able to qualify), spheres of pyrite (which don't occur in them) did
nevertheless come to mind. You see pyrite spheres in funny things,
and the alteration to haematite figures I guess.
 




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