by neufer » Thu Sep 27, 2012 1:53 pm
astronut2012 wrote:
From the structure an presence of cross bedding of the matrix in which the spheres are enclosed, I would guess that these are Oolites - calcium, phosphate or even haematite formed by accretion around a seed, unusually a sand grain. On earth ooids form in shallow lakes subject to current action, which rolls the particles back and forth, creating their spherical shape.
Certainly the iron rich "blueberries" are probably haematite ooids:
http://en.wikipedia.org/wiki/Hematite#Discovery_on_Mars wrote:
<<The spectral signature of hematite was seen on the planet Mars by the infrared spectrometer on the NASA Mars Global Surveyor ("MGS") and 2001 Mars Odyssey spacecraft in orbit around Mars. The mineral was seen in abundance at two sites on the planet, the Terra Meridiani site, near the Martian equator at 0° longitude, and the second site Aram Chaos near the Valles Marineris. Several other sites also showed hematite, e.g., Aureum Chaos. Because terrestrial hematite is typically a mineral formed in aqueous environments, or by aqueous alteration, this detection was scientifically interesting enough that the second of the two Mars Exploration Rovers was targeted to a site in the Terra Meridiani region designated Meridiani Planum.
In-situ investigations by the Opportunity rover showed a significant amount of hematite, much of it in the form of small spherules that were informally named "blueberries" by the science team. Analysis indicates that these spherules are apparently concretions formed from a water solution. "Knowing just how the hematite on Mars was formed will help us characterize the past environment and determine whether that environment was favorable for life,">>
But these suckers are
iron deficient:
APOD Robot wrote: Unusual Spheres on Mars
The
above image taken by Opportunity's
Microscopic Imager shows that some ground near the rover is filled with these unusual spheres, each spanning only about 3 millimeters. At first glance, the sometimes-fractured balls appear similar to the small rocks dubbed
blueberries seen by Opportunity eight years ago,
but these spheres are densely compacted and have little iron content.
Rather than assuming (life related?) calcium or phosphate is involved what about considering something like manganese:
http://en.wikipedia.org/wiki/Manganese_nodule wrote:
<<Polymetallic nodules were discovered in 1868 in the Kara Sea, in the Arctic Ocean of Siberia. During the scientific expeditions of the HMS Challenger (1872-76), they were found to occur in most oceans of the world. They can occur at any depth, even in lakes, but
the highest concentrations have been found on vast abyssal plains in the deep ocean between 4,000 and 6,000 m. Most nodules are between 5 and 10 cm in diameter, about the size of potatoes. Their surface is generally smooth, sometimes rough, mammilated (knobby) or otherwise irregular.
Nodule growth is one of the slowest of all geological phenomena – on the order of a centimeter over several million years. Several processes are involved in the formation of nodules, including the precipitation of metals from seawater (hydrogenous), the remobilization of manganese in the water column (diagenetic), the derivation of metals from hot springs associated with volcanic activity (hydrothermal), the decomposition of basaltic debris by seawater (halmyrolitic) and the precipitation of metal hydroxides through the activity of microorganisms (biogenic). Several of these processes may operate concurrently or they may follow one another during the formation of a nodule.>>
[quote="astronut2012"]
From the structure an presence of cross bedding of the matrix in which the spheres are enclosed, I would guess that these are Oolites - calcium, phosphate or even haematite formed by accretion around a seed, unusually a sand grain. On earth ooids form in shallow lakes subject to current action, which rolls the particles back and forth, creating their spherical shape.[/quote]
Certainly the iron rich "blueberries" are probably haematite ooids:
[quote=" http://en.wikipedia.org/wiki/Hematite#Discovery_on_Mars"]
<<The spectral signature of hematite was seen on the planet Mars by the infrared spectrometer on the NASA Mars Global Surveyor ("MGS") and 2001 Mars Odyssey spacecraft in orbit around Mars. The mineral was seen in abundance at two sites on the planet, the Terra Meridiani site, near the Martian equator at 0° longitude, and the second site Aram Chaos near the Valles Marineris. Several other sites also showed hematite, e.g., Aureum Chaos. Because terrestrial hematite is typically a mineral formed in aqueous environments, or by aqueous alteration, this detection was scientifically interesting enough that the second of the two Mars Exploration Rovers was targeted to a site in the Terra Meridiani region designated Meridiani Planum. [b][color=#0000FF]In-situ investigations by the Opportunity rover showed a significant amount of hematite, much of it in the form of small spherules that were informally named "blueberries" by the science team.[/color][/b] Analysis indicates that these spherules are apparently concretions formed from a water solution. "Knowing just how the hematite on Mars was formed will help us characterize the past environment and determine whether that environment was favorable for life,">>[/quote]
But these suckers are [b][u][color=#FF8000]iron deficient[/color][/u][/b]:
[quote="APOD Robot"][url=http://apod.nasa.gov/apod/ap120925.html][img]http://apod.nasa.gov/apod/calendar/S_120925.jpg[/img] [size=150]Unusual Spheres on Mars[/size][/url]
The [url=http://photojournal.jpl.nasa.gov/catalog/PIA16139]above image[/url] taken by Opportunity's [url=http://marsrover.nasa.gov/mission/spacecraft_instru_mi.html]Microscopic Imager[/url] shows that some ground near the rover is filled with these unusual spheres, each spanning only about 3 millimeters. At first glance, the sometimes-fractured balls appear similar to the small rocks dubbed [url=http://apod.nasa.gov/apod/ap040405.html]blueberries[/url] seen by Opportunity eight years ago, [b][u]but these spheres are densely compacted and [color=#FF8000]have little iron content[/color][/u][/b]. [/quote]
Rather than assuming (life related?) calcium or phosphate is involved what about considering something like manganese:
[quote=" http://en.wikipedia.org/wiki/Manganese_nodule"]
[float=right][img3="[b][color=#0000FF]Polymetallic/manganese nodules, are rock concretions on the sea bottom formed of concentric layers of [u]iron & manganese hydroxides[/u] around a core.[/color][/b]"]http://upload.wikimedia.org/wikipedia/commons/thumb/0/05/Manganknolle.jpg/800px-Manganknolle.jpg[/img3][/float]
<<Polymetallic nodules were discovered in 1868 in the Kara Sea, in the Arctic Ocean of Siberia. During the scientific expeditions of the HMS Challenger (1872-76), they were found to occur in most oceans of the world. They can occur at any depth, even in lakes, but [b][color=#0000FF]the highest concentrations have been found on vast abyssal plains in the deep ocean between 4,000 and 6,000 m[/color][/b]. Most nodules are between 5 and 10 cm in diameter, about the size of potatoes. Their surface is generally smooth, sometimes rough, mammilated (knobby) or otherwise irregular.
Nodule growth is one of the slowest of all geological phenomena – on the order of a centimeter over several million years. Several processes are involved in the formation of nodules, including the precipitation of metals from seawater (hydrogenous), the remobilization of manganese in the water column (diagenetic), the derivation of metals from hot springs associated with volcanic activity (hydrothermal), the decomposition of basaltic debris by seawater (halmyrolitic) and the precipitation of metal hydroxides through the activity of microorganisms (biogenic). Several of these processes may operate concurrently or they may follow one another during the formation of a nodule.>>[/quote]