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NASA Rover Helps Reveal Possible Secrets of Martian Life
"John Curtis" skrev i en meddelelse oups.com... wrote: Scientists have been able to deduce conditions in the Meridiani Planum region of Mars were sometimes wet, strongly acidic and oxidizing. Those conditions probably posed stiff challenges to the origin of Martian life. Wet, strongly acidic and oxidizing environment results from a process called acid mine drainage, which is strongly associated with bacteria: http://www.mines.edu/fs_home/jhoran/ch126/microbia.htm Acid mine drainage converts pyrite into iron (lll), sulfate,hematite, goethite and jarosite, all found at Meridiani. The source of pyrite is the black smoker, which is invariably accompanied by bacteria even before the chimney is formed: http://66.102.7.104/search?q=cache:O...ystem%22&hl=en The article reference hydrogensulfid oozing out of the smoker, not pyrite. Pyrite is a (biotically mediated) diagenetic product of seawater sulfates and iron. I've never met pyrite in any rock that doesn't have a marine progenitor, but my experience is no standard for comparison. The article also mentions oxygen as part of the metabolic process, and I consider that an obstacle for comparing it to martian conditions. I'm not aware of how oxygen is released from MORB processes, and if you acknowledge the smoker as a recirculation of initially cold oxygenated water, the oxygen in the smoker may afterall originate from our (assumed biologically mediated) oxygenated atmosphere. The only chemical equations on the mine-trailing page that does not involve free oxygen reduces ferric iron to ferrous - that the inverted result. Carsten |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
Carsten Troelsgaard wrote:
"John Curtis" skrev i en meddelelse oups.com... Wet, strongly acidic and oxidizing environment results from a process called acid mine drainage, which is strongly associated with bacteria: http://www.mines.edu/fs_home/jhoran/ch126/microbia.htm Acid mine drainage converts pyrite into iron (lll), sulfate,hematite, goethite and jarosite, all found at Meridiani. The source of pyrite is the black smoker, which is invariably accompanied by bacteria even before the chimney is formed: http://66.102.7.104/search?q=cache:O...ystem%22&hl=en The article reference hydrogensulfid oozing out of the smoker, not pyrite. Hydrogen sulfide is accompanied by iron, copper and zinc. On contact with water, they precipitate as insoluble salts: pyrite, chalcopyrite and sphalerite. Pyrite is a (biotically mediated) diagenetic product of seawater sulfates and iron. I've never met pyrite in any rock that doesn't have a marine progenitor, but my experience is no standard for comparison. The article also mentions oxygen as part of the metabolic process, and I consider that an obstacle for comparing it to martian conditions. Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en Ancient Mars had more water and thus more oxygen. I'm not aware of how oxygen is released from MORB processes, and if you acknowledge the smoker as a recirculation of initially cold oxygenated water, the oxygen in the smoker may afterall originate from our (assumed biologically mediated) oxygenated atmosphere. The only chemical equations on the mine-trailing page that does not involve free oxygen reduces ferric iron to ferrous - that the inverted result. There is little free oxygen at the black smoker. There is no quartz, no hematite or any other mineral that requires free oxygen for its formation. The minerals at the black smoker are insoluble salts of oxyanions, such as silicate, phosphate, vanadate, chromate and sulfide salts. All of these minerals require water for their formation. http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif John Curtis |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
"John Curtis" wrote in message oups.com... Carsten Troelsgaard wrote: "John Curtis" skrev i en meddelelse oups.com... Wet, strongly acidic and oxidizing environment results from a process called acid mine drainage, which is strongly associated with bacteria: http://www.mines.edu/fs_home/jhoran/ch126/microbia.htm Acid mine drainage converts pyrite into iron (lll), sulfate,hematite, goethite and jarosite, all found at Meridiani. The source of pyrite is the black smoker, which is invariably accompanied by bacteria even before the chimney is formed: http://66.102.7.104/search?q=cache:O...ystem%22&hl=en The article reference hydrogensulfid oozing out of the smoker, not pyrite. Hydrogen sulfide is accompanied by iron, copper and zinc. On contact with water, they precipitate as insoluble salts: pyrite, chalcopyrite and sphalerite. Pyrite is a (biotically mediated) diagenetic product of seawater sulfates and iron. I've never met pyrite in any rock that doesn't have a marine progenitor, but my experience is no standard for comparison. The article also mentions oxygen as part of the metabolic process, and I consider that an obstacle for comparing it to martian conditions. Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en Umm, that doesn't explain why the earth's atmosphere was largely devoid of oxygen for nearly 3 billion years while there was plenty of water and UV light around during that time. Ancient Mars had more water and thus more oxygen. I'm not aware of how oxygen is released from MORB processes, and if you acknowledge the smoker as a recirculation of initially cold oxygenated water, the oxygen in the smoker may afterall originate from our (assumed biologically mediated) oxygenated atmosphere. The only chemical equations on the mine-trailing page that does not involve free oxygen reduces ferric iron to ferrous - that the inverted result. There is little free oxygen at the black smoker. There is no quartz, no hematite or any other mineral that requires free oxygen for its formation. The minerals at the black smoker are insoluble salts of oxyanions, such as silicate, phosphate, vanadate, chromate and sulfide salts. All of these minerals require water for their formation. http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif John Curtis Silicates require water in order to form? So you are saying that the mantle, which is full of silicates (i.e., olivine, plagioclase, augite, etc.), is also full of water? I think some in this group (sci.geo.geology) might take issue with that claim, especially since olivine is very reactive in the presence of water, usually forming serpentine in the reaction process. george |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
In message .com, John
Curtis writes Carsten Troelsgaard wrote: The article also mentions oxygen as part of the metabolic process, and I consider that an obstacle for comparing it to martian conditions. Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...shington.e du /endsofworld/+%22The+ultraviolet+glow+of+hydrogen+escaping+from +the+Eart h%22&hl=en Oxygen in the atmosphere results from photosynthesis. A search for "The origin of atmospheric oxygen on Earth" gives 508 hits, though the first 8 are about this paper http://www.pnas.org/cgi/content/full/98/5/2170 |
#5
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NASA Rover Helps Reveal Possible Secrets of Martian Life
"John Curtis" skrev i en meddelelse oups.com... Carsten Troelsgaard wrote: "John Curtis" skrev i en meddelelse oups.com... Wet, strongly acidic and oxidizing environment results from a process called acid mine drainage, which is strongly associated with bacteria: http://www.mines.edu/fs_home/jhoran/ch126/microbia.htm Acid mine drainage converts pyrite into iron (lll), sulfate,hematite, goethite and jarosite, all found at Meridiani. The source of pyrite is the black smoker, which is invariably accompanied by bacteria even before the chimney is formed: http://66.102.7.104/search?q=cache:O...ystem%22&hl=en The article reference hydrogensulfid oozing out of the smoker, not pyrite. Hydrogen sulfide is accompanied by iron, copper and zinc. On contact with water, they precipitate as insoluble salts: pyrite, chalcopyrite and sphalerite. Pyrite is a (biotically mediated) diagenetic product of seawater sulfates and iron. I've never met pyrite in any rock that doesn't have a marine progenitor, but my experience is no standard for comparison. The article also mentions oxygen as part of the metabolic process, and I consider that an obstacle for comparing it to martian conditions. Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en Ancient Mars had more water and thus more oxygen. Do you blame me for feeling, that something doesn't add up, when there is no problem making O2 and H2 from H2O, - and insurmauntable problems in turning iron into ironoxide/hematite without the need of biology? I'm not aware of how oxygen is released from MORB processes, and if you acknowledge the smoker as a recirculation of initially cold oxygenated water, the oxygen in the smoker may afterall originate from our (assumed biologically mediated) oxygenated atmosphere. The only chemical equations on the mine-trailing page that does not involve free oxygen reduces ferric iron to ferrous - that the inverted result. There is little free oxygen at the black smoker. There is no quartz, no hematite or any other mineral that requires free oxygen for its formation. The minerals at the black smoker are insoluble salts of oxyanions, such as silicate, phosphate, vanadate, chromate and sulfide salts. All of these minerals require water for their formation. http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif John Curtis |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
George wrote:
"John Curtis" wrote in message Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en Umm, that doesn't explain why the earth's atmosphere was largely devoid of oxygen for nearly 3 billion years while there was plenty of water and UV light around during that time. One possibility, that it took 2.8 billion years for ultraviolet to destroy enough water so that land could emerge above the water line into an oxygenated atmosphere and experience the great oxygen surge of 2.2 Ga. There is little free oxygen at the black smoker. There is no quartz, no hematite or any other mineral that requires free oxygen for its formation. The minerals at the black smoker are insoluble salts of oxyanions, such as silicate, phosphate, vanadate, chromate and sulfide salts. All of these minerals require water for their formation. http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif John Curtis Silicates require water in order to form? So you are saying that the mantle, which is full of silicates (i.e., olivine, plagioclase, augite, etc.), is also full of water? I think some in this group (sci.geo.geology) might take issue with that claim, especially since olivine is very reactive in the presence of water, usually forming serpentine in the reaction process. Until samples are retrieved from below the Mohorovicic discontinuity, the composition of the mantle remains in doubt, except for hydrogen, helium, neon and abiogenic methane. John Curtis |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
"John Curtis" wrote in message oups.com... George wrote: "John Curtis" wrote in message Oxygen in the atmosphere results from UV splitting of water and hydrogen escaping into space: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en Umm, that doesn't explain why the earth's atmosphere was largely devoid of oxygen for nearly 3 billion years while there was plenty of water and UV light around during that time. One possibility, that it took 2.8 billion years for ultraviolet to destroy enough water so that land could emerge above the water line into an oxygenated atmosphere and experience the great oxygen surge of 2.2 Ga. The only porblem with that is that new evidence points to emerged continents as early as 100 million years after the earth formed. The fact is that the data show that the earth had no substantial levels of oxygen until about 2.2 Ga, and the reason for that is because that is when photosynmthetic bacteria evolved and began releasing substantial amounts of O2 into the atmosphere. Oxygen in the earth's atmosphere is primarily biogenic, John. George There is little free oxygen at the black smoker. There is no quartz, no hematite or any other mineral that requires free oxygen for its formation. The minerals at the black smoker are insoluble salts of oxyanions, such as silicate, phosphate, vanadate, chromate and sulfide salts. All of these minerals require water for their formation. http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif John Curtis Silicates require water in order to form? So you are saying that the mantle, which is full of silicates (i.e., olivine, plagioclase, augite, etc.), is also full of water? I think some in this group (sci.geo.geology) might take issue with that claim, especially since olivine is very reactive in the presence of water, usually forming serpentine in the reaction process. Until samples are retrieved from below the Mohorovicic discontinuity, the composition of the mantle remains in doubt, except for hydrogen, helium, neon and abiogenic methane. John Curtis |
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NASA Rover Helps Reveal Possible Secrets of Martian Life
Jonathan Silverlight wrote Oxygen in the atmosphere results from photosynthesis. A search for "The origin of atmospheric oxygen on Earth" gives 508 hits, though the first 8 are about this paper http://www.pnas.org/cgi/content/full/98/5/2170 One picture is worth a thousand words: http://66.102.7.104/search?q=cache:z...Earth%22&hl=en John Curtis |
#9
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NASA Rover Helps Reveal Possible Secrets of Martian Life
In message .com, John
Curtis writes Jonathan Silverlight wrote Oxygen in the atmosphere results from photosynthesis. A search for "The origin of atmospheric oxygen on Earth" gives 508 hits, though the first 8 are about this paper http://www.pnas.org/cgi/content/full/98/5/2170 One picture is worth a thousand words: http://66.102.7.104/search?q=cache:z...shington.e du /endsofworld/+%22The+ultraviolet+glow+of+hydrogen+escaping+from +the+Eart h%22&hl=en John Curtis You've already posted that link. Would you care to post the figures for the rate of loss of hydrogen? |
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