tracer Posted April 11, 2009 Share Posted April 11, 2009 not too long ago i kind of got interested in the processes by which "fossils" become fossilized, which ended up leading me to the conclusion that bacteria sort of rule the world. then i started wondering about carbonates and sulfates and iron's role in so many things and pyrite and marcasite and well - a little learning is a dangerous thing. is there a point to all this? well, yeah, kinda. the grand teen and i at times find fossils that are apparently preserved with a metallic twist to them. i'm putting three pictures below to illustrate what i mean. one is a bone with obvious iron content, but also gunmetal colored, bluish "plated" looking areas. then there's an alligator osteoderm which is also very bluish and metallic looking. then there's some pieces of turtle shell which have the bluish, platey look. i'm leaning toward thinking the bluish metallic look is caused by maybe an iron sulphate/sulphide juxtaorbitionation. but really, what i wanted to know is....what do YOU think, thinkers of the world? (i almost get stage fright sometimes when i realize i'm talking to everyone on the planet who has internet access. that's a fair amount of people.) Link to comment Share on other sites More sharing options...
Pool Man Posted April 11, 2009 Share Posted April 11, 2009 Hi, I researched this topic a bit also. I believe the bluish black is manganese. I also read that its common for fossils(in florida at least) to contain rare earth elements,but I havent figured out what that means yet Link to comment Share on other sites More sharing options...
Phoenixflood Posted April 12, 2009 Share Posted April 12, 2009 I think we all need to go out and get metal detectors The soul of a Fossil Hunter is one that is seeking, always. Link to comment Share on other sites More sharing options...
Seldom Posted April 12, 2009 Share Posted April 12, 2009 Hi, I researched this topic a bit also. I believe the bluish black is manganese. I also read that its common for fossils(in florida at least) to contain rare earth elements,but I havent figured out what that means yet The beach on the Island has pockets of blue black sand that I was told by A&M was high in magmanese. Even coins I dig will metal detectoring or black and modern shells look like fossils. Think I might go get 5gls of it and put some chick bones in it just to see will let you know. Seldom Galveston Island 32 miles long 2 miles wide 134 bars 23 liquor stores any questions? Evolution is Chimp Change. Life is not about waiting for the storm to pass; it's about learning to dance in the rain! "I like to listen. I have learned a great deal from listening carefully. Most people never listen." Ernest Hemingway Link to comment Share on other sites More sharing options...
PaleoRon Posted April 12, 2009 Share Posted April 12, 2009 The two most common metallic stains I encounter are iron (usually red, brown, or yellow) and manganese (usually black). Blue can be from the phosphate mineral vivianite. I have attached a few pics that show a sample of crystalized vivianite that was colorless when I found it but turned blue when it was exposed to sunlight, and a vivianite stain on the tip of my Siberian mammoth tusk. The rest of the tusk shows no sign of vivianite. The crystal specimen was found in a layer just below a Miocene marine bonebed and it is probable that it was formed from phosphate that leached out of the bones in the upper layer. Link to comment Share on other sites More sharing options...
tracer Posted April 12, 2009 Author Share Posted April 12, 2009 it seems like manganese gets thrown around a lot as the basis for blackness in stuff, and i've got some crystals tj and i got out of a mountainside in arkansas that are manganese stained, but i've been more of the opinion that the high frequency of black coloration of fossils may, as i've previously said, be due to bacterially precipitated iron sulphate. we need a biochemist or something on the forum to give me the straight poop all all my wonderings. a lot of black stuff also seems to be from carbon from ancient volcanic activity. some of the blue platey stuff i've found has even had a fine coating of oxidation on it. wondering about this is all quite fascinating, particularly in that it distracts me frequently from things i ought to be doing... Link to comment Share on other sites More sharing options...
Seldom Posted April 12, 2009 Share Posted April 12, 2009 Yes Tracer we need a biochemist to help Galveston Island 32 miles long 2 miles wide 134 bars 23 liquor stores any questions? Evolution is Chimp Change. Life is not about waiting for the storm to pass; it's about learning to dance in the rain! "I like to listen. I have learned a great deal from listening carefully. Most people never listen." Ernest Hemingway Link to comment Share on other sites More sharing options...
Auspex Posted April 12, 2009 Share Posted April 12, 2009 Did someone mention biochemestry? As it applies to fossil preservation, it is a field which can overturn time-honored "facts" and provide new insight into the organism itself. Here's a link to a paper which shows that "carbonized" feather traces are not the result of the action of feather-degrading bacteria, but are the robust remains of melanin. What this little piece of chemistry leads to is that a feather's color pattern can thus be preserved, which can then lead to studied speculation about the reasons for patterned plumage. All of a sudden, paleo-behavior has entered the picture, thanks to a couple of chemists! Paper: http://www.eeb.yale.edu/prum/pdf/Vinther_etal_2008.pdf Yes indeedy, I wish I had a better grounding in biochemestry... "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Shamalama Posted April 12, 2009 Share Posted April 12, 2009 Iron Sulfate is commonly know as Pyrite and when that oxidizes in the presence of water (hydroxide) it can become an oxyhydroxide mineral called Goethite which is a black, slightly dull mineral or or Limonite which is a little redder. (Thank you Wikipedia and my college geology courses!) This is why some fossils that are preserved with Pyrite slowly tarnish over time to a dull black. Here is an OLD picture I took of a pyrite cube in my collection. The exterior of the piece is mostly altered and only a small amount of the original gold color is left near the top. Dave -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
ashcraft Posted April 13, 2009 Share Posted April 13, 2009 The important thing to remember is that most of these minerals are being formed in an anoxic environment, where there is little or no bacterial growth, which , if present, would eat the fossil. If there was oxygen present, different minerals would form, or the future fossil would break down completly. What metals are being incorporated into the structure are based on what is present in the ground water. There are some bacteria that do feed on chemical compounds, generally sulfur based (chemoautotrophs), I know that some bacteria can feed on iron sulfide (pyrite) in the presence of oxygen, and there maybe some bacteria that use pure metals in reactions due to their reducing nature (seems like I remember something about iron in this respect......) -I think what I am trying to say is: -Fossils form because the dead organism does not rot -The easiest way to retard rotting is rapid burial in an impervious clay type soil -Clay, or other burying strata, including water, contains many minerals whose metals undergo replacement reactions with the material in the dead organism -Depending on what mineral are present, and the amount of free oxygen, you get different mineral deposits on and in the fossil -These mineral deposits will change over time, as metal ions in the groundwater, etc. change. Of course this is my opinion only, I don't have much experience in geologic chemistry Brent Ashcraft ashcraft, brent allen Link to comment Share on other sites More sharing options...
Auspex Posted April 13, 2009 Share Posted April 13, 2009 ^ What Aldo Leopold referred to as "that dark laboratory we call soil". "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
tracer Posted April 13, 2009 Author Share Posted April 13, 2009 actually, the more i look into the matter, the more i'm learning that the intuitive, logical view of fossilization isn't really how it all works. if you're interested, you might read up on Geobacter metallireducens and Geobacter sulfurreducens. these types of anaerobic bacteria do their thing without access to normal oxygen sources and precipitate out solids that add to the ones already present in the environment. there were apparently periods in the past when the entire oceans went anoxic for a while, and it seems as if bacteria have gotten really, really good at thriving in some bizarre environments. i've read that there are many different bacteria that can live in diesel fuel, for instance. and if you want to get gross, apparently anaerobic and aerobic bacteria can team up to deliver a one-two punch in environments like sewage treatment to ruin fixtures by first reduction to get hydrogen sulfide and then oxidation to get sulfuric acid. i gotta go see if i can find an article i want to link to. be back. maybe. Link to comment Share on other sites More sharing options...
tracer Posted April 13, 2009 Author Share Posted April 13, 2009 well, anyway, i don't have any patience at the moment, but the following is one example of stuff i've found about all the chemical weirdness that bacteria do when they're throwing pyrite into your fossils... buy this book Link to comment Share on other sites More sharing options...
mommabetts Posted April 14, 2009 Share Posted April 14, 2009 Very informative, thanks for posting. Link to comment Share on other sites More sharing options...
Guest solius symbiosus Posted April 14, 2009 Share Posted April 14, 2009 I too have been reading of late about pyrite preservation; specifically, its mechanism in soft-body preservation in the Beecher Trilobite Beds. Anyway, here is another book found on google that might be worth a peek: Exceptional Fossil Preservation Link to comment Share on other sites More sharing options...
tracer Posted April 14, 2009 Author Share Posted April 14, 2009 I too have been reading of late about pyrite preservation; specifically, its mechanism in soft-body preservation in the Beecher Trilobite Beds. Anyway, here is another book found on google that might be worth a peek: Exceptional Fossil Preservation how dare you think about the same stuff as me! i thought about it first! <leaping at the screen, clutching the laptop and rolling around on the ground with it, kicking at it with my feet like a deranged cat would> now look what you made me do! you owe me a laptop! i'll read the link later. right now i have to go figure out the logical contradiction that exists from the fact that i finished this post after supposedly trashing the machine i was hacking it on... Link to comment Share on other sites More sharing options...
Auspex Posted April 14, 2009 Share Posted April 14, 2009 ...i'll read the link later. right now i have to go figure out the logical contradiction that exists from the fact that i finished this post after supposedly trashing the machine i was hacking it on... <sigh> another tricky day on planet tracer... "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
tracer Posted April 14, 2009 Author Share Posted April 14, 2009 omg, sorry, i was in such a mood during that last post. but since then, i've totally bogged down (there's a pun in there somewhere) trying to understand redox situations. to make matters worse, i've discovered that apparently pyritization can occur to some extent in living critters, which strikes me as some sort of redox paradox atrox. (see there's gold in them there forams!). so anyway, i'm wondering just how far i can take it with my attempt to understand electron transfers and such. i'm also wondering how much of this i knew back when my brain was young and attempting to master high school and college chemistry. sort of makes me regret that great axiom of youth. oh, you don't remember the great axiom? i think it was usually used at garbage-can-punch parties and went something like, "SURE drinkin' kills brain cells, but only the WEAK ones!!!!" of course i'm joking, impressionable yute, and you still need to go off to college, for two reasons. first, because it's a whole lot easier to keep you out of the house than to get you out of the house in the first place. and second, because that's your last opportunity to try to meet a bunch of upwardly mobile, fine-looking members of the available kind and hook yourself to a rocket before you have to look for gainful employment on your own. try hanging out and "studying" in the engineering section of the library. engineers are steady earners. gotta go study chemistry some more. hoping i'll just immerse myself in it enough that i'll learn something through osmosis. Link to comment Share on other sites More sharing options...
Shamalama Posted April 15, 2009 Share Posted April 15, 2009 I too have been reading of late about pyrite preservation; specifically, its mechanism in soft-body preservation in the Beecher Trilobite Beds. Anyway, here is another book found on google that might be worth a peek: Exceptional Fossil Preservation Maybe it's just me, but I think "Framboidal Pyrite" would make a great band name. Dave -Dave __________________________________________________ Geologists on the whole are inconsistent drivers. When a roadcut presents itself, they tend to lurch and weave. To them, the roadcut is a portal, a fragment of a regional story, a proscenium arch that leads their imaginations into the earth and through the surrounding terrain. - John McPheeIf I'm going to drive safely, I can't do geology. - John McPheeCheck out my Blog for more fossils I've found: http://viewsofthemahantango.blogspot.com/ Link to comment Share on other sites More sharing options...
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