Beaumont Formation Colors

[darrow]

I'm accumulating these Beaumont Formation pleistobits from a very small dredge spoil area and noticed, perhaps not suprisingly, the color of the fossils somewhat parallels the distinct colors of clays in the dredge spoils. I've just kinda assumed tan fossil/tan clay, brown fossil/brown clay, black fossil/black; but everything has been chopped up by the dredge and the tides and currents tend to wash the fossils clean before I picke them up so I'm not really sure if that the case.

Edited September 9, 2011 by darrow

[darrow]

Anyway, while sorting bits by color and assembling matching pieces, I noticed a few pieces with layered alternating colors so I was thinking maybe the layered colors were the result of the bone being shuffled around to different environments that formed the different Beaumont clays during the fossilization process and then I found this really dark brown/black black fossil bone fragment incased in this very light gray hardened clay/rock stuff.

So is this "typical" for Beaumont formation colors and is my reasoning even in the ballpark?

Darrow

[tracer]

bone, teeth, and clay don't necessarily assume the same colors when they are in proximity to each other for long periods of time. it has to do with whether minerals are being added to the fossils, and if so, by what process, and to what degree. if minerals are being added by a purely osmotic-type process where dissolved minerals in the groundwater are permineralizing the fossil, then there could be a strong similarity in color, since the same mineral is going through everything.

but if the color is being caused by something like bacterial action, the fossil may be the only thing being "worked on" and changing color.

additionally, the porosity of the things and the depth at which they're buried and length of time there affects things. picture if you had a vat of dye, and you tossed in a hard rock, a porous and soft rock, a piece of wood, some cloth, and a porcelain tile. would all the things come out the same color? not at all. i think on some of your bones, the stuff is different ages, plus some of it may have lain exposed to the sunlight for a while and bleached back out a bit. you can find bones where they are differentially colored based on exposure. the end that was in the ground stayed dark, and the end that was in the sun for a month or a year before you found it gets bleached out.

as far as the "layered" look where a fossil has different colors, i think that has more to do with the composition of the fossil than it being shifted around to different locations. if some layers of the fossil are harder/denser than others, then you'll get different colors. for the bones that are dark on the outside and light just underneath, i would be suspicious of their age as possibly being much younger than other stuff.

a final point is that i would not assume that you are finding exclusively beaumont material in that you're looking at dredged stuff from an area that may have been dredged multiple times in the past and it's just really sort of a snarge shoot what you are looking at.

but having said all that, the colors do give clues to the conditions in which the fossils formerly existed, so sorting them isn't a bad idea. have fun with your hunting.

[Vordigern]

bone, teeth, and clay don't necessarily assume the same colors when they are in proximity to each other for long periods of time. it has to do with whether minerals are being added to the fossils, and if so, by what process, and to what degree. if minerals are being added by a purely osmotic-type process where dissolved minerals in the groundwater are permineralizing the fossil, then there could be a strong similarity in color, since the same mineral is going through everything.

but if the color is being caused by something like bacterial action, the fossil may be the only thing being "worked on" and changing color.

additionally, the porosity of the things and the depth at which they're buried and length of time there affects things. picture if you had a vat of dye, and you tossed in a hard rock, a porous and soft rock, a piece of wood, some cloth, and a porcelain tile. would all the things come out the same color? not at all. i think on some of your bones, the stuff is different ages, plus some of it may have lain exposed to the sunlight for a while and bleached back out a bit. you can find bones where they are differentially colored based on exposure. the end that was in the ground stayed dark, and the end that was in the sun for a month or a year before you found it gets bleached out.

as far as the "layered" look where a fossil has different colors, i think that has more to do with the composition of the fossil than it being shifted around to different locations. if some layers of the fossil are harder/denser than others, then you'll get different colors. for the bones that are dark on the outside and light just underneath, i would be suspicious of their age as possibly being much younger than other stuff.

a final point is that i would not assume that you are finding exclusively beaumont material in that you're looking at dredged stuff from an area that may have been dredged multiple times in the past and it's just really sort of a snarge shoot what you are looking at.

but having said all that, the colors do give clues to the conditions in which the fossils formerly existed, so sorting them isn't a bad idea. have fun with your hunting.

thanks for the great info Tracer really helps clear up some things I was wondering about