Fossil or Pseudofossil?
Click on pictures to Magnify
image
1 
image 2
The “fossil” measures 8 mm x 6 mm
Click Here Original Large (unedited) picture of image 2
Images captured with a Dino-Lite digital microscope
This specimen was found in central Colorado in the Pennsylvanian Minturn Formation.
The Minturn Formation contains mostly near-shore marine deposits, with typical
late
Paleozoic invertebrates. This specimen was found associated with brachiopods,
crinoid stems, gastropods, and echinoids plates.
I have been trying to decide if this is a fossil or
not. If it is a fossil, I would appreciate
help with determining what kind of fossil it is.
Dennis Gertenbach
Viewer Comments
1. Possibly a tiny weathered echinoid or crinoid plate with visible bumps at 12 O'clock to 5 O'clock.
2. My opinion - not a fossil. More along the lines of a small septarian nodule cut in half.
3. It could be a remnant "pond"
of original evaporitic calcite or gypsum(?) lamina, or an in-filling (replacement)
of original (evaporitic?) lamina introduced during the course of sediment
de-watering or later diagenetic processes.
Some "rivulets" of the same(?) mineral(s)
appear to flow into-or-out from the "oval pool's northern shore."
Because the mineral appears to be more resistant to weathering than the limestone(?)
matrix I will suggest it is not gypsum or calcite; though possibly aragonite;
but more likely barite, strontianite, or a layered encrustation composed of
more than one mineral.
Microbial colonies, including stromatolite-builders,
inhabit many environments, including ancient sabkha-type marginal-marine depositional
systems evident in the Minturn Fm. strata. It seems possible to me that it
may be a fossil of a microbial colony preserving original dessicated "sun-cracked"
surface texture.
Go-Back Text
Menu or Thumb
Menu
Home
Page
Photo
Album search engine
search the Photo Album or the Web