Formation Question

[icycatelf]

When adding a photo to the Members Gallery, it says to include several details. One of these is Formation.

Thanks to a geologic map, I now know that the hill behind my house is part of the Hyden Formation and the area around the creek below my house is part of the Pikeville Formation (both Pennsylvanian-age). However, the map labels the area between them as Alluvium (Quaternary-age).

So my question is, if I upload a fossil that I found within the Alluvium area that is, for example, clearly Pennsylvanian-age (such as Calamites), would I still say that it came from the Alluvium Formation?

(It should be noted that I'm a surface-collector, so it's possible that these fell from the hill or washed up from the creek during a flood.)

Edited January 20, 2016 by icycatelf

[Fossildude19]

I believe you would try to assign it to the correct formation,based on where it was found,... but if it was found as float - ie: after a flood or lying loose, and if you are unable to identify the formation based on color of the matrix or differences in fauna/flora, ... you could label it as "Found as float,... possibly from the Hyden or Pikeville formations."

If one formation is entirely marine deposits, and the other formation is terrestrial deposits, you could assign the fossil to the corresponding formation, based on the type of fossil.

It is obviously more difficult if both are terrestrial or both are marine in origin. In this case, if both formations share fauna/flora, ... again, the difficulty is present.

Lacking that type of clear cut delineation, I would go with the "Found as float,... possibly from the Hyden or Pikeville formations" designation.

The alluvium designation indicates younger topsoil or strata dividing the two formations, and that the formations outcrop in the stated locations on either side.

Interested to see other's opinions on this .

Regards,

[icycatelf]

Thanks for the feedback.

I was mostly asking because I wasn't sure how to label this trace fossil (ID'd as tracks of a marine invertebrate). (I had already uploaded it, but realized that I probably labeled it wrong after further educating myself.) I found it pretty much exactly halfway between each formation. I'm guessing that it actually originated from the Pikeville Formation, as I've not found any info on marine fossils being found in the Hyden Formation but have found one, my recent ammonoid, in/by the creek (Pikeville Formation). There was a big flood years before I moved here that the previous owners said had entirely filled the bottom yard, so maybe it washed up then?

Edited January 20, 2016 by icycatelf

[Herb]

rocks fall down hill, it would probably be from the higher up formation. Unless from a stream bed that is between both formations then who knows

[Herb]

nice quality pix, btw

Edited January 20, 2016 by Herb