Re-examined rock from the North Sulphur

[BobWill]

I posted this a while back and someone identified it as boxwork. The North Sulphur River has Late Cretaceous and Pleistocene fossils. It has been suggested that it may be travertine instead. What do you think?

edit: correction...this piece is not what was identified as travertine. A very similar specimen also found there by another collector looks so much like mine I assumed they were the same. Now the geologist who identified hers says mine may be boxwork afterall. I will try to get permission to post her picture here for comparison.

Edited May 25, 2016 by BobWill

[ynot]

Does not fit with travertine in My opinion.

Tony

[Guguita2104]

Interesting piece...

IMO, it is mineral in origin (travertine is a good hypotesis).

Regards,

[doushantuo]

https://www.researchgate.net/publication/259556084_Travertine_Distinctive_depositional_fabrics_of_carbonates_from_thermal_spring_systems

some structural geology(IJES):

https://www.researchgate.net/publication/226402610_Studying_travertines_for_neotectonic_investigation_Middle-Late_Pleistocene_syn-tectonic_travertine_deposition_at_Serre_di_Rapolano_Northern_Apennines_Italy

Edited May 25, 2016 by doushantuo

[doushantuo]

https://www.researchgate.net/publication/232716862_low-temperature_geothermal_system_Sarteano_Central_Italy_Tectonic_control_on_travertine_and_calcareous_tufa_deposition_in_a

Edited May 25, 2016 by doushantuo

[caldigger]

I'm not seeing Travertine either. Sure fits the boxwork visually.

[abyssunder]

I agree with caldigger. Looks boxwork to me, also.

[DPS Ammonite]

Bob,

The specimen is boxwork.

Boxwork and travertine are very different rocks formed by different processes. Travertine is always limestone that is deposited layer by layer in a parallel or subparallel manner on the surface or in a cavity such as a cave. Travertine is deposited when the calcium carbonate comes out of solution because of changes temperature, pressure, chemistry and presence of living microscopic organisms such as bacteria or algae. Travertine is often precipitated in springs.

Boxwork is a description of the pattern of veins of minerals in rock. The veins can be calcium carbonate but are usually other vein forming minerals such as quartz. Boxwork veins cross the rock in many different planes. When a rock with veins weathers the harder veins stand out in positive relief and create a pattern of polygons or boxes that enclose softer areas in the rocks.

I hope that this helps.

John

[BobWill]

Here is the specimen that was identified as travertine. I can see where it looks different from mine. Since they were found in the same area and look similar I didn't look very closely when I assumed they were the same. Would you all say this is travertine?

[ynot]

I would not call this travertine either. Travertine is a smooth layered stone and seldom has that type of erosion effects. IE it would not have all of those holes in it.

This looks like a fossiliferous limestone that has had the fossils weathered out of it.

Tony

[DPS Ammonite]

Bob,

It looks like travertine formed around plant stems, roots and leaves consistant with spring deposits and deposits from rivers that flow thru limestone rich areas. Is it layered as it looks in the photo? Are those leaf fossils with a central vein in the upper central and lower right corner of the photo? Is it limestone, does it fizz in acid?

Edited May 25, 2016 by DPS Ammonite

[BobWill]

Sorry John, I can't answer any of those questions. This is the sample someone else found that I thought looked like mine. I asked her to bring it to the next DPS meeting so we could do a side-by-side comparison so we'll have to wait to find out. She did say it looked like leaf fossils in it but it's hard to tell from the photo.

[Darktooth]

I have found travertine in two different location in N.Y. which look nothing like your specimen. And traverine is a form of calcite

[abyssunder]

The second one, I think, could be similar to these : http://www.thefossilforum.com/index.php?/topic/26478-tangled-pennsylvanian-tube-worm/?p=648879

http://www.thefossilforum.com/index.php?/topic/64609-help-on-id/

[JohnJ]

Here is the specimen that was identified as travertine. I can see where it looks different from mine. Since they were found in the same area and look similar I didn't look very closely when I assumed they were the same. Would you all say this is travertine?

13265951_10209271863543937_8409017346806371312_n.jpg

This looks similar to the tufa I've found associated with Central Texas spring environments.

[fifbrindacier]

For the first one i also think its a boxwork.

[BobWill]

Thanks for the help everybody. I will see what my geologist friend thinks about all of this. He has only had pictures to go by so it may be a couple of weeks until we have the samples in hand.