Odd thin rock. Fossil?

[ClearLake]

Bubbling in vinegar means it is made of calcium carbonate, which is what limestone and therefore travertine are composed of.  Travertine forms when the water from hot springs evaporates leaving behind a deposit of minerals that were contained in the water. 

 

By active, I meant is there an active hot spring currently producing water and forming travertine now (as opposed to a spring that was active a million years ago and left behind deposits, but no longer exists).  My point of that was that if there are travertine deposits being formed now (think Yellowstone, or active cave systems), the covered leaf could be 10 years old or any age since the spring started.  I was just trying to get some feel for the fossil nature of your find, if it was covered say 100 years ago, its still pretty cool, but not technically a fossil.  If the spring is not active, then it is more likely to be a fossil deposit.  

[jnicholes]

There is a waterfall about 250 yards away from the spot. I sent you the exact location in a PM.

[jnicholes]

Hi everyone,

 

I did some research on the edge of the canyon where I found these, trying to figure out terraces and stuff, and I figured out that the canyon was probably formed by the Bonneville flood in the late Pleistocene, about 15,000 years ago.

 

That’s all I’ve been able to come up with so far. I will continue to research, to try and find out the age of these fossils.

 

 

[ClearLake]

Just to clarify some more on this post for future reference.  @jnicholes was kind enough to let me know specifics of the location and collecting via PM and we were able to piece together what the deposits are that he collected this from.  They appear to be caliche type deposits within the Snake River canyon (the canyon cuts through Miocene/Pliocene aged igneous rocks).  From the little bit he and I have read so far, the canyon itself was formed, or at least significantly modified by the great Lake Bonneville megaflood during the Pleistocene.  There are one or more terrace levels within the canyon (that presumably post-date the flood) that have caliche covered surfaces, which apparently if you know which terrace you are on, can be dated.  For those not familiar with caliche, it is not technically a rock but rather a soil hardened and cemented by calcium carbonate leaching out of the rain and/or groundwater.  Those of you living in arid regions are probably much more familiar with this than I am.  

[jnicholes]

Hello everyone,

 

I believe I found the age of the fossils.

 

According to a YouTuber, who did a video on Shoshone falls, which is near where I found the fossils in the canyon, the basalt layer was formed about 2,000,000 to 3,000,000 years ago. Interestingly enough, I found the fossils in the layer right underneath the basalt layer.

 

This give me a rough idea of the age of the fossils, which might be 2,000,000 to 3,000,000 years old, maybe older.

 

Then again, I don’t have much experience with geology and aging fossils from the looks of the canyon.

 

I could be wrong.

 

 

[ClearLake]

4 hours ago, jnicholes said:

According to a YouTuber, who did a video on Shoshone falls, which is near where I found the fossils in the canyon, the basalt layer was formed about 2,000,000 to 3,000,000 years ago. Interestingly enough, I found the fossils in the layer right underneath the basalt layer.

 

This give me a rough idea of the age of the fossils, which might be 2,000,000 to 3,000,000 years old, maybe older.

 

Then again, I don’t have much experience with geology and aging fossils from the looks of the canyon.

 

I could be wrong.

Your age assumption would be true if you found the items in the actual canyon wall, within the layers of basalt that blanket the area.  But from what you told me and showed me in pictures, you did not find the items in the actual canyon wall, but in the talus slopes that cover the area from the canyon wall to the flood plain.  The geologic map for your area vey clearly shows Quaternary aged talus deposits from the area you indicated the items originated (see snippet below, the grey colored area labelled Qt are the talus deposits).  Talus is the rock and debris that has fallen off the cliff wall over time and formed a pile down to the flood plain.  It will consist of chucks of basalt (can be any size from pebble to car sized boulders) intermixed with weathered sand and clay, old river deposits, wind blown deposits, caliche, etc.  The main point is, these talus deposits all are younger than the basalt itself and in fact have to be younger than the canyon cutting event (~15,000-18,000 years ago). And when you say you found them "right underneath the basalt layer", that doesn't make much sense because the basalt in the Twin Falls area is 500-5000' thick, extending well beneath the river level.  There are many small individual flows within the basalt, but its overall thickness is quite a bit.

 

Yes, what you found is physically below the basalt showing in the cliff face, but that is due to gravity, not deposition before the basalt.  I will repeat what I said before, from what you have told me about where you found them, you items are somewhere between 1 and15,000 years old and most likely closer to the younger end.

 

 

Here is a Google Street View from down about river level looking back towards Perrine Coulee Falls.  The Canyon wall is between the red lines, every thing below the lower red line is talus slope and not in place basalt.  The basalt extends much deeper than what you can see here.  I hope this helps make it clearer for you.

 

Edited February 14, 2023 by ClearLake

[jnicholes]

My mistake, thanks for pointing that out.
Like I said, I’m not that experienced.