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Platte River Rock, Denver


Jdeutsch

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I have a box of petrified Jasper wood that I collected over the years in Denver in the Platte piver and tributaries. The geologic strata information is complex but spans the Cretaceous-Paleogene boundry

I was looking at some of the wood pieces that I have in a small pile today and saw what looks like a piece of bone- the piece is somewhat triangular from the end- so it has 3 sides, more or less, each about 5x10 cm, and the two 'triangular' ends are about 5 cm high.

If it is bone, it would be from something large- depending on where it came from (as material from both sides of the K-Pg boundary could wash into the Platte) , and assuming bone- it could be dinosauer or mammal..

I expect that no one can say much about this rock, but would appreciate any opinions

The pictures show each larger surface, with one close up, followed by the two ends

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Hi. Unfortunately I don't think it's bone; I think it's just a rock but I'm not sure what rock type it is.

Daniel

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I'm no expert on bone, but your specimen looks to me to be a piece of heavily calcified limestone. Water movement through it made the swiss cheese holes, and dissolved some of the calcium carbonate and deposited it in other places. We get that a lot in certain types of limestone formations here in Florida. You might find some fossils in the rock, though, and also some voids of where fossils used to be, so they are worth a look-over.

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vuggy limestome,alright.Those holes are not osteocyte lacunae

Osteocyte Lacunae is the name of my band. :P

-Dave

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I'm no expert on bone, but your specimen looks to me to be a piece of heavily calcified limestone. Water movement through it made the swiss cheese holes, and dissolved some of the calcium carbonate and deposited it in other places. We get that a lot in certain types of limestone formations here in Florida. You might find some fossils in the rock, though, and also some voids of where fossils used to be, so they are worth a look-over.

Fantastic explanation!

I agree completely with it

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I am not convinced that it is limestone. The polish and pattern of wear suggests quartz or chert. Limestone is soft and usually does not last long in a river unless the source is nearby. Jdeutsch, does a steel knife scratch the rock? Chert will not scratch with a steel knife. Also Jdeutsch, since it is not bone, consider taking a piece off the rock so that we can see what is inside. Take a macro shot of the inside of the rock. There is a chance that the rock might have fossils inside. I have seen chert from the Mississipian Redwall Limestone in Arizona that has carbonate and silicified fossils inside.

My goal is to leave no stone or fossil unturned.   

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It looks like microcrystalline quartz

does not react with strong HCl

Does not scratch with iron tools

has bands like agate or jasper- see pic 1

could be degraded petrified wood- the river produces beautiful specimens of brown jasper wood - see pic 2

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