Coprolite

[Scottnokes2015]

Hello fellow Fossil friends.

 

I have what I was told is Coprolite. I've seen so much fake ones at shows that I never know what's real or what's fake 

I'm member of a very well respected and major Fossil club and they said "as far as they know, it's real." I got conflicting answers. Every time I go in my fossil cabinet, I just can't tell if I picked up a dud or a genuine piece.

The details are:

Miocene epoch

Wilkes fm

Salmon Creek

Washington

Thank you for any help anyone can assist me with this

[Scottnokes2015]

Photo#2 other side

[JohnBrewer]

I’m not convinced. Looks more like an iron concretion to me . @Carl @GeschWhat @ynot Will be able to help. 

[Darktooth]

I agree that it looks like an iron concretion. Could be wrong though.

[Al Tahan]

If you can try to measure the density of the specimen. Use the displacement method for volume and a food scale for weight. If it’s and iron concretion it should be considerably more dense than a typical piece of shale/sandstone/siltstone etc. 

 

Does it feel kinda “heavy” for its size?....I know really vague question lol

[abyssunder]

I like those little "blueberries". It looks like they have a little hole at one end. Very interesting.

[ynot]

I agree with a non fossil concretion.

[Mark Kmiecik]

This really piqued my curiosity, so I did some online searching and found this:

 

DEPOSITIONAL ENVIRONMENTS OF THE WILKES FORMATION AT SALMON CREEK, WASHINGTON: SOURCE OF SIDERITE 'COPROLITE' CONCRETIONS

YANCEY, Thomas E., Geology & Geophysics, Texas A&M University, College Station, TX 77843-3115, yancey@geo.tamu.edu and MUSTOE, George, Geology, Western Washington University, Bellingham, WA 98225, mustoeg@cc.wwu.edu The Wilkes Formation exposures near Toledo, Washington are famous for the occurrence of coprolite-shaped siderite concretions in exposures along Salmon Creek, where flat-lying strata are exposed in bluffs up to 30 m high. Continued documentation (after Mustoe, 2001, GSA Bull.v.113, p.673) of these strata in SE1/4 Sec. 34, R.1W, T.1N reveals a volcaniclastic character for the sediments. Sediments are characterized by poor sorting and high clay content, sparse sand layers and contain common carbonized wood throughout and a rich pollen/spore assemblage. There is a lower unit of volcanic mudflows, a middle unit of interbedded woody lignite and mudstones with thin mudflows and airfall ash layers and a top unit of pond/lake sediments containing siderite concretions. These are overlain by 2 m of terrace gravels with some clasts eroded from Wilkes strata. The lowest Wilkes unit (5 m) consists of multiple fine grained volcanic mudflows, with some coarser, texturally mature sediment, deposited on forested ground, preserving tree stumps in growth position. The mid unit (6 m) has three lignite couplets of lower and upper lignites with large pieces of wood sandwiching a mudstone; couplets are separated by 1-2 m volcanic mudflows. The mid mudstone of a couplet is interpreted as standing water deposit and along pond margins lignites accumulated with wood winnowed from mudflows. A 15 cm airfall ash bed with abundant phenocrysts and coarse vermiform kaolinite prisms provides a poorly constrained age of 11.6�0.4 Ma, indicating an mid-late Miocene age. The top unit (6 m) is mudstones and minor sand that probably accumulated in standing water. Siderite concretions of diverse sizes and shapes are common in the upper 2 m. Deposition is related to nearby volcanic activity generating mudflows that blocked existing drainages. Botryoidal shapes of concretions are common, both as primary forms and as secondary accretions on sinuous masses. Siderite concretions consist of unzoned micritic siderite (crystallite size ~ 10mm) partially altered to hydrous iron oxides. Carbon isotope ratios (d13C = -13.0 to -11.4 o/oo PDB) of siderite indicate that dissolved carbonate was probably generated near decomposing plant matter along with microbial methane production.

[Scottnokes2015]

2 hours ago, Al Tahan said:

If you can try to measure the density of the specimen. Use the displacement method for volume and a food scale for weight. If it’s and iron concretion it should be considerably more dense than a typical piece of shale/sandstone/siltstone etc. 

 

Does it feel kinda “heavy” for its size?....I know really vague question lol

Hi Al, it is pretty heavy for it's size, yeah

[Scottnokes2015]

Well , I've tried a magnet to it and it's not magnetic, so that would rule out iron.

Would slicing it open help confirm anything?

[ynot]

36 minutes ago, Scottnokes2015 said:

I've tried a magnet to it and it's not magnetic, so that would rule out iron.

Most terrestrial iron is not magnetic. Iron in the form of magnetite and sometimes hematite can be magnetic.

Your concretion is made of iron oxide (rust) and will not be magnetic. 

[Scottnokes2015]

12 minutes ago, ynot said:

Most terrestrial iron is not magnetic. Iron in the form of magnetite and sometimes hematite can be magnetic.

Your concretion is made of iron oxide (rust) and will not be magnetic. 

Ok, thanks. So it's just a concretion and not coprolite?

[ynot]

3 minutes ago, Scottnokes2015 said:

Ok, thanks. So it's just a concretion and not coprolite?

Unfortunately, yes.

Nature likes trying to fool us with all sorts of strange things.

[Carl]

I agree with the others that it does not have details consistent with a genuine coprolite. An ironstone concretion makes much more sense. But even more troubling is that it also doesn't at all look like the objects often called coprolites from that locality.

[Scottnokes2015]

Hi everyone, thanks for  all your time  and advice given. I decided to break it open and I don't see the structure of coprolite.

Am I correct? And is this still a iron

Concretion.

[Scottnokes2015]

[ynot]

Looks even more like a iron concretion.

[Scottnokes2015]

6 minutes ago, ynot said:

Looks even more like a iron concretion.

Ok thank you, im disappointed that the vendor ripped me off , but I guess you live and learn. I'm ok with fossils in general but coprolite I just have trouble with. What is a reliable dealer to by coprolite from

[ynot]

1 minute ago, Scottnokes2015 said:

What is a reliable dealer to by coprolite from

Members are not allowed to make dealer identifications in the open forum.

Most dealers are middle market, they have suppliers that they often get their information from (not always correct).

I am not a "buyer" of fossils, I mostly self collect.

I suggest You post pictures (without dealer information) on any pieces You are interested in.

Also, study what coprolites look like. There are many nice examples posted here on TFF.

Good luck with Your endeavor.

[Mark Kmiecik]

@Scottnokes2015 Rather than buying fossils you might enjoy collecting them instead. You're in a great location in that within 150 miles of you there are the following states: Illinois (obviously), Indiana, Kentucky, Tennessee, Arkansas and Missouri. You can build a truly respectable collection there without ever seeing a dino bone. Here in Illinois alone we have the Mazon Creek fossils, and although it's a bit of a ride for you, people from all over the world have heard of it and wish they could personally see and explore.

 

If you gotta buy them, post as many photos of the item in the ID topic on this forum and we will help to determine what it is. The guys that specialize in any particular biota can tell you what it is without fully waking up to do so. Take advantage of their help. They eat it up. So do I. Yup.