Raindrop impressions Trace fossil – raindrops

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IMG_1073_FossilRaindrops_600.JPG

Trace fossils Raindrop impressions, Triceratops Trail, Dinosaur Ridge, Golden, Colorado.

16 Comments

just fyi, this is not a trace fossil. It is an inorganic sedimentary structure in the same category as ripple marks, flute casts, etc. Trace fossils are the result of organism-sediment interaction.

So footprints are trace fossils, but ripples are not? How should I have titled the entry? Fossilized raindrops? The trail marker said “Raindrop impressions.”

Reminds me of a classic song:

Raindrops keep fallin’ on my head

Sigh. I have decided to remove these lyrics because they are subject to copyright. You may find them here, among other places. – Matt

Right- trace fossils are usually sedimentary structures, but most sed structures aren’t trace fossils. “Jurassic Raindrop Impressions” would be a good title. (I’m assuming it’s Morrison Fmt).

Cool photo!

“Jurassic Raindrop Impressions” would be a good title. (I’m assuming it’s Morrison Fmt).

No idea – I just take the pictures. But the link above says 68 Ma, which I guess is late Cretaceous and a bit recent for the Jurassic.

Matt Young said:

So footprints are trace fossils, but ripples are not? How should I have titled the entry? Fossilized raindrops? The trail marker said “Raindrop impressions.”

Ripples ???

Raindrops !?!

Clearly evidence of the flood.

Ergo, all that is known of science is obviously wrong.

Therefore you have now absolutely proven that everything poofed into existence on a sunny Tuesday afternoon about 6006 years ago.

Around tea time.

Thanks a lot Matt, you just ruined it for everybody.

This comment has been moved to The Bathroom Wall.

Byers, dear, the flood is supposed to have covered all the Earth. If there was sediment soft enough to have recorded the impressions of the raindrops that preceded the flood, how is it that these impressions were not washed away by the raging waters thereof?

First off, this is a difficult image to interpret without having the actual specimen in front of you to observe more closely. Having said that, I am not so sure these are raindrop impressions.

Raindrop impressions are generally evenly distributed across a bedding plane, but these appear to be absent from some portions of what appear to be a continuous bedding surface.

On a similar note, these impressions seem to define more linear features, and some appear to join up with others to produce distinct linear features that are raised above the bedding surface.

Also, the size distribution appears non-random.

Raindrop impressions are usually far more circular than these are here, especially in the region near the center of the image.

Something “funky” appears to be going on near the top right of the image, The impressions appear to cut across bedding planes, although this is the observation that could benefit the most from having the actual specimen on hand.

There are a few other things I see in the image, but these are the most confusing to me.

I agree with EJH: it’s hard to tell from the photo, but it’s not clear that these are a good match for standard raindrop impressions. Compare with the following better examples:

http://www.scientificamerican.com/m[…]anular_1.jpg

http://farm5.static.flickr.com/4110[…]1ee5a41d.jpg

http://lh4.ggpht.com/_SdomJ52ojTc/S[…]IMG_0311.jpg

http://gsabulletin.gsapubs.org/cont[…]F2.small.gif

As it happens, I attended a meeting of the Colorado Scientific Society last night. They are all geologists, and I showed them the picture. About 50 ms later, they said, “Those are not raindrops!” And indeed they are convex, very unlike the concavities in the links provided by N. Wells. One of the geologists speculated that they are concretions, but the consensus was that they are not raindrops.

Finally, I got an e-mail from someone at Dinosaur Ridge, who said that there was “another theory that these are gas bubbles from decomposition.” He also said that there is a better sample of raindrops nearby; I will check those out next time I am in Golden, but that may be a while.

I was also thinking that they might be concretions (check out http://www.geology.wisc.edu/astrobi[…]k2_img1.html ). However, the convexity is not absolute disproof, as the undersides of raindrop impressions would be convex downward, if we were looking at the underside of the bed rather than its top. The problem is more that they don’t seem to be restricted to one surface and are nonrandom in their distribution.

This comment has been moved to The Bathroom Wall.

How do you know this is from rain drops? I could think of many other explanations. Guess it is proof that raindrops have evolved. Watching the “smart guys” debate this shows how you guys pull this stuff out of your A_ _ to come up with an explination when you really just don’t know. Why not just admit. We are uncertain. It might be this but it might be something else. that is why I laugh when scientist take some fossil and extrapilate some unprovable theory. Really it is just speculation just like this. I have watched debates ove so called winged dinosaurs where scientists make wild assuptions to prove it is a predosesor to birds. Then another sees the same fossil and has a completley differnt spin. In the end it is just that Spin to prove a pre concieved belief or notion. Just like this. you want to believe this is rain drops.

azjones said:

How do you know this is from rain drops? I could think of many other explanations. Guess it is proof that raindrops have evolved. Watching the “smart guys” debate this shows how you guys pull this stuff out of your A_ _ to come up with an explination when you really just don’t know. Why not just admit. We are uncertain. It might be this but it might be something else. that is why I laugh when scientist take some fossil and extrapilate some unprovable theory. Really it is just speculation just like this. I have watched debates ove so called winged dinosaurs where scientists make wild assuptions to prove it is a predosesor to birds. Then another sees the same fossil and has a completley differnt spin. In the end it is just that Spin to prove a pre concieved belief or notion. Just like this. you want to believe this is rain drops.

Where to start?!?

First, I should point out to azjones that he really needs to read more carefully. Matt Young posted this image with the caption “Trace fossils Raindrop impressions,” but this was quickly modified when he crossed out “Trace fossils” after it was pointed out that raindrop impressions are not trace fossils. Matt Young did not hesitate or cringe (I don’t think) when this mistake was pointed out to him by other scientists, he simply updated his caption. Later I posted a comment and pointed out some inconsistencies I noticed with these features being called raindrop impressions, and several other geologists/earth science types quickly agreed with me. We have more training in recognizing raindrop impressions in the rock record; it’s not “rocket science” or “brain surgery” as the sayings go, but clearly our training helped us make this call.

We did not “pull this stuff out of our A**” as you so eloquently put it. We simply observed the image and recalled past experiences with raindrop impressions, both in the rock record and in Recent examples. There is always a bit of uncertainty in extrapolating from past experiences, and I am sorry if you mistook the statements by us (me, N. Wells, the members of the Colorado Scientific Society, and the person at Dinosaur Ridge who communicated with Matt Young) as hubris or out-of-control speculation. Pointing out that these are not raindrop impressions was not such a tough call – not nearly as tough as figuring out what they really are. Pondering whether these might be gas bubbles or concretions is just that, pondering. In other words, I don’t see any cause for you rant; this is not “science run amok” as you seem to imply; and your fossil extrapolation example is more than a bit off base.

I do not know you by any previous posts you have made on this site, so I might be in error thinking that you are more inclined to a Bible-based explanation for these features. I will just work with this assumption, and you can tell me I am wrong if that is the case. At any rate, taking one text (i.e., the Bible) and basing a worldview on it entirely leads to more instances of “wild assuptions (sic),” “speculation,” and “differnt (sic) spin” than I care to think about. If you want to use these features as some sort of proof of flood-based geologic concepts, than you are guiltier by far of using these to “prove a pre conceived (sic) belief or notion” than anyone else posting here.

Finally, no one here ever claimed to be smarter than anyone else; we just commented on the image based on our past experiences with raindrop impressions. I will give you a chance, though, to show us what you got. You claim that you “could think of many other explanations,” and I would like to hear some of them. Convince me azjones: what are these things?

Nice post. I finally took the plunge and bought an ssl certificate for my site, although I had no idea how confusing it would be to configure. I eventually got things straightened out, but I can’t help thinking there must be a more straightforward way to secure a web site. I dread the switch to IPV6!

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This page contains a single entry by Matt Young published on May 16, 2011 12:00 PM.

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