<p>Trace fossils are marks or things left behind by living things do their thing,  they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive or beaver dam those would also be trace fossils. Bioturbation is a specific type of traces fossil, marks of disturbances of the sediment itself animals leave behind, trackways and burrows are the classics.</p>
<p>Identifying bioturbation is tricky in a lot of cases, there are thousands of kinds which makes it worse, there is no way to give a direct answer. Your best bet is to find out what particular bioturbation they are referring to.  Burrows, trackways, feeding trails, nest, hold marks the list is endless. there are nearly as many trace fossils as there are organisms that crawl or dig.  Worse they are often very contextual and need examination of  micro-structure.  What is obvious a trace fossil in one formation will look identical to the naked untrained eye to something that is obviously not a trace fossil in a different formation. Generally you want to a specialized experts opinion before if saying something might be bioturbation someplace you don't expect it.</p>
<p>Even from a single location you can have a wide variety of forms,  here are a few <a href="https://www.researchgate.net/publication/284585442_Ordovician_trace_fossils_of_Argentina" rel="nofollow noreferrer">examples</a> from the ordovician, <a href="https://en.wikipedia.org/wiki/Ordovician" rel="nofollow noreferrer">...the second of six periods of the Paleozoic Era, 485.4–443.8 million years ago</a>.</p>
<p><strong>Bioturbation</strong></p>
<p><a href="https://i.sstatic.net/c2FjC.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/c2FjC.jpg" alt="enter image description here" /></a>
<a href="https://i.sstatic.net/9oIJX.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/9oIJX.jpg" alt="enter image description here" /></a></p>
<p>The photos from mars are not likely to be bioturbation but are almost certainly differential erosion of normal chemical variation in rock. They do not have any of the characteristics that scream &quot;this has to be biological activity&quot; like cross cutting bedding planes or parallel patterns. Sedimentary rocks are rarely homogenous and chemical processes combine with erosional ones can produce some weird results. for comparison here are a few things that are definitely NOT fossils.</p>
<p>**Pseudofossils AKA Leaverite **</p>
<p><a href="https://i.sstatic.net/gYecr.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/gYecr.jpg" alt="enter image description here" /></a></p>
<p><a href="https://i.sstatic.net/iJ1mb.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/iJ1mb.jpg" alt="enter image description here" /></a></p>
<p>Pseudofossils are things lake look like fossils to the untrained eye but are just rocks, usually the leftovers of a chemical or erosional process. the term leaverite comes from geologists telling others &quot;just leave're there&quot;</p>

CC BY-SA 4.0
2019-03-02T04:14:02.080Z
Thanks for the thorough answer, it's very helpful!
uhoh
CC BY-SA 4.0
2019-03-01T19:29:30.233Z
2019-03-02T04:13:17.543Z
2020-06-18T08:25:19.090Z
John
<p>There are some unusual structures in recent images from the Mars <a href="https://en.wikipedia.org/wiki/Curiosity_rover" rel="noreferrer">Curiosity Rover</a>'s MAHLI (<a href="https://en.wikipedia.org/wiki/Mars_Hand_Lens_Imager" rel="noreferrer">Mars Hand Lens Imager</a>) shown in the Space.com article <a href="https://www.space.com/39294-mars-rover-curiosity-weird-tube-structures.html" rel="noreferrer">Curiosity Rover Spots Weird Tube-Like Structures on Mars</a>.</p>

<p>An astrobiologist (not at NASA) is quoted as saying that they looked "...remarkably similar to Ordovician trace fossils..." while others are quoted as suggesting that these are visually reminiscent of <em>bioturbation processes</em> on Earth.</p>

<p><strong>Question:</strong> What are Ordovician trace fossils and bioturbation, and what do they look like on Earth?</p>

<hr>

<blockquote>
  <p><strong>below:</strong> NASA's Mars rover Curiosity captured this image on Jan. 2, 2018, with its Mars Hand Lens Imager (MAHLI). Using an onboard focusing process, the robot created this product by merging two to eight images previously taken by MAHLI, which is located on the turret at the end of the rover's robotic arm. Credit: NASA/JPL-Caltech/MSSS</p>
</blockquote>

<p>Cropped section are also included for better viewing, in the first one, sunlight can be seen below the structure near the bottom, showing that it extends somewhat upward from the rock below it.</p>

<p><a href="https://i.sstatic.net/7TPMN.jpg" rel="noreferrer"><img src="https://i.sstatic.net/7TPMN.jpg" alt="enter image description here"></a></p>

<p><a href="https://i.sstatic.net/ek5Xk.jpg" rel="noreferrer"><img src="https://i.sstatic.net/ek5Xk.jpg" alt="enter image description here"></a></p>

<p><a href="https://i.sstatic.net/WidjR.jpg" rel="noreferrer"><img src="https://i.sstatic.net/WidjR.jpg" alt="enter image description here"></a></p>

<blockquote>
  <p><strong>below:</strong> Curiosity Mastcam right image taken on Dec. 15, 2017. Credit: NASA/JPL-Caltech/MSSS</p>
</blockquote>

<p><a href="https://i.sstatic.net/mCfcX.jpg" rel="noreferrer"><img src="https://i.sstatic.net/mCfcX.jpg" alt="enter image description here"></a></p>

CC BY-SA 3.0
2018-01-06T10:40:28.377Z
Are you asking what is a trace fossil/bioturbation in general or are you specifically interested in Ordovician examples?
bon
CC BY-SA 3.0
2018-01-06T10:51:28.327Z
@bon I don't think it's an either/or situation; a short explanation together with a way to see what they might look like would be ideal.
uhoh
CC BY-SA 3.0
2018-01-06T14:29:12.767Z
My suggestion: do some reading about trace fossils and the science of ichnology, then ask a more pointed question. For some examples, try searching for some common trace fossils like Thalassinoides, Ophiomorpha, or Diplocraterion, all interpreted as burrows. (For what it's worth, my reading is that the 'Ordovician' bit was more of an offhand example than any kind of interpretation.)
Matt Hall
CC BY-SA 3.0
2018-01-06T15:50:11.297Z
@kwinkunks Thanks, but it would take quite a long time to become enough of an expert to be able to find examples that look similar to these on Mars. I've asked this question because there may be people here who have enough knowledge or experience so that after they see these Mars images, they will know much better than I would *which examples* on Earth look like what these scientists are likely to be thinking of. This kind of experience can't be gained by browsing Wikipedia. I'm not asking that kind of a question.
uhoh
CC BY-SA 3.0
2018-01-06T17:53:52.423Z
Naming the astrobiologist and citing the quote would contribute a lot to the answerability of this question.
Spencer
CC BY-SA 3.0
2018-01-07T08:25:32.917Z
@Spencer I thought carefully about that when posting and decided in this case against it; let me explain why. First there are several scientists quoted in the article (which is instantly available to everyone from the link in the first sentence without paywall) and I didn't want to start quoting all of them lest the question get unnecessarily complex. Second, I want to keep the focus of the question firmly on examples on Earth, *and not* appear to be asking about these scientists' evaluation of the images, lest it open up a debate on that.
uhoh
CC BY-SA 3.0
2018-01-07T08:25:39.930Z
@Spencer That might be very interesting and could certainly be asked about in a follow-up question if necessary, but for this question let's keep the focus on Earthbound specimens. That's the reason I'd originally had the words "on Earth (as opposed to Mars)" though it was probably way too long that way; https://i.sstatic.net/BpnMc.png
uhoh
<planetary-science><fossils><mars>
What are Ordovican trace fossils, and what do they look like?
uhoh
# What are Ordovican trace fossils, and what do they look like?

(Asked by: username_0 on 2018-01-06)

There are some unusual structures in recent images from the Mars [Curiosity Rover](https://en.wikipedia.org/wiki/Curiosity_rover)'s MAHLI ([Mars Hand Lens Imager](https://en.wikipedia.org/wiki/Mars_Hand_Lens_Imager)) shown in the Space.com article [Curiosity Rover Spots Weird Tube-Like Structures on Mars](https://www.space.com/39294-mars-rover-curiosity-weird-tube-structures.html).

An astrobiologist (not at NASA) is quoted as saying that they looked "...remarkably similar to Ordovician trace fossils..." while others are quoted as suggesting that these are visually reminiscent of *bioturbation processes* on Earth.

**Question:** What are Ordovician trace fossils and bioturbation, and what do they look like on Earth?

---

> **below:** NASA's Mars rover Curiosity captured this image on Jan. 2, 2018, with its Mars Hand Lens Imager (MAHLI). Using an onboard focusing process, the robot created this product by merging two to eight images previously taken by MAHLI, which is located on the turret at the end of the rover's robotic arm. Credit: NASA/JPL-Caltech/MSSS

Cropped section are also included for better viewing, in the first one, sunlight can be seen below the structure near the bottom, showing that it extends somewhat upward from the rock below it.

[![enter image description here](https://i.sstatic.net/7TPMN.jpg)](https://i.sstatic.net/7TPMN.jpg)

[![enter image description here](https://i.sstatic.net/ek5Xk.jpg)](https://i.sstatic.net/ek5Xk.jpg)

[![enter image description here](https://i.sstatic.net/WidjR.jpg)](https://i.sstatic.net/WidjR.jpg)

> **below:** Curiosity Mastcam right image taken on Dec. 15, 2017. Credit: NASA/JPL-Caltech/MSSS

[![enter image description here](https://i.sstatic.net/mCfcX.jpg)](https://i.sstatic.net/mCfcX.jpg)

**Tags:** planetary-science, fossils, mars

> **Comments:**
> **username_1**: Are you asking what is a trace fossil/bioturbation in general or are you specifically interested in Ordovician examples?  
> **username_0**: @username_1 I don't think it's an either/or situation; a short explanation together with a way to see what they might look like would be ideal.  
> **username_2**: My suggestion: do some reading about trace fossils and the science of ichnology, then ask a more pointed question. For some examples, try searching for some common trace fossils like Thalassinoides, Ophiomorpha, or Diplocraterion, all interpreted as burrows. (For what it's worth, my reading is that the 'Ordovician' bit was more of an offhand example than any kind of interpretation.)  
> **username_0**: @kwinkunks Thanks, but it would take quite a long time to become enough of an expert to be able to find examples that look similar to these on Mars. I've asked this question because there may be people here who have enough knowledge or experience so that after they see these Mars images, they will know much better than I would *which examples* on Earth look like what these scientists are likely to be thinking of. This kind of experience can't be gained by browsing Wikipedia. I'm not asking that kind of a question.  
> **username_3**: Naming the astrobiologist and citing the quote would contribute a lot to the answerability of this question.  
> **username_0**: @username_3 I thought carefully about that when posting and decided in this case against it; let me explain why. First there are several scientists quoted in the article (which is instantly available to everyone from the link in the first sentence without paywall) and I didn't want to start quoting all of them lest the question get unnecessarily complex. Second, I want to keep the focus of the question firmly on examples on Earth, *and not* appear to be asking about these scientists' evaluation of the images, lest it open up a debate on that.  
> **username_0**: @username_3 That might be very interesting and could certainly be asked about in a follow-up question if necessary, but for this question let's keep the focus on Earthbound specimens. That's the reason I'd originally had the words "on Earth (as opposed to Mars)" though it was probably way too long that way; https://i.sstatic.net/BpnMc.png  

---

## 1 answers

### Answer by username_4 on 2019-03-01. Score: 7 | Accepted answer

Trace fossils are marks or things left behind by living things do their thing, they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive or beaver dam those would also be trace fossils. Bioturbation is a specific type of traces fossil, marks of disturbances of the sediment itself animals leave behind, trackways and burrows are the classics.

Identifying bioturbation is tricky in a lot of cases, there are thousands of kinds which makes it worse, there is no way to give a direct answer. Your best bet is to find out what particular bioturbation they are referring to. Burrows, trackways, feeding trails, nest, hold marks the list is endless. there are nearly as many trace fossils as there are organisms that crawl or dig. Worse they are often very contextual and need examination of micro-structure. What is obvious a trace fossil in one formation will look identical to the naked untrained eye to something that is obviously not a trace fossil in a different formation. Generally you want to a specialized experts opinion before if saying something might be bioturbation someplace you don't expect it.

Even from a single location you can have a wide variety of forms, here are a few [examples](https://www.researchgate.net/publication/284585442_Ordovician_trace_fossils_of_Argentina) from the ordovician, [...the second of six periods of the Paleozoic Era, 485.4–443.8 million years ago](https://en.wikipedia.org/wiki/Ordovician).

**Bioturbation**

[![enter image description here](https://i.sstatic.net/c2FjC.jpg)](https://i.sstatic.net/c2FjC.jpg)
[![enter image description here](https://i.sstatic.net/9oIJX.jpg)](https://i.sstatic.net/9oIJX.jpg)

The photos from mars are not likely to be bioturbation but are almost certainly differential erosion of normal chemical variation in rock. They do not have any of the characteristics that scream "this has to be biological activity" like cross cutting bedding planes or parallel patterns. Sedimentary rocks are rarely homogenous and chemical processes combine with erosional ones can produce some weird results. for comparison here are a few things that are definitely NOT fossils.

\*\*Pseudofossils AKA Leaverite \*\*

[![enter image description here](https://i.sstatic.net/gYecr.jpg)](https://i.sstatic.net/gYecr.jpg)

[![enter image description here](https://i.sstatic.net/iJ1mb.jpg)](https://i.sstatic.net/iJ1mb.jpg)

Pseudofossils are things lake look like fossils to the untrained eye but are just rocks, usually the leftovers of a chemical or erosional process. the term leaverite comes from geologists telling others "just leave're there"

> **Comments:**
> **username_0**: Thanks for the thorough answer, it's very helpful!  

---

