Post by: Sierra Matz, Julien Heller, Linnea Smith, and Zach Busche

Link to Google Earth Map (Site 8)

GPS Coordinates: (44.045587, -123.072713)

Location and general description: The tracks are located right outside Willamette Hall on the sidewalk just east of the main entrance. A group member saw small animal prints and brought them to the group to analyze. These prints are interesting partially because they are so light and small they can be easily missed while walking. Although faint, these prints can tell us a lot about animal behavior and environment. The animal is unidentified and we are unsure if the tracks are intentional or not, however, we assume they are not. Prints are solidified in the cement but can be difficult to make out while wet and/or when leaves cover the sidewalk. 

Geological Observations: There are approximately 15 sets of prints that are likely squirrel tracks set into cement, that if fossilized, will be trace fossils. Trace fossils are fossils of traces animals leave, such as footprints, rather than a fossil directly of the animal’s body. Each paw is about 3 cm in diameter, though the middle toe makes the length of the paw very slightly longer than its 3 cm width. Each set of 4 prints are within a 10 cm by 15 cm space (Figure 1), and each set is spaced approximately 20 cm apart (Figure 2) from the others. Because of this, it appears that a squirrel was running by leaping with its front legs, pulling its back legs to the ground behind, and leaping again. This would account for the large distance between the sets of tracks, as well as the most common animals in this area.

 

 

 

 

 

 

 

 

 

 

 

 

 

How do fossils differ depending on how long ago they were formed?

Contributed by: Linnea Smith

 

Geological Question:

It’s likely that because they are in concrete, the fossils that form due to these squirrel prints will have some unique characteristics. Because of this, I was curious whether we have evidence of fossils that have already been made with characteristics that are specific to a certain time frame. Therefore, my question is: How do fossils differ depending on how long ago they were formed?

 

Description of scientific article:

To answer my question, I read an article about the fossilization of eldonids, a type of marine animal that are disc-like in shape, resembling a jellyfish without legs, and characterized by an internal coiled sac(MacGabhann et al., 2019). There was a gap in the fossil timeline because the animals of that time, which were primarily eldonids, lacked tissues containing a biopolymer called HMW, which is necessary to create typical fossils. This meant that the fossils that they made were so unlike most that scientists didn’t understand this process of fossilization until much more recently. These animals never went through the process of biomineralization(the process by which biological matter is converted into minerals that we call fossils), so they have several unique traits, including uncommon distributions of different elements in the rock, depending on what part of the body it’s near, such as more aluminum and iron nearest to the dorsal fin; certain parts of the internal organs, particularly a coiled sac, being visible; and very fine details included in the cast. Seafloor microbial mats create a layer over the floor of the ocean, and create a top layer to the fossils being made. Though formerly it was believed that this microbial mat mineralized before settling on the soon-to-be fossils, MacGabhann et al.(2019) says that it must have mineralized afterwards to create the unique features present in fossils of these animals.

 

Intersection between peer-reviewed research and observations on campus:

It is very rare for fossils to be preserved as long as the fossils of the eldonids, because of how specific the conditions had to be for the fossils to form in the first place, as well as to last all the way into the present day. For the eldonids, they fossilized only in specific types of rocks, and the seafloor microbial mats completed the process(MacGabhann et al., 2019). Furthermore, once the fossils were made, they still had to avoid erosion or transformations into other types of rocks long enough that they could be seen by humans. Squirrel tracks operate in a similar manner. For the tracks to even be made, there were a very specific set of circumstances that had to occur: the concrete had to still be wet, and unguarded, and a squirrel had to not only be active, but also happen to run across that specific part of the sidewalk at that time, leaving those footprints(Figures 1&2). Additionally, concrete doesn’t last nearly as long as actual rock, mostly due to erosion, so it isn’t very likely that the squirrel tracks will last to become fossils, facing the same rarity of both formation and preservation of the eldonids.

 

An answer to the question?

This article answered my question rather effectively. Though the age of fossils doesn’t always directly impact its traits, there are some cases where unique animals or situations of that time period lead to very specific fossils only being found from that time frame, and eldonids are a fantastic example of this.

 

What I learned and future questions:

I additionally learned that things can be fossilized from gravity(a gravity cast), from something falling from above(a death mask), or from any side(endorelief preservation). Though something can be fossilized from multiple angles, it is less common. The squirrel footprints(Figures 1&2) are an example of a gravity cast, and the eldonids fossils are usually gravity casts or death masks, depending on the fossil.

Eldonids are a specific type of fossil that is unique to its time period, and while I learned a lot about those, I’m still curious, what other types of fossils are there that have characteristics that only occur in their time period?

 

 

How can we gather information based on prehistoric and modern foottracks (how they run, how fast they can move, type of environment, etc.)?

Contributed by: Sierra Matz

Geological Question:

To be able to just analyze some foot tracks you’ve found on the ground and tell a story through them is so incredible! It’s a beautiful way to connect and discover how certain environments and walking/running patterns existed prehistorically, and are now more modern. Because squirrel tracks are interesting, I will dive deep into the movement patterns that dinosaurs utilize and connect them to the mighty modern squirrel (who may think it is a dinosaur). How can we gather information based on prehistoric and modern foottracks (how they run, how fast they can move, type of environment, etc.)? 

Description of article: 

This article discusses the very articulate way to calculate the stride length, hip height, and speed of transportation of a tridactyl (three-clawed dinosaur). It examines dual-gait features of theropod trackway 13 from Ardley Quarry, Oxfordshire, UK in Figure 1, and provides a graph of the correlation of pace angulation and stride length in Figure 2. I believe this article is a useful tool to answer the first part of my question (how certain species run and how that relates to their foottracks). the Ardley trackways offer new and fresh insight into dinosaur locomotor capacity (physical ability to move from one place to another).

The intersection of article and squirrel trace fossils:

Yes, squirrels are not dinosaurs! As it is a very important aspect/disclaimer to mention, the science is quite similar. Finding the speed of movement of the little creature who left these tracks requires information on hip height (h) and stride length. Hip height can be calculated from foot length (which equals the length of the middle toe) (Day, Norman, et al., 2022). We can absolutely use this technique on the pitter-patter of any animal tracks, especially with modern information and technological help. Observing Figure 2 in the scientific article, there is a clear correlation between pace angulation (the angle formed by three consecutive footprints of an animal in a trackway) and stride length (the distance covered between the moment one foot initially touches the ground and the next time that same foot touches the ground again ). With squirrel tracks and this information, we can learn how stable the squirrel’s walking pattern was at that time, and also possibly connect it to a certain weather pattern or an external, environmental impact. 

An answer to the question:

The article did provide a good, straightforward way of examining how to calculate the running speed of a species based on hip height, stride length, and length of foot. So, regarding the part of my question that relates to speed and the mechanics of how squirrels run, I’ve got a pretty clear answer! On the other hand, I was also curious to find out more about how to discover the type of environment the species was living through based on its tracks. Of course, we can infer in this case (Oregon is quite rainy, and the tracks must be relatively recent, so the squirrel was possibly scattering away from either rain or students passing by).

What I learned and further questions:

I learned how to calculate running speed through a series of calculations of hip length (using foot length, stride length, and knowledge of the species), and also how stability of transportation relates to how the trace fossils were laid out. I wish I could have learned more about the environmental aspect, especially on a Jurassic-related note. So, my future question would be: How can we tell what the environment was like for certain species of dinosaurs by using their foottracks/ trace fossils? 

Source: 

Day, J., Norman, D., Upchurch, P. et al. Dinosaur locomotion from a new trackway. Nature 415, 494–495 (2002). https://doi.org/10.1038/415494a

How does our anthropogenic footprint show up in geologic processes, and what inferences can we make about how they will appear in the future?

 

Contributed by: Zachary Busche

 

Geological Question: Animals have left trackways and trace fossils all throughout our planet, leaving their impression long after they’ve gone, forever cementing themselves in history. It’s hard to imagine that we will leave as gracefully and as discretely as our predecessors. As the worldwide population booms and industrialism is more present than ever, it is clear that all facets of the world have been conditioned by anthropogenic intervention. That’s why I think it’s important to investigate how our anthropogenic footprint shows up in geologic processes, and what inferences we can make about how they will appear in the future.

 

Scientific article chosen: To help me start answering this question, I read about the argument and conditions that need to be met in order to dedicate an epoch (the start of a distinct period) to anthropogenic intervention by Braje and Erlandson (2013). There is no debate that human intervention will show up in the geologic record, Braje and Erlandson (2013) claim that radioactive particles will persist from nuclear blasts, construction of mines, dams, and harbors will be prevalent for millions of years to come, and abandoned buried cities and towns will serve as artifacts and will persist in the geologic record forever. The list is seemingly never-ending. However, Braje and Erlandson (2013) make the argument that the start of the epoch could be dated thousands of years before the Industrial Revolution, this is backed up by the fact that humans have shaped and molded environmental ecosystems long before we would be able to detect a chemical signature of greenhouse gasses in sediments and ice cores. The economic expansion of the world a thousand years before European exploration, resulted in a massive increase and widespread of domesticated animals and common trade plants. Creating a distinct disbursement, impossible without human intervention (Braje and Erlandson, 2013). It is increasingly evident that future investigators will have no shortage of evidence to identify the period of human intervention.

 

The intersection between research and observations on campus: Braje and Erlandson and references therein (2013). note that concrete, plastics, and metals will persist in geological layers for potentially millions of years. Concrete and man-made structures built by the Greeks and Romans still stand strong and complete today, this indicates that the rebar-reinforced, more thoroughly constructed concrete today observed in Fig 1 & 2 could persist for even longer (Braje and Erlandson, 2013). Depending on the environment, strength, and durability of the concrete, it is unlikely but possible that the tracks we observe in Fig 1 & 2 may still be around for a hypothetical geologic investigator tens of thousands of years from now, still intact. If the tracks are preserved as they are today, investigators will easily determine the size of the squirrel, its stride, gait, etc. But if we wanted these tracks to eventually fossilize and persist for much longer, they would have to meet certain conditions. Trace fossils occur when an organism interacts with its environment, leaving evidence such as footprints that then solidify and get covered by other sediments (UCMP Berkely, n.d). And In order for our trackway to be recognized as a fossil, it has to be at least 10,000 years old by today’s criterium. In conclusion, we have a perfectly intact hardened trackway that demonstrates the squirrel’s interaction with the environment, in order to recognize it as a fossil, the tracks need to still be intact and visible after being inevitably covered by sediments 10,000 years later. If those requirements are met, then we will be the initial discoverers and documenters of squirrel trace fossils.

 

An answer to the question? My initial question was: How does our anthropogenic footprint show up in geologic processes, and what inferences can we make about how they will appear in the future? And the article absolutely answered my question. Braje and Erlandson (2013) mention a seemingly infinite number of ways in which anthropogenic intervention will show up in the geologic records. Braje and Erlandson (2013) talk about how dams create a recognizable artificial build-up of sediments, how the spread of livestock and plants can only be transported artificially, how cities and towns will persist in the geologic record after eroding and being covered with sediments, the list goes on and on. However, it did not become any clearer how I can identify if individual buildings or artifacts are sure to persist in the geologic record. There seems to be an infinite number of variables that decide whether something will stay or vanish from the record completely. When attempting to determine how long our squirrel tracks will be recognizable, I was met with variables such as the integrity of the concrete, if the concrete is rebar reinforced, how the Oregon rain will affect the tracks, how foot traffic will affect the tracks, etc. There is no rational forecasting for something so far down the road.

 

What I learned and future questions: I learned a shocking amount about human history, I now feel as if I have a more thorough understanding of the timeline of the world after learning about where trade, construction, the Roman Empire, and concrete stand in relation to colonialism and the European expanse. I also initially thought that our tracks were cast fossils, after investigating I found that they were not, but I learned and read all about cast and mold fossils, the difference between the two, and the conditions that need to be met for both of them to occur. For example, a cast fossil occurs when loose sediments fill an empty space left by a decaying or decayed organism that then harden and mold. I also learned that 10,000 years of age is what qualifies a fossil as a fossil, which I then researched, because why 10,000? And it’s just a somewhat random number so scientists can base it on something. In the future, I’d love to learn more about the ecological effects of anthropogenic activity, and ask the question, how long would it take for the environment to go back to its natural equilibrium if humans were to stop contributing and vanish? I’d also like to learn more about the conditions that need to be met in order to produce an intact and complete fossil, I feel as if they are super rare and I’m curious why that is.

 

Can scientists determine the age of animals based on trace fossils, specifically footprints? If so, how?

Contributed by: Julien Heller

Geological Question: Many of us have seen iconic images of footprints from various animals such as dinosaurs, lions, dogs, and even Bigfoot! But, when it comes to squirrel prints, these can seem insignificant to the average eye. Tracks left by animals can tell us some incredible information, such as animal behavior and physical characteristics. We can apply this knowledge to the smallest of creatures, even squirrels. After seeing these footprints, I was curious about a number of characteristics these squirrels could possess, but determining the age of the animal stood out to me the most. This curiosity led me to this question: Can scientists determine the age of animals based on trace fossils, specifically footprints? If so, how?

Description of scientific article: To help answer my question, I read an article by Farlow et al. (2000), which compares zoological, the study of animal behavior and physiology, and ichnological, the study of fossilized tracks, diversity in the Australian desert. Farlow et al. (2000) studied monitor lizards from Western Australia, which are the closest modern comparison to some dinosaurs. Characteristics like morphological features, differences in species’ track, the richness of the varanid (monitor lizards) species are all examined and these determinations and methodologies can apply to other studies of extinct vertebrates. The article provides a variety of graphs and illustrations to portray the data found, such as species and snout length, body size and limb proportion, and morphology of the varanid. Farlow et al. (2000) concluded that no matter how you analyze the physical characteristics of varanids, differences among species are subtle and muddled by variability. 

Intersection between article and observation: Unfortunately, the article that I reviewed does not directly discuss squirrels or how to determine age. However, Farlow et al. (2000) provided lots of insight into how we can use animal tracks to tell us about behavior and physiology. For example, one graph from the article compared different species’ hindlimb length versus forelimb length, as well as other extremities. We can use these methodologies and apply them to squirrel prints by comparing the distance between footprints and plotting them to create a graph. Farlow et al. (2000) also touches on the uncertainty of morphology determination if the species is unknown, which is a conversation integral to our topic. Our group states that these tracks are squirrel prints, but this is an educated assumption. Without knowing the species of the animal prior to analyzing, the number of possible trackmakers significantly increases (Farlow et al., 2000). Finally, although the article does not directly discuss determining age, Farlow et al. (2000) states that average adult size varies, which leads to an overlap in data between small adult animals and large juvenile animals. 

An answer to my question: Although Farlow et al. (2000) does not explicitly state how to determine age from trace fossils, it can point us in the right direction. As mentioned earlier, there is some overlap between the size of smaller adult species and larger younger species. From this information, we can make the conclusion that if we know the specific species of the animal, we can analyze the measurements between prints and determine the age. However, when we compare different types of one animal, it makes it more difficult to determine age, as we do not know whether the animal is adult sized or not fully grown. The size of some small animals could be the same size as the younger, larger animal. 

What I learned and future questions: I learned more from this article than I thought I originally would! I found it super interesting how Farlow et al. (2000) compared the patterns and characteristics of the varanids’ trackways to those of tetrapods, aka four-limbed creatures, from the Late Paleozoic and early Mezoic periods (~251 million years ago or in more scientific terms, a long, long time ago). These characteristics ranged from number of digits, to angles between toe marks, to trackway gauge. This brought up a curiosity about early tetrapods because I had never heard of this type of animal before. According to the University of California’s Museum of Paleontology, amphibians, reptiles, birds, and dinosaurs are the major groups that make up tetrapods, but any animal with four limbs is classified as a tetrapod (UCMP Berkeley). Because humans have four limbs, two arms and two legs, we also would be classified as tetrapods. Which led me to this question: What characteristics of early tetrapods helped develop the structure and function of modern human extremities? 

Sources:

Braje, T. J., & Erlandson, J. M. (2013). Looking forward, looking back: Humans, anthropogenic change, and the anthropocene. Anthropocene, 4, 116–121. https://doi.org/10.1016/j.ancene.2014.05.002

Farlow, James O., and Eric R. Pianka. “Body Form and Trackway Pattern in Australian Desert Monitors (Squamata: Varanidae): Comparing Zoological and Ichnological Diversity.” PALAIOS, vol. 15, no. 3, 2000, pp. 235–47. JSTOR, https://doi.org/10.2307/3515645.

Kuea, M. (n.d.). University of California Museum of Paleontology-Fossils. Fossils – window to the past. https://ucmp.berkeley.edu/paleo/fossilsarchive/trace.html

MacGabhann, Breandán Anraoi, et al. “Resolution of the Earliest Metazoan Record: Differential Taphonomy of Ediacaran and Paleozoic Fossil Molds and Casts.” Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 513, Jan. 2019, pp. 146–65. ScienceDirect, https://doi.org/10.1016/j.palaeo.2018.11.009.

University of California Museum of Paleontology. “Introduction to the Tetrapods.” UCMP Berkeley, https://ucmp.berkeley.edu/vertebrates/tetrapods/tetraintro.html. Accessed 4 Dec. 2024.