Time Scavengers

A seismically induced onshore surge deposit at the KPg boundary, North Dakota

Robert A. DePalma, Jan Smit, David A. Burnham, Klaudia Kuiper, Phillip L. Manning, Anton Oleinik, Peter Larson, Florentin J. Maurrasse, Johan Vellekoop, Mark A. Richards, Loren Gurche, and Walter Alvarez

Summarized by Jen Bauer, Maggie Limbeck, and Adriane Lam, who also comment on the controversy below

What data were used?

Data used in this study were identified from a new site, which the authors call Tanis (named after the ancient Egyptian city in the Nile River Delta), in the layers of rocks called the Hell Creek Formation. This formation is famous amongst paleontologists because it contains lots of dinosaur fossils from the late Cretaceous (about 66 million years ago). In this study, scientists found a new layer of fossils within the Hell Creek Formation that is unlike anything paleontologists have seen before. Those who found the site examined the rock’s features and fossils, which includes densely packed fish fossils and ejecta from the Chicxulub meteoric impact. The Chicxulub impact is what caused the dinosaurs to go extinct, and finding a layer of rock that was deposited minutes to hours after the impactor struck Earth is a very rare and exciting find.

Methods

This study included a variety of approaches. The rock features (called sedimentology) and fossil features of the Tanis area and event deposit are described to determine what caused this deposit in the first place. The authors also identified other pieces of evidence to aid in better understanding the situation at hand. Ejecta deposits were described as well, in comparison to ejecta deposits that are found closer to the impact site in the Yucatan Peninsula, Mexico.

Results

Much of the sedimentology can be related to other aspects of the Hell Creek Formation in southwestern North Dakota that is an ancient river deposit that has some marine influence. In the Cretaceous period, central North America’s topography was very low which allowed for a seaway to form. This was called the Western Interior Seaway, and was home to a diverse number of animals such as plesiosaurs, mososaurs, large sharks, and ammonites. Several rivers likely drained into the Western Interior Seaway, much like the Mississippi River drains into the Gulf of Mexico today.

From studying the characteristics of the rocks within the Tanis site, the authors of the study concluded that this site was part of one of the rivers that drained into the Western Interior Seaway long ago. When the impactor struck Earth in the Yucatan Peninsula, it send huge waves (tsunamis) into the Western Interior Seaway and into the rivers that drained into the seaway. These huge waves pushed fish, ammonites, and other creatures into the seaway and into the rivers. The Tanis site is one such place where these animals that were pushed into the rivers were deposited and preserved. But not only were marine animals preserved at the site, but also land plants, such as tree limbs and flowers.

The fossils found in the Tanis deposits are all oriented in the same direction, indicating that they have been aligned by flowing water. The abundance and remarkable preservation of these fossil fishes and tree limbs suggest a very rapid burial event (the best preserved fossils are often the ones that experience very quick burial after death). The orientation of the fossils at the site along with the mix of marine and terrestrial life further supports that these fossils were deposited from very large waves from the asteroid impact disturbed this region.

Within the Tanis deposit there are also ejecta spherules, microkrystites, shocked minerals, and unaltered impact-melt glass. These are features that are commonly associated with the Chicxulub Impactor. When the impactor struck Earth, it was so hot it melted the underlying rock, sending tiny bits of molten rock into the atmosphere. These bits of molten rock quickly cooled and eventually fell back down to Earth, where today they are found all over the world. Today, these ejecta spherules and impact melt-glass all mark the huge end-Cretaceous mass extinction event that occurred 66 million years ago.

Why is this study important?

The Cretaceous-Paleogene (K/Pg) extinction event is one of the ‘Big Five’ mass extinction events (click here to read more about extinction). Like many extinction events, it is often difficult to determine the specific causes of mass destruction. However, the K/Pg extinction event is unique because scientists have many lines of evidence that a huge impactor struck Earth, sending clouds of ash and gas into Earth’s atmosphere. The new Tanis site that the authors uncovered preserves a snapshot into this catastrophic event.

This finding is very important because scientists know better understand what happened directly after the impactor hit Earth. In addition, several new species of fish have been discovered at the Tanis site, which will be important for additional studies about fish evolution through time.

Citation:

DePalma, R.A., Smit, J., Burnham, D.A., Kuiper, K., Manning, P.L., Oleinik, A., Larson, P., Maurrasse, F.J., Vellekoop, J., Richards, M.A., Gurche, L., and Alvarez, W. 2019. A seismically induced onshore surge deposit at the KPg boundary, North Dakota. Proceedings of the National Academy of Sciences (PNAS), doi: 10.1073/pnas.1817407116

What’s all the commotion about?

It’s not every day that paleontologists make the national news, but this paper and the article written about it in the New Yorker (click here) caused a lot of commotion within the paleontological world. This is a great and potentially groundbreaking find, however, what caused the commotion was the sensationalist attitude of the New Yorker piece that left a lot of paleontologists uncomfortable. So what’s the big deal here? We break down a few (not all) of the issues with this article:

1. Breaking of Embargo

Although the published study is very exciting and will add greatly to our knowledge about the end-Cretaceous mass extinction event, the media hype around the study was handled very poorly for several reasons. All published studies go through peer review. This is when a paper is sent out to multiple other scientists who read the article and make sure that it is scientifically sound and is a good piece of science based upon other good science. During this waiting period while the paper is going through peer review or being finalized with publishers, the authors should avoid talking with popular media or publicizing their paper. When publishing in academia there is a period of time (embargo) where access to the findings of a paper is not allowed to the public. This is for a variety of reasons, having to do with copyright transfer, finances to support the journal or publisher, and more.

The New Yorker press article was released almost an entire week before being available for the community to examine. This means that the embargo was violated.

The reason embargos exist is to give journalists and the researchers they talk to some time to look at fresh findings and determine what the story is, whether it’s worth telling, and if there’s anything suspicious about what’s presented. – Riley Black (Slate article)

2. Paleontologists as Rough-and-Tough Dudes (and Unusual Folks)

The New Yorker article was also controversial because it framed paleontologists as belonging to a narrow demographic (read: white men who love the outdoors). Not all of us in paleontology are men, not all of us are white, and not all of us came into geology loving the outdoors (see the great diversity of folks working in paleontology on our ‘Meet the Scientist’ blog). Paleontologists have had to work very hard to break through the stereotypical conception of what we do and who we are, and this article did not help to address the great diversity of scientists working in the field of paleontology.

In addition, the New Yorker article only quoted and interviewed other male scientists, many of whom have been working in the field for decades. The article left out the voices of women and early-career researchers who have made valuable contributions to the field of paleontology. For more on this, read the Slate article by science writer, Riley Black “It’s Time for the Heroic Male Paleontologist Trope to Go Extinct”.

This article also reinforces the “lone-wolf” stereotype of geologists and paleontologists-a man going out west, few to no other people around, and spending his days looking for paleontological treasure. This image is perpetuated through the article because the author chose to continually highlight the privacy and secrecy asked by the De Palma. While this is certainly an attitude held by some paleontologists, the reality is that the majority of us work in teams. Time Scavengers is run by a large team of people and so is our research! Like working in any field, we all have our strengths and better science happens when we invite people to work with us who have different strengths and can help us.

Lastly, the article frames paleontologists in a not-so-flattering light. In one paragraph, the article states “…I thought that he was likely exaggerating, or that he might even be crazy. (Paleontology has more than its share of unusual people).” Firstly, what does unusual even mean? The STEM (Science, Technology, Engineering, Maths) fields are full of intelligent, diverse, and colorful folks from all walks of life. To imply that any one branch of science has ‘its share of unusual people’ is unfair and regressive.

3. Dinosaurs as the Star of the Show

Paleontology is not just diverse in terms of the people who work in the field, but also in terms of the different types of life that we work with. For example, our Time Scavengers team, we have folks who work with fossil plankton and echinoderms. In fact, most paleontologists work with invertebrates- animals that do not have backbones, or any bones at all. Some of the most foundational findings in paleontology are based on the fossil record of invertebrates and early vertebrates. Regardless, most of the public’s fascination lies with dinosaurs (we understand, they were gigantic, ferocious, and unlike anything that’s alive today).

However, this fascination with dinosaurs can lead to over exaggeration of studies and sensationalizing, which is exactly what happened with this article. The published study of the Tanis site only mentions one dinosaur bone out of all the fossils found. The real story here is about the wonderful assortment of fish, tree, and flower fossils, some of which are completely new to paleontologists.

Another article by Riley Black that gives more of a spotlight to the amazing fish found at the locality, “Fossil Site May Capture the Dinosaur-Killing Impact, but It’s Only the Beginning of the Story.”

Dr. Steve Bursatte, Paleontologist at University of Edinburgh commented on both the New Yorker article and the PNAS article on his Twitter account, click here to read more. He comments on the broken embargo and how the New Yorker article sensationalized the ‘dinosaur’ side of the story.

4. Proper Handling of Museum-Quality Specimens

The article that was published in the New Yorker raised a lot of concerns within the paleontology community regarding the handling and storage of the fossils that were found at the Tanis site. It is clear from the article that DePalma had a bad experience early on with fossils that he had loaned a museum not being returned to him, however, by maintaining control over the management of his specimens, it undermines those people working in museums who have degrees and years of experience handling fossil and other specimen collections. Anyone who has borrowed specimens from a museum knows the immense amount of paperwork that goes in on all ends to make sure the specimens leave a well documented trail.

Jess Miller-Camp, Paleontology Collections Manager and Digitization Project Coordinator at Indiana University commented on the New Yorker article and addressed her concerns as a museum professional, click here to read her Twitter thread. She comments on the process of loaning specimens to and from museums and proper ettiqute. Read her thread to learn more about this and why museums should be asked to comment.

In 1997, a T. rex nicknamed Sue was sold at a Sotheby’s auction, to the Field Museum of Natural History, in Chicago, for more than $8.3 million.

This quote is misleading. No museum would have adequate funds to secure Sue. The California State University system, Walt Disney Parks and Resorts, McDonald’s, Ronald McDonald House Charities, and other individual donors aided in purchasing Sue for the Field Museum. The Field Museum rallied resources to ensure this valuable specimen remained in a public institution.

In addition to proper storage and archiving of fossils, one of the key tenets of any kind of scientific research is reproducibility– how well can other scientists replicate the results that you got. In paleontology, being able to look at the exact same fossils that another scientists looked at is a key part to reproducibility, as well as allowing the science of paleontology to advance. Whenever a paleontologist finds something they think is “new” to science, or is a really important find (special preservation, currently undocumented here, etc.) if you want to publish a paper on that fossil, the fossil needs to be placed in a public institution like a museum or a similarly accredited fossil repository. This way, future scientists are able to track down that fossil you published on and continue working on understanding it, or using it in other studies. Keeping fossils that are published on in museums is also critical because it ensures that that fossil has a safe place to be stored after being worked on and is less likely to be lost in an office or lab space!

5. Respecting the Land and Indigenous People

In the field of paleontology, people, who are more often than not white, venture into another country or a part of the ‘wilderness’ to find fossils and sites that are completely new and never-before-discovered or seen. These lands that contain fossils were owned by indigenous people long before Europeans arrived in North America, and were likely known about centuries before. Often, when sensational popular science paleontology articles are published, the authors leave out the voices of indigenous people and respect for their land. In the New Yorker article, there was no mention of the indigenous people that lived in the Dakotas, or how their ancestors perceived the dinosaur and fish fossils in the area. To frame amazing paleontological finds as being in desolate wastelands is harmful and erases the narratives of people who have lived in these lands for centuries.

For a more thorough discussion on this topic, click here to read the Twitter thread by Dr. Katherine Crocker.

 

Click here to read a article written by Dr. Roy Plotnick in Medium that also summarizes the issues and causes of commotion surrounding this astounding find.