What does mercury analysis have to do with the mass dinosaur extinction?

Updated: Oct 14, 2021

Mercury was linked to climate change causing volcanism that may have triggered the end-Cretaceous mass extinction. An Ohio Lumex mercury analyzer helped measure it.


As one of the world’s leading mercury experts, we at Ohio Lumex always look for opportunities to offer our expertise where it is needed in the industry and share our knowledge about interesting mercury research that goes on in the world. When Princeton University told us that they would use our equipment to help shed light on the causes behind dinosaur extinction, we got intrigued and decided to find out more about the topic. We were fascinated with what we learned in the process and decided to put together this article that goes over the modern-day dinosaur extinction theories and how mercury analysis plays into it. We hope that you like learning about this as much as we did. Sit back and enjoy the read.


1. Did you know that no one REALLY knows why the dinosaurs went extinct?


Dinosaur sculpture in desert

Despite the prehistoric facts that most of us learned in school as definitive answers, no researcher truly knows (and might never know) what exactly killed the dinosaurs, leaving this mystery as one of the most fascinating of our time.


Even using the most advanced dating methods, analyzing chemical signatures of 66-million-year-old fossils is imprecise. Even a 1% error would mean dating estimates could be off by a few hundred thousand years!!! There is a significant amount of conflicting data worldwide, leaving its interpretation up to the researchers who don’t always agree. That is why the real cause of this extinction is a highly contentious topic among modern-day scientists.


Someone unfamiliar with paleontology research would be surprised to learn about the variety and number of possible theories, from obviously silly, to more realistic ones telling the story of the underlying causes of the mass fauna and flora extinction at the end of the Mesozoic era, scientifically known as the end-Cretaceous mass extinction (or K-T extinction) and colloquially known as the extinction of the dinosaurs. Among the many hypotheses surrounding this topic, two main paleontology camps exist today, providing a plethora of in-depth, well-publicized analyses backed by passionate followings among scientists and laypeople alike.


Despite a lot of common ground and general data shared by the two distinct ‘how dinosaurs really died’ camps, their ideas about what happened openly contradict each other creating, what American journalist Bianca Bosker calls ‘the nastiest feud in science.' Bosker’s article is an in-depth read that takes a deeper dive into this topic in case you are curious to learn more after reading our blog, the main goal of which is to paint a more simplistic picture of what the researchers are up against trying to understand this mass extinction.


We will also describe how one of the Ohio Lumex mercury analyzers used by the Princeton University Geosciences Group helped quantify some of their geological findings regarding this topic.


2. What are the two main dinosaur extinction theories that exist today?


The two schools of thought concerning K-T extinction consist of the ‘Chicxulub Impacters’ and ‘Deccan Volcanists,’ the latter often being considered as having a contrarian point of view since the former gained a much more streamlined public acclaim. Fortunately, the feud between the two schools has not prevented the study of mass extinction causation, instead made it a more engaging and interesting effort that produces a steady stream of present-day research.


Both parties agree that the K-T extinction happened due to a permanent climatic change on Earth, but what change-inducing triggers were predominant, as well as their timing and order, are some of the main points where ideas diverge.


‘The Chicxulub Impacters’


In 1980, a father-son pair of scientists, Luis and Walter Alvarez, announced their discovery of extraordinary iridium concentrations deposited worldwide. The deposits were found in the rock layer scientifically known as the K-T boundary. According to fossil records, this rock layer corresponds to the K-T mass extinction timeline.


Dinosaurs with asteroid hit

Iridium is a heavy metal that is rare on the surface of the Earth but abundant in space rocks. This information is the driving factor in the hypothesis of an asteroid hitting the Earth and depositing iridium, creating catastrophic events in the environment that set off a mass extinction in a matter of days. The asteroid impact theory devotees often refer to this extinction scenario as the ‘bad weekend,’ highlighting the idea that the whole event was a sudden and abrupt catastrophe.


No physical crater candidate existed to support the Alvarez hypothesis until 1991 when a group of pro-impact theory researchers pronounced the Chicxulub crater on the Yucatan Peninsula of Mexico as being the most likely place of direct impact that set off the chain of unfortunate events. The crater match provided the necessary factual support that not only solidified the brilliant asteroid-driven theory of extinction; but also, together with highly publicized endorsements from the scientific community, had it recognized as the closest theory to total certainty. After that, some considered (and still consider) the mystery of the end-Cretaceous extinction to be solved at last. However, there has never been an official settlement in the scientific community.


‘The Deccan Volcanists’


The idea that mass extinctions were caused by a prolonged series of massive volcanic eruptions has been around long before the asteroid impact theory. It is widely believed that all four mass extinctions before the K-T extinction, the fifth and largest one, were mainly caused by multi-thousand-year lasting volcanic activity that produced a steady stream of deadly airborne pollutants, slowly killing 90% of all large animals living on Earth at that time, including the dinosaurs. Contrary to the asteroid theory, this hypothesis says that the mass extinctions were much slower, taking thousands of years with dinosaurs and other animals, leading to their eventual death.


Mass extinction infographic with different species
(Source: Marash and Rossman, World Science Festival)

Gerta Keller, a Princeton University paleontologist, is the most prominent researcher and strongest advocate for the Deccan Volcanism theory. Although her viewpoints are openly debated in the scientific community, there is no debate that massive volcanic activity occurred at the time of the KT. This volcanic activity left behind a very conspicuous footprint in the shape of Deccan Traps in India, a 2-mile-thick formation of volcanic rock covering an area that equals the size of France. According to Keller, impact believers ignored everything about the Deccan traps and never addressed it until 2013 (in this interview on the Astro Channel).


Besides volcanic rock, Keller specializes in studying the bottom-of-the-food chain microscopic fossils of planktonic animals called foraminifera (forams, for short), another vital element of this theory. These single-cell marine animal species are a reliable proxy for other creatures’ well-being in a way that their population decline means the loss of sustenance sources for larger organisms that feed on them, eventually leading to their extinction. According to Keller’s group findings, forams experienced a gradual decline followed by a dramatic demise of their species (from over 60 to just one) at the time that aligns with the massive Deccan eruptions that began three hundred thousand years before the asteroid struck. Data shows that an abundance of carbon dioxide (among other climate change-causing pollutants) released from volcanic activity led to ocean acidification that disrupted marine ecosystems as witnessed by the forams’ fossils studies and triggered the extinction-bound chain of events.


Quick recap on the mass extinction reality


There is no definitive consensus as to what actually happened on our planet 66 million years ago. The main controversy comes from having two substantial climatic change triggers, one of the extraterrestrial nature in the form of an asteroid hitting the Earth, and the other of the Earthly nature, driven by erupting volcanoes. It is interesting to note that, according to an online article by the University of California Museum of Paleontology, the asteroid-driven hypothesis is mostly favored by astronomers and physicists, while most geologists and paleontologists lean towards the volcanic side. Struggling to determine which cause came first or caused more damage, some scientists are making attempts at combining the two theories, which seems to be a very logical way to go about it. A lot comes down to the interpretation, and it would be compelling to look at an entire theory developed jointly by both camps had they been more open to mutual collaboration.


The scientific community does agree on one thing. The modern-day ongoing extinction is on an even larger scale, with humanity having added another enormous climatic change trigger - the anthropogenic one. Working to understand the extinction causes of the past is helpful to deal with the extinction realities of the present, but that is a different story not covered in this article.


3. How does mercury factor into this mass extinction?


While working on this article, we reached out to our contacts at Princeton University’s Geosciences Department. They were responsive and eager to share some comments about how the RA-915F Mercury Analysis System from Ohio Lumex played a part in their research. They explained that mercury analysis is used to better understand the environmental conditions during the late Cretaceous period.


RA-915F Mercury Analysis System in Lab

According to one of their researchers, “Catastrophic climatic events are known to have been caused by massive outpourings of [mercury-containing] magma from deep within the Earth. The relationship between volcanism and extreme environmental disturbances is further reaffirmed by the radiometric ages of Large Igneous Provinces (LIPs) and the dates of mass extinctions. The Deccan Traps in India is one such Large Igneous Province that was active during the K-T mass extinction and is one of the largest volcanic formations on Earth... We have used mercury analysis (which has been relatively recently identified as a potential tracer for volcanism) to further confirm the relationship between the Deccan Traps and the KT mass extinction.”


In summary, the study done by Princeton University’s Geosciences Research Group revealed that each major Deccan Traps volcano eruption event showed a peak in mercury concentration in the corresponding sediment record. Matching these mercury peaks with climate changes is how scientists link volcanic activity to climate change and ocean acidification events (e.g. via foraminifera population studies) when dinosaurs (among other animal and plant species) went extinct. You can check out their recently published paper to learn more details about this study.


It is inspiring to learn that the Ohio Lumex mercury instrumentation serves the noble purpose of gaining additional knowledge about life-altering global planetary changes that occurred on Earth in the past, leaving us more equipped to deal with similar problems in the future.


We want to give special thanks to the Princeton University team for their eagerness to have an open dialogue and share their findings with us.