By Aaron Serianni Professor Elizabeth Niespolo is an Assistant Professor of Geosciences in Princeton’s Geosciences Department. She specializes in the field of geochronology, and her work focuses on precisely understanding the climatic, fossil, and archaeological records, and their relationships to environmental changes. As Professor Niespolo describes in my interview with her, isotope geochronology is a subfield of geology which studies the decay of radioactive isotopes to determine the age of rocks and fossils. The field of geochronology is closely tied with the fields of nuclear chemistry and physics. Many techniques and developments used in geochronology were originally developed by nuclear physicists during their research in radioactive isotopes. Clair Patterson, a geochemist who developed uranium-lead dating, worked at the Manhattan Project at Oak Ridge National Laboratory to separate Uranium-235 (weapons-grade uranium), where he learned how to use mass spectrometers, an instrument used to precisely measure the ratio of elemental isotopes in a sample. Mass spectrometers became instrumental to Patterson’s work in geochronology, where he used them to measure the proportions of uranium and lead in samples of rock. Using uranium-lead dating, Patterson calculated the currently accepted age for the Earth, of 4.55 billion years, revolutionizing our understanding of Earth’s history. During his efforts to precisely measure the amount of lead in samples, Patterson discovered lead contamination in many materials, including in the atmosphere and in his own hair. He realized the link between lead contamination, lead poisoning, and leaded products, especially in gasoline. Patterson then spent the rest of his career vigorously campaigning for the complete ban of lead, along with the professor and pediatrician Herbert Needleman, finally succeeding and solving a major environmental and health crisis. I think that the history of geochronology, specifically with the life of Clair Patterson, showcases the conflicting nature of much nuclear research. Without his work with radioactive materials, billions of people would still be experiencing the catastrophic effects of chronic lead exposure, and we would not have discovered the history of Earth. Yet, the same methods Patterson used for his discoveries directly lead to the creation of the atomic bomb. In my interview, I asked about Professor Niespolo’s experience with the ethical guidelines about direct fieldwork in Africa and Australia as part of her work. Speaking about ethical guidelines in fieldwork, she responded: “In the last couple of years, getting permission as one sort of almost minimum expectation for someone who's entering on lands of either indigenous or local people of any kind. I think that's actually a minimum at this point. People that aren't doing that are behind the times, and they need to catch up or get out. The better practice is to actually welcome collaboration with the local folks.” This response from Professor Niespolo reminds me of an article by David-Chavez, “A global assessment of Indigenous community engagement in climate research,” which discusses the need for best practices in scientific research. Furthermore, collaboration with local and Indigenous people can lead to new insights, such as with the ideas of TEK, traditional ecological knowledge. Furthermore, collaboration can lead to a better understanding of a place’s history for the benefit of the researcher and can counteract the colonialist and extractive nature of scientific research. As Professor Niespolo describes, the fields of archeology, paleontology, and geology, “…are extractive by nature, and, and prior to very, very recent times, have a very deep root in colonialism. That's a particularly sensitive topic in many of the areas that I work in Africa. It’s hard to grapple with, as somebody who is learning about the history, while simultaneously hoping to meet scientific goals. You can often learn about something after the fact and you are, ‘I wish I had known this history before.’ So I've been grateful that I’ve worked with people who are pretty aware of the history of these different countries, and they're much more sensitive to what's appropriate, what's not appropriate for them.” The following interview has been edited for length and clarity. Aaron Serianni Can you tell me about your work, and what is geochronology? Elizabeth Niespolo We take advantage of the decay of radioactive isotopes in natural systems that host small trace amounts of radioactive isotopes. Most of the materials that we tend to work with are natural materials that form in geologic environments; we can date the timing of formation of those rocks. My main interests are in utilizing natural samples to date deposits that host fossils or archeology. I utilize more commonly-known methods like radiocarbon, but in addition, other decay schemes that have longer half-lives, so that I can date deposits that are much older. Aaron Serianni What are some of the techniques that you used for dating, once you have a sample? Elizabeth Niespolo The main technique that we utilize for high precision work is called mass spectrometry. Aaron Serianni Do you go out and collect your own samples? Or do people come to you wanting to collaborate and bring their own sample? Elizabeth Niespolo It depends on the person. For me, I do both. Some samples I collect myself; sometimes, I will collaborate with paleontologists or archaeologists or other scientists who are interested in knowing how old something is. When I'm not the person that collects the samples and sees the field area myself, I try to work with people where I have a good sense of their field knowledge, because field context is very important for understanding and interpreting ages. Aaron Serianni What are these samples like? How do you deal with their radioactivity, and what is your interaction with Environmental Health and Safety? Elizabeth Niespolo The amount of radioactive material in these samples is usually very, very small, such that, if you were to take a Geiger counter, you wouldn't detect very much at all, it would be like any sort of background measurement. When we want to make really precise measurements, we often need known standard materials to compare to our unknown samples. We ask Environmental Health and Safety to review, what our plans are, what the intended usage is, and how much we're going to dilute those materials once they come to campus. Aaron Serianni Do you know any details about the disposal? Like, what's the facilities that you've taken to? And or do you have Environmental Health and Safety to take care of it? Elizabeth Niespolo It depends on the situation. In a lot of cases, we don't have anything left, so there's often no waste. In the case that there is waste, there are pretty specific procedures that you have to go through. One option is to dilute it to extreme amounts such that it is below MCLs, minimum contamination levels, so it can be disposed of as normal toxic waste. Aaron Serianni When you're collecting samples, what are some of the ethical guidelines you need to consider, especially when going on indigenous lands? Elizabeth Niespolo Yeah, that's a fantastic question, and it's highly variable with where you work. Getting permission is almost a minimum expectation for someone who's entering on lands of either indigenous or local people of any kind. The better practice is to actually welcome collaboration with the local folks. And making sure that they are as involved as they want to be, having them be involved in the scientific development of a project, not just asking if you can come and do your science on their lands. Aaron Serianni How do you contend with the history of archaeology and paleontology in these countries which has been very exploitative? Elizabeth Niespolo Yes, they are extractive by nature, and, and prior to very, very recent times, have a deep root in colonialism. I make every effort on my own to collaborate with African scientists and scientists of whatever nation I'm working in, to make sure that there isn't a colonial approach to science. Aaron Serianni Do you think the field of geosciences is improving on this front during the past few years? Elizabeth Niespolo I hope so. We are astonishingly behind when it comes to diversity in STEM fields. Even with all the efforts to progress in the right direction, we are lagging behind the other STEM fields by quite a bit. We are not likely to reach gender parity until 2050 whereas many STEM fields are already very close to gender parity. So we're very behind. It's a constant battle. I think no one person can fix it. But if we all make greater efforts, then it is better, and that's not even talking about racial inequities. Aaron Serianni Do you think there are other efforts to promote local researchers in these various countries, instead of having people come in from outside? Elizabeth Niespolo I would like to believe, especially the younger generation of scientists who are making a greater effort for that. Aaron Serianni Switching back, where do you work on the mass spectrometer, do you do it in Guyot Hall? Elizabeth Niespolo So, since I just got here, I haven't set my lab up. But in principle, yes. Some instruments will be set up here or in other buildings on campus. And then likewise, other professors who work with geochronology have their instrumentation in this building. Aaron Serianni How do you communicate with students who work in your lab that you have like radioactive material? Elizabeth Niespolo We have to have everything very clearly labeled. Anybody who works in a lab for geochronology has to have radiation safety training, and then typically students won't be the ones mixing standards. They’ll be working only with very, very diluted samples that are like background level concentrations of radioactive isotopes. Aaron Serianni Where do you get the standards? Do you know where they're sourced from or? Elizabeth Niespolo Mineral standards typically come from mines, and some of those are not US based. A lot of standards are left over from nuclear research, and that there is nothing to do with them now. It turns out to be very convenient for geochemists. We get to receive this leftover material that has no function anymore. Aaron Serianni Do you know of geochronologists who were involved in nuclear research? Elizabeth Niespolo This is another funny thing about geochronology. A lot of the people that discovered ways to date things are actually nuclear physicists. And then geoscientists were like, ‘hey, that would be really useful for us.’ Most of those guys ended up staying in their field, rather than continuing in geochronology. There is a little bit of a flip now though, some geochronologists end up going into nuclear science. Nuclear science today is about tracing the origins of concentrated ores and synthesized materials. It’s called nuclear forensics. Aaron Serianni Is the field of geochronology still developing and expanding? Elizabeth Niespolo Oh, absolutely. There was a big wave of new methods that started in the 50s, 60s, 70s. And now we're finding with higher precision and better capabilities to measure that we're learning a lot more about the complexity of Earth processes and we're expanding the ways we can apply these same chronology methods.
