You really can’t take it with you.
Kip Hodges spent much of his early scientific career at the Massachusetts Institute of Technology (MIT) establishing an argon dating lab with very specialized, very expensive mass spectrometers, high-powered lasers, and access to a nuclear reactor.
When he left MIT after 23 years, he had to leave his instruments behind.
Because the instruments were funded by grants, they belonged to the university. Whether anyone was going to use the instruments after Hodges left was also up to the institution.
“Are they going to hire a new faculty member who would use that particular instrument because they’ve got this unbelievably valuable piece of research instrumentation at the facility?” Hodges asked. “Quite often, that’s not what happens.”
MIT did not hire someone to replace Hodges, and though the laboratory was initially kept running by members of his research group, it eventually fell into disuse. A spokesperson for MIT confirmed in an email that “the argon dating lab no longer exists and there hasn’t been one for about a decade.”
“It was sad for me to see that instrument sort of go fallow after a few years, but at the same time I understand it,” said Hodges, a geoscientist who now directs the Noble Gas Geochronology and Geochemistry Laboratories at Arizona State University.
Argon labs can date rocks as old as the solar system and have been instrumental in clarifying the geochronology of occurrences ranging from the Chicxulub impact event to the volcanic eruption that famously buried Pompeii. They are expensive to maintain and require expertise to manage. When supervisors retire or leave, their argon labs often simply disappear, leaving equipment, as well as support staff and other scientists who relied on them, in the lurch. Some argon dating labs also run samples for external and industry clients, meaning that a shutdown disrupts research far beyond what was pursued in the lab.
“Sadly, what often happens is they get mothballed,” said Paul Renne, a geologist at the University of California (UC), Berkeley and director of the independent nonprofit Berkeley Geochronology Center, the longest-running argon lab in the United States. “And very often you’ll hear by various listservs or word of mouth that so-and-so is retiring, and there’s nobody in the queue to take over the lab, and so there’s a mass spectrometer for sale. This is not uncommon.”
In a field dedicated to the investigation of deep time, the argon dating community faces challenges when planning for the long term.
Even the renowned Australian National University argon laboratory run by Ian McDougall, the grandfather of the technique, could not escape this fate.
“His lab is basically abolished—it’s gone,” said Anthony Koppers, a marine geologist, associate dean of research at Oregon State University, and director of the school’s Argon Geochronology Lab. “It would have been such a cool lab to maintain because of simply the name recognition and the importance to the entire field.”
Therein lies the irony: In a field dedicated to the investigation of deep time, the argon dating community faces challenges when planning for the long term. These challenges also confront laboratories housing expensive and highly specialized equipment in other scientific fields when a lack of coordination or a plan for continuation after a lab director leaves leads to a cascading disruption for everything and everyone connected to the lab.
In the case of argon dating, the lack of coordination and planning is not for a lack of importance. Recently, a decadal report by the National Academies of Sciences, Engineering, and Medicine (NASEM) highlighted how essential geochronology is for the Earth sciences and recommended further funding for it.
“We’re not thinking about things on very long timescales,” Hodges said of the argon dating community. “We’re thinking about things over the next few months.… We don’t want to say, ‘Where is this mass spectrometer going to be in 15 years?’”
“No Blueprint” for Replacing Argon Lab Heads
There are about 20 argon dating labs in the United States—and about twice that number outside it—most of which are run by senior supervisors who are nearing retirement age.
“There aren’t a lot of young argon geochronologists,” said Courtney Sprain, a geoscientist at the University of Florida. “We’re very top heavy.”
The argon dating method, which was developed in 1966, “is just getting mature enough that you’re starting to get to where there is succession needed,” said Leah Morgan, a research geologist with the U.S. Geological Survey’s Geology, Geophysics, and Geochemistry Science Center in Denver.
And even when a scientist has their name on the lab, their control over its direction usually lasts only as long as their paychecks. “It’s sort of surprising to many that when faculty retire, they really don’t have any real influence over what happens to their labs,” Renne said.
Instead of looking for a candidate to take over this established resource that the university has invested in for decades, faculty search committees often look for the best candidate in a broader field. It can be difficult to balance the large monetary investments already made in buying equipment for the argon lab and hiring top-notch researchers who could augment the institution in other ways.
“I think that might be an issue in most high-level research departments you talk to,” said Brad Singer, professor and chair of the Department of Geoscience at the University of Wisconsin–Madison and director of the WiscAr Geochronology Lab. Singer himself chaired one such search committee to hire new isotope geochemists. “There’s no blueprint for this.”
In Geology, Timing Is Key
The status of argon labs is important for the field of geochronology, the science of dating Earth materials and geological events. Geochronology, in turn, touches all aspects of our understanding of Earth in its vast spatial dimensions by adding knowledge about that vast fourth dimension: time.
Argon dating, also known as argon-argon dating because it relies on measuring two isotopes of the element (argon-40 and argon-39) in samples, is a versatile technique that can date materials across a massive time span with a high degree of precision. “The argon-argon method can date materials as old as the solar system—theoretically older, but we don’t have any such things to play with,” Renne said. “So [we have material] 4.6 billion years old to really just a few thousand years old.”
“It’s great for a ton of geologic processes; we just can’t fundamentally understand them until we know rates and dates,” said Sprain. “We need to know how fast processes are occurring. And we need to know when they’re occurring.”
The technique can be applied to any rock or mineral containing the common element potassium (which decays to argon). It has been critical in dating events as wide-ranging as the most famous eruption of Vesuvius, meteorite formation, and milestones in evolutionary biology and history. Almost everything we know about the 66-million-year age of the mass extinction event associated with the Chicxulub crater, for instance, comes from argon dating, Hodges said.
But all the precision and versatility that the technique affords require costly equipment to be purchased, maintained, and staffed.
Samples first need to be irradiated with neutrons, so access to a nuclear reactor is required. A high-powered laser is needed to successively heat up the samples to release the inert argon atoms so they can be measured by a mass spectrometer. And because the air we breathe is roughly 1% argon, that air must be pumped out of the machine to prevent it from contaminating readings from the sample.
“You have to do everything under ultrahigh vacuum,” said Koppers. “The vacuums that we have in the mass spectrometers in our systems are better than space.”
The mass spectrometers at the heart of argon labs can cost upward of half a million dollars each, not including mineral extraction equipment and other necessary tools. When the building in which Koppers’s lab was located caught fire several years ago, he had to replace everything in the lab—at an expense of close to $2 million that, thankfully, insurance reimbursed.
“So [it’s] a really interesting and important problem: What happens to these older instruments?” Hodges said.
Mass Specs for Sale
The original mass spectrometer widely used in argon and other forms of noble gas dating, a mass analyzer product (MAP), is a reliable workhorse that decades after its invention can still be used, because there has been no change in the underlying technology, “the real guts of the mass spectrometer infrastructure,” Singer said.
“A good mass spectrometer will, if it’s taken care of through the years, last a whole lot longer than most faculty careers.”
“The electronics you have to replace and the magnet controller you have to replace and vacuum systems you have to update and all this sort of stuff, but they have a very long life,” Hodges said. “The point is that a good mass spectrometer will, if it’s taken care of through the years, last a whole lot longer than most faculty careers.”
However, the company that manufactured the original MAP instruments has gone out of business. As a result, the main way to acquire spare parts is to purchase them from other laboratories that no longer need them. When argon labs are mothballed, their machines are often put up on the noble gas network listserv to be sold to other labs for parts.
“People have literally driven across the country to go and pick up old mass spec parts,” Sprain said. “Usually, when a lab’s decommissioned, if the system is old, the university isn’t going to get a lot of money if they try to sell it.”
Newer mass spectrometers are available, however, and geochronologists starting their own labs typically invest in these instruments because of their higher sensitivity and throughput. Such an investment usually requires overcoming the substantial barriers of writing a successful grant application and negotiating a generous start-up package from a research institution.
When Kevin Konrad arrived at the University of Nevada, Las Vegas (UNLV) to start his new argon lab, there was still an old mass spectrometer there, but he opted to purchase a new machine in the summer of 2021. “The MAP was something of a time bomb, so if something broke on it, I would be a fish out of the water,” he said.
Konrad said he is hoping to sell the old machine, but the buyer would need to pick up and transport the instrument: It is difficult to ship anything that has encountered radioactive materials, as the MAP has, and the magnet inside weighs about 700 pounds (318 kilograms).
“If I can’t sell the whole mass spec, then I might actually put it as a museum piece in the lobby—put a little cage around it and basically say this is what a mass spectrometer looks like,” Konrad said.
Yet the older machines have more than just historical value.
Singer said his lab is converting an old mass spectrometer used for argon dating to make measurements of helium-3, which would allow the lab to start doing surface exposure dating, adding new research capacity.
Old mass spectrometers can also still generate reliable argon dating data. When Sprain started her laboratory at the University of Florida, she opted to purchase a new instrument because the university’s mass spectrometer had been broken for about 10 years following a lightning strike that rendered its magnet nonfunctional. Sprain said she hopes to obtain a replacement part for the magnet to get it running again.
“It’d be really nice to have just a good standard workhorse instrument on top of the new one,” Sprain said. With argon, she explained, whatever the sample may be (a single grain of a potassium-rich mineral, lots of crystals of one mineral, or a whole rock aliquot), it may be full of material that can “dirty up” the insides of the instrument. “So we could then even potentially run really dirty samples on the old system.”
Staff Left in the Lurch
The dissolution of argon labs affects not only the equipment but also the people who make them run. Replacing a lab supervisor is not easy, said Konrad. “Argon geochronology does one thing only, which is date rocks. And so if [an institution doesn’t] want someone who can date rocks, the whole lab has to basically go. You can’t just take someone who roughly knows about the field…and expect them to run [an argon lab], because it’s a very involved process.”
When Kathleen Zanetti arrived at UNLV in 1998, she and her supervisor, Terry Spell, built an argon lab and its then state-of-the-art mass spectrometer and mineral extraction line. As the lab manager, Zanetti was responsible for all daily operations, including maintaining and repairing the equipment and running and analyzing samples.
But when Spell retired in 2018, Zanetti was essentially left to run the lab alone, meeting with and running samples for external clients. However, “because [university officials] consider it a dead lab without having a supervisor, they were going to shut the lab down,” Zanetti said.
“So it was a little concerning. I started to look for new jobs,” Zanetti said. “But it was hard because I pretty much pigeonholed my career by doing argon dating for 23 years. There’s not much call for that, and a lot of other labs, you know, keep their technicians and managers for life.”
Zanetti estimated that it would take several years to train someone new to manage an argon lab, but it can be difficult for staff to transition to another argon lab that could use their expertise.
“They try, but they’re not always successful,” Renne said. “I think a lot of the people that are sort of orphaned when somebody retires, they go on to different positions, different lines of work.”
Hodges agreed. “The technical support problem is a big, big issue” when labs transition, he said. “And it’s something that as a geoscience community, we need to figure out.”
Zanetti, to her relief, was able to keep her job when Konrad was hired to take over the lab in 2020.
Loss of Institutional Knowledge
In addition to impacts on individuals and institutions, the closing of argon labs has a wider impact on the field at large. Institutional knowledge and technical know-how can be lost.
“The issue is a lot of the things in the actual lab—chasing leaks, trying to figure out what the best kind of settings are for certain measurements and everything—none of that will ever be published or made publicly available. It’s just lab knowledge,” said Konrad, who still occasionally emails Koppers, his graduate mentor, for advice.
“Someone’s had a lab for decades, and then they retire, and no one’s taking it over. Their legacy and everything they’ve built, and all of that knowledge that used to be housed at that institution, is gone,” Sprain said.
Though many institutions do not hire replacements for retired argon lab directors, a few argon labs have maintained a line of succession, passing the lab from generation to generation.
Koppers is the fourth director of his lab, now in its 52nd year of operation at Oregon State University. When Koppers arrived in 2007, he overlapped with his predecessor, Robert Duncan, and the pair wrote a grant proposal for a new mass spectrometer together.
“I think we got funded because of this concept of making a transitional period where there was overlap with two professors running the same facility,” Koppers said, noting that this allowed him to learn the ropes from Duncan and signaled to the community that a successor was already in place and that the lab could run for decades to come.
Similarly, there’s a long history of argon labs based at the U.S. Geological Survey, with the earliest started in Menlo Park, Calif., in the 1970s. And unlike at many academic institutions, “there is a vested interest in keeping an argon lab,” said Morgan. She coleads the Denver argon lab with the previous director, Michael Cosca, who joined the lab in 2008, allowing for an overlap in leadership.
The lack of a succession plan is the reason the Berkeley Geochronology Center exists now as an independent research institution, Renne said. His argon dating lab was created in the late 1950s on the UC Berkeley campus, but when cofounder Garniss Curtis retired, the department had no plans to replace him; fortunately, a new private institution, the Institute of Human Origins, was being formed nearby, and the lab was able to find a home there before ultimately branching off on its own.
But now lab leadership at the Berkeley Geochronology Center has learned its lesson and has a clear succession plan in place, Renne said. “We’re all still very much interested in what we do.… We obviously will have to have a next generation coming in within the next, let’s say, 5 years.”
“How do we make sure that these instruments have a life of their own that doesn’t depend on the whims of somebody who decides they want to change university or somebody who decides they want to retire?”
The Future of Argon Labs
“How do we make sure that these instruments have a life of their own that doesn’t depend on the whims of somebody who decides they want to change university or somebody who decides they want to retire?” Hodges said.
More organization within the field could help address this question.
In 2020, the NASEM decadal report on the Earth sciences recommended funding a National Consortium for Geochronology. Sprain and Morgan, with other researchers, have since applied to acquire funding to start building such a consortium to support workshops, increase community building, and bolster organization among argon geochronologists.
Another positive step could be establishing pipelines or networks of technical expertise to keep these valuable instruments running. For example, a national consortium or network of individual labs developing training programs for technical staff and lab managers could make these career paths in argon labs more viable for students, Morgan said.
“I think we need to be thoughtful; we need to be strategic as opposed to tactical,” Hodges said. “Right now, we’re all being tactical about this.”
In other words, to continue studying Earth’s deep past, the field must also look—and plan—farther into the future.
Author Information
Richard Sima (@richardsima), Science Writer