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October 25, 2018

Q&A: Provost Mark Richards’ welcome lecture asks: ‘What really killed the dinosaurs?’

The University of Washington this summer welcomed a new provost and executive vice president, Mark Richards, who also has an appointment as a professor in the UW Department of Earth & Space Sciences. As a lead-up to his welcome lecture, Richards sat down with UW News to answer a few questions about his work to solve one of Earth’s most intriguing scientific mysteries.

The lecture is Tuesday, Oct. 30, at 3:30 p.m. in the HUB Lyceum. It will also be livestreamed and available afterward online.

How did you get into studying dinosaurs? How does it relate to your expertise in Earth sciences?

The answer is, honestly, that I really don’t study dinosaurs. I’m not a paleontologist; I’m a geophysicist. I study the events that led to their extinction.

My expertise is in flood volcanism, caused by plumes of hot rock coming from deep in the interior up to the surface in what are called flood basalts. Mantle plumes also create features like Iceland or the Hawaiian Islands chain or the Galapagos Islands.

The last four mass extinctions on Earth are all closely associated in time with huge flood-basalt volcanic events. The largest mass extinction event was 251 million years ago, when about 90 percent of all species were wiped out. That event is very closely associated with a huge set of volcanic eruptions in Russia — the Siberian Traps eruptions.

Only the most recent mass extinction — the K-T mass extinction that killed the dinosaurs — is associated with a meteorite impact, the Chicxulub impact. The meteorite impact coincides almost exactly in time with the extinction event. But there was also flood volcanism at that time in India, creating the Deccan Traps. Why does the dinosaur extinction coincide with a big meteorite, and is it related to the volcanism? This has been a real conundrum in the science.

The Deccan volcanism had started before the impact, so the meteorite didn’t cause the volcanism. But what I and my group have proposed, and found increasing evidence for, is that the rate of volcanism increased by a factor of two or three at the moment of impact. In this case, it looks like there was an ongoing flood-basalt event whose activity was accelerated by the meteor impact. And we propose that the acceleration of the eruptions may have contributed to the K-T extinction 66 million years ago, when 70 percent of everything in the fossil record was wiped out.

So let’s jump to the question that everyone’s inner 8-year-old wants to know, and that is the title of your talk: What killed the dinosaurs?

Not to give away the answer, but the truth is that we don’t quite know. We know that it’s one of two things — meteor impact or volcanism — and the two events may have been related. It leaves us, right now, not knowing which of those two events was the leading cause of the extinction. My own prejudice is that it probably was the impact, but we just don’t know that yet.

Have these been the only explanations for how the dinosaurs died out?

People today seem to think that we always knew there were mass extinctions. But that’s not true. Very few people realize that prior to 1980, the majority of paleontologists did not believe in mass extinctions. They had all sorts of other explanations for how species had disappeared. Dinosaurs were fairly large and rare as animals go, so it’s not entirely obvious from the fossil record that they died off suddenly. There are some people even today who maintain that the dinosaurs died off gradually.

But in 1980, Walter Alvarez and his group at the University of California, Berkeley, published this amazing paper with evidence of an asteroid impact at the time of the K-T extinctions. That paper and the huge controversy surrounding it gave a lot of paleontologists the idea that there could be at least one major event that could trigger extinctions across the globe. When later in 1991 scientists discovered the Chicxulub Crater in the Yucatán, Mexico, people became very convinced that mass extinction events were possible.

Since then, paleontology has gotten better and better, and it’s now clear that there are at least five, and possibly six, mass extinction events in the past 600 million years of Earth’s history. The four that have happened since 260 million years ago are very clear in the fossil record.

How do you carry out your research?

What I’ve been studying is the causal mechanism of the K-T mass extinction. I’m mainly concerned about the volcanic processes, and how they change the conditions for life on Earth. That involves understanding the nature and timing of the Deccan eruptions.

For the last four years, our team has been going to India to the Deccan Traps lavas to obtain samples. Prior to the work that we’ve done, the dating had only been precise to about half a million years. But by using the latest methods for argon-argon isotopic dating, we can now date samples to a precision of about 30,000 years. This new technique has allowed us to say with increasing precision exactly when each lava sequence was laid down in layered rock formations that are about 3.5 kilometers (more than 2 miles) in total thickness.

We can also say rather precisely when the Chicxulub impact occurred. And we see profound changes in the nature of the volcanism in India just at that time. The Chicxulub impact caused a magnitude-11 earthquake, which we think triggered accelerated volcanism almost halfway around the world.

We had a very precise hypothesis that we were testing, and it’s turned out to be spectacularly confirmed. That doesn’t happen very often in science.

What should people expect from your talk?

The talk is designed for a general audience. I’m going to minimize the technical slides, and emphasize the places traveled, the adventure of it all, the people I’ve worked with, and highlight the most important scientific aspects on the way.

It’s unusual to introduce a provost with a research talk. Was that a deliberate choice?

 Yes. I very much want the faculty and students here to feel that I’m part of the academic mission of the university, and not just someone who lords over their budgets. (Yes, you can actually keep that line.)

The role of provost is mysterious to many people. How do you like to describe it?

 Officially, the provost is the chief academic and budget officer for the campus. It’s a huge amount of responsibility, especially for a place this large and complex. So, one way to think about it is that the president and the provost are both chief administrators, with the president as the boss and the provost beneath.

The president is a much more outward-looking person, who is the face of the university and is more publicly and politically visible. The provost is the person who’s more inwardly focused and looking at the running of the enterprise. President Ana Mari Cauce and I talk every day, and we don’t make major decisions without consulting each other. It’s really a partnership.

How do you balance your research with being provost, and why do you think it’s important to do both?

 I’ve had a lot of practice. I was dean for 12 years at Berkeley, and managed to keep my research going during that time. It’s mainly an issue of time management.

I think it’s important, if you’re in a position like dean or provost, for faculty to see you as a colleague. The main way to be seen as a colleague is to be a teacher or a researcher. Keeping a research program, which you can schedule during “off-hours,” is much more possible than maintaining a regular teaching schedule.

On the provost front, any areas that people should look for as initial priorities?

Some things that I think need renewed attention at the UW — in no particular order — are support for graduate students and restoration of infrastructure and facilities. Affordability for undergraduate students and the overall undergraduate experience, and diversity across all aspects of the university community, especially among the faculty are also significant priorities.

Anything else you would like to say to the university community?

 It’s an exciting university that is innovative and flexible, and I’m really happy to be here.

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Tag(s): College of the Environment • Department of Earth and Space Sciences • dinosaurs • Mark Richards • paleontology • Q&A

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