Impact that created Meteor Crater may have dammed the Colorado River, research shows

More than 50,000 years ago, a meteor hit Earth and formed what we now call Meteor Crater in northern Arizona. But new research finds that impact may have gone beyond that one site.

A paper hypothesizes that event may have also triggered landslides in the Grand Canyon — more than 100 miles away. Those landslides may have led to a damming of the Colorado River, creating a lake. The evidence for this, at least in part, comes from driftwood from Stanton’s Cave along the river inside the canyon.

Chris Baisan is a research specialist at the Laboratory of Tree-Ring Research at the University of Arizona. He joined The Show to talk about the findings.

UofA College of Science Laboratory of Tree-Ring Research

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Full conversation

MARK BRODIE: Chris, how surprising is what you found in the sense that one event triggered other events?

CHRIS BAISAN: Well, I think it's pretty unusual to — you know, it wasn't what we were looking for. This was not a research question when the initial investigation started. It was just an attempt to verify the dating on some wood that we had in our archive, as it might have been related to something that — that Jonathan Palmer was doing down in New Zealand.

BRODIE: So you were just trying to figure out how old this wood was and it kind of led you to this other discovery?

BAISAN: Yeah. So, Jonathan and some people down under there were investigating this magnetic pole reversal that occurred around 42,000-43,000 years ago with tree rings and radiocarbon work. And the wood that, this driftwood we had from Stanton's Cave had been previously dated to around 43,000 years. So we wanted to verify if it really was 43,000 years ago and therefore might bear on the research that Jonathan and his colleagues were already doing.

When we got the date back, it turned out to be over 50,000 years old. So, you know, it didn't have anything to do with that period of time that we had initially been interested in. And Jonathan had, previous to a visit to Tucson, had stopped at the Meteor Crater and was aware of the proposed date for the impact there.

And so when we got the date for the wood, he just kind of in an off-the-cuff way, the way that you might if you're having a conversation at a bar or something, "Oh, isn't that interesting? You know, that the meteor struck about the same time as the date, the radiocarbon date we got for the wood."

And the group of people that were involved with that radiocarbon dating and myself, you know, we just kind of kicked it around a little bit and said, well, that is kind of interesting. Maybe there's something there, maybe we should look into it.

BRODIE: Well, so how did you go about trying to connect one to the other?

BAISAN: So, the first was to investigate what the researchers who had looked at the driftwood in Stanton's Cave back in the 1970s and early '80s, see what they had said and what their reasoning was for why there was driftwood in this cave that's really high above the river.

And, you know, their hypothesis was that downstream from the cave, a section of the canyon wall had collapsed and dammed the river and made a lake. And this had raised the water level near the cave high enough to allow in flood times for driftwood to be deposited in, on the cave floor.

So the fact that there was this rock fall — which is unusual, I mean, there are not many events like that that have occurred in the canyon that people are aware of. This rock fall is an unusual event. The meteor impact is an unusual event. And we began to speculate that they might be linked.

Chis Baisan

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BRODIE: What is the significance of the fact that this one event triggered more impacts — I guess maybe impacts is not the right word — but more incidents on Earth?

BAISAN: Well, meteor strikes, of course, are a common occurrence in our solar system. But on Earth, there are not that many large ones that are recent. So Meteor Crater is an example of one that's, in geologic terms, relatively recent. The crater's well preserved, and it's possible to actually study it a little bit.

So, you know, it's a nice opportunity to maybe try to see if, you know, we can demonstrate that these things are actually connected. And the rock fall might well have been a consequence of the impact.

BRODIE: Is it possible that there are more consequences, more events happened as a result of the sort of the chain reaction here?

BAISAN: Well, I mean, there's been some work done estimating what the impact did in the, in the local area. Of course, it spread debris all over the place, kind of a rain of fiery debris, and probably caused wildfires. There's a sediment core in a lake that's not too distant from the crater, where there's a charcoal layer that might be associated with some fires that were caused by the impact.

And certainly the wildlife and, you know, things that were around the crater were highly impacted. But this is at some distance. It's over 100 miles away. ... So that's kind of interesting. And it, and it serves as just a, a reminder of, you know, you have an event, you can see the crater.

But then trying to understand what would happen, you know, if we were to observe such a thing today. That's an important line of investigation, I think.

BRODIE: Yeah, well, I'm glad you brought up the distance because as you say, you know, the Grand Canyon is not right next door to Meteor Crater here. It's, as you referenced, about 100 miles away.

Is there a significance to the fact that the impact at Meteor Crater could have an impact that far away? Like, does that tell us anything maybe about the size of the impact or about the dynamics of the impact in some way? That it could affect events so far away from where it actually happened?

BAISAN: We're hoping that some follow-on work will try to model the seismic effect of the impact and look at the structural geology of the terrain between the crater and the canyon, to see how effective that those rock layers might be to transmit the impact. And maybe provide a little more evidence that would support the hypothesis that we put forward.

BRODIE: So does that mean that it would be dependent on sort of what's below the surface to determine — would help you figure out like why something that happened at Meteor Crater affected the Grand Canyon?

BAISAN: ... So the impact caused an earthquake, you know, what we would refer to as an earthquake. But as opposed to the typical seismic activity that we have, when we think of, you know, the San Andreas Fault or something. Those occur well below the surface, sometimes many kilometers below the surface.

And this is a seismic shock that was delivered to the surface layers. So, the upper layers would be the ones that would transmit this laterally over to the canyon, and that's the Colorado Plateau. There's sedimentary layers that stretch all across there. So, it would be helpful to have a model that was specific to that region and then a simulation of what we think the explosive force was and how that might be transmitted.