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The Mojave River and Afton Canyon, from Late Quaternary Paleohydrology of the Mojave Desert, Marith C. Reheis and David Miller
On March 21, 2010, FOP had a conversation with Quaternary geologist Marith Reheis. She has been studying the Pleistocene for the past 40 years and is currently based in Denver, Colorado with the United States Geological Survey. She is also past chair of the Quaternary Geology and Geomorphology Division of the Geological Society of America.
FOP talked with Marith about her work studying Pleistocene Lake Manix in the Great Basin, how she sees the Pleistocene directly shaping the world of today, and the potential of artist/scientist collaborations to extend shared interests in deep time to broader audiences.
In the course of our conversation, we were reminded once again that, one way or the other, all things art and geology spiral back to Smithson.
FOP: When we asked if you would talk about what is it like to work and think in relation to deep time you sent us a message that said you didn’t really study deep time since the Quaternary is only the past 2-3 million years. Given our project, we find that remarkable because 2-3 million years seems like a very long time. How do you, as a Geologist, calibrate your own cognition to separate what is 2-3 million years ago from, say, 10-300 million years ago? What is it like to think in those terms?
MR: Interesting. One thing that I relate to very strongly is seeing the landscape as it is now, and as it might have been. I have always been a visual person, and because the effects of what happened during the Pleistocene are still with us, they speak to you more easily of how they were formed, or deposited, or tampered with in some ways, than the older rocks.
One of the things that first really entranced me about geology, when I was an undergraduate, was an exciting introductory class. It was taught by a guy did interpretation of photography from the moon. He also had done a lot of work with earth-based aerial photography and examining landscapes that you can see in stereoscopic 3D. If you have a stereo-pair, which is a pair of overlapping photographs taken by a airplane flying over the ground, and if you look at them through stereo glasses, then you see the landscape in three dimensions. It is just like flying over it, seeing it in incredible detail. It made the whole science come alive for me because you can really see the imprint of the underpinnings of the landscape, the geologic faults and folds controlling the way that rivers erode, and lakes form, and winds are funneled through wind gaps. It helped me to develop my interests, and led to learning how the landscape interacts with the modern processes that are operating on it – wind, rain, glaciers, oceans, currents and humans, and how they are changing that landscape.
I guess that is why I don’t think of a couple million years as deep time. You can see still these things. You can see that they have direct analog to processes that are operating right now.
A stereoscopic view, (c) Andrew Alden, “The basic technique is to cross the eyes so that the two images overlap completely. At that point the brain “locks in” on them and a 3D scene appears.” - about.com
FOP: Could you tell us about your background as a Geologist? How long have you been studying the Pleistocene?
MR: I started as an undergraduate in 1971 at the University of Georgia. I had an opportunity to join a field crew that was supporting a researcher at the University of Colorado. They were measuring the mass balance of cirque glaciers in the Front Range. In other words, they were seeing if the glaciers were growing or shrinking. It was a whole summer spent running up and down the high country of Colorado measuring ice, and it was a whole lot of fun. That’s what got me started on the Pleistocene.
Afterwards I got a Master’s degree in Quaternary geology and began work for the US Geological Survey in 1974. I was hired to do bedrock mapping for coalfields, so it was resource evaluation. After a few years, which were very valuable to me and I learned a lot, I wanted to get back to my real interest, which lay in Quaternary geology and soils. So, I went back to school and then returned full-time to the USGS in 1984 to work on Quaternary geology. I’ve been here ever since.
The American West has been my focus. Since 1984 my work has been based entirely in southern California, Nevada, and the Canyonlands area of Utah.
I’ve done a lot of different things within the scope of Quaternary geology. Quaternary geology is a term that basically means geology that isn’t very old—the most recent period of glacial-interglacial cycles in earth history.
Within that, I do research on how soil is formed, dust inputs to soils, climate cycles, human land use, effects on soil nutrients, invasive plants, and the whole interactive scene between dust and humans and climate and plants.
I’ve also worked a lot in the Great Basin and Mojave, trying to understand the past climate history recorded in pluvial lakes, the big lakes that formed during the glacial stages of the Pleistocene. They were not directly caused by glacial runoff, they were formed because it was colder and there was more precipitation and less evaporation. These internally drained basins filled up with water and their deposits can tell you a lot about what the climate was like.
FOP: Is there a particular Pleistocene lake that you are focusing on?
MR: The one I am working on now, and for the last five years or so, is called Lake Manix. Lake Manix was, for a long time, the terminus of the Mojave River. The Mojave River drains out of the San Bernardino Mountains in Southern California to the east, and ultimately ends up in a place currently called Silver Lake. During most of the Pleistocene, the river terminated upstream. It’s an area just east of Barstow.
Lake Manix was an extremely variable lake, because it was in a desert, but also a much lower hotter desert than the big lakes to the North, such as Lake Lahontan and Lake Bonneville. But, the Mojave River is also highly variable in terms of run-off, driven by both atmospheric circulation and climate change.
FOP: We’re interested in this idea that deep time can inform daily life, beyond being a Geologist. Do you find yourself seeing the world through the Pleistocene when you are not at work?
MR: Absolutely. It constantly keeps you aware of what underlies the surface of what you are looking at. I’m constantly thinking about what I see and how it got that way. It would be so boring if I couldn’t do that! It enlivens my world. I think I take an analytical approach to a lot of other things too, the long view, of how children will develop for example, rather than obsessing on all the details of the moment.
FOP: We are interested in creating a sense that the world we live in, is, in many ways, built upon or still directly influenced by the Pleistocene. We wonder if you have thought much about how to extend your views of the Pleistocene to broader audiences outside of Geology?
MR: I think the closest experience I have had to that was while I was doing fieldwork in Fish Lake Valley on the Nevada-California border. It is a very rural area with a lot of farming and ranching. There couldn’t have been more than 300 permanent residents in the whole valley. Maybe it was because they were people that lived on the land too, they were familiar with what their valley looked like.
On two or three occasions I gave a talk at their community center to try to describe to them what I was doing. When I did it, I always picked pictures that I knew had a story to tell geologically but also that they would recognize. And they really really liked it! I could show them how to look at a landscape that they knew so well, in a new way. I had people tell me: “Wow, I’m going looking for those kinds of things all the time now.”
So, maybe it is easier to make that jump or shift in focus if it is something you are already familiar with. It would be hard to try to make that shift when people aren’t even used to looking at landscape at all. Maybe one way to do it for urban dwellers would be to try to show them places in the cities where you can still see rocks and landscape histories. You could pick those kinds of places and make them come alive for people.
FOP: Do you know of collaborations between geologists and artists? Have you collaborated with any artists yourself? Or would you have an interest in doing so?
MR: No, I can’t say that I have, but it sounds interesting. How has this been done in your experience?
FOP: There would be various ways, but one might be where scientists are working with artists to make their work more accessible, by having them interpret it or give it an aesthetic experience or expression.
MR: I assume you know about the Spiral Jetty? I certainly relate to this as a way to merge geology and art. Because the Jetty is interacting with the lake’s waters [Great Salt Lake] as they rise and fall, depending on lake levels. It was completely submerged in the early 1980s when the lake rose, when we had a really wet period. It was once on dry land. Now that it is re-emerging it has the most intricate relationships with the really shallow ground water there and very high salt content.
So, the salts are controlled, in terms of where they are crystallizing, by the shape of the Jetty itself and by the rock walls that circle around, and by what part of it is closest to the water’s edge. It is a really interesting interplay between art and modern geologic process. It is something that is changing all the time.
I suspect, if you went out there and photographed it or analyzed it would change every season. I would guess this based on what I know about the fluctuations of salt crystallization processes during seasonal change.
FOP: It is interesting to hear you describe a process, in your language, as a scientist, about a place such as the Spiral Jetty that we have experienced as artists. As humans, we are sharing an experience of the same place, but speaking in very different languages. It makes us think that at this moment in human history, if we could find ways to translate across scientific and artistic languages we could create new ways of seeing and being in the world. Ways that we humans seem to need right now.
MR: This might help in some ways to bridge the gap between scientists who are working on global change and the people who are living on the planet and don’t know what to think about it all.
FOP: Some scientists hypothesize that the next ice age is coming soon, and that the present is just in an intermittent pause between ice ages. Do you agree?
MR: I wouldn’t venture to guess about that, the more that I read, and the more that I read between the lines. I think that assessment was based on the idea that most interglacials lasted at their driest or warmest period 10,000 years. But I think that is old data. The problem is that, as I understand it, some of the interglacial periods during the last half million years have been much longer than that. So, I think it is an open question, at this point, whether we are just half way through our current interglacial, or teetering on the brink of the next glaciation.
And that would be so if we weren’t imposing this grand experiment on the whole system. If we could somehow magically suck all this CO2 out to space somewhere and then see which direction things are moving we might be able to have a better idea. We’ve imposed such a huge perturbance on the system that it is really unclear to me, which way it is going to jump and when.
Richard Misrach’s Untitled, 2008, recently on view at Pace Wildenstein in New York
FOP: What do you think of the term the Anthropocene? Do you hear scientists using it?
MR: I can’t say that I have heard people using it as a common term in my office. But it is certainly one that everybody understands and would generally agree with in the sense that we are really changing things. It is going to be difficult to know for awhile just how big the changes are going to be.
You might want to look at David R. Montgomery’s work, I think it has some direct connections to what you are doing. He wrote Dirt, The Erosion of Civilizations. He is a soil scientist and is trying to show people what a huge geologic agent we are. In the last few hundred years we have moved more sediment faster than any known geologic process over the same amount of time. We have been a huge disturbing agent on the surface of the earth and what we have done is truly geologic in scale.
FOP: Could you tell us more about the history of the geologic Friends of the Pleistocene group? Your involvement with it and its history as you understand it?
MR: I think my first field trip with them was in 1979, but I had known about them before because one of my mentor-professors at CU had spent a lot of time talking about them and showing pictures from their trips.
The history of the Friends of the Pleistocene is pretty interesting. It goes back to the 1930s. In the East, some geologists who were interested in the glacial deposits decided they were going to get together and show each other what they had been working on and see if they could come to some kind of group decision of what it all meant.
It was a very informal thing and has been ever since. They called themselves Friends of the Pleistocene on that trip I think, and that is how it all started. They had so much fun and found it so rewarding that they began doing it on an annual basis and bringing their students along. It began to spread to different regions, first to the Midwest, because it was initially about glacial geology. Periodically a new group would form in a new region of the country, the Rocky Mountain cell is around 50 years old and the Pacific Cell about 40 years. There is also a Southeast, South Central, occasionally a Pacific Northwest, and I think now there is even an Alaskan cell.
The hallmark is informal and cheap, at least in the West. Here the spaces are big and there is plenty of room to roll a car caravan along. The trips tend to have no limits in terms of how many people can come. That’s not the case in the Midwest and East where the roads could become clogged as a result of a 50-car caravan. In the West, it is very very informal. There is a sign-up list, but people often do and generally do, show up unexpectedly. It has been pretty common for someone you happen to meet at the campground, who is there for their own reasons, finds what you are doing so interesting s/he decide to come along and then turns up on the next five trips.
Friends of the Pleistocene is informal and really meant as a way to show people what you are currently working on and get it out on the table before publishing it. A big part of it is to bring along your students and expose them to something that they wouldn’t ordinarily see as a part of classes. But beyond that it is quite open and relaxed. Anyone can come. I’ve been really involved with the Friends for a long time, ever since grad school and I like that part of it.
There might have been a year since 1984 that I didn’t attend, but I can’t remember when. This year the Pacific Cell is going to start in the Walker Lake area, in the Lake Lahontan Basin. The Rocky Mountain Cell is going to the Henry Mountains in central Utah, west of Moab. It would be a great art-oriented place. It is where a lot of classic Western geomorphology was developed back in the late-1800s, by some of the original geologists in the West. G. K. Gilbert wrote about the Henry Mountains in the 1800s. It would fun to interact out in the field on something like this.
FOP: Yes, that would be great next step for us, to have field experience with a geologist.
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