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Geophysical Surveys in Ohio with Dr. Jarrod Burks - Ep 160
273 Plays4 years ago
Dr. Jarrod Burks of Ohio Valley Archaeology, Inc joins us on the show today to talk about his pioneering geophysical work in Ohio. Dr. Jarrod Burks specializes in geophysically detecting the unseen archaeological record that surrounds us. He is also president of Heartland Earthworks Conservancy, an organization that works to study and save Ohio earthworks. Dr. Burks’ day job takes him all over the country, and beyond, to survey archaeology sites, cemeteries, and even look for lost WWII soldiers. Back home, he fell in love with Ohio’s Woodland period mounds and earthwork sites more than 25 years ago when he moved to Columbus to pursue his doctorate in Hopewell settlement research at The Ohio State University. He now spends a good amount of time each year surveying earthworks, retracing the footsteps of the 19th century mappers and travelers…as well as discovering previously undocumented sites.
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Transcript
Introduction and Sponsor Announcement
00:00:00
Speaker
We're excited to announce that our very own podcasting platform, Zencaster, has become a new sponsor to the show. Check out the podcast discount link in our show notes and stay tuned for why we love using Zen for the podcast.
Episode Introduction: Featuring Dr. Jared Burks
00:00:19
Speaker
Hello and welcome to the Archaeotech Podcast, Episode 160. I'm your host, Chris Webster, with my co-host, Paul Zimmerman. Today, we talk to Dr. Jared Burks about his work with geophysical detection of archaeological sites and features. Let's get to it.
Fieldwork Challenges in Northern Nevada
00:00:34
Speaker
All right, welcome to the show, everybody. Paul, long day for you today, huh? Oh, boy, has it ever been.
00:00:41
Speaker
out today, we had to literally move a tree out of the way on the path we were on. Then we did a lot of bushwhacking and then we backed out and went ridge top to ridge top and so it's just been going and going and going. Our last little jaunt out, it took us 45 minutes on terrible, terrible two-track
00:01:00
Speaker
just to get back to the mining hall road. And that's still a ways out. So we had a long, long day, but it looks like it's going to rain over the next couple of days. So we figured we'd do longer day to day expecting that we'll have short days for the rest of the project.
00:01:17
Speaker
Yeah. Yeah. Indeed. So yeah, Paul, for those who didn't hear last week's episode or last episode on the architect podcast is out here in Northern Nevada with me on a project. And actually he's been going out with my, uh, with my wife. She's the crew chief on this project. So they're tooling around and yep. And doing stuff on the, on the crazy high desert and high elevation mountains of Northeastern Nevada. So good times all around. Yeah. It's been a great learning experience, but wow. Yeah.
Expertise in Geophysical Surveys: Dr. Jared Burks
00:01:47
Speaker
Well, one thing we can't do here in these project areas is typically, you know, most geophysical surveys because it's like solid rock underneath our feet. So there's not a lot of soil deposition. So there wouldn't be too much of that. But our guest today is going to talk about some of that stuff that he's done over in the East Coast in the central Ohio Valley and those areas. Dr. Jared Burks, how are you doing? Doing good.
00:02:11
Speaker
All right. So as usual, we're all over the place. Paul and I happen to be in the same location, but Jared, you're over in Ohio right now. So anybody hears any weird things on the internet. I like to just call that out. Plus, like I said, Paul is in a, is in a laundry room by the router. So there could be some wind noise and some, some reverb and stuff like that. It's just the natural. It's not because this place is haunted. It's because there's a really squeaky vent up above.
00:02:37
Speaker
We usually try to be pretty good about our sound environment, but there's not a whole lot we can do about it when we're in the field.
Presentations at the Ohio Archaeology Council Meeting
00:02:42
Speaker
Anyway, Paul, you saw some presentations that Dr. Burks did. You want to talk about that to introduce the topic today? Yeah, absolutely. We've had Eric Olson on this podcast a couple of times in the past, and he's always been a very enthusiastic, very engaging guest.
00:02:59
Speaker
Actually, he guest hosted once when you couldn't meet. And he told me that, hey, you know, since you're getting back into CRM, well, back into, I've never been in CRM before, but since you're getting back into archeology and going to CRM, widen your horizons. Take a look at Ohio Archeology. We're doing a lot of great things. And by the way, we've got the Ohio Archeology Council annual meeting coming up. It's going to be hosted remotely on YouTube, I think it was. And certainly some of the discussions are now posted on YouTube, and we'll put that link in the notes afterwards.
00:03:27
Speaker
And as it worked out, I actually could watch a little bit of it. One of the presentations I watched was Jared Brooks's, where he was doing magnetometry surveys of great circles, if I recall. It's an archaeology that I'm not particularly familiar with. It's some terminology that I am familiar with, but not the area, not the region. But what I was really, really impressed with was just the clarity of the magnetometry that you're getting.
00:03:53
Speaker
much better than anything I'd seen before. And so I said, hey, we have to have him on. We have to discuss what he's doing and why he's doing it and how he's doing it. Because I think this would be of interest to our listeners. So yeah, that was the genesis of this.
00:04:10
Speaker
So let's, let's kick this off. And Jared, can you tell us and our audience, for those of that might not be familiar, cause I work a lot in the West and to be honest, there aren't a lot of geophysical surveys that happen in a lot of the high desert areas of the West. Some of our audience may not be aware. What is a magnetometer survey? I did this back in college and grad school, but just give us a little primer on magnetometry.
00:04:30
Speaker
Well, a magnetometer detects the Earth's magnetic field, so it's pretty simple in that regard. It's a passive instrument. It doesn't emit any kind of transmissions, so you carry it back and forth across the site, typically while it automatically logs readings.
00:04:46
Speaker
And what we're looking for are kind of small area changes in the Earth's magnetic field that might be associated with archaeological features. In particular, the magnetometer is pretty good at detecting burned things. Accumulations of topsoil in pits that have been dug into clay subsoil. It's also quite good at detecting iron objects. Maybe too good, especially those pin flags everybody uses to mark their shovel test locations.
00:05:13
Speaker
Do you know much of the physics behind this? Because I'm curious, I don't remember from grad school how a magnetometer that's detecting small changes in the Earth's magnetic field, how does disturbed soil or a burn feature affect the Earth's magnetic
Magnetometry in Archaeology: Basics and Applications
00:05:29
Speaker
field?
00:05:29
Speaker
That's a good question and I do know that part primarily because I'm an archaeologist and that's the kind of stuff we pick up. So there are different chemical reactions in topsoil versus subsoil and as long as there is some iron presence, some various iron minerals present like hematite and magnetite in particular.
00:05:54
Speaker
And there's another, there's a third one called magmite, and that's the most magnetic one. So these three minerals in particular, because of the oxidation and other things that happen in that topsoil zone, they kind of cycle back and forth amongst, you know, they change back and forth. And there are certain processes that happen, and some of this stuff is kind of unknown.
00:06:18
Speaker
And it's still under study, but even bacteria get involved in the process. And these minerals transform into the more magnetic types, making that topsoil more magnetic versus what's going on in the subsoil where there's less of that transformation happening.
00:06:36
Speaker
So there's just this natural increase in magnetism or magnetic susceptibility in the topsoil. The burning bit is kind of similar to that, but there's an added element and that is if these minerals are present and the temperature of the fire gets above a certain point known as a Curie point, something like 600 degrees centigrade or so,
00:07:00
Speaker
than those minerals, the magnetic signature, let's say, of those minerals kind of gets
00:07:08
Speaker
gets released and it points toward the most magnetic thing, which is often the Earth's North Pole. And then when the temperature cools down, they get stuck pointing in that direction. And if enough of those minerals end up pointing in the same direction, that magnetic moment is much stronger than the ground around it. And in fact, that's the source of archaeomagnetic dating.
00:07:34
Speaker
Yeah, because the Earth's magnetic field has changed over time so we can detect where they're pointing, basically, if it's undisturbed, right? As opposed to where the Earth's magnetic field is now, that's the difference that's being detected? Yeah, right. The difference. Are there certain soils that are more conducive to
00:07:56
Speaker
you know, becoming more magnetic, so to speak. Yeah, you bet. So for example, I can tell you that sandy soils aren't terribly magnetic. And thankfully, we don't have very many of those in Ohio. But there are regions that have lots of sandy soil. So there will be soil types that are, we might call them magnetically quiet. So when you do a magnetic survey across them, you see very little variability, whether there's archaeology there or not.
00:08:23
Speaker
And you could plow those quiet sites and you'd never see the plow marks. Whereas on magnetically busy sites, if you plow them, even if the top of the ground is flat, those plow scars below, you know, where the plow has gone a little bit deeper into the subsoil, they'll show up, you know, brightest day in a magnetic survey.
00:08:48
Speaker
But what's handy is usually those magnetically noisier soils, if people live on those landscapes and people living in a place increases its magnetism too because they burn things. They bring in organic material that those little magnetotactic bacteria like to chew on.
00:09:11
Speaker
And so people living on a spot can enhance a soil's magnetic potential as well. It's a process that's referred to as magnetic susceptibility. So human habitation impacts magnetic susceptibility. So that's an easy way. Believe it or not, we can sometimes use the intensity of plow marks to sort of map the distribution of archaeological midden.
00:09:36
Speaker
Okay. So you're not just looking though, I mean, from your presentation and actually there's the previous year's OAC presentation on YouTube, which are also linked in the show notes. You're not just looking at what dispersed evidence of people's activity doing things in a certain area, burning things, whatever, but you also have a
00:09:56
Speaker
a distinct focus on earthworks, or at least in the presentations, the two presentations of yours that I've seen, how did those earthworks affect the magnetic susceptibility?
Surveying Ohio's Ancient Enclosures
00:10:07
Speaker
Yeah, so my day job is all things archaeological and cemeteries. I spent a lot of time there. And then my personal research and my preservation hat is surveying these things we call earthworks. In particular, they're ditch and embankment enclosures of circles and squares and octagons and those kinds of things. They're all built something like 1,800 to 2,200 years ago in the Ohio Valley here.
00:10:37
Speaker
And because a lot of those enclosures involve digging ditches down into the subsoil, so that's below the topsoil and then down into that less magnetic subsoil, if those ditches become filled with topsoil, which they pretty much all do eventually, through erosion and plowing, then you've got a big old pile of topsoil there.
00:11:00
Speaker
on a landscape where the topsoil is usually pretty thin. So that spot will be more magnetic. Oh, I get it. And then interestingly, we've surveyed enough of these now that we can see how it varies from river valley to river valley. So where I live in the center of the state in the Scioto River Valley, soils here are amazingly magnetic. So it's typically pretty easy to find in these earthworks.
00:11:27
Speaker
They're really obvious, as you maybe saw in the magnetic data. But the next valley over to the east, the soil there is just different enough, probably different geology there, different bedrock, certainly different glacial activity there. They're a lot more quiet, so it's a little harder to find the earthworks there.
00:11:46
Speaker
We may be jumping ahead of ourselves here, but do you have to recalibrate your tools or your cleanup of the data afterwards in order to account for those different soil types and different susceptibility in different places?
00:11:58
Speaker
Well, I'll tell you what, you should be really careful in data collection no matter how magnetic the ground is, of course, and make sure you're not magnetic when you're collecting data, especially if you're carrying a magnetometer. I started off carrying a magnetometer, so I had to be very careful not to wear magnetic clothing.
00:12:18
Speaker
And I will admit, my very first magnetic survey that meant anything to the world, I ended up having magnetic shoes on. So you probably had metal grommets on your laces, right?
00:12:29
Speaker
Something like that. They were basketball shoes and they didn't look terribly magnetic, but they must have been so cheap. Maybe they were made with tire rubber or something. You can see just about every step I took in the magnetic dance. That looks a little strange. I've never seen that before in the publications.
00:12:48
Speaker
So, yeah, so, you know, from, from then forward, I always test new shoes against the magnetometer. And I've even taken the magnetometer into the shoe store, you know, I know this may look weird, but I need to make sure that these shoes aren't magnetic. Things you do in the field, right? Right. Yeah. The things you've been told, or you screwed it up once.
00:13:13
Speaker
Yeah, like when you forget some of your critical clothing, like your magnetometer shoes, you have to go to pay less and try to find some cheap shoes. Nice, nice. So we're going to go to break here in a few minutes, but I'm wondering just in general, you mentioned to us when you booked this appointment that you've worked with magnetometry, of course, ground penetrating radar, resistivity, you've done metal detecting, all kinds of stuff.
00:13:43
Speaker
Have you found that in general, like if somebody was going to get into one of these things, like in general, something is one of those techniques is often more applicable than others or is it just the right tool for the right job and everything's different? Yes and yes. I'd have to say though, that it will depend on where you're working and what you're looking for. So I chose to start with a magnetometer because it works so good in the region where I was doing most of my work.
00:14:09
Speaker
And also my PhD is in pre-contact period, you know, American Indian archaeology. And so that's...
00:14:20
Speaker
holes excavated into soil that are filled with soil. That's very tricky for the radar to detect, especially at the relatively low densities 20 years ago that we could do with the radar. So since we were mostly working on those pre-contact pre-sites, the magnetometer made the most sense. Since then, of course, we've added other instruments as we started to do a more historic period.
00:14:43
Speaker
surveys and cemetery surveys and all that. So the next tool, well, actually it was the third tool, I think, was the ground penetrating radar. They're all so expensive. You may need to slowly build up your toolkit. So some thought should be put into, which one should I go first? Yeah, we used to joke, my advisors project in the Middle East, they did
00:15:09
Speaker
GPR and it didn't work worth a damn on their site. So they called it the ground non-penetrated radar. But then they did magnetometry with some good results. And then another one of my my cohort, another project they worked on, they tried the same thing and it was entirely the opposite. The GPR was great and the magnetometry was awful. So there was soil pipes in the architecture that they were looking for and so on. But yeah, tool for the job, I guess is important.
00:15:36
Speaker
Yeah. That's why it's often a good idea to know what it is you're looking for. You know, have an objective and if you can know a little bit about how it appears in different kinds of data sets. And you know, we often try to bring more than one instrument. Yeah. That makes sense. Okay. Well, we are close enough to the end of this segment that we're going to take a break and then come back and continue talking all things geophysical with Dr. Jared Burks back in a minute.
00:16:01
Speaker
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00:17:24
Speaker
Welcome back to the Archaeotech podcast, episode 160. Paul and I are talking to Dr. Jared Burks about geophysical surveys and all kinds of things that he's done. One of the things that you sent us over is you've done a lot of geophysical survey in the CRM industry in Ohio. Is that where your day job is? Or you work for a CRM company or a CRM firm?
00:17:45
Speaker
Yep. Yeah. That's my day job. It has been for about 20 years. Wow. Well, there you go. And that's really cool because as I was saying earlier, I've worked, I've worked in the Southeast. I've actually worked in Ohio, worked in the Northeast, worked mostly in the West. No, I've worked in the Southeast and Ohio.
00:18:06
Speaker
It depends on the conference you're attending. That's true. That's true. But anyway, so I've worked all over the country, but I've worked mostly in the West and to be honest, in the inner mountain West of like, you know, Nevada and the mountains of California. And there's just not a lot of CRM firms doing geophysical surveys in those types of environments for, you know, good reason. So it's really cool to hear
00:18:27
Speaker
a CRM firm doing that. How has bringing geophysical methods into CRM changed or improved Ohio CRM archaeology?
Cultural Resource Management in Ohio
00:18:36
Speaker
So we weren't the first ones to do it by any stretch in Ohio. But I think one thing that set us off 20 years ago was that we were doing it a lot for ourselves. And so you can do a lot more trial and error when you're the one digging up the horseshoe or whatever it is that was supposed to be a cooking pit.
00:18:57
Speaker
So we got pretty good at interpreting the magnetic data. So we started to transition our, for example, our phase two work. So in Ohio, it's phase one, two, three, as it probably is elsewhere. Find sites on phase one, assess sites for eligibility on phase two, and then phase three is data recovery.
00:19:21
Speaker
So we kind of focused in on phase two as that point at which, you know, should we bring the backhoe out or not? And we started moving away from bringing the backhoe out because if the goal of the phase two is really just to determine if there's subsurface integrity, you know, and this site may be eligible for the national register, then hey, we can do that with a magnetometer because there's a lot of stuff in our region that's magnetic and it's pretty quick to find it with a magnetometer.
00:19:51
Speaker
So, a lot of archaeology sites are half-acre to two acres in size, and that's only like a day or two of magnetic survey with a handheld instrument back then. So, we could cover the whole place, whereas before, you might use your backhoe just to strip off a couple of 10-by-10-meter blocks or something like that, and you'd only sample a bit of it.
00:20:16
Speaker
Um, that's kind of the platform where we started to grow this approach and we had to show that it worked, you know, many, many times. I spent a lot of time going and doing surveys for nearby field schools, you know, interpreting the results and then say, Hey, dig here and you'll find cool stuff. And that helps, you know, spread the word. And, you know, eventually people realized these guys know what they're doing. They seem to be able to find things.
00:20:42
Speaker
with regularity and we gave kind of demonstrations too to our historic preservation office and you know the archaeology world's pretty small so you kind of already know all these people and you see each other at conferences and such. So they began to see how this might be not necessarily more cost effective but a more effective
00:21:05
Speaker
And it was up to us to make it more cost effective. And so we worked hard at that. And yeah, and that's how we kind of made it at least an integral part of our process. And it's become more common in Ohio, I think, because of how often we were doing it. And we're not the only ones that do geophysics in Ohio. Of course, there are plenty of other people that do.
00:21:29
Speaker
So getting your historic preservation office interested in it and seeing that it is actually quite effective and can find the resources that are important to find while also preserving those resources. Because when you dig, you're destroying what you're digging up. And those backhoes, while they're effective at finding buried features, they're also really effective at destroying stuff.
00:21:52
Speaker
What about clients? Is it tough to convince them that what you're doing is not going to get their permit pulled and get them fined because you said there was nothing there via magic and didn't actually dig anything?
00:22:09
Speaker
So you say that works better. You know, why do we want to do that? Right. Cause they don't want to find archeology. You know, they're, I mean, yeah, you don't want to find too much. And it's like, well, again, that's up to, I mean, the preservation office wants you to find what's there. That's what the law law really wants you to find that. So we're not trying to make your life harder. We're trying to make your life easier. So in fact, I mean, that's a really good question because we've had to.
00:22:39
Speaker
You know, before, even in Ohio, when we first started, it's like you find a feature. It's like, oh my God, shut it down. You know, this site is eligible for national registry. You better change your plans. And now it's like, well, okay. I mean, if this is decent enough archaeology for us to be doing a geophysical survey on this, probably going to be some features here.
00:22:58
Speaker
We'll find them and then we'll assess whether or not they're all eligible for the National Register because, in fact, there are millions of features in the state of Ohio and other places. Not every single post hole or little pit feature is going to make a site eligible, if you know what I mean. What? I know. Exactly. People have lived in Ohio for a while.
00:23:22
Speaker
Yeah, there have been a lot of people who have lived here over the years, and they really have liked digging into the ground. They've left quite a record behind. And in some cases, and I think one of you said that you'd worked in Ohio, so you know that there's just
00:23:39
Speaker
flint knapping debris everywhere because there's so many toolstone sources here that it's hard to not find it. Every shovel test on a project sometimes it seems that doesn't mean that there are subsurface features on a site like that. That's another thing we say is sometimes you can get the wrong impression from the plow zone assemblage. It may suggest that this site is amazing.
00:24:07
Speaker
But in fact, you know, there's like nothing left of it underground, or there never was anything there. So that's the kind of thing we can we can help puzzle out pretty quickly with geophysical survey. Right. So I just want a little more detail on you said cost effective and cost effective.
00:24:25
Speaker
You know, one is who's paying the cost, but another part is there are different ways you can measure it. You know, can you do more in a certain amount of time? Can you do a certain parcel faster or can you do it with more detail? Which way or do all three of those ways apply with what you mean by cost effective? Yeah, it's just all those things. So, you know, we often say, well, you know, what happens if you inadvertently find something and then you have to stop once you've got, you know, the really expensive construction people there, you don't want that to happen.
00:24:55
Speaker
I'm not sure that ever happens in any universe that we know, but it's supposed to happen, right? If they inadvertently find things, they're supposed to stop and tell someone. It's certainly a fear from the developer standpoint. Yeah. So if we can find all that stuff ahead of time and help them avoid it or whatever they want to do, you know, then that's got to be cost-effective because we're probably the least expensive part of what they're going to be doing, right?
00:25:21
Speaker
that road or that big building they're going to build is way more expensive than the archaeology. So if we can help them avoid delays in the expensive part of their project, then surely that's got to be cost effective for them.
00:25:35
Speaker
But also, we want to make the archaeology process cost effective in and of itself. And so, if we can do that faster, or if we can do it with fewer personnel, obviously those are ways to help keep costs down. Or if we can avoid bringing the backhoe out, because backhoe operators make more money than we do.
00:25:56
Speaker
if we can avoid bringing the heavy equipment on site, unless you really need it to strip off in an enormous area, then we can keep those costs down as well. So it's multifaceted. Yeah, I'm curious as to when you're doing this. And I'm not going to use phases because phases are defined differently across the country. But when you're doing, there's initial wide-scale shovel testing survey. Then there's close interval, either shovel testing or test unit testing. And then there's full-scale block excavation and some variations in between.
00:26:26
Speaker
What phase of those three things would you say you're using your geophysical methods on more, you know, initial survey testing or, you know, pre full scale excavation? Yeah, traditionally it's the middle one where you're trying to get a finer grain look at an archaeological site. You're trying to, you know, really, really determine the distributional patterns of, you know, within the middle and around here, that's in the plow zone.
00:26:54
Speaker
You're also trying to locate pit features and other kinds of features, structures, and all that. That's kind of getting a better sense of where stuff is. That's the middle part of this whole chain of processes. Traditionally, we've done geophysics mostly at that point.
00:27:14
Speaker
places where it can be used in the third step, where data recovery, where you're digging large portions of a site. And of course, depending on which state you're in, that could be some sample of a site or it could be all of a site. And of course, it depends on the size of the site too. But imagine if you're only doing a sample of a site and you don't have a good sense of
00:27:36
Speaker
where stuff is on that site, you could blow your entire budget digging nothing, you know, which would be sad because right next door, and this is the archaeologist nightmare, you know, one meter away is the golden idol that you missed, so to speak.
00:27:51
Speaker
the most important thing out there. That's one great thing about geophysical surveys. It can give you a whole lot more information that you can then use for sampling. You're not just relying on an artifact distribution. The nightmare is that you find that idol in the bulk on the last day. That's just Murphy's law of archaeology. It's going to happen no matter what I think.
00:28:18
Speaker
Sure. Yeah, so it can work for you at the data recovery level or the big excavation level by helping you direct your limited resources on those big excavations because you probably can't dig everything, but you want to get some kind of sample. So it not only finds archaeological features, but it tells you certain things about them.
00:28:43
Speaker
So, for example, in a magnetic survey, a cooking pit is likely going to be quite a bit more magnetic than, say, a storage pit, because there's been a fire or extremely hot rock, or maybe there's igneous rock down in the cooking pit, whereas in a storage pit, it's basically empty, except for it's been silted in or something.
00:29:06
Speaker
you can begin to differentiate feature types using geophysical data. That can really help you stratify your sampling universe by saying, hmm, I probably don't want to dig 50 cooking pits and only one storage pit. Maybe I want to mix it up a bit. Since you know where they're all at, you can also say, well, I don't want to dig
00:29:31
Speaker
you know, house, I don't want to dig 20 pits right outside house two, maybe I should dig a few from house 123 and four, you know, however you want to do it. So that's kind of nice. It really helps with strategy and project planning.
00:29:48
Speaker
especially if it's done before you do that kind of thing. So we've for years, and I know probably everybody who does geophysical survey beats this drum, but don't just tack it on the end of a project because it's actually kind of expensive to just tack on the end, build it in as part of the project, then it will be more cost-effective because it can guide the whole project if it's done properly, of course.
00:30:16
Speaker
I think it's fascinating talking about the difference between storage pit and cooking pit, which gets to the point that you've been doing this. You know what you're looking at, you know what you're looking for, you have a certain amount of experience in interpreting the results of your survey. What's been your role in bringing geophysics to Ohio archaeology and how do you use it on the regular? I mean, my role in bringing it is just doing a ton of it.
00:30:44
Speaker
Like, I was just sort of negotiating with my wife. I was like, hmm, would you mind if I go out on Saturday and do some geophysical surveys? Yes, I have an affliction. I can't stop doing it. But mostly because, you know, it's like you guys with your podcast. I mean, this is Show 160.
00:31:03
Speaker
You must be really excited about podcasting just like I'm excited about geophysical survey. So you see that it has merit and that it brings information to people and that's the same for me. I see this as an amazing tool and I like to learn more about it as much as I can and I like to show people how it could enhance the kinds of things that they want to do.
00:31:27
Speaker
So that's been traditionally how I've brought it to Ohio and beyond, but also I helped teach it to others. The National Park Service has had a geophysics workshop for archaeologists since the 1990s.
00:31:44
Speaker
And I've been fortunate enough to be an instructor in that since the early 2000s. So it's not only a place where I learn about the latest techniques, which is kind of handy, but I can also teach, you know, what I know to others and spread the love.
00:31:59
Speaker
Well, I will tell you, I wish somebody had told the company we were working for, my wife and I, the only project, I said I worked in Ohio, the only project we did was in Southern Ohio on the Rex East pipeline. And it was, yeah, I hear you the laughter. Wait, did you say Rex East? Does that mean Eastern Ohio?
00:32:19
Speaker
I don't know. That's just all they called it was Rex East. I don't know what it was east of, but that's what they called it. Well, we did, we did some surveys for that pipeline, but apparently not in your area, unfortunately, but we found quite a bit of stuff. So, well, we were.
00:32:36
Speaker
I know we were pulled in and we were doing phase two, you know, testing. It was like, I think it was a half by half meter, like 50 by 50 centimeter, five meter grid testing. Basically, they just, they found stuff in shovel testing and then they plopped this five meter, five meter space grid down of like 25 or so shovel tests that were 50 buys. And that's what we did. And not only that, but it was like February and early March and it was like five degrees was the high most days.
00:33:04
Speaker
Yeah, that's kind of brutal time in Ohio. Oh, it was terrible. It was absolutely terrible. That's when I do most of my magnetic surveys, though. Oh, yeah? Yeah, it's not always brutal like that. And you were just lucky, I think, in that year. But it's when the bugs and the poison ivy aren't out. So it's a great time to be doing magnetic surveys, at least if it's not super cold.
00:33:28
Speaker
You're not really selling Ohio. It's either five degrees or there's bugs in poison ivy. But yeah, I mean, that's everywhere in the East. That's true. That's actually at least north of north of a certain point. Yeah, yeah, indeed, indeed. All
Ohio's Earthworks: Cultural Significance
00:33:44
Speaker
right. Well, I think that's about time for our final break. We will come back and wrap up this discussion with Dr. Jared Burks back in a minute.
00:33:53
Speaker
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00:34:13
Speaker
Welcome back to episode 160 of the archaeotech podcast. And we are talking with Dr. Jared Burks. So I want to go in a slightly different direction than maybe CRM. I don't know. Maybe CRM is involved in some of this a little bit. But Ohio Earthworks, Ohio is
00:34:28
Speaker
relatively famous for earthworks. I mean, they're kind of all up and down this area of the country, but Ohio is just kind of like the Mecca of earthworks. Can you first, for some people that may not be aware of this or what these really are, can you define what really constitutes an earthwork and what they traditionally are? And then we'll talk about how you've used geophysical surveys to help preserve and learn about them.
00:34:52
Speaker
Yeah, so earthworks are enclosures and mounds. So we're all familiar with mounds because they seem to be everywhere in this part of the world. But enclosures are a bit more rare and by enclosure
00:35:08
Speaker
There are two types. There are earthen enclosures that are typically ditches with embankments or sometimes just embankments. And they're often in geometric shapes like circles in particular, but also squares and octagons and some other unusual shapes. And then there are also enclosures that are made of wood. And we're talking like woodhenge kind of thing. So Cahokia has got a famous example.
00:35:35
Speaker
But that's relatively recent in time. And the ones we're talking about in Ohio are the more ancient ones from the Woodland period. So, you know, about 2000 years old associated with this Hopewell and the thing that we call Edina. So it's just before Hopewell in the Ohio Valley. Yeah. So we're on the lookout for both of those kinds of enclosures, much easier to detect the earthen ones, a lot harder to detect the wooden ones because now they're just post holes. So they're pretty small.
00:36:05
Speaker
Yeah. Just as a quick aside before we get going, do you have any theories or have you read any theories about why there are so many earthworks in Ohio as compared to say other places? Cause you're right. Mounds are kind of all over the place. I mean, not really here in Nevada so much, but you know, um, at least in the, in the West.
00:36:24
Speaker
Oh, yeah, that's right. You guys said you were working on rock. You got to have some soil. That's that's step one, step one, have dirt. So why Ohio? Yeah. I, you know, I don't know why there's so many here is it's one of those that you guys always ask those questions. Why is that?
00:36:46
Speaker
But in part, it's because there has been a long tradition of earthwork building here. Mound construction began about 1,000 BC here. So people were moving soil to create things as long as 3,000 years ago. Now that's by far not even close to the oldest mounds in the eastern United States. Those are down in the southeast.
00:37:11
Speaker
But why these geometric enclosures? That's the real big question. I still have this question. I can't seem to answer it. I've worked on dozens and dozens and dozens of these sites and made all kinds of cool finds and still the most fundamental question like why so many
00:37:29
Speaker
is unanswered. Now I can tell you one thing that I have learned and that is that we don't have a clue as to just how many are here because we are really only aware of the tip of the iceberg. Now that's true for all archaeology of course, but as we've continued to do more geophysical survey, we've accidentally encountered new undocumented enclosure sites
00:37:54
Speaker
So, how often would you accidentally encounter something that's not, unless it's really common? So, just from those situations, I know that they're probably more common than we think.
00:38:09
Speaker
By common, as of 1914, there was a book published then called The Archaeological Atlas of Ohio. It had 587 enclosure sites in it. Not all of those verified, but some of them include the really famous ones like Serpent Mound and Humboldt Mound Group, New York, Earthworks, places everybody knows about.
00:38:29
Speaker
But there are a whole lot of really small ones that you've never heard of, and plenty that I probably haven't heard of. Some of those are also unverified. Part of the way they found out about sites was people wrote in postcards saying, I have a mound on my farm, and then they sent in the postcard in the mail.
00:38:48
Speaker
to Columbus, and they logged it in. A lot of those got verified, but plenty of them didn't get a visit from an archaeologist or something. We don't actually know if they're for real enclosures, but so many of those are. Unfortunately, they were compiled in this book, but this was in 1914 before
00:39:09
Speaker
anybody could really map their locations precisely, or accurately, I should say. And they've since become lost because of continued plowing. And many of them have been destroyed by all manner of things. What we also know is that there are a heck of a lot more out there that have never been recorded. And some of my colleagues have been systematically examining aerial photographs, for example, USDA photos,
00:39:34
Speaker
Kind of like we should probably be doing on all CRM projects. And new ones that we didn't know about have been popping up because, hey, nobody's actually done that before in Ohio, believe it or not. And lo and behold, I think he's found several dozen of these obvious ones and then some suspicious ones.
00:39:55
Speaker
the presentation that Paul mentioned seeing about this great circle that I talked about during the Ohio Archaeological Conference Council meeting, that was a new find by this fellow. His name is David Lamp. And we were kind of working together a bit. He was really geeked up about examining these aerial photographs. And so he would buy like a county's worth of these USDA photos from a particular year. And then after his kids would wind down and go to bed, he'd start looking at them systematically, you know, one after the
00:40:24
Speaker
other and often like at about 11 at night I would get a text from him you know like ping oh my phone goes off and I look at it and there's a photograph of his computer screen and there's a little circular thing on it and he's like oh I think I found one and
00:40:40
Speaker
And that went on for a couple of years. And I really, really enjoyed that period, you know, when he was making these discoveries. Because then my role was to sort of learn more about them and then see if I could get permission to go survey them. And that's the real hard part, as you probably know, getting access to private property can be challenging. But that big- I actually want to ask you about that.
00:41:04
Speaker
Yeah, that big circle was one of his finds and we eventually got permission. You were talking about going out and working in winter because you don't have these obstacles. Well, the major obstacles you would have, it seems to be crops, which implies that you're working on farms. And I wanted to ask you specifically, how do you actually go about getting permission to get on people's private property in order to survey them with your equipment?
00:41:33
Speaker
It's challenging. You have to convince people often that A, we already know it's there, so it's no great surprise to the world we can show that it's there in an aerial photograph. We can register this with the state without whether we go survey or not. But also, people are mostly worried that the government is going to take their land because something so amazing has been found there. Sure, these things are amazing, but the government's really not that interested in taking people's property.
00:42:02
Speaker
So it's largely an academic exercise as going out and surveying these things. Of course, our role is to get them registered with the state so that they're not inadvertently crossed by some pipeline or whatever, and inadvertently destroyed. So that's why we're doing it.
00:42:20
Speaker
And a lot of landowners, when you tell them that sort of things, like, oh, so this could be beneficial, actually, if we don't want someone to take our property or to put in that utility line, you know, then yeah, exactly. And some of our fines have been used in that way, too.
00:42:38
Speaker
Hey, I always tell people that they think if they go take off the fun, good, fancy projectile points and stuff like that from a site that now somebody can't come in and take their land. I was like, it's actually the exact opposite of that. If you take away all the good stuff, then we can't evaluate it or we can't evaluate it as eligible. Therefore, call in the bulldozers. You know what I mean?
00:43:01
Speaker
Yeah. Yeah, exactly. Yeah. That's a lot of what it is out here. Yeah. So I'm curious, aside from like anything from prehistoric, like built environment, you know, like you've got the stone structures and stuff down in the Southwest, and of course the earthworks of the Midwest and Ohio, aside from that just being super cool because it's
00:43:21
Speaker
It's just different than a projectile point or something else. It's something somebody built and you can see it and it's just neat. Aside from that, why the obsession with the earthworks? What else can you find associated with them? What are they indicative of? Or is it a number of things? Is it just all kinds of stuff? What do they usually tell you about what you could possibly find there aside from the earthworks?
00:43:43
Speaker
To get to the obsession question, one of the reasons I'm obsessed with them is because right tool, right place, right time. I've got the equipment to do it and I've got the time. Don't have any kids. My wife is forgiving mostly. I can do it.
00:44:06
Speaker
Why did those guys back in the 1800s spend all that time and effort to map the earthworks back then? Because they were interested. They wanted to know where these people came from. They had the time and the money to do it. It's probably some of that too. You can probably see that happen over and over and over in any scientific discipline. I'm hoping someone will eventually figure out how to do cold fusion in their garage for the same reason.
00:44:34
Speaker
As to why I study these places, it is part of my research and I see it as a way for me to contribute other than my day job. These things were made before corn agriculture, before people lived in villages.
00:44:50
Speaker
and kind of right at the cusp of what it was to be a farmer. We often refer to them as horticulturalists because we don't want to use the F word, farmer, with these folks, because it's before corn. But they're growing domesticates, Kena podium, little barley, knotweed, sunflower. They must be growing them in fairly large numbers because they suddenly appear in the archaeological record in fairly large numbers. They're, you know, like every hopeful site has these
00:45:19
Speaker
crops at it. And before, sure, you find it once in a while, but it's kind of rare. So, you know, there's something happening at that time period. And not only are they growing these domesticates, kind of all of a sudden, but they're also spending a tremendous amount of time, you know, moving dirt to build these earthworks, some of which are
00:45:41
Speaker
a thousand feet across and are aligned to major astronomical events that only happen once a generation, like the northernmost moonrise on the eastern horizon, the Newark Earthworks part of it are aligned to that event.
00:45:56
Speaker
You can't just observe that every night and then decide, oh, let's build an earthwork so we don't have to break out the telescope to see it. We can just sit there and watch it rise in the spot. Well, somebody had to sit there and watch it rise over the course of a whole generation to know that. So people must have known that the moon swings back and forth on the eastern horizon every day as it rises.
00:46:24
Speaker
And then there must be a northernmost point. And so we like this spot. So we're going to figure out where that is. And now we're going to build this amazing facility to observe this event. And won't that be amazing?
00:46:39
Speaker
when you can wow your neighbors and say, hey, you know what? I'll bet the moon rises right there in that opening in the earthwork, you watch. And then you can seem really impressive. So why did they do that? It had to be a very important part of their lives to be able to do that sort of thing.
00:46:58
Speaker
What I find intriguing is that this kind of way of life, building monumental architecture at this scale, but then living in a dispersed community because their settlements
00:47:10
Speaker
aren't very large, at least like you might expect a village to be where there are multiple households there. We're talking a settlement is one or two houses. Now, there may be a neighbor half a kilometer away, and the next neighbor may be another half kilometer away. These communities are dispersed across the landscape, so it's not like urban living. How do you get those people together in the same place?
00:47:36
Speaker
Well, it could be something like these earthworks are public meeting places. They're also burial grounds. And, you know, they serve all these functions. And that kind of way of life, it just doesn't really exist today in any great number. You know, it was a way of life that came and went. And so we really don't have opportunities to figure out, you know, why people did what they did in those kinds of settings, except with these archaeological contexts, you know, like these earthworks.
00:48:06
Speaker
sites and these folks who built them. So Jared, I can hear the enthusiasm as you're talking about these earthworks and what they meant decidedly. So you're not just using the geophysical survey because it is cool with bank technology, but you're using it to explore something that you like, these earthworks, recording them and hopefully preserving some of them. One of the projects you're involved with is the Heartland Earthworks Conservancy. Can you tell us a little bit about that and what
Heartland Earthworks Conservancy: Mission and Goals
00:48:35
Speaker
you do with them?
00:48:35
Speaker
Yeah, so we're a small nonprofit. And by small, I mean, you know, one of those all volunteer things, they're just a handful of us. And our mission has been, and we've been around since 2010. I helped found it, but the guy who founded it, the real heart and soul back then, has since passed away tragically from cancer. So we've had to sort of, you know, take the torch and keep it going.
00:49:00
Speaker
And for me, it's always been the geophysical stuff because that's what I can do in the archaeology part. But we've always been about research at these places to learn more about them, educating the public about them because, I mean, these things are in their backyards literally often.
00:49:17
Speaker
and then trying to preserve some sample of them, because even though we have archaeological parks like the Newark Earthworks or Hopeful Culture National Historical Park or Serpent Mound, that's like three earthworks out of what are probably thousands. So I'd like to boost the sample a bit if we can. And so just accidentally, we discovered that these geophysical survey maps, especially when the earthworks are kind of obvious in them,
00:49:45
Speaker
people just, they really can identify with that because they can, they can see it for themselves, you know, what's underground. And you might walk across, you know, one of the challenges with these places is A, they're really big. So even if they're well preserved, and they have a topographic expression.
00:50:03
Speaker
It's hard to see them because they're a thousand feet across sometimes, so you can't hardly see from one side to the other. But also, most of them have been plowed pretty flat, so what's left of them is below ground. But in these magnetic maps, it's like, wow, look at that. I can see it. And the other thing too is that you almost always find new things
00:50:23
Speaker
in the geophysical surveys when we go out and look at these sites, you know, stuff that didn't appear in the old maps. That, you know, that infects us with excitement and people can hear that in our voices and see it when we give talks. And so they get the infection. We call it earthwork fever. And they just get really excited about it. So it's a nice way to engage the public and direct efforts to preserve this important cultural heritage that's all around us.
00:50:53
Speaker
Oh, that's fantastic. All right. Well, we are just about out of time, but I've got, I mean, this is a tech podcast, so I've got to get this one last question in here just in the last couple of minutes. What are some future or maybe stuff that is currently being worked on geophysical survey advances that you think will be important for archaeology? And one thing I haven't heard mentioned was LIDAR. I don't know how effective LIDAR is in finding these, but it seems like it would be. But what else have you seen that is coming down the line that could help you find more of these?
00:51:29
Speaker
I mean, the whole state was flown in 2006 or so. Really? I mean, it's just topographic data, right? So it's just really good topographic data. And the Earthworks, a lot of them look gorgeous in it. So that's nice. Nice. And I can sit in my underwear at home and make really cool maps. And that's awesome. So on those really frigid days where I don't want to go outside, I just work on LiDAR maps.
00:51:44
Speaker
Well, I want to say that LIDAR, I didn't mention it because it's so darn common in Ohio.
00:51:55
Speaker
What's coming down the pike is incredibly exciting for me, and that is landscape scale survey with both magnetometry and ground penetrating radar. They've been doing it in other parts of the world for quite a while. For some odd reason, it's just never made it here, and maybe that's because our market can't bear the cost of that.
00:52:16
Speaker
Traditionally, that equipment is really expensive. So now that there's a bit more demand for it, it's a little bit more attainable for even CRM guys like us. So towing a magnetometer array and surveying
00:52:32
Speaker
you know, an entire field in a couple days, we can do that. We have done that. So that's really exciting. And then the other cool thing is that's happening in radar too. So radar traditionally is, you know, it's very laborious, it creates a ton of data. And so it takes a long time to process it. We're almost to the point where we can tow a radar around and
00:52:57
Speaker
and collects so much data that they now call it 3D radar, which is basically a smack in the face of people who only have one channel radar system. These are like 20 radars all connected together into one system, so it's very high density. It's the same technology that was used in Europe to find those
00:53:21
Speaker
those Viking longhouses and the ship burials recently. You've seen that in the news. Yeah. It's like, wow, that's amazing. I wish we could do that. Well, we can. We're right at that point now where that's going to be possible here too. So I'm thinking that some big discoveries are to come from that kind of technology when we start doing it.
00:53:42
Speaker
as phase one level stuff. There's probably a lot of features out there that we just never find because there aren't a significant number of artifacts with them. Dr. Jared Burks, thank you so much for being on with us today. We really appreciate it. I'm going to wrap this up because Chris's internet connection just dropped where it's really flaky up here.
00:54:02
Speaker
But this has been a very interesting discussion and I really encourage our listeners to go and watch the YouTube video that we'll have linked because again, it's some of the best magnetometry that I've ever seen and it's exciting that you're tying it into historical preservation, into your local environment in Ohio, all these things in teaching that really mattered to me and I'm sure to a lot of our listeners. So thanks for being here. Oh, yeah. Thanks for having me. It's been fun. All right. Take care.
00:54:38
Speaker
Thanks for listening to the Archaeotech Podcast. Links to items mentioned on the show are in the show notes at www.archpodnet.com slash archaeotech. Contact us at chris at archaeologypodcastnetwork.com and paul at lugall.com. Support the show by becoming a member at archpodnet.com slash members. The music is a song called Off Road and is licensed free from Apple. Thanks for listening.
00:55:03
Speaker
This episode was produced by Chris Webster from his RV Traveling America, Tristan Boyle in Scotland, and the Archaeology Podcast Network, and was edited by Chris Webster. This has been a presentation of the Archaeology Podcast Network. Visit us on the web for show notes and other podcasts at www.archpodnet.com. Contact us at chris at archaeologypodcastnetwork.com.
00:55:26
Speaker
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