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An Unseen World Beneath Our Feet - Caves, Sinkholes and Springs

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An Unseen World Beneath Our Feet - Caves, Sinkholes and Springs



David Russ: Well, good evening and welcome to the USGS. I'm David Russ; I'm the Regional Executive for the Northeast here at the USGS and we appreciate all of you turning out tonight. And welcome to our evening lecture series which showcases the work of USGS scientists locally and all around the world. The Science in Action Lecture Series is intended to give you a better understanding of the science-based issues that are meaningful to our daily lives.

Our speaker tonight is Randy Orndorff. Randy is the Director of the Eastern Geology and Paleoclimate Science Center. In his current position, Randy oversees projects dealing with geologic mapping, climate research, and volcano and landslide hazards. Randy started his career with the USGS over 30 years ago working as an intern in our office of International Geology. While working for the USGS, Randy earned both his Bachelor's and Master's Degree in Geology from Old Dominion University.

01:00

Randy has worked on several fields in geological mapping projects, developing significant expertise within the geological mapping community, and I might add with limestone and what they call carbonate petrology which is a type of rock that dissolves relatively easily, and we'll be hearing more about that tonight.

Randy's expertise led him to take the position of the Associate Program Coordinator with the National Cooperative Geologic Mapping Program in 2002 and has served as the liaison to the State Geological Surveys. You know there's a State Geological Survey in almost every one of our states across the country.

Randy has also served as Special Editor of the Geological Map of New Jersey, geologist for the Midcontinent Geological Mapping Project and Project Chief with the Karst Applied Research Studies through geologic mapping. Today, Randy has published 22 geologic maps and over 70 publications on a wide range of subjects related to Appalachian and Ozark Plateau geology.

02:02

Randy is actively involved in the geologic community serving on the Board of Directors for the National Cave and Karst Research Institute and is currently Editor of the Journal of Maps and Interdisciplinary Online Electronic Journal that aims to provide a forum for researchers to publish maps and spatial diagrams.

Randy is a very dynamic and engaging person and I think you will see that come out in his presentation tonight. So ladies and gentlemen, let me present Randy Orndorff, and he will speak to us tonight on 'An Unseen World Beneath Our Feet - Caves, Sinkholes and Springs'.

[Applause]

Randall Orndorff: Thank you, Dave. My gosh, 30 years. I remember when I was here as an intern 30 years ago sitting out here thinking, "Wow, someday I could end up here talking about something." After 30 years I’m here. Well, good evening everybody, I'm glad you're all here and tonight we’re going to talk about something that, as Dave mentioned, part of my career is looking at limestone terrains across the country and we’re looking at something we call karst.

  03:10

Now karst is a type of... The word 'karst' is actually from a Slovenian name. Actually, some of my colleagues are here. We spent time in Slovenia where the word karst comes from. Karst is basically divides the topography. It's a terrain that's formed on limestone and gypsum, any kind of rock that might dissolve in water.

And it's characterized by things like sinkholes, caves, losing streams, a lot of things you see. Anybody know what this means? You?

[Laughter]

Randall Orndorff: Basically what happens in rainy environments is you have rain water, it's a rain water in this area...? Something like that.

 04:04 So the rain water is actually acidic as it is. And as the rain water percolates, the precipitation percolates through the soil, it takes up carbon, carbon dioxide, and it creates a very kind of mild carbonic acid. When that gets down into the limestone, dolomite and other rock types, that's what causes the dissolution and you end up with things underneath your feet that are generally unseen. Large cave systems that are all throughout the country, caverns, caves, etcetera.

Now, 25% of the conterminous U.S. is underlined by karst. And as you can see, areas that we're familiar with are the Shenandoah Valley, the great valley of Virginia, of course Florida with all the water springs, the Ozarks of Missouri. We're going to see a lot of pictures tonight from areas in the Ozarks of Missouri and Arkansas and the Appalachians, various other places, and also places like the Black Holes.

 05:19 When you think about karst terrain, here's a typical terrain that you would see on the Shenandoah Valley. Generally flat line terrain and gently rolling hills. And then you see these rock outcrops every once in a while. And these are a piece of arc limestone. If you got it in the Shenandoah Valley, you'll see this].

And what's interesting is you see this rock outcrop limestone here, and you see another over here, and then just soil in between. And when you take the soil away, this is what you have. The rock topography underneath the soil in karst terrains are very, very deep, deeply gutted].

 06:01 So what happens in this case, you're looking at a foray. Before you can actually get the rock, limestones are used a lot for many roads, glass industry, what have you, but before they can actually use the rock, they have to get rid of the soil.

And here it almost looks like a moonscape. Here's one of my colleagues standing here, and you can see how deep the soil gets in this type of terrains, because the rock dissolves.

OK. As I've said, karst areas are characterized by the caves, the springs, the sinkholes. Also losing streams. This is a stream. I've got this picture back and I don't know what I was doing, taking a picture of a gravel road. This is not a gravel road. This is actually a stream in the Ozarks in Missouri. And you can see the trees, and this is a deciduous forest. It gets about 40 to 42 inches of rain a year just like you would out here. And then the streams are completely dry.

 07:01 It takes three to five inches of rain at one time to get water moving through these streams, because when it rains, the water hits this gravel and travels underground.

Here's another stream at the same area. It takes a very large floodplain across here, but you can see the channel about 30 yards wide. It was actually grass in that channel. At one time there was a water river but all that drainage is now underground, but now all of that's now underground in the case.

Let's talk about sinkholes. Here is a picture from Southwestern Virginia. And you can see the hole and pot marks. A sinkhole is basically a depression. And in this case, some pictures show it kind of slow-developing sinkholes like this. But in other cases, you get these catastrophic crevasses because you probably heard the news various times where you've got sinkhole collapses occurring around the area.

 08:05 This one here is in Missouri. You can see the big scar here. This is a big sort of impression, Howard is taking a picture right outside the sinkhole, 30 feet across. See this green thing right here? That's the top of a black oak.

This gentleman here, Tim called us up when we were in the area and he says, "Could you come up to my sinkhole?" Here's what happened. He says, "I was out on my property the other day and by black oak was gone. And so I called my neighbor Joe and I said, 'Joe, you cut down my tree. Where is my tree? You took my tree.' And Joe's like, 'Hey, I haven't touched your tree.' He says, "Well, meet me out there." "There's your tree."

[Laughter]

Randall Orndorff:
As you can see. That's a 60-foot tree and another 10, 15 feet above. Pretty simple, catastrophic collapse.

 09:00 So sinkholes develop basically in two different ways. And a lot of here what we call solution sinkholes. This generally happens with sandier soils. If you have a cave, in the rock, the sediment slowly pipes down these fractures in the rock, it creates a depression on the surface. The more it goes down, the deeper the concussion. And this tends to happen over years, tens of years, hundreds of years.

Then we have the what we call the cover collapse sinkholes, and those you don't have much to worry about. Most limestone terrain is the soil above is actually clay. So you get clay to do the same thing. It will still run down the piping into the cave below, but what happens is you have a void that develops above the rock, keeping a depression on the surface because the void holds itself. Then we get this basically like a land bridge move atop to the void, and pretty soon that void will not hold itself any longer and it catastrophically collapses.

 10:05

The reasons that the early... It's kind of interesting. Most of the times you hear on the news about sinkhole collapses during periods with a lot of rain. You have hydro suffocation events, because basically if you get a lot of rain on this bridge, you're having a lot of water, a lot of weight, and it will collapse.

Well, strangely enough the opposite is also true. During the times of drought, we see lots of sinkholes. Water has an adhesive effect. You put your finger into a pool, you can see the adhesive effect of water. It actually holds things quite well but when you dry it out, it loses that adhesive effect, and then it will collapse. Most sinkholes can be the side of a cow.

[Laughter]

Randall Orndorff:
Actually, tires too. I've seen pictures of cows, and the reason for that is a lot of the limestone areas across the country are agricultural areas. So that's why you see picture of a cow near a sinkhole. Luckily, this cow is alive because you know what those farmers are going to do if their cows are dead?

[Laughter]

 11:12

Randall Orndorff: Right in the hole, that's right.

These are very famous sinkholes over the years. Here's a fellow from Florida. This one right here was a famous one called the Winter Park sinkhole that happened back in the '80s. You see this happen on an industrial area and there's actually a car dealership, a Porsche dealership, of all things, and these sports cars lost in this sinkhole. As we saw earlier, we see these karsts, this is a very deep sinkhole here.

A lot of times, you not only see cows in sinkholes but in some, you see drillers. And there's another driller, and these are in Florida. Again, remember that diagram where you've got a lot of soil piping down into the cave, then if you take a drill there and you start sucking the mud up, you're actually enhancing that process. You're increasing the process. So a lot of times when drilling, it increases the risk of sinkholes.

 12:18

They had this gentleman from Virginia Department of Transportation, who was the king of fixing sinkholes. He worked a section between Stanton and Winchester on Interstate 81, and then he would fix on Interstate 81, and in a year, about 15 sinkholes on Interstate 81. And then there was probably at least 60 or 70 more on the back roads of Shenandoah Valley that were also through.

So this one here's in Kentucky. You can kind of see these are normal people driving along. What happens, and if you think about it, if you take the roads away, you take the buildings away, the rain is coming down onto the surface, like I said it's soaking into the soil, and this runs the natural process. And then we come along and we build roads and we put buildings there. And that water can no longer run and, it runs off. And we put ditches in, so it concentrates all that water.

 13:14

Water off gutters filters is concentrated. And then what happens is it gets in these, enhances and rapidly creates voids in the karst, and you get collapses. That's why you see it a lot in roads.

This one is very normal. If you remember back in 1995, I think. Nathan and his wife was part of us back then. This gentleman on a Saturday morning who lived in his house was drinking his cup of coffee one Saturday morning and he heard this horrible noise in his basement. And he walked up, opened up the floor of his basement to watch his furnace getting sunken down a hole in his basement. Within a matter of a couple of hours, the entire inside of the house was in the hole.

 14:03 This picture was taken about a week after the collapse. This picture is about a month after it happened. This is the roof of the house here. So you're talking about, this house is actually in the middle of the field. This is a rural area, agricultural area north of Marigold, Virginia.

And you can see, there's no other buildings out there. Me and my colleagues, we had studied this for quite some time. And interestingly, if you look at the maps of the area, there is actually a lot of old sinkholes. There are about 20 of them. Those are 20 sinkholes in a line that ran north-northeast along this trench.

Now, one thing I learned was why that sinkhole happened and how sinkholes happen. Before the gentleman went to sleep, two days before this happened, this gentleman got a new well drilled.

 15:00 So instead of the drill going through the hole, and again maybe working with the house and the hole. They were drilling and getting the mud... sometimes sinkholes occur in riverbeds. During the sinkhole down in Pennsylvania at the end of the bridge. And sometimes they actually happen in the water, as the water is draining down into the sub-surface.

Salt is also a solvent, and there's large areas in Texas where you have these big salt deposits. You have these salt dumps. You have the rock and the industry likes to take their drill waste and they actually pump it down into the salt area to be able to store it. I think that's pretty tight. But you have to be careful because, as we know, when you put salt in water, it will dissolve.

16:03

So this is called, this in Texas. You can see this picture here on the left where it looked like before and after. Here's that hole.

I'm going to play a short little clip here because this... When this happened, a lot of people, including The Today Show, was interested in how sinkholes happened. And there's very few videos that I know that actually show sinkholes in action, so I just wanted to show this clip. I can't stand the guy they interviewed for this though.

[Clip Starts]

Announcer: In 101, the Anatomy of a Sinkhole. They say everything is bigger in Texas, and that's especially true for this sinkhole that has swallowed a chunk of one town. And we will take you live to the scene for an update in just a moment, but first we have a sinking suspicion about what causes these things.

 17:01

For the last few days, we've watched these frightening images of this giant sinkhole at least 700 feet across and more than 100 feet deep and growing, swallowing everything in this Texas town. But could sinkholes like these be found in your town, even your house.

Randall Orndorff: About 25% to 30% of the US is made of rocks that dissolve: limestone, gypsum and salt and these areas are characterized by caves and also a lot of times by sinkholes.

Announcer: Randall Orndorff studies sinkholes at the U.S. Geological Survey.

Randall Orndorff: Generally, you have holes under the bedrock or whatever, and then you have the soil above. And then the soil actually gets flushed down into the hole that's under the bedrock.

Announcer: The culprit behind the soil drainage? Water. But too much and too little.

Randall Orndorff: Well, some of that still above tends to collapse even when it gets too wet. So it naturally occurs around times of hard precipitation. The weight of the rain water precipitation on the soil will form the collapse.

 18:11

And other times during drought as the soil dries and loses cohesion of the moisture in the ground that will also cause collapses and sinkholes.

Announcer: But can you predict where a sinkhole may strike next?

Randall Orndorff: It's very difficult to know what's actually underground, where those voids are. We don't have a way to actually look underground like that to see where these might be.

Announcer: But there are some warning signs.

Randall Orndorff: If you're living in a sinkhole-prone area, it's a good idea to just look out for a few things: cracks in the foundation, in sidewalks and driveways, the formation of small holes in the yard. In most cases, geotechnical engineers may be able to look at the situation and see if the karst void may have started. And there are situations where people have been able to save their homes and those things via engineering.

[Clip Ends]

 19:15 Randall Orndorff: So it's pretty amazing to actually see a sinkhole like that in action. And you can see all the tractors going in and stuff.

One of the things about that sinkhole, where you saw a tractor, you saw a big oil decks and stuff, pipelines that are snapped and contamination getting into the ground water.

So let's talk about that for a moment. This is a typical USGS topographic map. And what we did here is show Missouri. You can see the black dots here are individual sinkholes. Sinkholes, then, can be point sources for contamination into your ground water. Because the water's under the ground, it can get into wells and spring water. About 40% of ground water that's used for human consumption comes from karst.

 20:03

But one thing now I'm going to show you here is, when you see these are the sinkholes themselves, but if we look at the areas that actually drain into those sinkholes, it's actually quite a lot larger. It's like a magnitude 4 area that go into these sinkholes.

And this for instance, you've got a bunch of small sinkholes. Part of the area is draining. So you think if you've got a road going through this area and you have a truck carrying chemicals that spills, that it can get into the ground water system quite rapidly. So you have to be very concerned about understanding what these drainage places are into these sinkholes.

OK, enough about sinkholes. Let's talk about springs for now. OK, sinkholes, the water comes in; karst areas, the water comes out in springs. The cool thing about springs, in this case, it's not... Winchester or Shenandoah Valley. When you find one of these old springs, you find these really old, hell, one of the early late 1700's or 1800's homes out in the Shenandoah Valley were built right by springs. They had a source of water, usually seen as a nice little spring house. The constant water temperature kept things cool, this is what they used for refrigeration.

 21:14 Some springs land to the side of the mountainsides. Here's a cliff. It's a very large cliff here at a big dolomite rock ledge here in the cave system in Missouri. This is probably the largest sinkhole conduit spring in the entire U.S. This is all called, believe it or not, Big Spring. It's amazing what the name is, right?

This produces 279 million gallons of water a day on average. That's 13 cubic meters a second, 13 meters cubed, a second. This is just basically an instant river as it explodes out of the ground. And you can see here, from this vantage point, you can see how this forms out of the ground.

 22:04

Some of the springs are really quite beautiful. This is called, believe it or not, Blue Spring. You have blue stream coming out of the rock. The chemicals in the water is actually a beautiful blue, you get a nice little, it's almost like looking into an aquarium with the various plant systems underneath. So you have a very nice environs. Believe it or not, there are crazy enough people that actually will dive into these springs, myself, my friends here and also neighbors.

[Laughter]

Randall Orndorff:
I was talking about this with my son last night I was going to talk about... curious.

[Laughter]

Randall Orndorff:
Most people maybe want to crawl into the caves. What you're looking at is the aquifer, an old aquifer where you can actually get into the aquifer itself. This is a picture out of the Palm Springs in Florida, and look how beautiful, crystal clear the water is.

 23:05

One of the things we wanted to do to understand, we want to understand how the karst system works, how the waters flow into the system so we can understand what the resource is and how we contaminate and mineralize.

So we actually got some cave divers work with us. We worked with the Cave Diving Alliance in Missouri. You can see several cave divers here ready to go. This is a nice old place called Alley Spring. You can see the bubbles here. Those are cave divers that are being thrust at a little about 30 feet. They have to start doing decompression because your body can't handle that.

Now at these springs, you can see it's only... And the reason we chose Alley Spring instead of those big springs is you saw that big hole of the Big Spring? You can't just swim into there. This one, they could actually swim against the flow and do some mapping for us and understand the geology behind it.

So here's a picture, you can see this is not nearly as clear as the Florida spring system, but we actually used the cave divers to plot sinkholes for us, put into context and the geology.

 24:10 And they also do some maps for us. So here's a map view. Here's a spring hole that cave divers were kind of hanging out. In this cave they actually mapped all the limestone passage in the cave system.

And if you look at in the profile, this is where the spring issues. It basically goes down at a 30-, 45-degree angle and it just kind of bobs up and down. It actually doesn't get all that deep. And we found out this is actually gliding along a certain part of the geologic stratigraphic section.

And here we have a 3D model of that cave system, that spring system. And you can see a cave that is actually underneath a surface spring once perpendicular to the surface spring. So the springs and the way the water is going to the underground does not mimic what you see on the surface.

 25:02

Now let's talk about caves for a minute. One of the things that people look about caves is that the cave temperature is fairly constant throughout the year, and it actually records the average temperature of that region. So for instance in Virginia, our caves here are about 56, 58 degrees. Well, if you look at the temperature range from summer to wintertime and you average it, basically that's what you get.

I got some friends who did some caving in Iran. They were getting shorts and t-shirts because it was 80 degrees in their caves, and caves in Slovenia are about 45 degrees, a colder climate.

Just a couple of big facts. These are a lot of good records of caves that have been coming out in just the last few years. The deepest cave in the world is now Krubera Cave. It's in Georgia. It's 1.3 miles deep. That's a deep, deep cave.

 26:07 The longest cave system, a lot of people know, is Mammoth Cave over 520 miles according to the Survey. And the largest cave chamber now is known to be in Borneo. And recently we spent some time and we pretty much think and veered down this mountain river cave in Vietnam, I think it fits how many jumbo jets could fit in this one room.

A lot of engineers could not believe that you could have a chamber that size that would hold itself up. And the oldest cave system, around 30-40 million years old is a cave in Australia. Caves come in all different sizes.

This cave, Morris Cave in Missouri, it actually doesn't get any bigger than that for 300 feet. You probably can be in the hole for 300 feet before it comes up into a fairly large room. This is one of our colleagues from Slovenia. We had some international back and forth, which was great. We went to Slovenia. We said, "Let's go see a Slovenia cave!" After we took her here, I thought, "Well, I can't really do this to her."

[Laughter]

 27:18
Randall Orndorff: This is actually, it's sitting in the bottom of a spring valley. So one of those dried valleys I showed you before? If it rains really hard, yes it drains. So it flushes out.

What really makes me nervous about is, what happens when first began? Who's waiting in the other side of that? And then we have to emphasize the dry map cluster. Here is another cave in Missouri. It's so dark you can't see. All shapes and sizes.

So here's a Slovenia cave. Do you see the bridge there? And as you can see there's some people on the bridge. This is a can that's actually a cut.

 28:03 This is the tourist cave and you can actually see the caverns back in this area, and then they take you to over this overlook here before you get to the bridge the lights off, then they turn the lights on and you're looking about 100, 200 feet straight down.

And one of the things I want to show you, if you can see this little feature right here, that's actually the wall. That's carved into the rock, right there. As you can see this one, did you Dave? I don't know if I trust that guardrail, either.

Now this is basically a sheer wall where I think they drawn in, a bunch of Italians many, many years ago, I think the 1800s, and actually cut this notch in. As you can see it's just 150 feet straight down. Some of us, actually we have... This me in my own cave. I have a farm in Shenandoah Valley.

 29:02

Now I've been into over a hundred caves in my life, and I've never been content with my own cave. When I was a kid, my grandfather would always say, "Don't you boy go in that cave." That cave, that cave has lost... But then you get old, then you get to be a teenager. And when Granddad says, "Don't go to that cave!" it means go to that cave.

[Laughter]

Randall Orndorff: So my cousin, my best friend and I went into the cave. And my cousin went first, my best friend went second, I went third. The cave goes probably from about here to the wall. But it's a crawl the whole way. And I never had to be in the cave because there wasn't enough room.

[Laughter]

Randall Orndorff: So seven years ago I decided, "Doggoned, I'm doing all these caving. I haven't even gotten into my own cave!"

 30:00

So Dave and I went to my cave in Shenandoah Valley, I'm going to map my cave. Do you know the hole, the entrance to that cave got smaller since I was 16 years old?

[Laughter]

Randall Orndorff: It has, I swear! It took me 30 minutes to get into that hole. I'm smiling in this picture, I'm not that dirty yet. I'm sitting there, there trying to get through. The shoulders just don't seem to fit. Finally I realized if I did this, I slid to the bottom... I get on my hands and knees and that's it. And then I'd cruise about five feet in. And hit the curve.

[Laughter]

Randall Orndorff: Our friend May said that raccoon said, "Oh, shoot it!"

[Laughter]

Randall Orndorff: And Randy and I never saw it.

[Laughter]

Randall Orndorff: And do you know what he said? I am going to get into this cave. I am going into this cave. Jack?

 31:02
The thing about caves is, these are basically pipelines of water. You can think of them as pipelines of water. You know, most aquifers are filled with water and sands stuffed in holes or you see them in fractures. But caves actually do have rivers of water and actually have lines.

And so in this one we can see that it probably developed when it was underwater, but you can kind of see how this could have piped water at one time. Here's one out of Shenandoah Valley where you can see from the older cave passage here, and then a second one. Now you get the idea of a pipeline.

We can actually tell how fast the water goes through the caves. If you look here, you can see these are called scallops here on the roof of this cave. If you measure the distance between the apex of these scallops, we use a formula to figure out how fast the water would be moving through that cave.

 32:00

What a lot of people like about caves and cave formations, the various things that you see in the cave, little lake caverns and all that and places like that. Me, actually I'm interested in the hole. I'd like to understand how that hole got there. But it makes it kind of tough.

As you can see, these are all the pretty formations, a great reason to come down. Everybody knows about stalagmites and then the stalactites that come down. And then various one and it's great, because these are the natural sights. You don't get caverns with the pretty lights and all the stuff. But you don't see them in the natural environment. You get these very slow stones that come down here and on top of that. Right down holes, trying to go in. Those are kind of scary, but I don't know if anybody has been in a cave when this happens, in those caverns.

This is called a shield, and it's hard to see in this picture because it's two- dimensional, but what you're seeing here is this drapery that comes down for this what you call a shield here.

 33:03

It's actually an air space. You see those stalactites up here. This thing here in the center, it almost looks like it's hanging in mid-air but they're attached down here. I don't think we have a really good idea on how these actually form.

Again, here's more water stalactites, and you can see the water running down some of these, it's precipitated. And when the a stalactite, a stalagmite come together you get what we call a column. Some fairly large columns from the Round Spring Cavern. You can see the humidity is close to 100% in a lot of places.

So, of course, the stalactites and you generally have a central stone where the water in the sand. When that water hits the air and drips off, it's supersaturated with calcium hardening, so it will actually leave some of it behind to actually form stalactites, and then of course stalagmites build up from the ground.

 34:09 Again, thanks for Dan for this. One thing to do with stalactites and stalagmites is date. I don't understand how old that hole is. Do you know how hard it is to age a hole? Pretty hard to age a hole. But we can name a stuff that's in the hole. So we can at least get a minimum age of these caves.

So Grand Caverns was nice enough to let, Ann Arthur, one of our scientists in our science center to collect some stalactites. These were broken down stalactites and stalagmites. And they use different kinds of elements in the stalagmites, crystals that makes these things. Uranium-thorium is one. The uranium-thorium series. As uranium breaks down, its half-life turns into thorium. So you can look at the ratios of uranium and thorium to come up with ages.

 35:03

So here you can see on the monitor on the right, it's got some of the oldest ones. The older one is dated at 66,000 years before present and the tip of it is about 12,000 years old. The one here on the right is a lot older, 160,000 years old and the hole, about 60,000.

The other aspect about caves is that climate change is very popular. There's actually a lot we can do with isotopes in the stalactites and stalagmites and other things that you can probably use to help us build a climate record obviously the stone.

This is a very, we ran into a people who in this room have been there. Kevin, Dan have also been there. This is Naica. It's a mine in Mexico where you get these huge gypsum crystals. And you can see the size of these things were incredible. They sealed it off. And you can go in for how long?

36:09

Audience 1: Just a few minutes.

Randall Orndorff: A few minutes.

Audience 1: It's hot.

Randall Orndorff: Yeah. It's like 120 to 130 degrees. So it's very dangerous to go in here for very long periods of time. But this is the kind of thing... If you are going to be a caver, you want to understand that pipeline of water, you've got to get the dirt. A lot of us have and got into really tight places. And something you got to stuff a lot of people into these tight places. And if I'm going to go hole, to try to understand it, because what we're trying to do is to make maps of these caves to understand the geologic controls on how these various caves work.

So this little cave down here when I was here in Woodstock. You can see some type of screen, and that's what you get in some cases. Other cases, you get this more framework type of passages. But what we're trying to do is understand what the controls are on these cave systems.

 37:07

Cause you only see a very small part of you what used to be an aquifer so we can understand what those variations are in understanding the entire, say, Shenandoah Valley.
 
And when you come out, remember the lessons of blue. Sometimes you are assigned to wear white.

[Laughter]

Randall Orndorff: It's kind of interesting, I was coming back from one of our trips to Missouri trying to map the caves out there, when I was with a suit like this. And then I laid my suit down on the ground and hosed it and scrubbed it and the neighbor lady walks by and say, "What are you doing?" I said, "I've been to my cave here. I just came back from a trip to Missouri." And she goes, "I'm so glad my cousin's an engineer."

[Laughter]

Randall Orndorff: Three minutes

 38:00 Cave dwellers, obviously things that live in caves. This here is a little salamander thing, and you can this one's got color to it and you can see how it matches the cave wall. This is pretty close to the entrance.

Here's another one. It's got some blending in. As you're deeper into the cave system. You can see it doesn't have pigment. You can see where it used to have some eyes. It actually has some needles there. Cave fish, you probably heard about cave fish. Again, in this case, no eyes, no pigment, they live in the dark. They don't need the pigment, don't need the eyes.

Here's a cave crawfish. And be careful when you get close to the entrance of the caves, black widow spiders like to live here.

Well, you think of caves, you think bats, right? Here's a nice colony of bats at Branson Cave in Missouri. This is the species of bat that likes to hibernate.

 39:00

But I don't know if you've heard, because there is a disease now called White-Nose Syndrome. I've read a couple of articles on this. Back in, what was that, about six years ago now, Chris?

Audience 2: 2006.

Randall Orndorff: 2006, OK. So five years ago. They noticed there were these major bat die-offs in Vermont, New York, up in the Northeast. Something was going on with the bats that would make them wake up in the middle of winter and they were flying around. Of course they had nothing to eat. They were using up all their energy and they were dying by the millions.

And what they were noticing is this little white fungus that's floating around on their noses, hence the term White-Nose Syndrome. Since that time, this disease has spread southward into Virginia and Tennessee, over to West Virginia. And folks were finding bats in various places. Most of the bats in the map here, it's kind of interesting, as I said, it started in the New York, Vermont area.

 40:02

And then within a matter of a couple of years, it had moved its way down in the Appalachians here into Virginia, and it's actually been reported west of Tennessee. And all of a sudden, one day we get a phone call that said, "Hey, we found it in Wisconsin."

Well actually, we really wondered about how this karst system works. Actually this blue area karst here, wraps around the Michigan basin into Wisconsin. And I believe now it's confirmed in Oklahoma?

Audience 3: Yes, Oklahoma. Also in Missouri.

Randall Orndorff: Yeah, so Oklahoma and Missouri, see how that kind of travels down. And that's also the divide. But one thing we don't really know yet is exactly how the disease has been transmitted. And that's a very rapid-moving disease. Most caves in the area in east have been closed off. All the ones in the federal lands are closed off because of the concern that the fungus or whatever it is that's carrying it off may be dangerous.

 41:06 But there's also some methods that there's back-to-back transmission of the disease. So the USGS has been looking at it. We've got folks, biologists that are looking at it, so it's something that's very much a concern to us right now.

And actually, the other critters that live in caves, actually some people live in caves. This is a castle in Slovenia, which was first built in the 1200's. And if I remember the story correct, somebody who was held up in this castle many, many years ago, going back several centuries. And the police force or the whole town had surrounded the castle figuring that this guy had no way to go, so they could catch him. And they waited for months. And he never came out. And they said, "The guy's got to be starving to death," but he found a cave passage out of the cliff.

[Laughter]

 42:01

Randall Orndorff: And there was an orchard up on the top of a cliff.

[Laughter]

Randall Orndorff: So he was fine. So even people can be...

And this is a slide of the natural light inside of the cave at night.

[Laughter]

Randall Orndorff: Well, thank you very much.

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Title: An Unseen World Beneath Our Feet - Caves, Sinkholes and Springs

Description:

Randall Orndorff, Director of the Eastern Geology and Paleoclimate Science Center, discusses how Karst affects daily life. Beneath a quarter of the United States are rock types that can dissolve to form caves, sinkholes and other features. Nearly every state has rock layers of limestone, gypsum, and other soluble rocks we call ‘karst’. Karst is important for many reasons. Almost half of the ground water used for drinking comes from karst aquifers, and karst regions such as the Shenandoah Valley are some of the most productive agricultural lands in the nation. However, the rock layers underneath karst dissolve easily, sometime creating sinkholes that can be a threat to life and property. Yet these soluble rock layers also yield some of the most beautiful and unique natural environments, found in many of our national and state parks.

Location: Reston, VA, USA

Date Recorded: 4/4/2011

Audio Producer: Melanie Gade , U.S. Geological Survey


Usage: This audio file is public domain/of free use unless otherwise stated. Please refer to the USGS Copyright section for how to credit this audio.
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Tags: caves, geologic karst, mapping, natural sinkholes, springs

 

 

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