good afternoon. welcome to the departmentof the interior museum's lunchtime lecture series. we offer lectures that focus on thedepartment of the interior's various bureaus, and the workings that we do in each of thosebureaus, first wednesday of the month. i'm very happy to be introducing randy orndorff.he is coming to us from the us geological survey with a wealth of knowledge, and a longcareer with the us geological survey. he worked as an intern first in 1981, butsince has been working as a geologist specializing in the appalachian and ozark geology, geologicmapping, and karsts of caves and sinkholes, which we will be hearing about today.he has published 80 papers or geologic maps on subjects related to structural geology,stratigraphy, and karst. thank you so much
for joining us today.thank you, diana. great to be here. i'm out at reston, your usgs office in reston, anddo get down every once in a while to the department for meetings and things. i'm happy to be hereto be able to talk about something that i enjoy talking about, karst.i don't know how many people know the term "karst." a lot of people do, but not all,so hopefully today when you leave you'll know what karst is. you already knew, but don'tknow it. the good definition of karst, that's a terrain.it's a type of topography that we get on top of rock areas that have rocks that dissolve,like limestone, gypsum, and even salt. it's characterized by things like sinkholes, andcaves, and large springs, and underground
drainage.you all have seen that's there's been a bit of news lately about sinkholes. that's onepart of the term, "karst." i've got this wonderful chemical equation down here at the bottom,and usually when i start out with kids, i ask somebody, "you might want to explain thatequation to me"? they go, "no." i'm like, "ok. i can't explainit either, so forget it." [laughs] basically, you add water to a system, mostly here inthe humid east, and you create a very weak acid. we call it carbonic acid. as rainfallfalls to the surface and it's already acidic. it's about ph of between five and six, asit is. as that rain gets into the ground and goes in the soil, it picks up carbon dioxideand creates this acid. when you get the acid,
you get it into these soluble rocks like limestone,you start to get dissolve, the actual bedrock and create caves or voids in the system.most people are familiar with carlsbad caverns and luray caverns, and places like that. ittakes thousands, to tens of thousands, to hundreds of thousands of years to create thesetypes of landscapes. when you think about groundwater, people talkabout aquifers where we get our water from underground is generally, the aquifers aregenerally sand or hard bedrock and the water is in the pores of the sand or in the fracturesof the rock. there's not underground rivers. well, forkarst you can get underground rivers. about 20 to 25 percent of the us is underlainby some sort of karst or soluble rock. areas
like florida, which we know very much aboutnow. the appalachians running up from new york and down into alabama.the ozarks of missouri and arkansas and places out western texas, san antonio area. thenvarious places in the basin range. this is important because of two things, andwith karst is one. the hazard, sinkholes. the other is water. karst aquifers are a veryimportant source of groundwater for folks throughout the us.now think about, the number is about 40 percent of groundwater that's taken out for drinkingwater, comes from what we call karst aquifers. well, here's a typical landscape. this isan area out in western virginia, the shenandoah valley. you can see how that landscape ispretty flat. you can see a mountain of the
appalachians there in the background, andevery once in a while you see a rock outcrop. that's limestone. the soil builds up on topof that limestone. as it dissolves, as that rock dissolves and leaves the soil behind,it does it in a very wild way. if you remove the soil, you get this. yougo from this, remove the soil to get to the rock, and this is a moonscape you get.quarries, before they go into mine the limestone for aggregate, they need to remove the soil.so, you see these pinnacles of the rock. it dissolves in very differential ways.i got back from taking this picture back on this trip in the late '90s, and i said, "well,why now that i took a picture of a gravel road?" what that is, is a streambed in theozarks of missouri. you can see it's a humid
environment.you have deciduous trees. they get about 40 inches of rain a year. what we do around here,except there's no water in the stream, because of all those voids and all those caves underneaththe ground. the water is going underground as opposed to in the streambed.what it does in this area of missouri, it takes anywhere from three to seven inchesof rain in a very short period of time, to get any water running down these streams.think about a karst area as underground drainage. most of the water goes underground and isdrained that way through the cave systems, and not on the surface.let's talk about sinkholes, something that's been in the news quite a bit lately. thisis an area in southwestern virginia. a sinkhole
is a depression on the surface. it's all theway around, internally drained. kind of looks like divots on a golf ball,doesn't it? these generally happen over say, long periods of time as the soil creeps intothe voids underground. then we have these types that are these kindof catastrophic collapses. these are the ones that make the news. this one is in the ozarksof missouri. this is the interesting thing. i got this call from this gentleman who hadthis large farm. he says, "i got this problem. you've got tocome out and see this hole i have." what had happening is, he woke up one day and he waschecking out his fence line, and he noticed one of his trees was gone. he had this reallyimportant called blackjack oak in missouri.
he calls up his neighbor and starts to yellingat the guy. it's like, "why did you cut down my tree?" the guy says, "what are you talkingabout?" he said, "that was a great tree. you cut down my blackjack oak."he says, "no, i didn't." they met out in the field. that's the top of the blackjack oakright there. that tree was 60 feet high. you can see how big that hole was. you have avoid underneath and it dropped down. sinkholes happen two times, two ways. thisis the way, i like to do it simply. the bottom. let's think about the bottom. what we callthe "covered subsidence" sinkholes. on that first picture i showed that looks like thegolf ball divots. you've got a soil that's over top of a limestonebedrock. then you have a cave system, the
voids underground. that's the thing aboutall sinkholes. you have to have a void to be able to take the material from the surface,to create the sinkhole. the sandy soil, for instance. the soil creepeddown into the hole, and over time you start getting this depression on the ground. itgets deeper and deeper as more soil goes to fill out that cave, in the void.the ones that make the news, and the ones that we're most concerned about are what wecall "covered collapse" sinkholes. same situation. you got a cave. you have asoil. but, in most limestone areas the soil is clay. clay holds together quite well. you'veplayed with clay, how sticky it is. it's that void. as that material starts goingdown into that cave system, the void occurs
below the surface and you don't see an expressionon the surface. that void is almost like a bubble. more soilgoes down into that hole, the more that void heads toward the surface. to a point whereit can no longer hold itself and then, boom, you have a collapse and it collapses intothe void. people ask since the florida situation backa few weeks ago. "is there a sinkhole season?" the question is, well, i don't think you couldcall it a sinkhole season. yes, there is a connection between weather, and when we getsinkholes a lot of the cases. for instance, we see a lot of sinkholes occurafter very large precipitation events. if you think about it, if you've got the situationright here and you add water, a lot of water,
very rapidly to that system. you know howheavy water is? you've got a certain amount of weight on topof this bridge. you add that much weight with the water and you get collapses.another is droughts, the opposite situation. a lot of times with droughts, you're goingto drop the water table. the water table's up here somewhere, you're ok, but if you startdropping that water table down here. it's almost like flushing the toilet. all thatbuoyancy you have is now gone. another thing about clay is it holds watervery well. clay is cohesive. it binds things together. you ever take a drop of water andput it on the table and lift your finger up, it sticks to your finger a little bit. almostlike a glue to it. if you dry out the clay,
it also tends to help the system collapse.we have a joke with the geologists that most of the time you find a sinkhole, you're goingto find a tire in it or cows. not a lot of cows around sinkholes. it does make sense.most sinkholes, a lot of the areas, limestone areas in the country are agricultural areas.you have lots of agriculture, a lot cows around there anyway.then there are the ones that tend to happen in other places. this was a very famous oneback in the 1980's in winter park, florida, that took out a city block. this is what theycall the "winter park" sinkhole. there was a [inaudible 10:39] . they lostwhat, five cars down the hole? they got them out. this one you lost some pretty expensiveautomobiles.
as you see here, a couple of drilling rigsdown the hole. these were monterey, florida. this one is here in virginia. there is a linkto these. you think about other ways, how can humaninfluence effect sinkholes and make it more rapid? in this case, if you're drilling intothe ground and pulling water out, and you start pulling that mud to make that void,you're making that system happen a lot faster. people have to be very concerned when theydrill water wells, that they don't pull not only the water, but the material undergroundto exasperate the situation. highways, what happens a lot is in a karstor most areas, the natural environment, the rain hits the surface and it percolates downthrough the soils into the ground? we sit
there and we pave. we pave the roads, or weput up buildings and things. that's an impervious surface.water can no longer soak into the ground like it normally did. now, it runs off of thesesurfaces, into ditches, down into gutters. we concentrate all that water into the subsurface.that tends to wash out a lot of the soil and things. a lot of times on highways you getcollapses like this. i talked to a gentleman who did a lot of highwayrepairs, for virginia highway of transportation. the interstate 81 corridor between staunton,virginia and the west virginian line, they repair on average a dozen sinkholes a year.he said you add all the other roads in that area, and it's dozens and dozens a year.there's some we don't know about, and we don't
hear about. every once in awhile, people dodrive into them. this is interesting. does everybody know whereberryville is, berryville, virginia, out western virginia? back in the late '90s, we got calledon this one. a gentleman one saturday morning, drinkinghis coffee, reading his paper, hears this horrible noise in his basement. he opens uphis basement door just in time, to watch his furnace go down the hole.he got out of the house. within a matter of a couple hours, the whole entire part of thehouse was in the hole. although, the outside of the house still looked fine, like the onein florida. however, a week later, he had the house prettymuch gone. he still got the front steps and
it looks like the mudroom there, but withina month this was what the house looked like. that's the room to get in the... this wasonly about a 45, 50 foot deep sinkhole. the interesting thing here, let's go backto that drilling rig. can you prove why this sinkhole happened? it gets pretty touchy.it's a natural environment, but at the same time things are going on.a few days before this happened, they were drilling a well in the front yard of thishouse. the well driller was drilling away, and all of a sudden just started sucking upmud. he abandoned it. all he was getting was mud.what he had done is flushed out all the soil that was a cave underneath this house, andexasperated the situation.
if you look around, do you see any other houses?this is not in a neighborhood. this house was like the only house within a mile. there'sa farm across the street. you talk about bad luck. you've got hundreds of acres surrounding,and the hole happened underneath the house. as geologists, we looked at that area. therewas a line of 20 sinkholes, previous sinkholes, and this house sat right on the line. youcould draw a straight line across 20 sinkholes, and that house sat right in the middle ofthem. infrastructure, obviously. we already saw the road situation. here, thisis a bridge in southern pennsylvania. the sinkhole happened here. you can see how thebridge has broken down. if you think about it, people talk about,"well, we shouldn't be living on karst. we
shouldn't be living in areas that are proneto sinkholes, and things like that." when you have a country that has as much karstrain as we do, you can't avoid it. well, if you think about it, we've got cities likest louis and lexington. cincinnati. we're at cincinnati, nashville, and of course mostof florida. it's all about being smart. it's not engineering.it's about understanding the situation. that's where the science comes to play. if we canunderstand the system, then we can learn how best to live with it and live on it if wecan. we definitely have to take certain precautions,and you want to protect a system as much as you can.another aspect about sinkholes is environment.
here's the map of an area of missouri. allthe black dots are sinkholes. you think, "ok. that's not too bad." the fact is that thesesinkholes are natural inputs to the ground water, and very rapidly.if you look at the drainage basin around those sinkholes, all of this area for this one righthere, there's a road that runs right straight through there.if you'd have like a tractor trailer truck with some hazardous chemical spill here, itwould drain right into this big sinkhole. it would immediately end up in your drinkingwater. you have to be cognizant of the situationof how, rapidly we can get things into the ground water system, with hazardous materials.some would also say the corollary to that
is, "it can also rapidly get out of the system."some things can, not all things. anyway, let's move to springs. springs area large part of the karst area. as the water flows through the caves, it's almost likea natural river systems, invariably they come back to the surface.i like this picture here. this is outside of winchester. it's called "spanglish spring."see the old house here? if you go out in the shed into an alley, you can usually find thesprings when you find those 1,700 houses. these were water sources and in some casesstill are. springs come in different ways. here is this big cliff. here, you've got astream, this cave stream coming out. this is i would say the single largest conduitspring in the country. florida has the largest
number and the largest production of springs.this one, believe it or not, they call it "big spring" in missouri, 287 million gallonsof water a day. a lot of water! that's an instant river.here is the spring here. you see it boiling up. this is what they call a "rise cool" area.it's an instant river. here it is. you can see it actually boiling up. here's the entrancearea. it comes out with such force, 13 cubic meters a second. it's a huge amount of watercoming out. this one is amply named "blue spring." asyou can see, nice blue water coming out. it's the same situation as the last one, but notas much water is coming out. people, yes, are crazy enough to go into springs.you have cavers that do caving. some people
like to get into the springs and do underwatercaving. i'm not one of them. i don't know anybody else in the room that goes down todo this? people can die in different ways. i'm notgoing that way. this is one of the cave systems in florida. look how clear that water is...beautifulblue ocala spring system. they'll go down for...they have to stage their bottles. theyhave to have certain air mixtures and stuff. we wanted to understand the geology in thewhole karst system, in the ozarks that we were working on. we wanted to know more aboutthose cave systems. we can get into the dry caves. i'll go into the dry caves, but i'mnot going into the ones that are active today. we had a partnership with the ozark cave divingalliance, and these guys were going to do
this little rise pool of one that was onlyproducing, 81 million gallons/day. obviously a lot less...but they would dive into thisrise pool and be able to bring us back rock samples.we found out there was a geologic control and that's what we're studying. what is thegeologic control on these karst spring st. paul, cave systems? they gave us a nice mapand you can see here's the rise pool. once you go down into the cave it goes upand down, and it pretty much goes along. we found out it goes underneath a certain rockunit that played an important role. these maps that we were able to get from thesespring caves, were very helpful in us understanding the system. let's look at our caves....theones i'll go in.
the thing about a cave is that the temperaturein a cave is fairly constant. you go to, like, luray caverns or [inaudible 19:54] the temperatureis 57 degrees, or whatever. that is a good proxy for what the average temperature ofan area is. it's a good climate indicator. in virginiathe average cave is about 56 degrees [inaudible 20:10] . if you take your highs and your lows,all year long that's what you're going to get. i met some guys from croatia, who hadbeen to iran and their caves were 80 degrees. they were caving in shorts. they were sweatinga lot. i got to go into some caves in slovenia and they were 45 degrees. i was quite cold.it was quite a shock to be in those caves. caves can tell us a lot. caves can be differentsizes.
they can be a small one like this. in thisone you go in that hole, it gets no bigger than that for about 350 400 ft. you crawlthrough that little passage for a long way. yet you have other caves in the same areathat are the size you can drive a, mac truck through.caves come in various sizes...various shapes. this one, when i went to slovenia, that'sa bridge...those are people standing on the bridge...and there's a passage over here onthe left. when you go into this cave system this is postojna at postojna.it's almost like luray caverns. you go into this cave you walk down it like a regularcave tour then they walk you up to this fence, lights are off, and you stand there and theyturn the lights on and it looks like this
huge canyon. i mean those blocks down thereare the size of a tractor, on tractor trailers. see this right here? that's actually a pathway.those pathways...these are like shear walls. back in the 1800's after they discovered thesecaves, people went in. it's a shear wall. well, how're you going to get a trail there?they would dig into the mountain...right into the side of the cave and then put a notch,so you would have a place to walk like that. that's a lot of blackness let me tell you[laughs] . now, this part had a little hand rail.i didn't trust it [laughs] . it's a spectacular cave system. slovenia is what we call thehome of karst. then name karst comes from kras, k r a s, which was an area in this partof europe which is now slovenia, formerly
yugoslavia.think about caves ...deepest cave that we know right now is in the country of georgia.it's about 1.3 miles deep. what'd they say 60 percent of average [inaudible 22:40] that'sa deep cave. everybody understands that mammoth cave is the longest cave system.it wasn't for a long time, until people started making connections. there's something calledthe cave research foundation that got together many decades ago, and their job was to goin and map mammoth cave area, and they put a lot of it together.we're now left over 500 miles surveyed in mammoth cave. the largest chamber was thedeer cave in borneo. i've got some great stories about that one. that's for another time. now,this mountain river cave in vietnam is now,
considered the largest chamber.they can fit like a 747 easily fit a 747 into a chamber. what they think is the oldest cavenow is in australia. it's 340 million years old they believe. my question is how do youdate a hole? we'll talk about that in a minute. it looks like caves come in different sizes.how did i get interested in caves? this is me entering orndorff cave. i grew up on afarm with a cave. that got me interested when i was a little kid a teenager i guess. mygrandfather would always say, "don't you go in that cave!" i mean talk about stories..."thiscave goes to lost river. "it goes for miles and everywhere and everything".he kept saying "we don't go in that cave!" as teenagers, what do you do? you go in thecave! my buddy and my cousin and i went in
the cave. my cousin went first, and my friendand i was last. the cave went as far as, i don't know, a littleways. i never got to the end. it was such a tight passage. years later i said, "youknow, i've never been to the end of my own cave!" i got my caving gear, and my partner,and we decided that we were going to go down into orndorff cave.i'm going to go to the end of my cave. the cave goes down about 30 degrees about as highas the ceiling here, and then you get down into a passage which is only about, shoulder'swidth and a crawl. you crawl for about six to seven feet and then the cave bends to theleft. i did the bend to the left and i came faceto face with this raccoon. my caving partner's
on the surface and he says, "man, i heardthat raccoon go, 'oh, crap'!". it took me 30 minutes to get in the cave. it took me30 seconds to get out. i've been into well over 100 caves aroundthe world. i've never been to the end of my own cave. something happened, because i usedto be able to get into that cave. [laughter]that cave...it got smaller. the cave opening definitely got smaller.here's a typical cave passage. people like a lot of pretty stuff in the cave...the stalactitesand stalagmites, but i like to look at the morphology, because you can see the differentrock layers and how they affect the cave formed. in this case, it's dark to see here, but youcan see this nice rock ceiling and mud floor
here. well, there's a fracture that runs acrosshere something we call a bedding plane. rocks are layered some of the rocks are layeredwide extensive layer. bedding plane is a very important featurethat we found out drove the development of the cave, in the ozarks. here's a cave, right?here's the top part. you can imagine, these are like two pipelines.these are strictly natural pipelines with water that were moving from, one place. water'salways trying to get from a higher elevation to a lower elevation, driven by gravity likea river. in this case, it's like a pipeline, a natural pipeline.then there are the stalactites and stalagmites, and the things that grow from the ceilingsand the floors. sometimes you see interesting
morphologies. these are what we call scalloped.as the water is rushing through these old natural pipelines, they'll erode with littleeddies on the ceilings and floors. you can measure the distances between thecrusts of these areas we call scallops, and run equations and figure out what the velocityof the water was running, through some of these cave passages.this is what we call a cave shield. it's hard to see it's in two dimensions. but this isthe ceiling. you see some stalactites there. then there's this empty space. then you havethis thing here with all these flood stones coming off of it we call a shield.i don't think anybody knows exactly how these things formed. they're like sitting out there.they're anchored down here to the rock. but
how did that form like that? grand cavernsis the best place you're going to see it in the country, grand caverns, virginia.this is from endless caverns out in the shenandoah valley. all right, you've got stalactitesand stalagmites and after many thousands and thousands of years, they come together andyou get what we call these tiles. some more of these round springs. unfortunately,i don't have anything for scale cause. i didn't want to get too close to them, but these thingare twice the size of the round was. generally, you have water that's supersaturatedwith calcium carbonate. it's in the water system, it starts to drip down, and as ithits the air or gets agitated, the mineral gets re mineralized. calcium carbonate willre mineralize as either a stalactite, or a
stalagmite.the good this is, we can date the carbon that's in these things. these were two speleothems,what we call speleothems, in this case we take the stalagmites and you can see, almostlike tree rings. can you see the little rings here?that's how it's built. as the water would drip, drop by drop, it would leave its calciumcarbonate behind and would build these things. you can see with this one, it's anywhere from66,000 years old to about 12,000 years old. this one here we've been able to date to 116,000years old. finally, we can have an idea; remember how i was talking about how to date a hole?well, at least we can date things that are in that hole. we know that the cave has gotto be older than 116,000 years.
obviously, to do the work, you know the mappingthe cave...to get into the caves and look at...make maps of the caves tells us a lotabout that cave system. you've got to put yourself in some pretty crazy, tight, muddyplaces. we can look at these caves, look at some variousmeasurements, and understand the orientations of these passages, which tells us somethingabout how the cave formed. you're saying, "why would that be important? who cares thatthis cave has this kind of development?" well, if we can understand what that pipelineof water was in the past, we can have a good understanding of how the ground water is movingtoday. if we can understand that, we can manage our water resources that we're pulling outof the ground in these areas.
you find every little tight hole you can stickyourself in to make sure you get a good map and tend to end up looking like this. i cameup from one of the trips looking like this and took my cave clothes out, threw it outinto the yard, got my hose and my brush and bleach and everything.i'm scrubbing away and my neighbor walks by, and she starts shaking her head. i said, "what?"she goes, " [inaudible 30:25] my husband's an accountant". [laughs] that's it.live in caves. there are things that live closer to the edge of the caves that are closeto the openings, that may have....you can see...they camouflage themselves into thevarious types of lizards. then there's others, proteus and various lizards, but you'll noticethat they all have the pigment.
you can see some red in some eyes in thiscave lizard. they're living in the pure darkness. they don't need eyes to see. they have othersenses they're using to find their food, and to get around. obviously, without any sunlightthere's no reason to have much in the way, of pigment.there is some cave fish. this one completely lost any idea of having any kind of eyes.here's a cave craw fish, again no pigment. we were surprised to see when we had thosecave divers in the ozarks, going in those springs that they would go in almost a mileand find these things, so deep into the cave system that there's that much food to be had.the other thing are bats. here's a colony like this various, obviously many speciesof bats. we got somebody here who knows something
about bats. this species here, they tend tocongregate together as one big mob as they hibernate.a lot of people have heard about what's happening here in the last, how many years has it beensince 2000.2000. so 2007 was the first report of what we call "white nose syndrome."they were finding up in the new york vermont area in some of the caves and mines up there,that the bats were flying around up in january. that's generally their hibernation time.there's not much for them to eat. they were seen not hibernating, but at least sleepingclose to the cave entrance where it was still cold.people were noticing, this one here doesn't
seem to have much, but you can see the littlewhite fuzz or fungus around the nose of the bats, what they call the term "white nosesyndrome" and still being studied today. if you go back to that cause map that showsthe area, we can see it spread from new york down to virginia in three years, by the timeit hit 2010. we first saw in virginia 2009. also, people were going in doing bat counts,and noticing the bat population decreasing greatly and noticing the bats flying aroundcrazy times, of the year. as years went on, we kept finding it further and further awayfrom new york. all of a sudden i got a call one day, andthey were finding them in a cave in wisconsin. if you think about it, there's a limestonearea in new york. it goes up into canada around
ontario, and wraps around michigan basin thenback into the us around wisconsin. now, it's as far west as oklahoma. for thelongest time, a lot of the public caves have been closed for many years.what is your name again? sallysally [inaudible 33:49] was telling me she works on the white nose syndrome, and someof the caves are now being opened. as cavers we go in and we try to it's a fungus thatwe are finding in the soils in the caves. if you're in a cave that's got it you're carryingthat soil with you you go to another cave you could be carrying a disease and spreadingthat disease. the idea of the vector of how the diseaseis spreading or the fungus spreading, i haven't
heard a whole lot more about it. we are tryingto figure out is it, because of the people going cave to cave or is there a bat to batconnection? some species are more prone to it than others.the virginia long ear bat doesn't seem to be affected whereas, a lot of other speciesare. obviously, the environment in the caves are very important.let me end with this is a natural picture inside the cave at night. thank you[laughter] [applause]