WEBVTT - From the Vault: Sinkholes, Part 1 0:00:05.720 --> 0:00:07.560 Hey, are you welcome to Stuff to Blow your Mind? 0:00:07.680 --> 0:00:10.600 My name is Robert Lamb and I'm Joe McCormick, and 0:00:10.720 --> 0:00:13.560 today we're bringing you an episode from the vault. This 0:00:13.640 --> 0:00:16.720 is our part one of our episode on sink Holes, 0:00:16.800 --> 0:00:25.680 which originally aired on January. We hope you enjoy Welcome 0:00:25.760 --> 0:00:29.400 to Stuff to Blow Your Mind production of My Heart Radio. 0:00:35.159 --> 0:00:36.960 Hey you welcome to Stuff to Blow your Mind. My 0:00:37.040 --> 0:00:40.280 name is Robert Lamb and I'm Joe McCormick, and today 0:00:40.360 --> 0:00:43.520 we're gonna be talking about sink holes. This is actually, 0:00:43.600 --> 0:00:47.320 I think, in a way a listener request topic that 0:00:47.440 --> 0:00:50.279 turned out to be very interesting. But it's, uh, it's 0:00:50.320 --> 0:00:53.520 sort of leap frogging off of some some previous episodes 0:00:53.600 --> 0:00:56.080 we did. Rob did the did the sink Whole journey 0:00:56.120 --> 0:00:58.319 begin when we were talking about the star Lac from 0:00:58.320 --> 0:01:01.120 Return of the Jedi. I think that is the original context. 0:01:01.160 --> 0:01:03.440 I think that was the original point at which we 0:01:03.480 --> 0:01:06.600 begin to hear listener males about the idea of in 0:01:06.600 --> 0:01:09.600 a sink Whole episode, because we talked about the star 0:01:09.720 --> 0:01:13.959 Lac and then we talked about some ideas and was 0:01:14.000 --> 0:01:19.440 it meso American uh? Mythology concerning uh entities of the 0:01:19.480 --> 0:01:22.400 ground that swallow things up. Oh, that could be it. Well, 0:01:22.400 --> 0:01:24.240 I know we ended up talking about the Bible, which 0:01:24.240 --> 0:01:26.280 will revisit in a minute here. But one of the 0:01:26.360 --> 0:01:29.200 questions that came up was, you know that scene in 0:01:29.319 --> 0:01:32.360 movies where there's an earthquake and and then suddenly a 0:01:32.480 --> 0:01:34.880 crack opens up in the middle of the street and 0:01:34.959 --> 0:01:37.679 it's you know, miles deep, and it just swallows people 0:01:37.800 --> 0:01:40.600 down into it. Uh. The question was like, does that 0:01:40.720 --> 0:01:43.200 kind of thing really happen? Does during an earthquake? Does 0:01:43.240 --> 0:01:45.760 the earth open up and open these deep pits and 0:01:45.880 --> 0:01:50.560 chasms that people fall down and disappear into. And our 0:01:50.560 --> 0:01:53.240 previous answer to that was, well, not really, or it 0:01:53.240 --> 0:01:56.240 seems like that's that's extremely rare if it ever happens. 0:01:56.280 --> 0:01:59.440 That's not like a common feature of what happens to 0:01:59.480 --> 0:02:03.560 the surf is topology during an earthquake. But sinkholes, a 0:02:03.640 --> 0:02:06.200 listener pointed out, or a very different story, and sinkholes 0:02:06.240 --> 0:02:10.160 could explain many of these stories, uh, from from mythology 0:02:10.160 --> 0:02:12.440 and all that of the earth opening up and swallowing people. 0:02:12.440 --> 0:02:13.880 We can get back into that in a bit. But 0:02:13.919 --> 0:02:17.200 you actually turned up a really interesting photo essay about 0:02:17.240 --> 0:02:21.440 a fascinating sudden opening of a sinkhole. Uh just earlier 0:02:21.480 --> 0:02:26.480 this year, that's right. Well, actually it was last year, remember, 0:02:27.440 --> 0:02:30.639 oh god, Yeah, I haven't turned the calendar fully yet. 0:02:30.680 --> 0:02:33.560 It's still it's still It's like that year is kind 0:02:33.560 --> 0:02:35.920 of like the the other world in hell Raisers. So 0:02:36.000 --> 0:02:37.919 it's got chains with hooks and them, and they shoot 0:02:37.919 --> 0:02:39.839 out of the walls and so the hooks are still 0:02:39.880 --> 0:02:43.560 in my brain, but I'm slowly methodically rebuilding my body 0:02:43.600 --> 0:02:47.239 to escape. All right, Well, this is this story takes 0:02:47.280 --> 0:02:51.600 us back to April. So Um. What happened is a 0:02:51.680 --> 0:02:53.919 whole opened up in the front yard of a home 0:02:54.040 --> 0:02:58.600 in Black Hawks, South Dakota. Uh, specifically in a housing 0:02:58.639 --> 0:03:03.400 development there that is called perfectly enough, the Hideaway Hills development. 0:03:05.320 --> 0:03:07.200 That just doesn't sound great. I mean no offense to 0:03:07.240 --> 0:03:09.560 the people who live there, but it doesn't sound like 0:03:09.720 --> 0:03:11.120 a place I want to go. It sounds like a 0:03:11.120 --> 0:03:13.239 place where, I don't know, where you like retreat after 0:03:13.280 --> 0:03:16.959 you've committed a crime. What was the housing development on 0:03:17.080 --> 0:03:24.400 arrested development, Sudden Valley or Sudden Yeah Appa, so Um, 0:03:25.000 --> 0:03:28.000 Like you pointed out, there's an incredible photo essay photos 0:03:28.040 --> 0:03:30.560 series on this on board Panda about this. If you 0:03:30.600 --> 0:03:34.200 look up board Panda Black South Dakota sinkhole, you will 0:03:34.240 --> 0:03:38.640 find it because uh this photo essay, if you will, 0:03:38.720 --> 0:03:42.400 it takes us through a journey by a local caving 0:03:42.440 --> 0:03:47.040 group called Pahsapa Grotto as they decided to venture down 0:03:47.080 --> 0:03:49.440 into this hole that opened up in this front yard 0:03:49.680 --> 0:03:54.000 to explore the world beneath the suburbs. Now, this sinkhole, 0:03:54.520 --> 0:03:56.360 it turns out it's going to be very different than 0:03:56.440 --> 0:03:59.040 most of the sinkholes we're talking about in this episode. 0:03:59.600 --> 0:04:04.160 Most sink holes open up over some kind of void 0:04:04.440 --> 0:04:06.440 that is formed in the rock below, and as we'll 0:04:06.440 --> 0:04:08.040 get into a lot of that usually has to do 0:04:08.120 --> 0:04:11.600 with water and hydrology. But in this case, the void 0:04:11.840 --> 0:04:15.120 in the rock below the neighborhood was was more was 0:04:15.360 --> 0:04:18.360 of a more artificial persuasion, right. That's because there was 0:04:18.400 --> 0:04:22.520 an abandoned gypsum mine beneath the housing development, and so 0:04:22.640 --> 0:04:25.240 the cavers had they had to lower down in on ropes, 0:04:25.640 --> 0:04:28.400 you know, had to use like actual caving equipment into 0:04:28.480 --> 0:04:32.320 the dark and sometimes flooded tunnels beneath reportedly over two 0:04:32.320 --> 0:04:35.320 thousand feet across in a hundred and fifty feet wide 0:04:35.360 --> 0:04:39.200 this tunnel um complex. Uh, and they encountered the remains 0:04:39.240 --> 0:04:42.800 of what looks like an old, like nineteen fifties automobile. Uh. 0:04:42.880 --> 0:04:45.640 There's just a whole world down there, like a whole 0:04:46.040 --> 0:04:51.200 uh Minoan maze beneath this you know, rather mundane looking 0:04:51.200 --> 0:04:54.440 housing development. It's like two levels of weird. So first 0:04:54.440 --> 0:04:57.440 of all, it's yes, the suburban you know, neighborhood, and 0:04:57.480 --> 0:05:00.280 then just in the middle of somebody's front yard a 0:05:00.680 --> 0:05:03.599 pit opens up, so that's the sinkhole. But then it's 0:05:03.680 --> 0:05:06.800 that the sinkhole goes to this maze. And yeah, like 0:05:06.839 --> 0:05:09.200 you said, there's like an old Chevy convertible down there, 0:05:09.440 --> 0:05:11.760 And I'm wondering, why is that down there? Did somebody 0:05:11.839 --> 0:05:15.040 drive it into the mind before the mind was sealed up? Yeah, 0:05:15.160 --> 0:05:17.000 I don't know. Like, it's just it's a place full 0:05:17.040 --> 0:05:20.440 of questions, is a place full of the past, of mysteries. 0:05:20.839 --> 0:05:23.080 And so the article itself gets into some of the 0:05:23.080 --> 0:05:25.560 community fall out over all this. But but what I 0:05:25.600 --> 0:05:28.600 love about this episode is it illustrates for us this 0:05:28.680 --> 0:05:32.680 divide between the surface world so tightly manicured and controlled 0:05:32.839 --> 0:05:35.359 so much of the time, and a world beneath that 0:05:35.440 --> 0:05:38.560 we have only a shaky understanding of like something out 0:05:38.560 --> 0:05:41.960 of a mash up between Poltergeist and The Descent. You know, 0:05:42.240 --> 0:05:45.480 a gateway to that hidden underworld might open up at 0:05:45.480 --> 0:05:49.120 any moment and reveal its secrets to us, invite us in, 0:05:49.320 --> 0:05:53.080 perhaps swallow us entirely, and then we'll be part of 0:05:53.080 --> 0:05:57.000 that underworld. Because if we're being you know, perfectly rational 0:05:58.000 --> 0:06:02.320 without any supernatural ideas like that, that idea alone is terrifying. 0:06:02.360 --> 0:06:04.960 You know that the earth might open up and we 0:06:05.080 --> 0:06:08.000 might fall, you know, into a pit. But then if 0:06:08.000 --> 0:06:11.360 you begin to layer in beliefs and superstitions, then yeah, 0:06:11.440 --> 0:06:15.320 become this whole becomes a portal to other realms. Yeah, exactly. 0:06:15.400 --> 0:06:18.520 Now we've talked about natural features in the landscape taking 0:06:18.560 --> 0:06:21.200 on religious significance before, Like in we did a couple 0:06:21.240 --> 0:06:24.400 of episodes called The Sacred Mountain, which was about mountain 0:06:24.440 --> 0:06:27.520 peaks that were considered to be holy or supernatural or 0:06:27.520 --> 0:06:30.520 the dwelling places of gods or places that Win explored. 0:06:30.560 --> 0:06:34.400 People often reported having supernatural experiences, They're like One of 0:06:34.400 --> 0:06:36.000 the things that came out of that was the the 0:06:36.120 --> 0:06:40.400 often reported third man syndrome, feeling that mountain climbers sometimes 0:06:40.400 --> 0:06:43.000 have very high up but we talked about possible ways that, 0:06:43.400 --> 0:06:46.800 like the effects of the sun or that altitude sickness 0:06:46.880 --> 0:06:51.160 could contribute to that um. But there are also ways 0:06:51.160 --> 0:06:55.520 in which sinkholes can take on similar types of religious significance, 0:06:55.520 --> 0:06:59.480 can have a similar mythological appeal, And one great example 0:06:59.560 --> 0:07:02.440 is we is some of the sinkholes are also known 0:07:02.440 --> 0:07:05.400 as sinnotes that we see throughout Mesoamerican religion in the 0:07:05.440 --> 0:07:09.240 Yucatan Peninsula and among the ancient Mayan people. But I 0:07:09.240 --> 0:07:11.840 guess well, we'll come back to that more later. I 0:07:12.160 --> 0:07:15.480 wanted to get to this question about the the idea 0:07:15.680 --> 0:07:18.240 that the earth can open up and swallow you. It's 0:07:18.240 --> 0:07:21.720 an image that seems like to perfectly fit ancient myths 0:07:21.720 --> 0:07:25.160 and texts. You would imagine passages like this appearing in 0:07:25.320 --> 0:07:28.200 you know, Babylonian texts or something. It definitely appears in 0:07:28.240 --> 0:07:31.280 the Hebrew Bible, for example, in the Book of Numbers, 0:07:31.320 --> 0:07:33.720 there's a passage where Moses is speaking to people and 0:07:33.720 --> 0:07:36.240 he's trying to demonstrate that he was in fact sent 0:07:36.280 --> 0:07:39.600 by the Lord and he uh he, he says, and 0:07:39.880 --> 0:07:42.080 basically he makes a promise that hey, if the Lord 0:07:42.120 --> 0:07:44.560 has sent me he'll he'll send a sign, and you'll 0:07:44.600 --> 0:07:47.400 know it, because there will be this group of people 0:07:47.480 --> 0:07:50.040 that will be swallowed up alive into a pit that 0:07:50.120 --> 0:07:52.800 opens up suddenly in the earth. For very these wicked 0:07:52.840 --> 0:07:56.080 people who have rejected the Lord. And the passage says 0:07:56.160 --> 0:07:58.240 in Uh in the Book of Numbers. Now it came 0:07:58.320 --> 0:08:00.800 to pass, as he finished speaking all these words, that 0:08:00.840 --> 0:08:03.680 the ground split apart under them, and the earth opened 0:08:03.680 --> 0:08:06.720 its mouth and swallowed them up with their households, and 0:08:06.760 --> 0:08:09.240 all the men of Cora, with all their goods. So 0:08:09.360 --> 0:08:11.880 they and all those with them went down alive into 0:08:11.880 --> 0:08:14.960 the pit. The earth closed over them, and they perished 0:08:15.000 --> 0:08:18.480 from among the assembly. And so I wonder, I mean, obviously, 0:08:18.520 --> 0:08:21.320 with passages like this, I wonder if it's this kind 0:08:21.360 --> 0:08:24.120 of thing that inspired that scene in every movie that 0:08:24.160 --> 0:08:26.720 has an earthquake in it where suddenly a bottomless pit 0:08:26.800 --> 0:08:30.200 opens up in the ground and people get sucked into it. Yeah, 0:08:30.440 --> 0:08:33.280 you know, this could also be graboids. If I think, 0:08:33.280 --> 0:08:35.880 if they want to make another Tremor's film, which they will, 0:08:35.960 --> 0:08:39.320 I'm sure they should go for you know, some biblical 0:08:39.360 --> 0:08:42.160 flare here, go for an Old Testament Tremor's movie with 0:08:42.160 --> 0:08:45.120 with Moses being our central character, and that's a very 0:08:45.120 --> 0:08:47.560 good direction. Now, one thing I want to say, because 0:08:47.880 --> 0:08:49.320 I feel like I have to bring this up every 0:08:49.320 --> 0:08:52.920 time we talk about geo mythology. Uh, there's this question 0:08:52.960 --> 0:08:56.280 of is this story in the Bible based on something 0:08:56.400 --> 0:09:01.079 that someone in history witnessed witnessing a real world geological event, 0:09:01.360 --> 0:09:04.480 perhaps a sudden collapse of a settled area due to 0:09:04.520 --> 0:09:06.880 a sinkhole. Uh. And as I pretty much always do 0:09:06.920 --> 0:09:09.280 whenever we talk about geomethology, I want to emphasize that 0:09:09.400 --> 0:09:12.960 fantastic imagery and in myths and legends and religious text 0:09:13.040 --> 0:09:17.439 doesn't necessarily need to be explained by someone actually having 0:09:17.520 --> 0:09:19.640 seen something physical in the world. I think we can 0:09:19.679 --> 0:09:24.200 sometimes go overboard looking for naturalistic explanations of this kind 0:09:24.240 --> 0:09:27.000 to explain what somebody thought they saw that appears in 0:09:27.000 --> 0:09:30.000 a story. You know, people are highly imaginative, and sometimes 0:09:30.000 --> 0:09:33.880 stories are just stories. But there's always also the possibility 0:09:34.000 --> 0:09:36.679 that stories like these could be based on people hearing 0:09:36.760 --> 0:09:39.280 stories about having seen I don't know, there was a 0:09:39.360 --> 0:09:41.320 there was a castle or a building or something like 0:09:41.360 --> 0:09:43.960 that that was just swallowed up into the earth, which 0:09:44.040 --> 0:09:47.040 if you didn't have any kind of geological understanding with 0:09:47.040 --> 0:09:50.240 which to to to interpret that. It would certainly seem 0:09:50.320 --> 0:09:52.520 to be a you know, a supernatural event. I don't 0:09:52.520 --> 0:09:54.600 I don't know how else you would interpret it. Yeah, 0:09:54.640 --> 0:09:57.319 because I think one of the things that really drives 0:09:57.360 --> 0:10:00.280 home and when we we see examples of sync holes 0:10:00.280 --> 0:10:03.240 and we hear stories like this, we see cinematic interpretations, 0:10:03.720 --> 0:10:08.040 is that idea that the that terra firma is not 0:10:08.679 --> 0:10:11.640 that firm, is not that fixed, that it could change, 0:10:11.760 --> 0:10:15.040 that the that the firm ground beneath our feet could 0:10:15.080 --> 0:10:18.560 suddenly give way, you know, like that alone is just 0:10:18.600 --> 0:10:23.640 this kind of uh, you know, horrifying idea that that 0:10:23.720 --> 0:10:26.280 it that it easily applies as a metaphor to everything 0:10:26.280 --> 0:10:28.440 else in our in our life. You know, that the 0:10:28.480 --> 0:10:31.959 thing that is the order that we depend upon might 0:10:32.040 --> 0:10:34.720 go away at any moment. Yeah, it's interesting to think about, 0:10:34.760 --> 0:10:39.040 like a vertical spectrum of of ways the natural world 0:10:39.080 --> 0:10:41.760 can intrude on our lives and how most of the 0:10:41.800 --> 0:10:44.319 stuff that we're that we're used to thinking about taking 0:10:44.320 --> 0:10:48.439 into consideration, worrying about as as possible threats, all basically 0:10:48.440 --> 0:10:50.800 takes place like on the surface of the earth. And 0:10:50.920 --> 0:10:53.320 that you know, when you go to the vertical ends 0:10:53.320 --> 0:10:56.199 of that spectrum, you've got like impacts from space coming 0:10:56.200 --> 0:10:59.520 from above, sinkholes up and opening up from below, and 0:10:59.559 --> 0:11:01.880 these fen I'm gonna intrude on that day to day 0:11:01.960 --> 0:11:06.240 understanding of physical forces. Yeah, so it's it's no surprise. 0:11:06.280 --> 0:11:09.040 We were talking about this before the podcast started rolling 0:11:09.080 --> 0:11:12.760 here that if you start looking around for sinkholes online, 0:11:13.000 --> 0:11:16.880 you'll find just so many galleries, top ten lists, lots 0:11:16.880 --> 0:11:20.960 of click bait about sinkholes. Like sinkholes are kind of 0:11:21.520 --> 0:11:23.080 they're kind of like a like they're kind of like 0:11:23.080 --> 0:11:27.719 true crime, you know there um there. You also see them, 0:11:27.720 --> 0:11:30.800 like I was noticing, like very tabloid sites sites that 0:11:31.200 --> 0:11:34.720 otherwise they're not going to really have anything related to geology, 0:11:35.080 --> 0:11:37.640 but they'll have sinkholes. You know, it'll be celebrity gossip, 0:11:38.120 --> 0:11:42.400 um and you know, maybe some conspiracy theories. But then also, uh, 0:11:42.640 --> 0:11:45.240 big old holes opening up in the earth. Chump boxes 0:11:45.240 --> 0:11:47.920 are full of sinkholes. Have you ever noticed this? These 0:11:47.920 --> 0:11:51.320 are the like the link um grids at the bottom 0:11:51.360 --> 0:11:53.600 of blogs and whatnot. Yeah. Yeah, so, like you know, 0:11:53.840 --> 0:11:57.120 like most websites on the Internet these days are just 0:11:57.200 --> 0:12:00.000 being more and more infected by ads that a since 0:12:00.000 --> 0:12:02.760 really take the form of malware. But if you scroll 0:12:02.840 --> 0:12:05.760 down to the bottom of most articles or any text 0:12:05.800 --> 0:12:08.320 image based website, you'll usually see one of these boxes 0:12:08.400 --> 0:12:13.240 that's full of just like extremely tacky, distasteful images that 0:12:13.280 --> 0:12:16.360 are either like something that's kind of sexually suggestive and 0:12:16.440 --> 0:12:20.520 a gross way, or something that is uh sort has 0:12:20.559 --> 0:12:22.800 some kind of like health vibe, Like it looks like 0:12:22.840 --> 0:12:27.240 infected skin or holes in skin, or some kind of 0:12:27.280 --> 0:12:32.080 bite or something like the kind of a necrotic bite 0:12:32.160 --> 0:12:34.319 that you might imagine someone would get in their worst 0:12:34.400 --> 0:12:37.960 nightmares from a brown recluse, you know that kind of thing. Um. Yeah, 0:12:38.000 --> 0:12:42.200 they they tie into our like deepest, most primal fears 0:12:42.200 --> 0:12:47.959 and desires, just pure eroticism or just pure in necrotic 0:12:48.080 --> 0:12:51.920 damage or indeed holes opening up in the earth. You know, 0:12:51.960 --> 0:12:54.040 it's got to be something extreme like that to make 0:12:54.040 --> 0:12:57.480 it into that grid of horror. Yeah. The toilet with 0:12:57.520 --> 0:12:59.840 the rat coming up through it, remember that one. Oh, 0:13:00.080 --> 0:13:01.480 I think I've seen that when I was a common 0:13:01.520 --> 0:13:04.360 chumbox image or the like. You know, doctors say never 0:13:04.440 --> 0:13:08.000 eat this vegetable, but they don't tell you what it is. Yeah, yeah, yeah, 0:13:08.040 --> 0:13:11.680 sometimes it is. Um. It. It's economic as well. You know, 0:13:11.720 --> 0:13:13.560 there'll be some sort generally it's like a picture of 0:13:13.600 --> 0:13:16.640 an old person and just a few like alarming words 0:13:16.800 --> 0:13:20.000 about you know, investments and retirement or something. Right, but 0:13:20.200 --> 0:13:24.199 that is the world. Well, sinkholes are actually in their 0:13:24.200 --> 0:13:26.040 own way. I mean, of course they can be horrifying, 0:13:26.080 --> 0:13:28.240 they can be destructive to human life, but they are 0:13:28.320 --> 0:13:31.160 also fascinating in their own way. In the natural way, 0:13:31.160 --> 0:13:35.800 they are wonderful. Uh. There can be beautiful uh legends 0:13:35.800 --> 0:13:39.000 and stories attached to them, and so I don't know, 0:13:39.040 --> 0:13:42.800 I feel like they are the most uh naturally beautiful 0:13:42.880 --> 0:13:46.160 thing that that fits in the chum box. I mean 0:13:46.160 --> 0:13:48.400 the rat and the toilet can't compete. I mean the 0:13:48.559 --> 0:13:50.000 rat and the toilet. We could do an episode on 0:13:50.000 --> 0:13:52.679 that as well. But yeah, I agree, the sinkholes need 0:13:52.720 --> 0:13:55.840 to be rescued from the chum box. Uh. And and 0:13:55.880 --> 0:13:58.240 that's kind of what we're doing in in this episode 0:13:58.240 --> 0:14:00.760 of Stuff to Blow Your Mind and the possible second 0:14:00.760 --> 0:14:10.199 episode of Follan. Alright, so sinkholes are formed in a 0:14:10.320 --> 0:14:14.839 number of ways, but most naturally occurring sinkholes, like most 0:14:14.920 --> 0:14:17.520 other things on planet Earth, in the end, come back 0:14:17.559 --> 0:14:20.560 to the power of water. Water, of course, is the 0:14:20.600 --> 0:14:23.640 molecule of life, largely because of its power as a 0:14:23.720 --> 0:14:27.200 master solvent, and in much the same way really that 0:14:27.280 --> 0:14:31.200 water created life on Earth, probably it also creates many 0:14:31.280 --> 0:14:35.560 of Earth's most astounding geologic features. And so this is 0:14:35.560 --> 0:14:37.880 how we we get sinkholes for the most part. So 0:14:37.920 --> 0:14:40.880 as carbon dioxide in the air or in the soil 0:14:41.640 --> 0:14:46.120 mixes with rain water, that mixture forms a weak acid 0:14:46.280 --> 0:14:49.480 with the with the chemical formula H two c O three. 0:14:49.920 --> 0:14:51.640 So what you've got there is you've got your H 0:14:51.680 --> 0:14:53.360 two oh the water, and then you've got your C 0:14:53.520 --> 0:14:56.320 O two the carbon dioxide. They react, they make a 0:14:56.360 --> 0:15:00.440 compound with two hydrogens, one carbon and three oxygen's. And 0:15:00.560 --> 0:15:03.360 this weak acid formed in the atmosphere or in the 0:15:03.400 --> 0:15:06.760 soil is known as carbonic acid, and it is the 0:15:06.800 --> 0:15:11.720 primary reason that caves exist. Now most caves in the world, 0:15:11.760 --> 0:15:15.920 not all, but most are formed by the drainage of 0:15:16.200 --> 0:15:21.320 acidified water through what you might call soluble rock and uh. 0:15:21.400 --> 0:15:25.280 Soluble rock are types of rock that can react chemically 0:15:25.360 --> 0:15:29.480 with this water and be dissolved and carried away. Now 0:15:29.480 --> 0:15:33.160 they're they're multiple kinds of soluble rock, including minerals like 0:15:33.440 --> 0:15:36.720 salt and gypsum, But probably the most important, or at 0:15:36.760 --> 0:15:40.360 least the most charismatic, is limestone, which is in itself 0:15:40.800 --> 0:15:44.680 a fascinating and even mind boggling rock. And sometimes I 0:15:45.560 --> 0:15:48.680 really do think a lot about limestone, and maybe people 0:15:48.760 --> 0:15:51.880 are aren't inclined to be as impressed by it as 0:15:51.920 --> 0:15:54.119 I am. But if you don't believe me that limestone 0:15:54.160 --> 0:15:58.000 is amazing, I think it's worth considering that if you 0:15:58.040 --> 0:15:59.440 live in an area of the world you know this 0:15:59.560 --> 0:16:02.440 primary resting on limestone, which in the United States would 0:16:02.480 --> 0:16:06.360 include huge portions of like Florida and the coastal southeast, 0:16:06.480 --> 0:16:08.800 big parts of the Midwest. If you live in a 0:16:08.800 --> 0:16:12.600 place like that dominated by this this carbonate rock, you 0:16:12.640 --> 0:16:16.160 are walking around every day on rock that is probably 0:16:16.240 --> 0:16:20.320 mostly built out of dead bodies. Limestone can be formed 0:16:20.320 --> 0:16:22.200 in a number of ways. Some of those ways are 0:16:22.240 --> 0:16:25.680 a biotic, but one of the major processes that forms 0:16:25.760 --> 0:16:30.400 limestone is the gradual deposition of the shells and other 0:16:30.520 --> 0:16:34.880 hard calcium carbonate body parts of animals and other tiny 0:16:35.040 --> 0:16:38.520 organisms in the oceans and rivers and lakes where they 0:16:38.560 --> 0:16:42.920 accumulate on the bottoms of these water sources over millions 0:16:42.960 --> 0:16:46.880 of years, and apparently feces also in general, waste products 0:16:46.880 --> 0:16:51.080 can contribute as well. So the calcium based body parts 0:16:51.080 --> 0:16:54.800 of algae and coral and oysters and all kinds of 0:16:54.880 --> 0:16:58.200 creatures of the sea settle in the deep, and then 0:16:58.200 --> 0:17:01.480 they're pressed down and paved over by time and pressure 0:17:01.840 --> 0:17:06.040 until they become layers of sedimentary rock. I really just 0:17:06.080 --> 0:17:09.680 think about that. Sometimes limestone is largely made out of 0:17:09.800 --> 0:17:13.520 life that has died and become rock, like the fallen 0:17:13.560 --> 0:17:16.240 creatures of Earth pile up and become part of the 0:17:16.280 --> 0:17:19.560 crust of the Earth itself. Wow, it's like it's like 0:17:19.600 --> 0:17:24.240 the Medusa's layer, right, all these like the petrified bodies. Oh, 0:17:24.280 --> 0:17:25.760 that's I wish I had thought of that when we 0:17:25.760 --> 0:17:28.320 were doing our Medusa episodes. Except I guess in the 0:17:28.320 --> 0:17:31.760 Medusa Garden that they keep their form right here. They 0:17:31.880 --> 0:17:34.120 just sort of like go back to whence they came. 0:17:34.240 --> 0:17:38.320 They become part of this mass. But anyway, it's via 0:17:38.480 --> 0:17:41.240 rocks like this that we get so many of the 0:17:41.320 --> 0:17:44.840 naturally occurring sinkholes on the Earth. So how do they form? Well, 0:17:45.080 --> 0:17:47.760 imagine that there is a storm, it rains here in 0:17:47.800 --> 0:17:50.639 an area with some kind of soluble rock. Let's say 0:17:50.640 --> 0:17:53.239 it's a it's a carbonate rock, it's like limestone, and 0:17:53.440 --> 0:17:56.160 rainwater collects on the surface of the earth and then 0:17:56.240 --> 0:18:00.280 runs downhill. And if that rainwater drains down in two 0:18:00.359 --> 0:18:04.920 cracks insoluble rock like limestone, things begin to happen much 0:18:04.960 --> 0:18:07.240 in the same way that you can dissolve table salt 0:18:07.359 --> 0:18:10.560 or sugar and a glass of water. The crystal contents 0:18:10.600 --> 0:18:14.040 of these soluble rock surfaces are gradually dissolved in and 0:18:14.160 --> 0:18:18.320 carried away by that acidified water. And over tens or 0:18:18.400 --> 0:18:21.840 hundreds of thousands of years, that dissolution of the rock 0:18:21.960 --> 0:18:24.720 by acidic water can turn what might have started as 0:18:24.760 --> 0:18:28.760 this tiny stress fracture in a chunk of bedrock into 0:18:28.880 --> 0:18:32.240 an underground cavern large enough for a human to climb into. 0:18:32.560 --> 0:18:35.080 And of course, as the centuries go on, these these 0:18:35.320 --> 0:18:39.239 voids created by the drainage pathways of water can just 0:18:39.280 --> 0:18:42.040 get bigger and bigger. They can form underground rivers that 0:18:42.119 --> 0:18:46.080 form larger and larger voids. And it's this dissolution of 0:18:46.119 --> 0:18:49.280 soluble rock by water that usually leads to the creation 0:18:49.320 --> 0:18:53.159 of sinkholes. Uh though these voids in the rock, I 0:18:53.160 --> 0:18:56.560 think sometimes maybe geologists will get picky about this, these 0:18:56.640 --> 0:19:00.240 voids in the rock are not technically themselves sinkhole, and 0:19:00.400 --> 0:19:02.320 we would normally think of them as voids or just 0:19:02.520 --> 0:19:05.720 caves right there, their caves in the rock. Um. Rather, 0:19:05.800 --> 0:19:10.159 a sinkhole is more of a topographical designation. It's a 0:19:10.200 --> 0:19:13.960 topographical concept about the ground and the surface of the earth. 0:19:14.600 --> 0:19:17.879 So according to the U S Geological Survey, a sinkhole 0:19:17.960 --> 0:19:21.120 is quote an area of ground that has no natural 0:19:21.359 --> 0:19:25.719 external surface drainage. So like in one of these areas, 0:19:25.720 --> 0:19:29.159 if it rains, water just pools in and there's nowhere 0:19:29.200 --> 0:19:32.879 on the surface level that allows this water to run out. 0:19:33.119 --> 0:19:35.800 So if the water leaves, it's either evaporating into the 0:19:35.840 --> 0:19:39.920 air or it's draining out through somewhere in the bottom. Sinkholes, 0:19:39.920 --> 0:19:43.480 of course, can form gradually over hundreds or hundreds of 0:19:43.520 --> 0:19:46.800 thousands of years, often of steady dissolution, or they can 0:19:46.840 --> 0:19:50.280 form quite suddenly. For example, when the ground over a 0:19:50.359 --> 0:19:54.359 void in the limestone below is suddenly just suddenly there's 0:19:54.400 --> 0:19:56.359 not enough for it to support its own weight, and 0:19:56.359 --> 0:19:59.400 then it just collapses and reveals the void that had 0:19:59.440 --> 0:20:02.240 been there for so long. Uh. And we know that 0:20:02.280 --> 0:20:04.840 the sudden appearance of a sinkhole can have these devastating 0:20:04.840 --> 0:20:08.119 effects on human settlements and uh whatever is lying on 0:20:08.160 --> 0:20:10.600 the surface, which will get into more later, but it 0:20:10.680 --> 0:20:15.399 can also have strange, otherworldly effects simply on the geological 0:20:15.800 --> 0:20:19.800 and hydrological landscape itself. And I wanted to share one 0:20:19.840 --> 0:20:22.639 amazing example that I came across while I was reading 0:20:22.680 --> 0:20:25.840 up for this episode. This was the opening paragraph in 0:20:25.960 --> 0:20:29.640 an article for The New Yorker by David Owen. There 0:20:29.680 --> 0:20:33.240 was an article about sinkholes called Notes from Underground, and this, 0:20:33.240 --> 0:20:35.639 this paragraph really gave me chills when I got to 0:20:35.680 --> 0:20:37.680 the end of it. So, uh, if you don't mind, 0:20:37.760 --> 0:20:39.920 I just want to share this here. In the fall 0:20:40.000 --> 0:20:44.320 of nine, much of Lake Jackson, a four thousand acre 0:20:44.480 --> 0:20:47.960 natural body of water just north of Tallahassee and a 0:20:48.000 --> 0:20:52.800 popular site for fishing, water skiing, and recreational boating, disappeared 0:20:52.840 --> 0:20:57.720 down a hole like a bathtub, emptying into a drain trophy. 0:20:57.760 --> 0:21:02.080 Bass became stranded in rapidly shrinking eddies, enabling children to 0:21:02.160 --> 0:21:05.480 catch them with their hands and toss them into picnic coolers, 0:21:05.960 --> 0:21:08.919 and many of the lake's other fish, turtles, snakes, and 0:21:08.960 --> 0:21:13.560 alligators vanished into the earth at various times. During the 0:21:13.600 --> 0:21:18.480 next few years, the lake partially refilled, redrained, and refilled again. 0:21:19.359 --> 0:21:23.000 Jonathan Arthur, who is Florida's state geologist and the director 0:21:23.040 --> 0:21:26.240 of the Florida Geological Survey, was among several people who, 0:21:26.320 --> 0:21:30.240 during a dry period descended a ladder into the main opening, 0:21:30.480 --> 0:21:33.880 which was about eight feet in diameter. Quote, you could 0:21:33.880 --> 0:21:37.040 climb down twelve feet or so and then walk under 0:21:37.080 --> 0:21:40.160 the lake bed. He told me recently, I hadn't gone 0:21:40.240 --> 0:21:43.080 very far before my red flags went up, and I 0:21:43.119 --> 0:21:48.520 was like, maybe I won't go any farther. So that image, 0:21:48.600 --> 0:21:51.160 it combined with the way it's phrase that that really 0:21:51.160 --> 0:21:54.480 gave me goose bumps. Yeah. Yeah, the idea of yeah, 0:21:54.480 --> 0:21:56.280 I mean, it really feels like like a place you 0:21:56.320 --> 0:21:59.240 do not belong. The you know, the the cave beneath 0:21:59.240 --> 0:22:02.200 the lake that is uh yeah, that that that could 0:22:02.200 --> 0:22:04.840 potentially fill back up at any moment. Well. And also, 0:22:04.880 --> 0:22:07.399 I mean, I think anybody who, especially people who do 0:22:07.440 --> 0:22:12.280 like scuba diving and stuff, are made uniquely aware of 0:22:12.359 --> 0:22:17.320 the dangers of of being in places that combine water 0:22:17.480 --> 0:22:22.040 and overhead rock. Like Yes, absolutely that that can be 0:22:22.119 --> 0:22:27.480 an especially dangerous and and suddenly dangerous surprisingly dangerous combination 0:22:27.560 --> 0:22:30.040