Speaker 1: Hey, welcome to Stuff to Blow Your Mind. My name
Speaker 1: is Robert Lamb. It's Saturday. We're venturing back into the vault.
Speaker 1: This is going to be part one of our let's see,
Speaker 1: this was a four part series that we did on mud.
Speaker 1: You know, if you listened recently, you may have heard
Speaker 1: our series on dust. Well, similar we're talking about mud
Speaker 1: and there so we get into all sorts of different
Speaker 1: angles here in these four episodes. So it might seem
Speaker 1: mundane on the surface, but once you sync into it,
Speaker 1: I think you'll find it as fascinating as we did.
Speaker 1: This episode originally published on seven six, twenty twenty three.
Speaker 1: Here we go.
Speaker 2: Welcome to Stuff to Blow Your Mind, a production of iHeartRadio.
Speaker 1: Hey, welcome to Stuff to Blow your Mind. My name
Speaker 1: is Robert.
Speaker 3: Lamb, and I am Joe McCormack. And today we are
Speaker 3: going to be starting a series of episodes on mud,
Speaker 3: a topic that I promise is more interesting than you
Speaker 3: might think. And to get us started today, I wanted
Speaker 3: to talk about a section from an English epic poem
Speaker 3: that endorses the belief that mud just happens to give
Speaker 3: rise to monsters or monstrous creatures of various shapes. So
Speaker 3: the poem in question is a late sixteenth century epic
Speaker 3: poem by the English poet Edmund Spencer called The Fairy Queen.
Speaker 3: I took a class in college where we read this,
Speaker 3: or we read part of it. To be honest, there's
Speaker 3: a lot that I forget about it. But it's very
Speaker 3: much your classic epic poem, with heroic knights, the Red
Speaker 3: Cross Knight, and damsels in distress and witches and ogres
Speaker 3: and all that. And there's an interesting passage toward the
Speaker 3: beginning of The Fairy Queen. I think it's in book one,
Speaker 3: Canto one, where Spencer implies a belief about the way
Speaker 3: nature works, a belief that the mud, specifically the mud
Speaker 3: of the Nie River, spawns monsters, and Spencer writes quote
Speaker 3: as when old father Nilus gins to swell with timely
Speaker 3: pride above the Egyptian veil, his fatty waves do fertile
Speaker 3: slime out well and overflow each plane and lowly dale.
Speaker 3: But when his later spring gins to a veil, huge
Speaker 3: heaps of mud he leaves wherein their breed ten thousand
Speaker 3: kinds of creatures, partly male and partly female, of his
Speaker 3: fruitful seed, such ugly, monstrous shapes elsewhere may no man read.
Speaker 3: And then Spencer later cites the same belief again as
Speaker 3: a kind of illustration of a general principle. He writes,
Speaker 3: but reason teacheth that the fruitful seeds of all things
Speaker 3: living through impression of the sunbeams in moist complexion, do
Speaker 3: life conceive and quickened are by kind. So after Nilus inundation,
Speaker 3: infinite shapes of creatures men do find inform in the
Speaker 3: mud on which the sun hath shined. So I think
Speaker 3: he seems to be saying like mud plus sunshine equals monsters,
Speaker 3: or at least creatures of infinite shapes, which in some
Speaker 3: passages he seems to think might be monsters. Maybe among
Speaker 3: infinite variation there will necessarily be some monsters. And I'm
Speaker 3: interested in this belief because, on one hand, it just
Speaker 3: sort of reflects some ancient beliefs that are carried over
Speaker 3: into the Medieval and Renaissance period about where life comes from,
Speaker 3: ideas now obsolete theories like spontaneous generation that you know
Speaker 3: that life forms, which is sort of like arise in
Speaker 3: the mud or in like a wet bag of flower
Speaker 3: or something. But I also like it because it imagines
Speaker 3: the mud in the floodplain of a great river like
Speaker 3: the Nile as a source of both like sort of
Speaker 3: mystery and danger but also great possibility. And this does
Speaker 3: correspond to the kind of the double nature of mud
Speaker 3: and of a river like the Nile. So you think
Speaker 3: of the Nile River delta, it is a place of
Speaker 3: incredibly fertile soil that you know, that supplies food and
Speaker 3: crops for all of the areas around. But also if
Speaker 3: you know, you get stuck in the mud, that's a
Speaker 3: place you don't want to be. And it is a
Speaker 3: place where you will find lots of life that is
Speaker 3: maybe life that's kind of strange to you. You don't
Speaker 3: usually go wading into the mud, and if you do,
Speaker 3: I don't know, all kinds of weird little mollusks and
Speaker 3: creepy crawleys and critters are in there, and you don't
Speaker 3: know what you might find.
Speaker 1: Yeah, yeah, this is really interesting. We should also note,
Speaker 1: you know, it does accurately, though monstrously refer to the
Speaker 1: the the inundation of the Nile, which is a topic
Speaker 1: we did an entire episode at least one episode on
Speaker 1: in the past. I mean, the Nile overflows its banks
Speaker 1: and it brings life and has this this very prominent
Speaker 1: role in especially in ancient Egyptian belief and mythology. But yeah,
Speaker 1: this dual nature of mud is quite interesting and something
Speaker 1: that that we're going to be talking about quite a
Speaker 1: bit in these episodes because it at once it is
Speaker 1: like you want to build something, well, you're gonna need
Speaker 1: something like mud or mud itself. But of course it's
Speaker 1: also the place where you know, many a famous military
Speaker 1: campaign has perished in the mud, so you know, it's
Speaker 1: the thing from which monsters emerge, but it's all you know,
Speaker 1: it's the thing where you might find a pig, but
Speaker 1: you also will find gleaming butterflies, you know, cascading and
Speaker 1: swirling around something some stinking pile of mud. So yeah,
Speaker 1: it does seem to have this dual nature, at least
Speaker 1: from the human vantage point.
Speaker 3: So our goal is after we're done with this series,
Speaker 3: you will never think about mud the same way. And
Speaker 3: when it gets stuck to your shoes, you might still
Speaker 3: be mad, but there will also be a part of
Speaker 3: you that that's kind of reflective and stops to be
Speaker 3: amazed at what it is. Your dog has just gotten
Speaker 3: all over your couch.
Speaker 1: Yeah, and if you're like me too. Just even thinking
Speaker 1: about this topic, it means that you've had the Primus
Speaker 1: song my Name is Mud just flipped on in your brain.
Speaker 1: I haven't even listened to it to encourage or extinguish it,
Speaker 1: but it's just there as I read these various papers
Speaker 1: about mud or mummama mud, Right, I guess that's the way.
Speaker 3: It's said, and so I'll take your word for it.
Speaker 1: It's a solid jam. It's got some colossal bass and
Speaker 1: drums on there.
Speaker 3: Oh yeah, that's primus. They rattle the furniture. But anyway,
Speaker 3: we should go straight to the question what is mud?
Speaker 3: What is it made of? In general, mud seems to
Speaker 3: have a kind of loose definition. We all know it
Speaker 3: when we see it, but there may not be strict
Speaker 3: scientific criteria about what counts, except maybe in certain contexts,
Speaker 3: like when you're talking when you get to some things
Speaker 3: we'll get to in a minute about like particle size
Speaker 3: and what solidifies into certain kinds of rock. But just generally,
Speaker 3: I mean, mud is some sort of wet soil, but
Speaker 3: exactly how wet, Exactly what are the properties of the
Speaker 3: soil for it to count as mud versus just being
Speaker 3: kind of like I don't know, damp, gross stuff that
Speaker 3: might be in the eye of the beholder, of the
Speaker 3: beat or of the bee treader.
Speaker 1: Yeah, I would. I would. I think that sometimes we
Speaker 1: know it when we see it, but we definitely know
Speaker 1: it when we step on it or step in it.
Speaker 1: I guess that's the thing, right. If I'm able to
Speaker 1: step on it, well maybe it's not fully mud. But
Speaker 1: if I'm in it, well I am in mud now.
Speaker 1: But I think the other Yeah. The other interesting thing
Speaker 1: about mud is a lot of it does depend on
Speaker 1: where you're coming from, you know, like if you were
Speaker 1: a domesticated hog, well, mud is just simply good. There's
Speaker 1: not much else to say about that, though. We will
Speaker 1: get into how various animals use mud later on in
Speaker 1: a subsequent episode, but just from the human perspective, it's
Speaker 1: kind of interesting. One of the books I was looking at,
Speaker 1: and we'll come back to later when we get more
Speaker 1: in depth on this is a book titled Mud, a
Speaker 1: Military History by ce Wood, which, if you haven't thought
Speaker 1: about it much before, or you haven't you're not like
Speaker 1: a military history enthusiast, you might not realize that, oh yeah, mud.
Speaker 1: Mud is the sort of thing that you could write
Speaker 1: an entire book about just from the perspective of war
Speaker 1: and military operations. But that's what this book is.
Speaker 3: When I think of mud and armed conflict. Obviously, you know,
Speaker 3: terrain and especially mud have played a big role in
Speaker 3: worse throughout history, but I think especially of Eastern Europe
Speaker 3: for some reason.
Speaker 1: Yeah, big big war machines, big tanks stuck in the mud,
Speaker 1: or as as Wood mentions a time or two, the
Speaker 1: idea of one of these colossal tanks just going down
Speaker 1: a muddy hill, as if it were like a sled
Speaker 1: on a snowfield or something, you know, just out of control.
Speaker 1: Things like that. Occurring mud changes what you can and
Speaker 1: can't do in many instances with any with things ranging
Speaker 1: from infantry to horses to modern industrial war machines. But
Speaker 1: like I said, we'll get back to that more in
Speaker 1: the future. But I thought it was interesting that Wood
Speaker 1: opens just dealing with his basic ambiguity concerning mud and
Speaker 1: writes that, Okay, if we're going to be just very
Speaker 1: broad about it, it comes down to soil consisting of
Speaker 1: mineral and organic matter combined with moisture at such a
Speaker 1: level relative to the exact compositions of the soil to
Speaker 1: make it unstable and likely to move and flow underfoot
Speaker 1: or underhoof or under wheeler track, etc. Wood points out
Speaker 1: that while many military minds have considered mud and other
Speaker 1: soil issues beneath their strategic consideration, but they have always
Speaker 1: done so at their peril, because mud, as we'll get
Speaker 1: into later, does make a difference in war has come
Speaker 1: to very famously define certain war zones. He points out
Speaker 1: that not everyone has certainly ignored this fact, and in
Speaker 1: nineteen forty four, the US Army conducted a series of
Speaker 1: tests regarding mud. They're like, all right, let's get down
Speaker 1: to it. Let's classify some mud. Because we have only
Speaker 1: so many resources for our rubber tires, so we needed
Speaker 1: to decide where we need to send them, where we
Speaker 1: need to prioritize our best tires. And so this is
Speaker 1: a situation where we're dealing with sort of a narrowed
Speaker 1: perspective concerning mud. This is just mud concerning like, let
Speaker 1: me roll some vehicles across it. But they classified mud
Speaker 1: into two types and two subtypes. Okay, Type one bottomless mud. Now,
Speaker 1: this just means that the MUD's consistency cannot support a
Speaker 1: vehicle with tires that have twenty pounds of pressure, or
Speaker 1: that the underlying hard layer of earth beneath the mud
Speaker 1: beneath the layer of mud is too far beneath the
Speaker 1: vehicle's ground clearance.
Speaker 3: Okay, so this sounds like dangerous mud.
Speaker 1: Yeah, this is the mud that your vehicle is going
Speaker 1: to get stuck in and or sink into. And then
Speaker 1: type two is just all other types of mud. But
Speaker 1: this does feature two subtypes, Type A and type B.
Speaker 1: Type A has a quote unquote cleaning quality, meaning that
Speaker 1: it contains enough moisture to work as a liquid. So
Speaker 1: like this, like type A mud gets on your vehicle
Speaker 1: and you know, it kind of flows off. I mean
Speaker 1: it's I don't think cleaning quality means that your tank
Speaker 1: or your truck is going to be clean after the
Speaker 1: mud has a rent stock a little bit. Yeah, it
Speaker 1: flows away, but it's it's this a cleaning quality. Type
Speaker 1: B is adhesive or sticky. So this is the the
Speaker 1: mudd in type of mud. This is the type of
Speaker 1: mud that the the big pickup pickup truck driver seeks
Speaker 1: out when they go out into the wilderness to make
Speaker 1: sure that they return to city life with a vehicle
Speaker 1: completely encased in mud. Okay, So more on the military
Speaker 1: angle later on. So this is not necessarily a helpful
Speaker 1: way to understand mud as a whole, but rather to
Speaker 1: a way to underline that the meaning of mud kind
Speaker 1: of depends on what you're trying to do in it
Speaker 1: or through it, and mud therefore could be your threat
Speaker 1: or your treasure, depending on what you're looking to get
Speaker 1: out of the situation.
Speaker 3: Very true. Now, I found an article that I thought
Speaker 3: was helpful. It was from two thousand and three in
Speaker 3: the Washington Post, and being in the Washington Post, I
Speaker 3: would say a little overly concerned with these specific types
Speaker 3: of mud found around the Washington d C. Metro area.
Speaker 3: But I'm mostly ignoring those parts because it does helpfully
Speaker 3: consult a bunch of soil scientists on the definitions and
Speaker 3: categories of mud. So it was called a World Gone
Speaker 3: Mud by Joel Aikenbach from June fifteenth, two thousand and three.
Speaker 3: First of all, it consults a researcher named Trish Steinhilbert
Speaker 3: from the University of Maryland Agricultural Nutrient Management Program, who says,
Speaker 3: you know, we would just call it wet soil. So
Speaker 3: that's one perspective. It's just wet soil, But then the
Speaker 3: article cites another soil physicist, or sorry, another soil researcher,
Speaker 3: this time a soil physicist also from the University of
Speaker 3: Maryland named Robert Hill, who says mud should be differentiated
Speaker 3: from merely wet soil because it has different physical properties.
Speaker 3: As commonly understood, like we've been saying, mud is sticky
Speaker 3: in a way that not all wet soils are, and
Speaker 3: this stickiness is due to the presence of a higher
Speaker 3: proportion of smaller particles, especially clay particles. So, as you
Speaker 3: probably know, soil is made from a mixture of different materials.
Speaker 3: Some of those materials are organic, so they can be
Speaker 3: you know, decaying organic matter or decaying bits of plants
Speaker 3: and animals and all that, but also inorganic matter, and
Speaker 3: we're going to focus on the inorganic matter for the moment.
Speaker 3: The inorganic solid particles that make up soil are generally
Speaker 3: produced by the erosion and breakdown of larger rocks over time,
Speaker 3: which can happen due to physical forces like wind, rain,
Speaker 3: and ice, or it can be due to break down
Speaker 3: by organisms like fungi and bacteria. And we all know
Speaker 3: soil can have different consistencies you stick your hands into
Speaker 3: the soil in one place, it just feels different than
Speaker 3: the soil in another place. One of the major factors
Speaker 3: that you can use to sort soil into different categories
Speaker 3: is the average particle size in the soil. So if
Speaker 3: particles are bigger than two millimeters, that's gravel. You know
Speaker 3: that's going to pop under your car tire. Particles of
Speaker 3: less than two millimeters in diameter but more than zero
Speaker 3: point zero five millimeters are sand. Then smaller than sand,
Speaker 3: you've got silt, which is made of particles less than
Speaker 3: zero point zero five million meters in diameter. And then
Speaker 3: at the very bottom, the finest grain soil is clay,
Speaker 3: which means particles smaller than zero point zero zero two
Speaker 3: millimeters in diameter. Now, apart from particle size, there are
Speaker 3: also some at least common chemical properties you'll find at
Speaker 3: these different areas, like they tend to derive from different
Speaker 3: types of minerals, like clay typically features a standard mineral constituent,
Speaker 3: which is hydrous aluminum philosilicates. But for the moment, we
Speaker 3: can just think about these as particles of different sizes.
Speaker 3: So by one definition, any sufficiently wet soil made of
Speaker 3: any mixture of these particles could be mud. But if
Speaker 3: you're going with the definition of mud as sticky slop
Speaker 3: that kind of sucks to the bottom of your shoes
Speaker 3: and you might get stuck in it usually means it's
Speaker 3: made up of mostly silt and clay sized particles. Silt
Speaker 3: sized and clay sized particles, and things get especially sticky
Speaker 3: if it has a lot of clay.
Speaker 1: And again there's this fine line, Like I know, I
Speaker 1: instantly think back to some cave environments that I've been in,
Speaker 1: and mud at just the right consistency, it's like it's sticky,
Speaker 1: but you're not slipping in it. It's almost something you
Speaker 1: want to walk on. But that line is very thin
Speaker 1: between between that and like the treacherous mud that you
Speaker 1: will slip in. So it's fascinating when you start getting
Speaker 1: into the way this breaks down.
Speaker 3: Yeah, is the mud grippy like maybe rubber? Or will
Speaker 3: it fly out from under you like a banana peel?
Speaker 3: And that does, I think come down to something having
Speaker 3: to do with the water content as well as the
Speaker 3: particle size. So if mud is wet soil or sticky
Speaker 3: wet soil, we've explained the soil part. It tends to
Speaker 3: be the smaller particle sizes clay sized and silt sized
Speaker 3: particles that make mud. But there's also the wetness angle.
Speaker 3: How wet does soil have to be for it to
Speaker 3: be mud. Here we get to the concept of cohesive
Speaker 3: soil and what are called Aderberg limits. So cohesive soils
Speaker 3: are soils that tend to stick or clump together as
Speaker 3: opposed to crumbling. Cohesive soils tend to have again more
Speaker 3: clay sized particles. Smaller particles stick together better, and cohesive
Speaker 3: soils can be in three states, depending on how wet
Speaker 3: they are. These states are non plastic, plastic, and viscous.
Speaker 3: Non Plastic means hard, you know, difficult to mold or deform.
Speaker 3: This is usually when they're dry. Cohesive soils dry up
Speaker 3: kind of hard like bricks, and they form tough earth,
Speaker 3: so you can think about like hard clay ground, you
Speaker 3: know what that's like. When cohesive soils get wet, though,
Speaker 3: they can cross one of these Aderberg limits, that the
Speaker 3: plastic limit and become plastic, so this means they become
Speaker 3: soft or moldable, think about wet clay, and then beyond
Speaker 3: that limit there's another limit, another limit which is the
Speaker 3: liquid limit, and this is the viscous stage where there's
Speaker 3: sort of like a liquid goop. So you can add
Speaker 3: water to non plastic soil until it crosses the plastic limit,
Speaker 3: becomes soft and mouldable, you can add more water until
Speaker 3: it crosses the liquid limit. Where the liquid limit is
Speaker 3: explained in this Washington Post article as if you cut
Speaker 3: a groove in the mud, the mud will flow back
Speaker 3: in to fill it. That's the liquid limit, which actually
Speaker 3: has some analogies in the culinary world, like if you
Speaker 3: ever did the back of the spoon test for the
Speaker 3: thickness of a sauce in the kitchen. The French term
Speaker 3: for that is nape, where if you like wipe your
Speaker 3: the tip of your finger along the back of a
Speaker 3: spoon coated in the sauce, it should leave a trail
Speaker 3: rather than having the sauce flow back in to fill
Speaker 3: the gap. That's nape.
Speaker 1: One of the many culinary techniques in you just like
Speaker 1: jab your finger into things like.
Speaker 3: Yeah, stick, yeah, stick your finger in the food.
Speaker 1: Yeah, let the meat touch your face, and that will
Speaker 1: determine if it is the right temperature.
Speaker 3: But so the definition of the liquid limit is that
Speaker 3: it does not pass the back of the spoon test
Speaker 3: if you cut a groove in it, it will flow
Speaker 3: back in to fill the gap. So it sounds to
Speaker 3: me like the definitional sweet spot for mud is a
Speaker 3: wet cohesive soil. It's made primarily of silt or clay
Speaker 3: sized particles, especially if there's a lot of clay sized
Speaker 3: particles that is above the plastic limit and below the
Speaker 3: liquid limit. Somewhere in there, though, I was thinking that
Speaker 3: even sort of fully liquid glop we do sometimes call mud,
Speaker 3: don't we, But that's not usually the first kind of
Speaker 3: substance I think of.
Speaker 1: Right, right, Like, I come back to the example of
Speaker 1: mud pies. You know, I think a lot of us
Speaker 1: did this as a kid. If you're allowed to play
Speaker 1: in the mud, do you get some little like pie
Speaker 1: crust or little whatever, you know, cups and pans pour
Speaker 1: the mud up, slap the mud together, and then you
Speaker 1: set it in the sun too dry into mud cakes.
Speaker 1: But yeah, it's like if you're pouring it, if you're
Speaker 1: just complete all you know it is completely pouring it
Speaker 1: into the pan, that doesn't really feel like mud. That's
Speaker 1: just like mud water or something that's like on the
Speaker 1: way to mud. But not mud quite yet. The moisture
Speaker 1: still level is too high. And I guess in baking
Speaker 1: you have variations of that as well. Right like you said,
Speaker 1: the sauce is too runny, the batter is too runny,
Speaker 1: et cetera.
Speaker 3: Oh, I think the mudpie test is a good one.
Speaker 3: And you know what, that actually brings me to the
Speaker 3: next thing I want to talk about, which is this
Speaker 3: might be something you've never considered before. Was there a
Speaker 3: time on Earth when it would have been really difficult
Speaker 3: to make a mud pie? I would argue, based on
Speaker 3: some research I've been reading about that, Yes, if you
Speaker 3: go back before five hundred million years ago, go to
Speaker 3: the pre Cambrian period, and you walk around on Earth's
Speaker 3: continents trying to find a place to make a mud pie,
Speaker 3: you're gonna probably strike out. You're gonna be out of luck,
Speaker 3: because there was a time basically before there was mud
Speaker 3: on land on Earth, or before there was very much
Speaker 3: mud to be found on land. So here I want
Speaker 3: to go to an article I was reading in the
Speaker 3: journal Science in the year twenty eighteen by Woodward Fisher,
Speaker 3: who is a Caltech geobiologist. The article is called Early
Speaker 3: Plants and the Rise of mud, and this article is
Speaker 3: primarily summarizing and contextualizing a study that was published by
Speaker 3: a couple of different authors in the same issue of
Speaker 3: the journal Science in twenty eighteen. This article is very
Speaker 3: good in putting these findings in context. So Fisher mentions
Speaker 3: that you know, life on Earth has several times that
Speaker 3: we know about reshaped fundamental geophysical features and processes at
Speaker 3: the Earth's surface. There are ways in which you could
Speaker 3: say that life has fundamentally changed the planet itself, at
Speaker 3: least what's happening on the surface and in the atmosphere.
Speaker 3: So perhaps the first example that will likely come to
Speaker 3: your mind is the oxygenation of the oceans in the atmosphere.
Speaker 3: It was the evolution of photosynthesis in cyanobacteria and other
Speaker 3: life forms that triggered this shift. You know, we didn't
Speaker 3: always have an oxygen atmosphere. Another major geophysical change triggered
Speaker 3: by life that Fisher mentions is the evolution of mineral
Speaker 3: skeletons by life forms, again, particularly algae, and the presence
Speaker 3: of those skeletons change the way that ocean floors are formed,
Speaker 3: and then subsequently the kinds of rock lay that would
Speaker 3: form when they solidified. Over the eons. But this article
Speaker 3: is focused on another discovery of this sort, how the
Speaker 3: evolution of land based plants changed the Earth by affecting mud.
Speaker 3: So the citation for the study here is William J.
Speaker 3: McMahon and Neil S. Davies. The article is called evolution
Speaker 3: of alluvial mud rock forced by early land plants again
Speaker 3: Journal Science, twenty eighteen. So when soil made mostly out
Speaker 3: of clay or silt sized particles gets compacted in the
Speaker 3: ground and lithifies into rock, the resulting rock layer is
Speaker 3: called mud rock, and there are many kinds of mud rock.
Speaker 3: When geologists look for layers of mud rock from the past,
Speaker 3: they notice something interesting. There is extremely little mud rock
Speaker 3: from river bottoms and floodplains before a geologic period in
Speaker 3: the history of the Earth. So if you look in
Speaker 3: the pre Cambrian era or the early Paleozoic era, there's
Speaker 3: very little mud rock on the continents. And I'll do
Speaker 3: a little refresher on the basic geologic timeline of the
Speaker 3: early to mid Palaeozoic, So you've got the Cambrian period.
Speaker 3: This is roughly five hundred million years ago. Before the
Speaker 3: Cambrian period, most life on Earth is small soft and unicellular,
Speaker 3: and then the Cambrian period represents a sort of explosion
Speaker 3: of life, a massive proliferation in the diversity of life forms.
Speaker 3: Life Forms get bigger, more complex, with hard body parts
Speaker 3: that get fossilized. So think of the age of trilobytes
Speaker 3: and anomalicaras. That's a period of like forty or fifty
Speaker 3: million years, roughly five hundred million years ago. And then
Speaker 3: you've got after that the Ordovician period, which is about
Speaker 3: four hundred and eighty five to four hundred and forty
Speaker 3: four million years ago, more diversification of life forms, primarily
Speaker 3: in the ocean, arthropods, molluscs, so forth, and the appearance
Speaker 3: of the very first primitive land plants. Then you've got
Speaker 3: the Silurian period, which is like four forty four to
Speaker 3: four nineteen million years ago. Note that this is separated
Speaker 3: from the previous era by the Ordovisian Silurian extinction event.
Speaker 3: There's often an extinction event separating these periods. This period
Speaker 3: shows diversification in fish and other marine fauna, but it's
Speaker 3: also important because of sort of a terrestrial revolution, the
Speaker 3: terrestrialization of many branches of life. Suddenly a lot more
Speaker 3: is happening on land instead of just in the ocean.
Speaker 3: So you have the evolution of vascular plants and terrestrial fungi,
Speaker 3: and these lead to changes in land ecosystems, including the
Speaker 3: ones we're talking about now. Also, land based arthropods diversify,
Speaker 3: so you get the ancestors of animals like spiders and
Speaker 3: insects and so forth. After that, from like four nineteen
Speaker 3: to three hundred and fifty nine million years ago, you've
Speaker 3: got the Devonian Period, sometimes called the Age of Fishes.
Speaker 3: Obviously there's a lot of fish diversification here, the terrestrial
Speaker 3: revolution continues, and then later in the Devonian period, this
Speaker 3: is the first time that you have the continents covered
Speaker 3: in forests of plants of the kind of things we
Speaker 3: would recognize as trees. But coming back to how this
Speaker 3: geologic timeline relates to mud, So in the Precambrian in
Speaker 3: continuing into the early Paleozoic, there is very little river
Speaker 3: mud rock showing up in the geologic strata. Instead, lithified
Speaker 3: river beds seem to contain sand and gravel, and as
Speaker 3: the Paleozoic era progresses, there is a rise in the
Speaker 3: formation of mud rocks in river deposits, which seems to
Speaker 3: indicate a global change in how sediment gets pushed and
Speaker 3: pulled around by rivers, and this change is associated with
Speaker 3: the colonization of the continents by plant life. There's an
Speaker 3: interesting analogy which is Mars. Mars we believe once had
Speaker 3: flowing rivers, but presumably did not have plants. And it
Speaker 3: also appears that Mars has very little mud rock in
Speaker 3: its river deposits.
Speaker 1: Though we will come back to the topic of mud
Speaker 1: on Mars. Is there mud on Mars? You might ask,
Speaker 1: how we'll tune in to a future episode.
Speaker 3: Mars needs goloshes. Yeah. So the authors of this twenty
Speaker 3: eighteen paper, McMahon and Davies, they wanted to zero in
Speaker 3: on this change in mud rock deposition in Earth's history
Speaker 3: and understand it better. So they were looking at samples
Speaker 3: of rock strata from ancient river beds before and after
Speaker 3: the land plant revolution all throughout this time period to
Speaker 3: measure the relative amount of mud rock corresponding to the
Speaker 3: different eras, and after crunching the numbers, they concluded that
Speaker 3: the fractional portion of mud rock the geologic strata rose
Speaker 3: by more than an order of magnitude an order of
Speaker 3: magnitude is ten times, so more than ten times increase
Speaker 3: in the proportion of mud rock I think in their
Speaker 3: abstract they actually say it was one point four orders
Speaker 3: of magnitude. This is after land plants evolved, so when
Speaker 3: plants colonized land, it made a huge profound change in
Speaker 3: what was happening with sediment, meaning mud, primarily in river
Speaker 3: bottoms and floodplains. The increase in these rocks made out
Speaker 3: of mud began in the late Ordovisian and continuing to
Speaker 3: the beginning of the Silurian, and this does implicate early
Speaker 3: land plants, but it's also interestingly it's earlier than the
Speaker 3: researchers expected to find it, perhaps in part because or
Speaker 3: perhaps their expectations for finding increases in mud rock in
Speaker 3: this period were low, because the earliest land plants here
Speaker 3: were they're really, I think mostly like bryophytes. They're these
Speaker 3: kind of little patchy green things that would resemble mosses
Speaker 3: or liver warts, so you know, we're not talking about
Speaker 3: jungles yet. Vascular plants meaning plants that have tissues that
Speaker 3: allow them to grow tall because they can conduct water
Speaker 3: and mineral nutrients up their stems. They start to appear
Speaker 3: in the late Silurian and early Devonian, but the earliest
Speaker 3: of these plants would only be a few centimeters off
Speaker 3: the ground and could only survive in wet environments. It
Speaker 3: isn't until again the Late Devonian, maybe like three hundred
Speaker 3: and seventy million years ago or so, that you first
Speaker 3: get what we would think of as forests, landscapes thick
Speaker 3: with relatively tall, vascular plants. But according to this research,
Speaker 3: even these earlier phases of puny, little baby plants, little mossy,
Speaker 3: liver warty type things, made a pretty big difference in
Speaker 3: how mud was distributed on the earth. But when you
Speaker 3: get to the later div and then into the Carboniferous period,
Speaker 3: there is an even bigger shift. This is the phase
Speaker 3: where there would again be forests of like impressive woody
Speaker 3: trees with deep root structures, like the things we think
Speaker 3: of as forests today. Rob I'm including an illustrated graph
Speaker 3: with a timeline from this article for you to look at.
Speaker 3: You can see that the amount of mud rock starts
Speaker 3: to go up during the period of like the bryophytes,
Speaker 3: these little primitive land plants, and then it really reaches
Speaker 3: its peak in the era of vascular plants, and especially
Speaker 3: like woody trees and later vascular plants, it seems like
Speaker 3: those deep root systems played a big role in that
Speaker 3: later period. However, I think, to come back on this,
Speaker 3: it's really worth noting that the Earth was not without
Speaker 3: mud as a planet before the proliferation of land plants.
Speaker 3: It looks like land plants played a huge role in
Speaker 3: forming these continental mud rock But there was mud before
Speaker 3: the plants. A sediment of clay and silt sized particles
Speaker 3: has been produced by erosion of surface rocks for billions
Speaker 3: of years. So what appears to have changed with the
Speaker 3: evolution of land plants is that mud started to stay
Speaker 3: on land, to stay on the continents, as opposed to
Speaker 3: just being blown or washed out to sea and settling
Speaker 3: on the seafloor. So the question is why did the
Speaker 3: evolution of plants lead to the retention of mud on land?
Speaker 3: And the article mentions a few ideas. One thing, first
Speaker 3: of all is that the authors say that the presence
Speaker 3: of land plants may actually have helped produce more mud
Speaker 3: particles to begin with, lead to erosion processes that would
Speaker 3: produce more mud. Now, how would plants help produce more
Speaker 3: mud well. For one thing, I was reading this in
Speaker 3: another article that plants with strong root structures actually break
Speaker 3: and crumble large pieces of rock. Those roots can break
Speaker 3: up the rocks physically, crack and break them, but can
Speaker 3: also lead to changes in the chemical composition of soil
Speaker 3: that break down rocks even further into smaller pieces. But again,
Speaker 3: we don't need plants for mud to exist. There's always
Speaker 3: been these mud sized the soil particles. So what other
Speaker 3: changes did plants introduce? Fissure rites quote. It is therefore
Speaker 3: likely that early plants affected the mechanics of flood plain construction.
Speaker 3: For example, the presence of plants on the landscape decreases
Speaker 3: erosion rates, and thus it was long hypothesized that erosion,
Speaker 3: in particular by wind, removed sediment from pre vegetated landscapes.
Speaker 3: Even if mud was deposited on pre vegetated floodplains, its
Speaker 3: removal by erosion might have been efficient. So before there
Speaker 3: were plants on land, it was just too easy for
Speaker 3: small particles of soil to get washed out to the
Speaker 3: sea one way or another. They could get by wind,
Speaker 3: they could get carried along by the flow of water
Speaker 3: after storms and rain, and they would all just end
Speaker 3: up on the floor of the ocean. So it seems
Speaker 3: like plants and their root structures helped prevent small soil
Speaker 3: particles that form mud from escaping into the sea. But
Speaker 3: it doesn't stop there. Plants and the mud that the
Speaker 3: plants retained changed how rivers form, Fisher writes quote. In
Speaker 3: addition to an inhibiting erosion, plants also interact with river
Speaker 3: flows and promote the deposition of fine grained sediment. This
Speaker 3: can help armor river banks and slow their lateral migration.
Speaker 3: Such process might also aid in preserving muddy floodplain deposits,
Speaker 3: so plants might sort of help stabilize the structure of
Speaker 3: rivers and keep the banks from drifting all over the
Speaker 3: place and changing too rapidly, especially during floods, which helps
Speaker 3: protect the mud that gathers in floodplains and keeps it there.
Speaker 1: Fascinating. Fascinating that the plant's kind of corralling the mud
Speaker 1: in many cases. And I think if you've ever been
Speaker 1: in a like especially I'm thinking of like estuary type
Speaker 1: environments that I've visited, Like you see these elaborate root systems,
Speaker 1: You see the mud and the sediment. So that's what
Speaker 1: I'm picturing during all of this.
Speaker 3: Oh yeah, yeah, yeah. And so actually, to help us
Speaker 3: better picture it, I found another great article that's on
Speaker 3: the same subject, that's on this type of research, but
Speaker 3: it includes a lot more context and imagery to help
Speaker 3: us understand it. So this other article was called the
Speaker 3: Origin of Mud from a magazine called Knowable, written by
Speaker 3: a writer named Laura Poppic, published in August twenty twenty,
Speaker 3: and I thought this was interesting. This article starts with
Speaker 3: this anecdote about one of the two authors of that
Speaker 3: twenty eighteen study, the geologist Neil Davies. It starts with
Speaker 3: this anecdote about him picking through a large fossil formation
Speaker 3: from about four hundred and sixty million years ago in
Speaker 3: Bolivia containing just tons of smothered fish fish that all
Speaker 3: seemed to die at the same time. And apparently this
Speaker 3: is not uncommon for marine fossil formations from this period.
Speaker 3: You'd have large numbers of fossil fish living near an
Speaker 3: ancient shoreline that appear to have all died around the
Speaker 3: same time by being choked by mud. So the explanation
Speaker 3: for this is probably that there's all this muddy sediment
Speaker 3: that is suddenly washed into the water into the ocean
Speaker 3: along the shore, possibly by a storm, and then the
Speaker 3: fish underwent death by mud. So this was four hundred
Speaker 3: and sixty million years ago before the proliferation of land
Speaker 3: plants Poppic writes quote magnified this effect globally, and the
Speaker 3: impacts would have been substantial, not just on coastal life,
Speaker 3: but on the landscape of the entire planet. Before plants,
Speaker 3: rivers would have stripped continents of silt and clay key
Speaker 3: constituents of mud, and sent these sediments to the seafloor.
Speaker 3: This would have left continents full of barren rock and
Speaker 3: seas with smothered fish.
Speaker 1: So primordial muddy oceans.
Speaker 3: Yes, especially at least around like where the rivers would
Speaker 3: drain into them, and landscapes with very little mud at all,
Speaker 3: you know, I mean, you can just let your dog
Speaker 3: run all over it and then come inside the house.
Speaker 3: There's no problem.
Speaker 1: Yeah. I keep wondering if a wellsy and time traveler
Speaker 1: would have to bring his Victorian galoshes in visiting this
Speaker 1: time period.
Speaker 3: But of course plants change all of this. Vegetation, especially
Speaker 3: along river banks, gave mud sized particles something to cling to,
Speaker 3: and so the mud stayed on land rather than getting
Speaker 3: washed or blown out to sea. And in the words
Speaker 3: of Neil Davies, this retention of mud on land quote
Speaker 3: fundamentally changed the way the world operates.
Speaker 1: Wow.
Speaker 3: And so there are some examples of how this mud
Speaker 3: revolution changed the continents, changed the world. Essentially, one thing
Speaker 3: is that the geological record reveals that before the evolution
Speaker 3: of plants, earth rivers probably would have looked more like
Speaker 3: the comparison that Poppuic uses is the rivers found around
Speaker 3: the Gravelly Coast of Alaska today, And she describes these
Speaker 3: I'm trying to say, so like, imagine if you've ever
Speaker 3: seen the kinds of branching, braided channels you see as
Speaker 3: a stream flows into the ocean across a sandy beach.
Speaker 3: So not mud, but you've seen like a stream flowing
Speaker 3: over a sandy beach.
Speaker 1: Yeah.
Speaker 3: Yeah. What you'll usually notice is there is not a
Speaker 3: very strong, unified channel. Instead, there's just lots of little
Speaker 3: threads of channels crisscrossing and always changing. This is referred
Speaker 3: to in several sos as I looked at as a
Speaker 3: braided structure of alluvial flow. The introduction of plants seems
Speaker 3: to have changed this by holding mud in place, and
Speaker 3: the mud being sticky would solidify the form of river banks,
Speaker 3: and this led to stable single channel rivers with fixed
Speaker 3: banks and boundaries, rather than these little shrubs of different
Speaker 3: rivulets changing all the time, so you end up with
Speaker 3: the curving, defined s shaped rivers that we see today.
Speaker 3: These rivers are made possible by the presence of mud,
Speaker 3: which is held on land by plants. Now, these changes
Speaker 3: in rivers had all kinds of interesting biological consequences. For example,
Speaker 3: the bins in a river can alter things like the
Speaker 3: temperature and chemistry and the water compared to a straight
Speaker 3: flowing river, which can create different micro environments along the
Speaker 3: river's length, so that gives all kinds of different little
Speaker 3: tiny eco systems and habitats that organisms would have to
Speaker 3: adapt to. But the presence of mud itself is also
Speaker 3: biologically relevant because mud is a habitat, so it takes
Speaker 3: special skills and evolutionary adaptations to live in mud and
Speaker 3: move around and navigate your way through it. For example,
Speaker 3: it takes different types of adaptations for movement for a
Speaker 3: small animal to get through mud than it does to
Speaker 3: get through sand or some other type of surface. And
Speaker 3: Poppy's article consults a geologist at the University of Oxford
Speaker 3: named Anthony Shalito on this subject. I thought this was
Speaker 3: so interesting, so Shaldo says, here, I'm quoting from popic quote.
Speaker 3: To get through mud, and animals such as a worm,
Speaker 3: creates cracks to shuffle through by contracting its body, extending it,
Speaker 3: squeezing water out of the way, and moving forward. This
Speaker 3: is mechanically different from traveling through sand, which requires an
Speaker 3: animal to excavate material out of the way. Chiledo says,
Speaker 3: so early land worms and insects would have had to
Speaker 3: evolve body parts equipped to deal with muckier movements, but
Speaker 3: then in turn the animals that adapt to those muddy
Speaker 3: environments change them because Poppic then sites a paleobiologist from
Speaker 3: Yale named Lydia Tehran who says that you know, like
Speaker 3: these animals living in the muddy soil around river banks,
Speaker 3: they dig in the mud, they excavate the mud, and
Speaker 3: this for one thing, it affects the chemistry of the mud,
Speaker 3: but it also sort of like breaks and loosens it up,
Speaker 3: which allows the mud to further disperse throughout the rivers
Speaker 3: and then also across flood plains, so you know, the
Speaker 3: valleys where rivers form between the higher areas of the land.
Speaker 3: So because you get these single channel s shaped rivers
Speaker 3: with more defined banks, you get these downstream processes that
Speaker 3: lead to the build up of muddy flood plains around them,
Speaker 3: which don't form as easy along the kind of rivers
Speaker 3: you see forming in sand or gravel.
Speaker 1: This is fascinating. I'm looking forward to getting back to
Speaker 1: some of this in our episode that's going to deal
Speaker 1: more with the specifics of some of the animals in
Speaker 1: the world today that make their home on the mud.
Speaker 3: Oh yeah, absolutely. But I love this story because it's
Speaker 3: just one of these amazing examples of how much, you know,
Speaker 3: sometimes we don't stop to appreciate the inner play between
Speaker 3: like earth and water and life, and the way that
Speaker 3: they all are constantly changing each other. That there's this
Speaker 3: like massive, you know, process like the mud revolution caused
Speaker 3: by the evolution of plants on land further gives rise
Speaker 3: to all of these these changes in land based life,
Speaker 3: which helps give give rise to more changes in like
Speaker 3: how mud accumulates and how sediment is distributed in floodplains
Speaker 3: and so forth. So I guess by way of research,
Speaker 3: we have once again and arrived at cliche. But sometimes
Speaker 3: that's how it is. I mean, it's the life and
Speaker 3: the inorganic systems that support life, the surface of the earth.
Speaker 3: It's a web of interactions.
Speaker 1: Yeah, And I think it is easy to sort of
Speaker 1: fall back on just sort of the school textbook mental
Speaker 1: image of fish flops onto a beach, fish flops onto
Speaker 1: some rocks, and now life on earth has begun, you know,
Speaker 1: like sort of not considering mud is this vital realm
Speaker 1: of evolution and transference.
Speaker 3: And human culture and technology, Because this is another thing
Speaker 3: that Poppic gets into in her article, like she quotes
Speaker 3: Woodward Fisher talking about how there are still things that
Speaker 3: we don't fully understand about mud and the way that
Speaker 3: riverbanks work and stuff, and this research could help contribute
Speaker 3: to that, for example, by giving us better ideas of
Speaker 3: how to do river engineering projects like dam construction. You know,
Speaker 3: if you have a better idea of the way that
Speaker 3: vegetation controls the flow of rivers and how the banks
Speaker 3: of the rivers change and respond to flood conditions, you
Speaker 3: could better anticipate and prevent, for example, river engineering failures.
Speaker 3: The example given in the article here is like flooding
Speaker 3: along the Mississippi River. But you know, this is of
Speaker 3: concern to societies all around the world.
Speaker 1: All of this reminds me of that great quote from T. S.
Speaker 1: Eliot from four Quartets quote. I do not know much
Speaker 1: about gods, but I think that the river is a
Speaker 1: strong brown god, sullen, untamed and intractable.
Speaker 3: Well, that's beautiful. And to know that that god may
Speaker 3: have been formed out of many other lesser gods over
Speaker 3: time by the accumulation of mud by plants. Oh, this
Speaker 3: is just a random thing I remembered, but I wanted
Speaker 3: to throw it in quickly. Another interesting thing mentioned in
Speaker 3: that popic article is the idea that once forests are
Speaker 3: formed on land, they can also help contribute to the
Speaker 3: accumulation of mud on the continents because they act as
Speaker 3: a sort of filter for dust and sediment that is
Speaker 3: blown by the wind. So the wind, you know, you
Speaker 3: can imagine it picking up fine grain particles of soil, clay,
Speaker 3: and silt, blowing them around when they're dry, and normally
Speaker 3: they just get blown out to sea. But if there
Speaker 3: are forests, they get stopped by the forests, they get
Speaker 3: stuck in the sort of the sieve of the trees
Speaker 3: they fall to the earth, and then they can accumulate
Speaker 3: and become mud on the forest floor, flow down into
Speaker 3: a river over time with the wash of the rains
Speaker 3: and so forth, and then become new muddy banks.
Speaker 1: It's amazing. Yeah, it's so easy to take mud for granted, because,
Speaker 1: like I say, if you're just coming at it from
Speaker 1: the perspective of someone who wants to go on a
Speaker 1: walk in the woods, and then mud is what happens
Speaker 1: when when something has failed or or conditions are not optimal.
Speaker 1: But this, this look at the MUD's roll in the
Speaker 1: emergence of life and the sort of the construction of
Speaker 1: the world as we know it, Yeah, really really casts
Speaker 1: it in.
Speaker 3: A different But we're by no means done with this topic.
Speaker 3: I think we should wrap it up for today. But
Speaker 3: when we come back, we will be talking about mud
Speaker 3: and warfare, Mud in human civilization, Mud on Mars, mud
Speaker 3: and animal behavior and more mud, monsters. There's all kinds
Speaker 3: of stuff. Yeah.
Speaker 1: Yeah, So this is one of those where we definitely
Speaker 1: don't know how many episodes it'll be, so we can't
Speaker 1: give you a heads up that this is going to
Speaker 1: be two episodes, three episodes, We're just going to have
Speaker 1: to listen to the mud and follow the mud and
Speaker 1: let it take us. Like someone's stepping in it on
Speaker 1: a muddy path. We just got to let it see
Speaker 1: where we go, how far we're going to slide into mud?
Speaker 1: All right, Well, on that note, we're going to go
Speaker 1: ahead and close it out, but we'll be back next
Speaker 1: time with more mud. So just remember that. Our core
Speaker 1: episodes of Stuff to Blow Your Mind publishing the Stuff
Speaker 1: to Blow Your Mind podcast feed on Tuesdays and Thursdays.
Speaker 1: Mondays we do listener mail, Wednesdays we do a short
Speaker 1: form artifact or monster Effect, and on Fridays we do
Speaker 1: Weird House Cinema. That's our time to set aside most
Speaker 1: serious concerns and just talk about a weird film.
Speaker 3: Huge thanks to our excellent audio producer JJ Posway. If
Speaker 3: you would like to get in touch with us with
Speaker 3: feedback on this episode or any other, to suggest a
Speaker 3: topic for the future, or just to say hello, you
Speaker 3: can email us at contact at stuff to Blow your
Speaker 3: Mind dot com.
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