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Intro to Sediments - Geology 101: Sediments Part 1 · PlanetGeo: The Geology Podcast

• 0:01
  SPEAKER_00: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:12
  SPEAKER_00: Hey folks, welcome back.
• 0:14
  SPEAKER_00: It has been a while since we have released anything new, and I apologize for that, but we've got some uh some cool stuff to announce today, and we've been announcing over the last couple weeks here.
• 0:23
  SPEAKER_00: We will get to new content coming at you in the next couple weeks here.
• 0:26
  SPEAKER_00: Today we are going to re-release some of our intro to geology, our audio textbook for the geosciences.
• 0:33
  SPEAKER_00: This is sedimentary rocks.
• 0:34
  SPEAKER_00: Chris and I, a couple years ago, recorded this episode talking about sedimentary rocks with the images in the audiobook format that we love on the Camp Geomobile app.
• 0:43
  SPEAKER_00: So that's what's coming at you today.
• 0:44
  SPEAKER_00: But before we get to that, I really want to highlight our new launch of the audiobook series related to the roadside geology of Colorado and the Colorado Rocks series.
• 0:54
  SPEAKER_00: So a little more than a year ago, the Geological Society of America acquired the library of content that was formerly owned by Mountain Press, that is the Roadside Geology Series.
• 1:03
  SPEAKER_00: If you are a geologist and you drive around looking at rocks, which many of us do, you know the roadside geology series.
• 1:09
  SPEAKER_00: Chris and I used this all the time when we were out collecting rocks, driving around the country.
• 1:15
  SPEAKER_00: We would have multiple books of the roadside geology sitting in the truck with us, partnering with us as we go along.
• 1:21
  SPEAKER_00: So I'm really happy to announce that we have a Roadside Geology of Colorado audiobook available now on the Camp GeoMobile app.
• 1:28
  SPEAKER_00: We produced it in partnership with the Geological Society of America.
• 1:31
  SPEAKER_00: So I'm asking you a favor.
• 1:33
  SPEAKER_00: Go to the Camp GeoMobile app, check that out, purchase it if you're interested at all in the geology of Colorado and listening to the Roadside Geology.
• 1:41
  SPEAKER_00: Give us feedback, but most importantly, tell your friends, share it with people.
• 1:45
  SPEAKER_00: I'm really excited to do this.
• 1:47
  SPEAKER_00: I think it's a great idea.
• 1:48
  SPEAKER_00: I want it to stick.
• 1:49
  SPEAKER_00: Um, and we're really excited to be able to do this.
• 1:52
  SPEAKER_00: And I would love to scale this up and do it for more versions of the Roadside Geology series.
• 1:57
  SPEAKER_00: So if you think this is great, great idea, love it, but I'm not going to Colorado anytime soon.
• 2:02
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• 2:07
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• 2:09
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• 2:10
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• 2:11
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• 2:14
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• 2:16
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• 2:18
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• 2:20
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• 2:23
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• 2:25
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• 2:28
  SPEAKER_00: All right, sedimentary rocks.
• 2:37
  SPEAKER_00: Chris Bullheis.
• 2:38
  SPEAKER_00: How are you doing, Jesse?
• 2:40
  SPEAKER_00: I'm well.
• 2:40
  SPEAKER_00: I'm well.
• 2:41
  SPEAKER_00: This is exciting.
• 2:42
  SPEAKER_00: Chapter two.
• 2:43
  SPEAKER_00: Before we get into it, we should do some quick introductions.
• 2:45
  SPEAKER_00: You're Chris Bullheis, high school teacher extraordinaire from the great state of Michigan, and my former teacher.
• 2:52
  SPEAKER_01: That's right.
• 2:53
  SPEAKER_01: And you are now, well, you're Professor Doctor.
• 2:57
  SPEAKER_01: Hold on.
• 2:58
  SPEAKER_01: I couldn't even say that.
• 3:00
  SPEAKER_01: That's good.
• 3:01
  SPEAKER_01: Professor Doctor.
• 3:02
  SPEAKER_00: I like that.
• 3:04
  unknown: Okay.
• 3:05
  SPEAKER_01: All right.
• 3:06
  SPEAKER_01: That's right.
• 3:07
  SPEAKER_01: And you are Professor Dr.
• 3:08
  SPEAKER_01: Jesse Rymake.
• 3:09
  SPEAKER_01: That's a long title.
• 3:11
  SPEAKER_01: Yeah.
• 3:12
  SPEAKER_01: Yeah.
• 3:12
  SPEAKER_01: You are a professor of geoscience at Penn State University.
• 3:16
  SPEAKER_00: That's right.
• 3:16
  SPEAKER_00: And chapter two is sedimentary rocks.
• 3:19
  SPEAKER_00: And we have six episodes in this chapter.
• 3:22
  SPEAKER_00: And uh we're going to lead off talking about sort of the importance of sedimentary rocks.
• 3:27
  SPEAKER_01: That's right.
• 3:28
  SPEAKER_01: Today we're going to talk about what sedimentary rocks are and why it's important to study sedimentary rocks.
• 3:34
  SPEAKER_01: We're also going to cover the three categories of sedimentary rocks, and then also where does the sediment that makes up these rocks, where does that sediment come from?
• 3:42
  SPEAKER_00: Perfect.
• 3:42
  SPEAKER_00: So why are sedimentary rocks so important, Chris?
• 3:46
  SPEAKER_00: What do you tell your students, you know, when you're leading in this unit in class?
• 3:50
  SPEAKER_01: Yeah, I mean, uh, you know, the sedimentary rocks are they're not abundant on the earth's, you know, on the earth's surface.
• 3:56
  SPEAKER_01: Well, they're abundant on the surface, but they're not one of the most abundant rocks.
• 3:59
  SPEAKER_01: They they make up maybe what, seven percent of the earth's crust, but they cover about 75% of the surface.
• 4:05
  SPEAKER_01: And so in sedimentary rocks, this is where we find uh, you know, uh evidence of fossil fossil records.
• 4:12
  SPEAKER_00: Yeah, and that's your first image in your stack of this episode is uh pie charts just showing how sedimentary rocks are small volume but large fraction of the stuff on the surface.
• 4:23
  SPEAKER_01: Right.
• 4:24
  SPEAKER_01: So yeah, we've almost all the fossils that we um to study come from sedimentary rocks.
• 4:29
  SPEAKER_01: We get clues about ancient climates, landscape, topography, the conditions of the oceans and where they where the oceans once were that they're no longer there.
• 4:38
  SPEAKER_01: You know, we have uh this all over the place in Michigan.
• 4:41
  SPEAKER_01: We get chronology, we get order, you know, because most of the time sedimentary rocks are oldest on bottom and youngest on top.
• 4:48
  SPEAKER_01: You know, almost all of our really important resources come from sedimentary rocks, you know, things like fracking is at the center of the rock shale.
• 4:57
  SPEAKER_01: Okay, because and and fracking is you know one of the most controversial things going on now.
• 5:02
  SPEAKER_01: And so that makes shale like a controversial rock, very controversial.
• 5:06
  SPEAKER_00: And I think just to add to that, when planetary scientists or when people are planning trips to, for instance, Mars and trying to figure out where do they want to land or over on Mars, what rocks do they want to study.
• 5:16
  SPEAKER_00: Sedimentary rocks are usually some of the most important targets for that, just because the sediment averages a huge area of the planet.
• 5:25
  SPEAKER_00: So you can look at a sediment, you can understand all of this ancient history, what formed the sediment, and you can also get an average of sort of what the rest of the crust looks like because it's kind of averaged in this processes of sedimentation and sediment delivery, the processes that we will cover in this chapter.
• 5:42
  SPEAKER_00: I love studying igneous rocks, that's really where I spend most of my time is thinking about igneous rocks.
• 5:47
  SPEAKER_00: But we've published a couple papers on sediments because they're really important and they're really interesting because they do this averaging kind of uh process.
• 5:54
  SPEAKER_01: You know, two of the most important resources for humanity is petroleum and natural gas, and both of those resources they come out of sedimentary rocks.
• 6:04
  SPEAKER_00: So they're extremely important.
• 6:06
  SPEAKER_00: What is the definition, Chris?
• 6:07
  SPEAKER_00: Let's move into the definition of sedimentary rocks.
• 6:10
  SPEAKER_00: And really, we have three different categories of sedimentary rocks or three different ways that sedimentary rocks form.
• 6:18
  SPEAKER_01: Right.
• 6:18
  SPEAKER_01: When you know, really, whenever we talk about any of the rocks, whether it's sedimentary igneous or metamorphic, they're defined based upon how they form.
• 6:28
  SPEAKER_01: And so sedimentary rocks form from three basic things.
• 6:33
  SPEAKER_01: We're gonna kind of go by order, I think in order of importance or order of abundance, right?
• 6:38
  SPEAKER_01: And so sedimentary rocks, they can form by the compaction and cementing of fragments from other rocks that got weathered and then eroded and so on.
• 6:45
  SPEAKER_01: They can form by the accumulation of organic material, you know, things like the marine organisms that take ions out of the water and use it to make their shells.
• 6:54
  SPEAKER_01: They live, they die, and they accumulate that on the ocean floors.
• 6:57
  SPEAKER_01: And then lastly, by the precipitation of minerals and ions that were dissolved in the water, and when that water evaporates, it leaves behind those salts.
• 7:06
  SPEAKER_01: And so those are the three ways that sedimentary rocks form.
• 7:10
  SPEAKER_00: Yeah, and those detrital ones or the ones the compaction and cementing of other little pieces, fragments from other rocks, that's best represented in your image number one in your stack.
• 7:20
  SPEAKER_00: The bottom pie chart shows in the green colors the distribution, shale, sandstone, and limestone.
• 7:26
  SPEAKER_00: Those are different types of sedimentary rocks, and those are the three most important by far, by volume.
• 7:32
  SPEAKER_00: And shale and sandstone are made up of little pieces of other rocks.
• 7:36
  SPEAKER_00: So odds are if you're wherever you're standing or sitting, driving, listening to this, you're most likely standing or sitting on a sediment, a sedimentary rock, and most likely you're sitting on a shale or a sandstone.
• 7:49
  SPEAKER_00: A sediment made up of pieces of other rocks that were moved and aggregated in a location.
• 7:55
  SPEAKER_00: Okay, so let's start talking about the three categories of sedimentary rocks.
• 8:00
  SPEAKER_00: And we're gonna start, like you said, Chris, with the most important one detrital or clastic.
• 8:04
  SPEAKER_00: And these are sedimentary rocks made of visible fragments of other rocks.
• 8:09
  SPEAKER_00: And detrital and clastic, those are two terms that are used kind of interchangeably in the geological community.
• 8:15
  SPEAKER_00: I think they make some intuitive sense, Chris.
• 8:17
  SPEAKER_00: Detrital is kind of like detritus, that you know, lots of debris in classic is kind of like clasts, like separate classes of little pieces of rocks.
• 8:26
  SPEAKER_00: I don't know.
• 8:27
  SPEAKER_00: Do those make intuitive sense?
• 8:28
  SPEAKER_01: Yeah, I you know, it's interesting.
• 8:30
  SPEAKER_01: I prefer clastic for some reason.
• 8:32
  SPEAKER_01: I don't know, maybe that's just the way I was educated and and brought up, you know.
• 8:37
  SPEAKER_01: But classed means fragments, you know, and so to me, like I I use them interchangeably in my classes.
• 8:43
  SPEAKER_01: I or I try to anyway, I throw in detrital, but I almost always, when I speak, I refer to it as clastic.
• 8:49
  SPEAKER_00: Yeah.
• 8:50
  SPEAKER_00: So the image number two in the stack is a conglomerate, and this is a really nice representation of a rock.
• 8:56
  SPEAKER_00: That picture shows an entire rock, but it's made up of a bunch of pieces of other rocks, the red ones, the sort of gray ones, the darker gray ones.
• 9:04
  SPEAKER_00: Those are all different rocks that were aggregated together to form a new rock, and that's a detrital or clastic rock.
• 9:10
  SPEAKER_01: That's right.
• 9:11
  SPEAKER_01: So again, clastic sedimentary rocks are made up of these pieces or fragments of other rocks, and those fragments get to where they were deposited by you know what we call uh agents of erosion.
• 9:23
  SPEAKER_01: Okay, things like glaciers, streams, wind, and of those three typical agents of transport or you know, the what moves the sediment, streams is easily the most important agent of erosion or of you know moving sediment from one place to another place.
• 9:40
  SPEAKER_00: Yeah, and I think wind is always one that people don't really think of too much, but it is it's not as important as streams at all, but it is fairly important.
• 9:47
  SPEAKER_00: Think of you know, when it's a really windy day, you kind of get your ankles blasted by sand, you're kind of getting sand blasted with that.
• 9:54
  SPEAKER_00: That's moving material around and that can be deposited somewhere that forms a later sedimentary rock.
• 9:59
  SPEAKER_00: But any of those ages can do that.
• 10:02
  SPEAKER_01: Geologists, we kind of get in the weeds a lot, and uh there was a whole debate about you know whether or not wind can actually move sand, because sand is a really specific designation of like sediment size, right?
• 10:15
  SPEAKER_01: But is it something you know smaller than sand and so on to spark this whole like nerdy online debate about whether or not wind can actually move sand or lift sand more than like six inches above the surface.
• 10:27
  SPEAKER_01: So, anyway.
• 10:29
  SPEAKER_01: All right.
• 10:30
  SPEAKER_01: Let's move on.
• 10:31
  SPEAKER_01: The second category of sedimentary rock, so clastic was one.
• 10:35
  SPEAKER_01: The second one is what is called biochemical.
• 10:38
  SPEAKER_01: I uh prefer the term bioclastic because bio means living and clast means peace.
• 10:44
  SPEAKER_01: So these are fragments from organisms that were once alive.
• 10:49
  SPEAKER_00: Yes, and the fragment size can vary dramatically from individual shells that are aggregated together.
• 10:57
  SPEAKER_00: Like your image number three in the stack, where you can see individual shells that are all kind of welded together to form a new rock.
• 11:05
  SPEAKER_00: That would be very much bioclastic, but you can have biochemical limestone that is formed from very, very tiny microscopic pieces of calcium carbonate that were formed originally by animals pulling calcium and carbonate out of the ocean water to make their shells.
• 11:20
  SPEAKER_00: So biochemical is this very broad category.
• 11:23
  SPEAKER_00: It's a very important process for forming chemical sedimentary rocks, but they're mediated by biology.
• 11:30
  SPEAKER_00: They're ultimately linked to biology.
• 11:32
  SPEAKER_01: So I prefer the term bioclastic.
• 11:34
  SPEAKER_01: Do you prefer biochemical?
• 11:36
  SPEAKER_01: Is that what you use in your classes then?
• 11:37
  SPEAKER_00: Yeah, I use it a little bit just because it covers the range of large fragments and small fragments, but they're interchangeable.
• 11:44
  SPEAKER_01: Cool.
• 11:44
  SPEAKER_01: Okay, and then moving on, the last category of sedimentary rocks is referred to as the chemical category.
• 11:50
  SPEAKER_01: So again, clastic, biochemical, and then lastly is the chemical sedimentary rocks.
• 11:56
  SPEAKER_01: And these are the ones that just simply come from evaporating salty water.
• 12:00
  SPEAKER_01: And then when water evaporates, it leaves those salts behind, it precipitates them and it forms the chemical sedimentary rocks.
• 12:07
  SPEAKER_00: Yeah, think of your high school chemistry class where you had to do these random experiments where you're basically precipitating various solutions of different colors, right?
• 12:16
  SPEAKER_00: That's all that's going on here.
• 12:18
  SPEAKER_00: You generate a solution, usually water, that is supersaturated in some salt, whether it's halite or gypsum or calcium carbonate, and it just precipitates out with no life involved.
• 12:29
  SPEAKER_00: Or at least life is not a major vector for precipitating this stuff out.
• 12:34
  SPEAKER_00: And these are important, these are very important economic mineral deposits frequently.
• 12:38
  SPEAKER_00: They're important, but they're pretty small volume.
• 12:40
  SPEAKER_01: Right.
• 12:41
  SPEAKER_01: And the fourth image in your stack is actually it's got two images.
• 12:44
  SPEAKER_01: One is of the Bonneville salt flats um near Salt Lake City.
• 12:48
  SPEAKER_01: Really, really salty water that evaporated and laid down sodium chloride.
• 12:52
  SPEAKER_01: And then the other image that's embedded in there is just from one of my lab samples.
• 12:56
  SPEAKER_01: It's a it's a piece of limestone that you drop acid on, and when you drop hydrochloric acid on limestone, it will effervesce, it'll bubble a lot.
• 13:03
  SPEAKER_01: Yeah, and that's one of the ways that you can identify oh, this is the rock limestone.
• 13:07
  SPEAKER_00: So those to just to review, those are the three.
• 13:10
  SPEAKER_00: We have clastic or detrital, biochemical or bioclastic, and chemical sedimentary rocks.
• 13:16
  SPEAKER_00: Now, Chris, entrenched in this conversation is the fact that we have sediment or elements that are able to be deposited.
• 13:24
  SPEAKER_00: So let's kind of go one step back further and talk about how the material that forms sedimentary rocks, how is that material actually formed?
• 13:33
  SPEAKER_00: How do we get sediment, how do we get ions dissolved in water in the first place?
• 13:38
  SPEAKER_01: Yeah, that's right.
• 13:39
  SPEAKER_01: We're gonna just briefly touch on this today to kind of set the stage for you know sedimentary rocks.
• 13:45
  SPEAKER_01: We're gonna do later on a whole chapter on weathering and erosion.
• 13:49
  SPEAKER_01: Um, but that's really it.
• 13:51
  SPEAKER_01: The sediment that forms sedimentary rocks comes from what we refer to as the weathering of other rocks, which is the breakdown.
• 13:58
  SPEAKER_01: Weathering it refers to the breakdown of rocks at the surface.
• 14:02
  SPEAKER_01: There are two types of weathering that we refer to in geology.
• 14:05
  SPEAKER_01: Jesse, what are those two types of weathering?
• 14:07
  SPEAKER_00: Yeah, we've got mechanical and chemical.
• 14:10
  SPEAKER_00: Those are two relatively simple things.
• 14:11
  SPEAKER_00: The first is pretty easy to understand, I think.
• 14:14
  SPEAKER_00: Mechanical, it's just taking the rock fragments and making them smaller.
• 14:17
  SPEAKER_00: So you just crush it.
• 14:19
  SPEAKER_00: If you had a hammer and you bashed a rock, you would be doing mechanical weathering with that.
• 14:24
  SPEAKER_00: And then the other one is chemical, which is a little bit sometimes more difficult for people to understand.
• 14:29
  SPEAKER_00: But acid rain is a very extreme, unnaturally extreme example of this.
• 14:34
  SPEAKER_00: But the last image in your stack here, image number five, shows a statue that has been chemically eroded.
• 14:41
  SPEAKER_00: All the really nice features that were originally pristine have been dulled, and you can see that this thing is like pock barked and weathered.
• 14:50
  SPEAKER_00: Right.
• 14:50
  SPEAKER_01: So let's go back and talk specifically about mechanical weathering a little bit.
• 14:54
  SPEAKER_01: Okay.
• 14:54
  SPEAKER_01: So mechanical weathering is like you said, where it gets broken down into smaller clasts or fragments, right?
• 15:00
  SPEAKER_01: And then the ways that this happens in like a natural setting, the most common kind of mechanical weathering is what's referred to as frost wedging a lot of times in books.
• 15:11
  SPEAKER_01: I actually I don't like that term.
• 15:13
  SPEAKER_01: I I I refer to it usually as ice wedging because it's ice really that does the work.
• 15:17
  SPEAKER_01: When water freezes, it expands by about 9%.
• 15:21
  SPEAKER_01: And so it will pry then rock apart from itself in this way.
• 15:26
  SPEAKER_01: And then, you know, when you get this freeze-thaw, freeze-thaw cycle, then water just keeps working deeper and deeper into cracks and crevices, freezes, thaws, freezes, and so on and so on, and so on.
• 15:37
  SPEAKER_01: Really important mechanism for weathering, mechanical weathering.
• 15:41
  SPEAKER_00: Yeah, it's really important to start the process because it often happens in mountainous regions where it's often cold up high, and you have these freeze-thaw cycles at various stages up on the mountain face.
• 15:52
  SPEAKER_00: So that's why it's usually the first starting point.
• 15:54
  SPEAKER_00: But then once you have those big broken down blocks, the transport of those blocks typically rounds them and breaks them apart.
• 16:02
  SPEAKER_00: Think of a boulder falling down a cliff.
• 16:05
  SPEAKER_00: That thing is going to get rounded, it might break apart, and those little smaller pieces are constantly being rounded as well.
• 16:10
  SPEAKER_00: And this occurs all the way from falling down a cliff and being carried in a stream, a high-energy mountain stream, all the way to a lower energy, much bigger meandering stream down closer to ocean level.
• 16:21
  SPEAKER_00: And that's usually like saltation of pebbles, things bouncing along the bottom of the riverbed.
• 16:27
  SPEAKER_00: They're broken apart occasionally.
• 16:29
  SPEAKER_00: And other vectors like sand, wind, heat expansion can do this too.
• 16:33
  SPEAKER_01: Yeah.
• 16:34
  SPEAKER_01: Heat expansion and contraction, it was once thought to be a major player, makes sense, you know.
• 16:38
  SPEAKER_01: When rocks get hot, they expand, and when they cool off, they contract.
• 16:42
  SPEAKER_01: Rocks can't just kind of huff and puff in a natural sort of way, and so they would break apart as they do this.
• 16:47
  SPEAKER_01: But that that's been actually proven to not be a major player in the breakdown of rocks in a mechanical way.
• 16:54
  SPEAKER_00: All right, so that's mechanical weathering.
• 16:56
  SPEAKER_00: Chemical weathering, I mentioned earlier, is sort of like acid rain, is a extreme unnatural example of chemical weathering.
• 17:03
  SPEAKER_00: But this happens all the time in the background, even it with without the acid part of acid rain.
• 17:09
  SPEAKER_01: Yeah, but you know, all rainwater is going to be slightly acidic.
• 17:13
  SPEAKER_01: And that's because, you know, you when you take water and you dissolve carbon dioxide, which is a natural component of our atmosphere, when carbon dioxide dissolves in the water, it forms a weak acid called carbonic acid.
• 17:23
  SPEAKER_01: So all rainwater is going to be slightly acidic anyway.
• 17:27
  SPEAKER_01: And so, you know, water is a powerful solvent, right?
• 17:30
  SPEAKER_01: And then if you take water and you make it slightly acidic or more acidic, it's going to be even a more powerful solvent where it dissolves things.
• 17:39
  SPEAKER_01: And that's a major part of chemical weathering.
• 17:42
  SPEAKER_01: It takes rocks and puts them in solution.
• 17:45
  SPEAKER_00: Yeah, and it does this not only just rainwater falling on rocks, but it also does this within the groundwater.
• 17:50
  SPEAKER_00: It does it within soils as water is percolating through soils.
• 17:53
  SPEAKER_00: It is reacting with the minerals in the soil.
• 17:56
  SPEAKER_00: And it's doing this on the surface of rocks with natural rainwater.
• 17:59
  SPEAKER_00: Anywhere there's water hanging around in contact with rocks or minerals, this chemical weathering is going on in some way.
• 18:06
  SPEAKER_00: And another important part about this is chemical weathering happens faster with smaller grain sizes because the more surface area you have per unit volume, the faster this is happening.
• 18:18
  SPEAKER_00: So it happens faster when water is flowing through sand than it does if water is flowing around boulders.
• 18:23
  SPEAKER_00: We'll talk about this later in uh weathering and erosion chapter.
• 18:26
  SPEAKER_00: But yeah, the smaller it becomes, the more vigorous this chemical weathering becomes.
• 18:31
  SPEAKER_01: One of the dominant processes in chemical weathering is a process called hydrolysis.
• 18:35
  SPEAKER_01: And I could sit there and talk about that, but you know what, Jesse, you are a geochemist.
• 18:41
  SPEAKER_01: This is this is your thing.
• 18:43
  SPEAKER_01: So I'm not going to talk about hydrolysis, but we have the benefit of listening to you.
• 18:47
  SPEAKER_01: So can you please like outline real quick, like in simple terms, right?
• 18:51
  SPEAKER_01: What hydrolysis is and how why it's an important process.
• 18:54
  SPEAKER_00: So hydrolysis is really this common breakdown.
• 18:58
  SPEAKER_00: It's really a category of reactions that occurs anytime water is interacting with stuff and water is dissolving stuff.
• 19:04
  SPEAKER_00: It's very common in the weathering process where anytime carbon dioxide is absorbed into water, it forms bicarbonate or carbonic acid.
• 19:13
  SPEAKER_00: And that is pretty reactive.
• 19:15
  SPEAKER_00: That helps break those mineral bonds that we talked about in chapter one.
• 19:18
  SPEAKER_00: And once those mineral bonds are broken, the ions can be carried away in the water.
• 19:23
  SPEAKER_00: They're in solution now.
• 19:24
  SPEAKER_00: And so anytime there's respiration, soil organisms or CO2 from the atmosphere getting into the water system, this hydrolysis is actively working to break down the mineral bonds, the bonds within the minerals, and then carry those elements away.
• 19:39
  SPEAKER_00: So, Chris, there's one really important one that, or one sort of overview one, and that's the breakdown of feldspar.
• 19:44
  SPEAKER_00: So what happens when feldspar breaks down?
• 19:47
  SPEAKER_01: Right.
• 19:48
  SPEAKER_01: Well, it's important to point out or to re-point out anyway that feldspar is the most abundant mineral that exists on the crust.
• 19:55
  SPEAKER_01: So this is the dominant mineral that it's exposed at or near the surface, right?
• 19:59
  SPEAKER_01: And feldspar is very susceptible to breaking down chemically into clay minerals.
• 20:05
  SPEAKER_01: Okay.
• 20:05
  SPEAKER_01: Now we're not referring to clay as a particle size here, we're referring actually to clay minerals, minerals like bentonite and kaolinite and so on.
• 20:14
  SPEAKER_01: And so feldspar breaks down chemically into clay, and then clay forms this really important and abundant rock called shale.
• 20:24
  SPEAKER_01: And so it's if you think this through, you know, feldspar is the dominant mineral, it turns into clay.
• 20:30
  SPEAKER_01: Clay forms the rock shale.
• 20:32
  SPEAKER_01: Shale is the most abundant clastic sedimentary rock that exists at the surface of the earth.
• 20:38
  SPEAKER_00: Yeah, and that makes complete sense because feldspar is so abundant in Earth's crust, right?
• 20:42
  SPEAKER_00: So those two go hand in hand, and therefore this is a really, really important process.
• 20:46
  SPEAKER_00: And we'll come back to talking about this throughout the next several episodes.
• 20:50
  SPEAKER_00: So, Chris, we've covered how important sedimentary rocks are.
• 20:54
  SPEAKER_00: We've covered the three types, detrital or clastic, biochemical or bioclastic, and chemical.
• 21:00
  SPEAKER_00: We've covered those three, what they are in broad terms.
• 21:03
  SPEAKER_00: We're gonna dive into some more details of those in the coming episodes.
• 21:06
  SPEAKER_00: And then we finished off by talking about a brief intro to how sediments or the parts, the constituent parts of sediments are actually made at the source.
• 21:14
  SPEAKER_00: And there's two types there mechanical and chemical weathering.
• 21:17
  SPEAKER_00: And so where we're going from here is we're gonna give an overview of these important sedimentary rocks and how they're formed in the coming episodes.
• 21:25
  SPEAKER_00: Jesse, that's a wrap then.
• 21:27
  SPEAKER_00: That's a wrap.
• 21:28
  SPEAKER_00: But not quite because we have questions, Chris.
• 21:31
  SPEAKER_00: Oh, all right.
• 21:33
  SPEAKER_00: You're trying to you're trying to get out of here before you get your question asked.
• 21:37
  SPEAKER_00: Okay.
• 21:37
  SPEAKER_00: Oh, it's my favorite part.
• 21:38
  SPEAKER_00: I love the questions.
• 21:39
  SPEAKER_00: Okay.
• 21:40
  SPEAKER_00: So because you know, previously you've indicated that my questions were subpar, I've decided to focus and just provide one question, and I'm trying to make them good ones here.
• 21:49
  SPEAKER_00: So for this episode, what is the here's your question.
• 21:53
  SPEAKER_00: You ready, Chris?
• 21:54
  SPEAKER_00: Okay.
• 21:54
  SPEAKER_00: Prepared?
• 21:54
  SPEAKER_00: I'm ready.
• 21:55
  SPEAKER_00: I'm yeah.
• 21:55
  SPEAKER_00: Okay.
• 21:56
  SPEAKER_00: I don't know why you can get on the edge of my seat.
• 21:58
  SPEAKER_00: It's just you.
• 21:59
  SPEAKER_00: Okay, fair enough.
• 22:00
  SPEAKER_00: Perk up, come on.
• 22:01
  SPEAKER_00: You know, get excited.
• 22:02
  SPEAKER_00: Let's go.
• 22:03
  SPEAKER_00: What is the most basic requirement to form sedimentary rocks?
• 22:07
  SPEAKER_00: Okay.
• 22:08
  SPEAKER_00: A rocks exposed above sea level.
• 22:12
  SPEAKER_00: B water to move and sort sediments, or C and ocean to put sediments into.
• 22:20
  SPEAKER_00: What is the most basic requirement to form sedimentary rocks?
• 22:23
  SPEAKER_00: What was A again?
• 22:24
  SPEAKER_00: A was rocks exposed above sea level, B water to move and sort sediments, and C and ocean to put sediments into.
• 22:34
  SPEAKER_01: Well, they're all important.
• 22:35
  SPEAKER_01: They're above.
• 22:37
  SPEAKER_00: Which is the most basic requirement.
• 22:40
  SPEAKER_01: Alright, so it's gotta be A.
• 22:43
  SPEAKER_01: A is the correct answer.
• 22:44
  SPEAKER_01: You gotta have the rocks above.
• 22:46
  SPEAKER_00: Celebrate balloons and stars.
• 22:47
  SPEAKER_00: You get a star, Chris.
• 22:48
  SPEAKER_01: But it it is an interesting, it's a hard question though, because it you know, all of them are important.
• 22:54
  SPEAKER_01: For sure.
• 22:54
  SPEAKER_01: All of them are important in the so but I yeah, I guess starting with the beginning, you have to have the rocks exposed above sea level.
• 23:01
  SPEAKER_01: So I think that's probably why that's the best answer to that.
• 23:04
  SPEAKER_00: Yeah, I would completely perfect.
• 23:06
  SPEAKER_00: You nailed it.
• 23:06
  SPEAKER_00: I think we ended with weathering.
• 23:08
  SPEAKER_00: How do we form the sediment that actually makes sedimentary rocks?
• 23:11
  SPEAKER_00: I think that's kind of where I was going with this, is that's the most important part.
• 23:15
  SPEAKER_01: I don't think you can stump me.
• 23:16
  SPEAKER_01: So I don't know.
• 23:17
  SPEAKER_01: Okay.
• 23:18
  SPEAKER_00: Well, let's wait till next episode.
• 23:19
  SPEAKER_00: Let's see what we can do.
• 23:20
  SPEAKER_01: Okay.
• 23:21
  SPEAKER_01: All right, Chris.
• 23:22
  SPEAKER_01: Well, hey, that's a wrap.
• 23:23
  SPEAKER_01: Let's wrap