a jogger first welcome back so we are going to start talking about weathering and mass wasting we have been talking about how the earth builds itself up and also the climate of course but now we have to look at the way that the earth just breaks itself down so let's go over basics of weathering and then mass wasting so with with every process basically that we're gonna look at with this with weathering with how fresh water carves out the landscape without how the ocean carves out the landscape all that there's kind of three processes there's sort of the initial erosion and then there's the transportation and then there's the deposition so we're gonna see those three things over and over and over again pretty much from here until we talk about soil so we are looking at the weathering the erosion so the breaking down the transportation and then the deposition so the earth builds itself up and then it all these other processes work to break it down and so breaking it down the initial breaking it down is called weathering or erosion and then that material now that it's loose and broken down it gets transported so that transportation that's mass wasting is one type of transportation there's a lot of different types of transportation though you can have material that's transported in a river you can have a material that's transported by wind by ice all kinds of different ways so mass wasting is just one type of transportation and then it gets deposited somewhere so things get broken down moved deposited we're gonna go over those themes over and over and over again erosion weathering transportation deposition so we're gonna start with just basic weathering and then mass wasting which is the movement of a lot of materials there's gonna be a lot of transportation that comes up but mass wasting is when we have like a massive material so we're talking about landslides avalanches that's mass wasting you have a whole lot of material that's been loosened and something happens like an earthquake or like a massive storm and now you have flow that happens a lot of material okay let's look at our PowerPoint and again of course I've posted videos to go along with this show you avalanches and landslides and stuff like that so weathering and mass wasting we're looking at weathering that's the erosion and the breaking down the slope process is the mass wasting transportation and then eventually we look at deposition but not in this one yeah actually in this one okay so weathering basic basic definition all processes that physically or chemically disrupt so there's two specific types of weathering physical weathering and chemical weathering so physical weathering is literally the breaking down of the material from some sort of outside force so if you have a rock and it gets broken into because ice gets in there and wedges in and breaks it apart or wind is hitting it or the ocean is constantly hitting it like literally physical processes processes that come from outside and break down rock that's physical weathering I'm gonna give you some examples of physical weathering chemical weathering is when you introduce something new so you introduce something new a new remember what a rock is a rock is two or more minerals and remember that a mineral is a chemical crystalline compound so if we have a chemical that has new chemicals introduced to it what can happen be that that entire Rock can change so a chemical weathering is a little bit different it literally is the introduction of a new chemical that changes the composition of that rock once again breaking it down but through changing composition regolith this is a good word to know it's gonna be mentioned a whole lot in the next couple of lectures serega lip is a surface of weathered rock particles that lies above solid rock so we're gonna eventually go inside the earth not lupus fear inside the earth we already did that but kind of like inside them the closer layers to us so we're standing on top of maybe grass or some sort of some sort of landscape and then you've got soil underneath that we want to understand soil and we will eventually in a lecture and then underneath soil so soil just so you know there's a balance of a couple different things broken down biomass and eroded rock eroded rock is the parent material and then biomass is the organic material plus oxygen a good 50% of soil is just oxygen so those two things together but once you get past sow you get into just rock so the biomass is coming from up here biomass is lighter than the rock so it's gonna be closer to the top but then you're gonna eventually get to just a pile of broken-down rock no biomass that's Regal if and then underneath that you run into and include I'll go over what that means in a later lecture you run into basically an impenetrable layer of rock bedrock occlude those are works that you might have heard before that's the layer of rock that now like nothing is getting through it's just solid rock so regal it's is that weathered rock below soil soil has biomass in it regal lip is just rocked mass wasting like I said it's transportation and we're gonna go over a lot of different types of transportation from now until we get to soil but this is a lot of it this is when you have like a whole lot of material that's broken down an avalanche is mass wasting you have you know snow that just collapses down a hillside landslides if you have lived in Santa Barbara for a while you might know that LA conchita is an especially vulnerable place to landslides why can't you - is that little community between Santa Barbara and Ventura that there's often if you're driving like a long past Rincon there's like avocados for sale and I don't know it's always like signs for like ten avocados for a dollar and stuff like that and there's a little community there little community is right underneath a very steep slope and that steep slope can be very dry Santa Barbara is a dry place that has it has like bouts of drought we have long dry summers so what happens if you have a long dry summer and there's not a whole lot of foliage there's nothing living on the side of that mountain it's a very steep hill that very steep hill think about it if it has a lot of plants on it those roots get into that soil and they keep they help keep it in place but if you just have soil sitting on a hill and that hill gets drenched with water now that soil is gonna be very very heavy and what's it gonna do slide down like a whole chunk of the hill is literally gonna slide down and if you happen to be a house in ma Conchita right underneath that you're gonna be slid over more recently we've had a debris flow in Montecito Montecito as you probably know a couple of years ago had a debris flow and think about what happened leading up to that debris flow so we had a fire the Thomas fire it swept through Montecito and what a fire does is I know you know it burns but it also remember roots what plants do is times do so much but one thing that they do is they keep the soil in place if you imagine soil you have plants that their roots here it helps kind of like keep that soil stable the other thing that plants do is they soak up a lot of water you know a tree can take in fifty-two thousand gallons of water in a rainstorm so if you have a fire that now takes away those roots that help stabilize the soil and takes away these trees that are basically like huge sponges for the environment that can suck up like fifty-two thousand gallons of soil in a storm you don't have any of that you get hit with five inches of rain in an hour which is what happened in Montecito by January and you have a debris flow you basically have a free flowing river of mud that goes over anything that's in its way so that's mass wasting those are all examples of mass wasting there's lots of other transportation that's not mass transportation misses mass can use regolith so there's soil see there's what's living cuts grass that soil which is a mixture of biomass and eroded rock and then underneath that you just have the eroded rock reading okay so weathering a couple of different things that are going to affect weathering one is your vulnerability kind of rock are you are you a rock that is Sam stone Sam stone sedimentary rock remember we talked about rocks sedimentary rock is a whole bunch of sediment that's been compressed together well that's gonna be a pretty vulnerable rock right that's a rock that might be easy to break down with a good amount of wind a good amount of water a good amount of ice so depending on the kind of rock the kind of rock is going to affect the vulnerability of the wind or the water or whatever to weather away that rock that's one thing so the type of rock makes a big difference with weathering one - how much of the rock is exposed does the rock have like multiple sides exposed now that you have multiple sides exposed it's easier to kind of chip away if you look at this picture right here once upon a time this would have been one big solid piece of rock but water and ice wind came along and essentially broke down all these different parts of what would have once upon a time been a wall of rock and so now even more of its exposed so now though the water and the wind and everything get to work on multiple different sides and continue to break it down even faster so the vulnerability of the rock the type of rock how much of the rock is exposed those two things are very important and over time more and more of you are is going to be exposed so you're even more vulnerable what kind of climate urine if you're in a desert deserts are dry so remember what we learned about temperature temperature hangs on to water so if you don't have any water in your air you see very extreme temperature changes through through like a 24-hour period if we were camping in Death Valley it could be a hundred degrees and during the day and freezing cold at night like 30 degrees Fahrenheit at night so in between that time think about what Rock does in heat it expands what does it do and when it's cold it compresses so if you have this expanding and contracting that's gonna increase your vulnerability if you're in the desert and you have lots of wind you might have gets so cold in places like Death Valley if it's below freezing then water will freeze and if you have a rock that is particularly poor if you have a type of remember the type of rock makes a difference if you have a type of rock that like water can get into and then overnight it freezes when water freezes it expands by 9% so now it's in this crack it's frozen and what does it do acts as a little like wedge so the type of rock how much of the rocks Rock is exposed where the rock is all of that is going to make a difference but how quickly it weathers versus how slowly it weathers fractures are gonna make a difference with how you weather as well fractures are natural fractures or if they meet together two fractures made together it's called a joint so if you have a fracture aligned in a rock or a joints by the way fracking ever heard of fracking has to do with fracturing basically it's it's finding the fractures the weak part of the rock and then taking a drill and going like two miles into the soil in order to break apart so you can get natural gas Kansas okay so Kansas you know the state in the middle of the u.s. is now as vulnerable to earthquakes as California so we know California has earthquakes because we are on the Pacific and North American plate boundary we know that we have fissures faults right running through California we know earthquakes happen here why are they happening in Kansas because Kansas has fractured its fracked a whole bunch of its basically taking drills and drilled several miles into the surface of canvas can't black canvas Kansas in order to break apart and extract natural gas and it's increased their vulnerability to earthquakes so Kansas is now as likely to have an earthquake as California's so Frank's fractures those are lines and they're generally they generally don't move so they're generally like the lines of a broken basically broken line in my uniform rock and then were those two meet that's a joint mechanical weathering increases the amount of surface and so it's gonna increase little increases amounts of surface that's exposed so that's going to increase your vulnerability weathering and it works faster and faster there's all kinds of analogies in there too like human personality you know you could talk about like your vulnerability when you're all kind of in the beginning of something you're you're less vulnerable you have your walls up but after a while like your walls get broken down more and more more vulnerable having to walk to our joint so looking at this right here these are the joints see for the two fracks the two fractures meet together that's a joint and then pours rocks depending on the rock has different pullers ah is a type of lava rock basalt lava rock is a Hawaiian term and uh uh is really really porous basically if you have been to Hawaii and seeing like really porous lava rock that it's like big holes that's created from gases if you have like a very gassy magma imagine like the gas is kind of like bubbling out as the magma hardens so those pores are gonna guess what increase your vulnerability as little things can get in there water can get in there and freeze animals can get in there animals and living things both mechanically physically weather and biologically I'm sorry I'm chemically weather so biological plants and animals can both mechanically weather and chemically weather so by mechanical weathering that's when stuff from the outside right he's breaking you down so imagine you have like something an animal come and burrow into your little pore imagine you have I don't know what else but animals do scratch stuff right and then the way that plants and animals might chemically alter a rock would be introducing a new chemical to it so if you have plants they grow on a rock like late June for example and then die on that rock those chemicals are couldn't alter the rock so biological organisms can both physically and chemically alter a rock whether a rock come back to that in just a minute one of the ways they do that is by getting into your pores so physical weathering that's what I've been talking about it's the break up of rock by physical forces water wind waters like the most powerful water is the one that's kind of like constantly physically altering rock like wind as well and other processes plants animals think about like a like a root if you've ever lived in a house that a big tree has is living next to and like that tree's roots start to break its way up through the house you know and get like roots that make their way into pipes there you can get roots that literally like come out the corner of your house that would be that would be an example of how I mean I know that's house it's not a rock but that's an example of biological physical weathering right just the growing of that tree that root is going to split apart in that case it was a house but imagine was a rock so frost action is a type of physical weathering frost action is what I was describing with how water gets into maybe a pore or gets into a little crack or a fracture and when it freezes it expands by 9% and it breaks something like it's gonna slowly just break it apart you're gonna see that in arctic regions high mountain environments desert environments anywhere where you see like extreme temperature changes you see extreme cold frost can happen salt crystal growth so salt is both a chemical that can chemically alter but it can also physically alter so salt when it gets warm unlike remember when when water gets cold when it freezes it expands when salt gets warm it expands so just imagine you're walking along the beach and there's a lot of rocks on the beach and if you've ever noticed on butterfly beach for example they're taking a walk on butterfly beach there's a lot of rocks on butterfly beach that have these like perfect holes in them and those perfect holes are from salt crystal growth so imagine like the ocean comes in high tide the ocean leaves it's you know like it gets hits the rocks and then some of that salt water gets left on top of the rocks the ocean may be low tide it retracts a little bit and then you have this ocean water left on a rock now that ocean water is going to heat up and the water is going to turn to vapor it turns to vapor when water goes from liquid to vapor it leaves its minerals behind it leaves that salt behind and that salt is gonna snow sit exposed on the rock it's gonna get hot from the Sun and salt expands when it gets hot and so now you have these like perfect kind of circles that are literally scooped out as a result of salts getting hot so if you have a porous rock that's gonna be especially especially like erosional to this kind of thing because imagine like salt gets stuck in a pore and then it expands and expands you're gonna see that next to the ocean you're gonna see that semi-arid regions basically were there salt and weathers heat exfoliation so exfoliation if you exfoliate your skin at all you know that you exfoliate it by like taking something like apricot scrub or something like that over your skin and what does it do it takes away like dead skin cells it takes away you know whatever it's supposed to do the same thing is happening to rocks so exfoliation this is if you've been to you somebody if somebody has granite and you know somebody looks like if you're looking at the rock some of it looks so smooth it's like you could like lie down on top of it and it would look like it almost looks like squishy and comfortable it's not it's granite rock but it kind of has that appearance it's because of exfoliation so exfoliation is common if you've had a glacier for example so a glacier supercool loved glaciers glaciers are huge frozen rivers gigantic frozen rivers so imagine that if somebody valley once upon a time it was carved out by a glacier once upon a time there was a glacier in Yosemite Valley and so frozen like literally a frozen river can imagine how massive that would be and how heavy that would be at the bottom of that frozen river of that glacier it's right up against the earth and the earth has at least a little bit of geothermal heating so that geothermal heating leads to like a nice little slip inside slip-and-slide is what I meant to say a glacier up against the earth there's a little bit of geothermal heating happening and so you have a nice little like slippery slighty part in between the two and then gravity moves this glacier along so just imagine as that glacier is moving along the granite what it's doing its exfoliating it's like slowing away any of the surface debris any of the rock and it's basically polishing that granite which is why it looks so smooth and so nice the other thing that can happen with exfoliation if you have something really heavy on top of the rock and then it moves because let's say it's a glacier and at a glacial pace moves along and the melts now this very heavy thing it's gone so that rock is gonna expand a little bit and when it expands you can have pieces of like the surface pieces sort of break off and that is also exfoliation so if you have rock that's Rock is exposed at the surface you have something really heavy kind of like moving along and like sandpaper basically just smoothing that rock that's exfoliation any type of exfoliation as you remove something very heavy and the top that rock expands it has more space and so like the whole kind of top layer of the rock just cracks and breaks off and now you have this new layer underneath like microdermabrasion so that's exfoliation so two other types of exploration are sorry physical weathering thermal action so talk about frost action but with thermal action that would be heat so with frost action frozen right but the thermal action if you have like I said earlier you have a rock that gets warm it expands it gets cold it gets denser that can break pieces off of it you know break apart and then biological action that's what I was talking about with how a trees root might get into a rock in between a rock and that trees root continues to grow and grow and grow and I break things down you have little animals that make their way inside rocks and like you know cozy in there they they what's the word I'm looking for I'm not hibernate they I don't know they dig what I was trying to say yeah burrow good girl so they get in there they burrow that's gonna that's biological action it's basically like plants and animals that are moving and growing as they're doing that they are breaking away the rock chemical weathering is okay now so we've talked about physical breaking down like literally breaking down that rock but chemical weathering is different in that remember a rock is two or more minerals minerals or chemicals if you introduce new chemicals to old chemicals you might have a chemical reaction if you remember a couple years ago there was this cleaning fad rocks OxiClean OxiClean was like the thing that was supposed to be the best stain remover ever you know you'd spray it on your clothes or carpet or something basically used oxidation he's oxygen he used a chemical reaction with oxygen and took like dirt was supposed to take dirt and through that oxidation like lift the dirt away from your clothes so oxidation is something if you have oxygen and water an acid or oxygen and water and let's say a metal an iron you can have oxidation so if you have a rock that or if you have a mineral if you iron just on its own or if you have a rock with strong iron presence and you have oxygen and water introduced to that it has a chemical reaction and it's going to change what that rock looks like so chemical precipitation like we talked about earlier in the semester chemical precipitation you have to soluble materials - like liquid if you imagine - liquid and when they come together they create a solid so chemical precipitation in sedimentary rocks because sedimentary rocks have a lot of organic material in them you can have a lot of chemical precipitation the organic material has its own chemicals you have that the chemicals of the rock and now you have this they're chemically precipitated you have this new solution basically that is created as a result this happens in warm moist climates water is a great way to introduce new chemicals to Iraq some different types of chemical weathering hydrolysis that's the water element right and depending on the rock - so you have these you have water that might introduce new chemicals but then you have you have your water that introduces new chemicals but then just depending on the type of rock is also going to make a difference as well limestone for example limestone is a sedimentary rock it has a particular vulnerability to carbonic acid so if you imagine you have like a layer of limestone and you have water it comes down and goes through soil soil soil stores a whole lot of carbon so that water goes through the soil it picks up carbon and then it hits that that limestone and because limestone is particularly vulnerable to carbonic acid when you have bedrock that's limestone meeting water that's absorbed carbon it just breaks down and it creates these huge caverns we're gonna go into something called karst landscape later karst landscapes are our mine stone rock that has that is particularly vulnerable to chemical to carbon carbonic acid which is a result of rain coming through soil and picking up the carbon and then you have these like huge underwater caverns that are made as a result and then carbonation began carbon so those are three types of chemical processing weathering oxidation and oxygen and water react carbonation that's carbonic acid what I was just talking about dissolves limestone crates caverns you can pause this this is what I just explained that we can pause this and look at it mmm all right so I'm gonna come back and talk about mass wasting and with mass wasting we now have a whole lot of material that's been broken down broken-down material gets pulled down a slope comes to the bottom here that's where it's going to be deposited so it's broken down eroded transported and then deposited yeah so I will come back and you will talk about mass wasting