so that's the big zone um so we have our igneous intrusion here so this is our hot source so let's hot magma and then we have the big zone around it the closer you are the higher the grade the further you are the lower the grade and then this is how we could get some of that fluid in there sometimes you could get fluid that actually um might have some dissolved minerals in it coming off of the igneous intrusion itself sometimes you could have some water coming down and fractures of the rock interacting with it so all of this kind of fluid all of this kind of motion is what's helping to recrystallize the rock here now remember we said that this kind of big zone creates those star minerals and that they're economically important there was a um we there's mines across the us ducktown tennessee you could go there you could find what's called sulfide mines which have iron and copper in them um those are mainly tapped out now um there was a iron mine it was actually the largest iron deposit um east of the lake superior region um that was in pennsylvania that was actually an area where they mined iron and copper for the revolutionary war um these minerals are highly um prized because you have those concentrations of those util minerals in terms of tools and other other mechanisms this is actually the mine i was telling you about in pennsylvania this is um this operated for 234 years it's no longer operational um you do have these piles of rock these are pictures i took when i went there um you could go on these piles of rock if you have permission this is actually a scarring deposit that was um created in the um triassic so this was the age of the dinosaurs um it has copper co vault um minor amounts of gold it was discovered in 1739 um and it was um actually toured by george washington himself at one point in time um when i was going through these tiling piles i found some malachite and unusual minerals we were there with a professor whose specialty is it or minerals and so i would find these minerals that i was having a hard time identifying i'm i know a lot about minerals um but i'm there are some minerals that are so unusual that i can't identify right at first sight and i took it to him and he couldn't even identify them for first sight so there were samples i picked back and i intended on analyzing them i just never got around to it but because of all these fluids because of all this heat and pressure you start to find form these really unusual minerals in this in these regions where you have these scarred minerals so that's our contact metamorphism now we're going to move on to our regional metamorphism so regional metamorphism um this is going to have to do with plate motion this is going to have to do with squeezing pushing pulling um sliding anything that could create some kind of friction some kind of pressure some kind of temperature change so here we have our um continental crust and our oceanic crust in the subduction zone right where i'm circling this is where you're going to have that rubbing that's where you're going to have your increase in temperature and pressure and that's because you have that compression that's because you have that shearing creating that regional change in that temperature pressure that's necessary to dehydrate to recrystallize to transform the appearance of those rocks so here we have this is the part of the diagram that we're familiar with we have our magma coming up we have a volcano well the part that i want you to focus on is this part right here this part right here yes this says sedimentary rock up here i'm going to season a second maybe maybe not um here we have this pressure where this plate is being pushed against and so we're going to start to metamorphose this creationary wedge which is now become the edge of this continent and this is the area where i want you to think about in terms of that pressure in terms of that energy from this subduction zone again i hope this is um making some sense to you clicking some sense in your head if you have any questions please don't hesitate to contact me i'm happy to go over this with you or answering questions that you may have um this says regional metamorphism convergent margin um convergent margin in this case that is the same thing as saying a subduction zone for these diagrams here um this area of the lecture this portion of the lecture i always start i always feel like i've stepped into a dr seuss book red fish blue fish one fish or one fish two fish red fish blue fish um well now we're gonna be talking about green schist and blue schist um these are just um basically named from the colors that are in them so green just look primarily a little bit green they've got a lot of chloride in them lucious look blue because it has well a mineral called blackophane do i care that you know the name glycophane no but that's what gives it its blue color um and what's actually happening is because you have that motion because you have that movement um you actually have um minerals that start to be lined up and so you're actually starting to squash those minerals you have that heat and that pressure to start to dehydrate and make new minerals so at chest notice that's a that's a pretty high grade metamorphic rock it's a medium to high we're going to start to form micas this is going to be a lot of temperature and pressure changes and this is where we're going to have our regional and then if we go further inland we might have our contact nearby now some of our highest grade of metamorphic rocks are going to actually be associated with mountain building events so remember our mountain building events were when we had those two continental crusts that combined and then they uplift when those mountains start to break apart we could find evidence of where those chains were once connected and start to rebuild that story again rocks helped us read the history of the earth rocks help us tell a story so rocks are basically um characters their plot lines their um environments we're going to start to think about all these characteristics of these rocks and try to extrapolate how can we know what happened in the history of these rocks um so we're going to in our mind take a trip to scotland here now the appalachians um are on the eastern part of north america and they're on the western part of scotland um but in scotland they don't call them the appalachians they call them the caledones if we look in this diagram i'm going to give you a moment to kind of think to yourself i know you can't talk to me but think to yourself where do you think the high grade metamorphism is and where do you think the low is so um i'm going to give you a little um these down here i'm not sure if you see these as green but these green ones are your high grade and this yellow and red here are our lower grade so i want you to take a moment to look at where you have your high grade so these are your high grade and where you have your low grade and then um there's also some words here like slate and nice that are written but i want you to look at it for a second and then i'll explain to you what i want to show you here okay so hopefully you've pieced together that the slate here where the chloride is and where the arrows that says slate is pointing to this is our lower grade stuff and where it points to the nice and this green this is our higher grade so i want you to remember when we flip to the next slide that our highest grade was kind of um it was running north kind of on like a north east line going from well north south but heading towards east um but it was on the outside towards the atlantic ocean where we had our highest grade of metamorphism i want you to think about that let's take our ship across the ocean to north america um here we have here this purple this blue this red here this is our high grade medium grip and then this kind of yellow green and orange are our low grade i want you to look at this again um just like you looked at the other one and i want you to decide i'm going to tell you here this part of massachusetts is unmetamorphosed and long island isn't on metamorphosed um i want you to look at this area and i want you to think about um where you see the high grade and where you see the low grade and then we're going to think about what that tells us in terms of what use where the where the appalachians and the caledonia is and how they're related to one another did you notice that these colors these blues purples seem to be along the coastline we have them by maine by new hampshire here by connecticut rhode island we have some of that medium grade here into new jersey and to the lower part of new york here and then as we got closer to vermont canada and the upper part of new york here we had more of the lower grade remember if we had scotland here so let's think about this in our head um scotland's somewhere over here um where did we have our high grade our high grade was along this edge right right here right well if we bring these closer together so if we imagine our head this is reconnecting with this area in scotland our high grades are going to start to collide and line up right well the appellations were kind of split partly um by the formation of the atlantic ocean so it makes sense that the coastlines here have the highest grade of metamorphism because that would have been the heart of mountain ranges when they formed 420 million years ago i don't know about you but that is mind-blowing to me it's really awesome and really exciting that we could start to see how we can build the story just by looking at rocks so here we have a picture of a mountain belts now here's the difference between a mountain and a volcano a volcano will erupt a volcano will have lava come out of it a mountain will not um the reason the mountain does not have any lava coming out of it is because you're not feeding it any water so there's not enough temperature to actually melt and it's too high of pressure to have decompression melting but you do have enough temperature changes that you can make some um igneous intrusions at the very heart of that mountain chain and then as you move away from that hurt you're going to get lower so it's going to be the highest grade oops in the center of this mountain chain and then it's going to gradually get lesser as you move out so at the heart of the mountain where you have the highest grade amount of metamorphic rock you're going to have minion height makeup tight is the highest grade of metamorphic um this is basically nice that almost melted what you could think about it yes um we can see from that migmatite as we move away so this line here showing your magnetite here is in this heart we move away well now we get to our nice as we move away even further we get our shifts as we move even further we get our slate and so notice we all of that energy from colliding these crusts folded it bent it and created all that temperature and pressure um this is our um mid-ocean ridge so since i don't know if you can see the top i'm gonna write ocean ridge here so here we have um that water is heating up well where's that water coming from well some of it's from the magma because we have that decompression melting some of it is water that's actually seeking in through crust sinking not seeking sinking in through the crust cracks you have the heat here so you can actually start the metamorphosis basalt so we have our high temperature we have our low temperature we have our higher pressures here we have our lower pressures here so we're going to have lower metamorphism here higher grade over here but that basalt is going to start to change the reason that basalt is going to start to change is because you have this magma that's hot and it's squeezing out like toothpaste and so this whole region again when we're thinking about regional locate you could also call it local um metamorphism there's a reason why so with the mountains they had the crust colliding with subduction zone you have them sliding underneath each other now you have them being pulled pulled apart by this magma squeezing up so we're thinking local regions creating these temperatures and pressures so what's our series of events here to metamorphose basalt so here we have the salt then here we have green gist which is chlorite um and here we have our amphibolites our amphibola will actually look like little needles all stacked on top of one another um if we want to put this in a chart we have our low grade which is low temperature low pressure that's our green chest then uh if we just increase pressure and we're not increasing temperature then we get our balloost now if we increase temperature but we don't increase pressure we get our amphibolite now if we increase temperature and pressure we get eclegite so the rock name on over here this is green just um the rock name here lucious rack name here amphibolite the rock name here eclogite eclide has garnets in it so this is going to be the eclogite is your high pressure your green shift is your low temperature low pressure amphibolite into indicate the low pressure but high temperature and then your blue shift is higher pressure but low temp i hope this is starting to click with you again um come to me sooner rather than later because i'm here to help um here we have um those are our red garnets in this eclegite so we have these kind of pyroxenes and these garnets within this rock this is an example of an ecleggite for our high temperature this is our highest grade of metamorphism so we're going to put a note here highest grade of metamorphism highest grade of metamorphism so if i ever ask you which rock has the highest grade of metamorphism here we go migmatite um you can see it almost looks like paint swirls we have so much temp we have such um a high pressure within that mountain that almost starts to melt that rock and so it becomes this soft mushy-ness um kind of like you could think of like a cookie dough or like a silly putty texture and so that pressure can actually start to bend that nice and then so migmatite almost looks like melt like it wants to melt but it can't quite get there so this is metamorphic textures again the i don't know how much of the top you can see again um if you have any questions just contact me but also um as a reminder i do also post these slides onto um canvas so um if you ever just want to review the slides and not necessarily have to watch the video um slides just the slides are available for you those are not necessarily narrated or lectured over but if you just want to see the picture or just want to see the slides again those are all available to you on campus so here we have our favorite famous sequence shale to slate to phylite to schist to nice we're not only changing our minerals so we know clays to more micas to some garnets to some quartz and feldspars but we're also changing our grain size so we're going from finer grains increasing our grain size the larger the grain size the more dramatically we're going to be able to identify our layers so we're going to see this larger grain size is also going to indicate that we're increasing our grade of metamorphism so let's see what this all means so let's write this out we know that shale that when we're when we're increasing metamorphic grade we go from shale which is clay and sedimentary then um next to so we go from shale which is clay to slate which is more dense clay um it's going to have a foliation type that we call the foliation type or layering type is going to be called laminated and it's going to be um very fine grain um minerals or crystals might not even be seen or grains might not even be visible um and then our next step is going to be to from from shale to slate to clay so from shale to slate now we're going to go to phylite twilight is fine grain it has micas it might be silvery um it might have kind of like a glimmer to it i wouldn't necessarily say shiny but like a glimmer to it it might have small rust spots um which would mean garment um and then to schist um schist is going to be mica it could look like fish scales um it could have garnet in it it could have kyanite in it um it's going to have medium grain size i want to go back up to if i like highlight but the overall texture is going to look wrinkled or crinkled and then from from schist we go to nice so nice is going to have things like feldspar quartz um it's going to have amphibole um could have burned it but this is going to have very coarse grains meaning the minerals are very easily seen help did it um let's see if i can move that oh that didn't work so i'm going to just retype that over here so we went from shale to s to slate e over on the other side see the right side um to phylite which is again fine grain mica and burn it um those would look like rust spots and then this is going to have a wrinkle or crinkled appearance to just which is medium grain it's going to look like fish scales um it's gonna be very it could look flaky um gonna start to have mica um it's gonna it could be very shiny um you're gonna start to have things like garnets um you're going to start to have things that possibly kyanite and then we're going to go to to nice nice is um very fine very coarse grain mineral is very easily seen we're going to start to have quartz feldspar um etc um so you see that we're changing our grain size as we increase our temp our our um metamorphic grade we're changing our minerals all of that is happening um so here's this picture here is our picture of slate of um slate you can see this is what we mean by that laminated layers it kind of looks like pages of a book as we increase that pressure this gets to our shifts you can see that it looks um very kind of shimmery kind of flaky and then finally we get to our nice we have garnets here and we have those distinct layers so we're going to again stop sharing and i want to show you examples of each of these oops so we're gonna start with our slate so our slate here i'm gonna have to be moving our camera up and down but that's okay um our slate here let's see this lighthouse uh kind of um did help more than that one um kind of um so here we have our slate we can see on edge here that it looks like i if i took a really small chisel i could blank it along this line here this is actually how we make how um you get really flat things like um pool tables and like use slate sometimes for like tables and um like tiles roof tiles because you could break it into really flat pieces so this is yours this is your slate now our next step is our phylite so this is an example of phylite um this phylite you can see it kind of has a shimmer to it but it's not really really shiny um but these dots here um all of these little red dots see like closer if that helps there goes um so all of these little red dots that you see those are all garnets that have started to rust out if i turn it on its side here camera map you can see all of these red dots here every single one of them that's a garnet um you can see this kind of wrinkly appearance on it um it's kind of hard to see but it's a little bit wrinkly um you can really see the wrinkles here kind of looks like it has some layers to it um you can see the kind of shine in the light but you can't but it's but you can't actually make out the mica even though it's actually in this rock this is an example of phylite i can tell you it feels almost soapy if you get this wet and try to walk on it'll be very slippery now as we move up here's one example of schist so you can see it's very shiny you can almost see the layers there you can see how all these minerals look like they're stacked on top of one another you can see that there's larger chunks you can see that there's more minerals to be seen in this rock um it's very reflective another example of schist is right here this one has kind of like a gray a greenish tint to it again that has more of like that fish scale flakiness you could see um the layers really well here how the minerals look like they're all stacked on top of one another and you can see that kind of reflective nature another example of shifts is this guy right here this one has a lot of um shininess to it you can see how the mica looks like it's almost stretched but it's all layered on top of each other this is called foliation um this from this type of layering that we keep i keep pointing out time and time again is what we call foliation and this is a this is going to be a unique um texture for metamorphic rocks because you have that sort of um pressure and we're going to talk more about how that forms later but you can see the shininess and how large minerals are on this just finally we have nice we've got a couple different nicest here this nice um has primarily dark but you have the str the lines of light but notice how it looks like it's banded like layers of light and dark alternating that's very characteristic of nice this is what we call a actually banded texture so you can see that layering in that rock it's actually really clear right now layering in that rock here's another example of layering in a rock nope wrong one i have a pile of rocks here that i'm going through um so here you can see um that layers those lines you can see that the black lines look like they're tracing through they're not like zebra stripes but you can definitely see that there's a stacked pattern to these um black minerals if i look on the other side of this rock it's it's even more dramatic and that you have a broad band here and then a smaller band if we compare this to igneous rock we can see right away that in this igneous rock there's no pattern that's how you actually tell an igneous rock from a metamorphic rock because this igneous rock lacks that pattern that that metamorphic rock ass i hope that this is helpful and let's move on so when we talked about um english rock we talked about composition in terms of mafic felsic and um in terms of metamorphic rocks we're talking about um going from like clays to the micas to the garnets um for the textures for igneous rocks we had things like porous and porphyritic and aphanitic and pegmatitic for metamorphic rocks we only have to worry about two textures um but those differences in textures are important so the two textures are the two textures in metamorphic rocks this is going to be foliated which is what i was just showing you examples of this means layered or stacked minerals and non-foliated this means that it will look like a solid mineral um no distinct pattern i say no distinct pattern because um you might see examples like this this looks like it has a line in it but the line isn't consistent and there's not other lines that are nearby um this is limestone and this is marble so this is very similar to the rocks that we were looking at before this is a clastic texture you've got a lot of fossils that are glued together this is a chemical texture that's that recrystallization so new calcite has grown over this the foliated so foliation actually so foliation actually is indicative of a non-uniform or inconsistent press or pressure um non-foliated equals uniform stress or consistent stress so that's the differences in these four in these two different textural changes for metamorphic rocks so again we know the ways that we could form a metamorphic rock we have the contact in the regional now we have our two different textures and how they form and see the difference here we have this major kind of emphasis on pressure it all depends on whether that pressure is consistent all the way around or whether it's inconsistent meaning that it's being squeezed in more than one direction or it's being pulled in more than one direction when you start to have that squeezing you're gonna actually start to line up those minerals i'll let you think about that for a second we'll continue meanwhile i'm getting some play-doh out so we could play with something or i guess i'll play but you'll watch so this goes back to what i was trying to show you with the igneous rock this one versus the metamorphic rock that has those banded lines on um the igneous rock could have produced that metamorphic rock or that metamorphic rock could have come from shale but when we're looking at rocks this is how understanding what the story tells us can help us identify them because by looking at this we can look at it and have um some kind of reference to the fact that this rock experience pressure coming in on both sides whereas this one just was equal pressure on all sides so the minerals didn't have an orientation it didn't push it so think about if i had a dropped a stack of papers that's going to be completely random like this but usually when you're putting them back into order you push them in different directions right well that's what the foliation is it's helping to organize those minerals does that make sense so a confining pressure or a uniform stress means that everything is being squeezed equally from all directions that's not going to result in squeezing or stretching or anything else so we can take an example of this styrofoam cup the styrofoam cup was taken below sea level and so this is what it looked like at sea level this is what it looked like when it was taken below sea level and it was actually um 2 000 it was taken to 2 250 meters below sea level and look at what that pressure beneath that ocean squeezed down on this cup these were the same size but notice it still looks like a cup it's just smaller so uniform stress will just combine everything and make things smaller and more condensed so same thing happens with rocks when they're buried they're squeezed in all directions and when they're squeezed in all directions they just get confined they get buried and so now it's just a smaller more compact unit so this is what's happening with non-foliated rocks so uniform stress for thinking non-foliated rods bleated metamorphic rocks um this also happens with sedimentary rocks and happens with igneous but for our purposes for metamorphic rocks we're thinking non-foliated that's our goal when we see uniforms non-foliated rocks now uniform non-uniform stress means that we are stretching something or we are squeezing something or we are shearing something now this is how we could line up minerals in a foliated rock we're going to take this off um and we're going to say this is what forms foliated rocks so how does that work in terms of lining up minerals i'm gonna stop sure for a second i'm gonna show you i have a ball of well on your screen it looks it looks blue but it's purple and then orange and what i'm going to do is i'm going to put both of these balls next to each other in my hand now i'm going to push that so you see they're next to each other i'm going to push down and worlds this is a type of hearing and this would be a type of non-uniform stress but we can see that what i've managed to do is line up and stick together the orange and the blue or purple and you can see that they've lined up with one another so what i've actually done and is given a demonstration of what actually happens with minerals as they're recrystallizing that pressure lines them up so even if it's a shearing pressure those minerals are still going to be in parallel lines roughly parallel lines instead of just one big ball that would be that uniform pressure because when i go like this it's just uniform pressure hope that helped kind of illustrate so um i was just using play-doh you could use a silly putty that's what this drawing is showing you um when you compress it you can make an oval or you could actually like make a smile or frown you could actually stretch it out um so that tensional stress would would create that that actual stretching whereas that compressional makes it shorter and then our cheering will actually be like if i had a deck of cards here and i slid it across or a piece of paper or a stack of paper and slid it across that's your sheer so when i was rolling that plato that's a sheer stress so this is showing you in mineral form what i just showed you in playoff those those minerals initially um when we first have them they're they're just completely irregular that's like those two balls of play-doh that were next to each other when i smashed them and rolled them that's what this part c is showing so part b was when i just smashed them down and then part c is when i started to roll them so you saw that our play-doh line lines up just like these plating minerals start to line up so when we were looking at the examples of the rocks remember we started to see those layers well that's what this foliation is and that's how this pressure creates this foliation it seems like it would be a really good test question doesn't it so here we have if it's equal pressure all the way around those crystals are not going to be forced in any sort of pattern so we get a non-foliated rock if you have that pressure squeezing down on you in one direction you're going to be limited in how you can move but you're going to be limited in how those crystals can grow so that's how you get that foliated rock so this would be an example of igneous this would be an example of metamorphic here we have a conglomerate which has been metamorphosed a conglomerate is a sedimentary rock that has a lot of pebbles in it these pebbles you can see have been flattened and stretched and so when they were recrystallized they created this metamorphic texture you can see how they're all stacked and lined up and parallel to one another um so when i was showing you the slate i was telling you to kind of imagine if you could um take a a knife or like a chisel and go straight down um one of these um rocks here um they use cleavage planes as a definition but that's just because they're they're talking about cutting there i don't like to use that term because make students think about minerals and minerals and cleavage and this has nothing to do with minerals and cleavage this is a facili facility um and this reflects the alignment of those minerals within the rock um so here we have it looks like pages of a book that's your slate or laminated and again this isn't going to be as visible as say the banded or those distinct layers that we were talking about you can see and the nice and that's because it's such a fine grain rock it's going to be more difficult it's not going to be as stark or as easily identified but you can see this looks like library books stacked on top of one another that's that laminated cleavage and again this goes by why they used it for chalkboards why they use it for pool tables because you could actually break it along those planes and make really flat surfaces that are durable um oops this is that kind of wavy or crinkly um texture that we see in a phylite this um is again you could see that kind of layers here within this bigger broader picture you can kind of see that shimmering to it this wavy foliation again it's a little bit more distinctive because the grains are a little bit bigger but it's not in your face big so it's a little bit more difficult to see and again these are all due to that differential or non-uniform stress this is that kind of fish scale look it actually looks like you could peel it off like the plates of mica or like that big piece i was showing you where it looks like it's stretched this is your schistose foliation and it looks like it's flaky or scaly and it's getting easier to see because the mineral grains are growing and the mineral grains because they're growing and specifically it's becoming those mica that's why you get that really shiny reflective fish scale like appearance um sometimes it looks like it's stretched like that big rock i showed you because it's this mic that's growing over um in this like chunks of um garnet or straw light or whatever might be in there here's a picture of that nice where again it doesn't look like zebra stripes so you can make out where those lines are um those are alternating light and dark bands that nice or banded foliation this is going to be the hallmark of a nice as soon as you see that banded formation when we start to look at these rocks to identify that's what you're looking for that's your nice it's going to be so stark so easy to see because the grain sides are so big so we start with lower grade this is our shale we go to our slate notice our shale we could kind of see lines but our slate it's much more defined and then from our slate we go to our phylite where we've got that kind of wrinkle appearance and then we go towards our schist that has our fish scale appearance and then from our schist we go to our nice which has that banded appearance so here's a summary of what we just went through so step one we go from the shale to the slate and that's your slate foliation we also called that laminated um then from that slate we go to phylite which has that wavy which has that crinkled or wrinkled appearance um then from the phylite we went to the schist which has that mica flaky fish scale like and then from that shift we went to the nice which has that nice or banded foliation so these are our steps that we're taking i'm going to pause here let you kind of digest what we've been talking about this is kind of summarizing everything that we've been talking about i told you that this this sequence is going to be a reoccurring theme in this lecture and this is kind of an overview and summary of everything that we've talked about with the sequence why this was so important and it will keep coming up it's a reoccurring theme and yes it will be on tests so this diagram does a pretty good job of giving you an overview of everything we've talked about in terms of how a metamorphic rock forms so here you could have your contact metamorphism with our igneous rocks here we have our plate tectonics so we have our mountain building so at the heart of our mountains the deepest down part of our mountains we have our highest grade of metamorphism as we go towards the top of our mountains we're going to get gradually less just like at our closest part of our contact we have our highest and as we go away we get our gradual less here we have some of that contact metamorphism rock happening near the surface so we can't have contact in regional happening in the same general area but we're going to have different minerals and we're going to have different processes in each um so migmatites never ever ever completely melt if they did they'd become an igneous rock it do become this kind of soft solid kind of um moldable um and so that's why you get this kind of um stirred or folded nice like texture so migmatite is actually one step higher and nice this is an example of our non-bulleted texture so for our non-foliated texture we have marble and quartzite marble is made out of primarily calcite whereas quartzite's made out of primarily quartz so um do i have examples of each um so let's go back to our camera here so this little piece here that's our core our quartzite our quartzite is this gray piece and then this pink orange is our marble if i take this quartzite i just scratched up our marble this is harder if i tried to do the same thing with this marble on this quartzite i can't do it and that's because the minerals are different this has quartz in it so this is a harder mineral and we can see that that scratch i made i can't get rid of another difference here between these two is if i had my bottle of acid and i don't know what happened to the bottle here's my bottle of acid um i could make this one fizz but if i put the acid on the cord site it just runs off and so this goes back to understanding our mineral properties and why it's so important to understand our mineral properties because it really does give us clues to identifying our rocks this also gives us clues to the differences in properties of quartzite versus marble so marble is soft and because marble is soft it's often used in building and in carving um the lincoln memorial is made out of marble the these a leaning these steps at leaning power pisa nobody carved out these footsteps that was just from years and years and years of people walking on them where i went to undergraduate augustana college in rock island illinois we had an older building that had marble steps in it and i was in choir when i was in college so i would walk up the steps in my um to go to a choir concert and whenever the females um in the choir were wearing our dress shoes um we could feel the bumps and it made it it made it uneasy because that marvel was wearing away because it's so much softer had that material been made by that quartzite like this quartzite here notice it scratched that marble but it's also harder to carve and it but it would be more resistant to weathering than the leaning tower steps here or the steps i walked up um so um this here is actually not foliation this actually is remnants of that original um layering from that sedimentary rock and then when it metamorphosed you can still see the hint of it this is quartzite from baraboo wisconsin so this goes back to the importance of understanding not only the minerals in terms of identifying but the mineral properties in terms of why different materials are used in different ways um here's a outcrop that i went to um this is actually near fishkill new york um you can see what we do on these field trips when we go um we don't often know what we're looking at beforehand actually usually this was for a class and even if i went there and i was doing research not for a class um you might look at some maps ahead of time um you might do some research so you have some idea of what you might be looking at but in general you want to look at the rock outcrops without any sort of bias or as limited bias as possible so you want to go there with an objective viewpoint to make some observations so what you see here is these are the pictures of exactly what we do we go out there um we have our rock hammers we have our notebooks that's what this gentleman's writing in here and we start to take pictures we start to make observations and we start to try to piece together the story um here we have notice i've seen said things like maps notebooks um maybe doing a little research i haven't said everything on the internet or i haven't said we go there and we've written up a whole history on the internet and we've googled it all and we know that we know the whole history no geologists and scientists in general are natural born skeptics so we want to go there and make the observations for ourselves so it's not look it up we are constantly trying to learn something new that's how science is we're constantly trying to learn something new we might give and give some information so that um that we know at a time but information is constantly evolving constantly changing um so here we have some minerals that were there you could see this looks like there's a band in there um this is you could see some layers here so i was thinking this was a nice when i first saw it um you could see um she's i'm five foot six so she's around five foot six five foot seven to give you an idea of height here um she you can see here it looks like somebody um or paint down this i had actually never heard of migmatite before going on this field trip but these are examples of migmatite um and this is near fishkill new york so this would have been in the heart of the appalachian mountains at one point in time this is actually victors from my favorite place i've ever been on a geologic field trip um this is beavertail state park in rhode island um here we have each of these little red dots are garnets this is a whole cliff made out of this this is all phylite the whole beach is nothing but cliffs of phylite i've been there twice the first time i was there was a sunny day well actually actually kind of overcast but it wasn't too bad to walk on second time it was raining and let me tell you the stuff because there's mica in it it's really slippery to walk on but it's just beautiful in the sun even when it's wet it's just beautiful because it glimmers and it just shines because of that silveriness of the mica in it and so that's the lecture um i hope you found this helpful and again if you have any questions please don't hesitate to contact me i'm here to help um in any way that i can so good luck and thank you