 Okay, good. All right, so talk to Chantel. We were trying to figure out some presentation we could do for Science Circle and I thought of the eruptions of the volcano in Hawaii in Kilauea and thought I would talk a little bit about volcanoes. So I'm going to start out really simple and then we'll progress and get into the concept a little more detail as always feel free to interrupt. I'll be keeping track on the nearby chat so you can always type a question in there and I have a problem stopping and I'll do the best we can to answer them. Like I said, I'm going to start off simple. I want to summarize some of the results that volcanologists have come up with. And at the very end, I want to talk about some research that I've done with James Mass in university on some igneous rocks and ancient volcanoes in northern Virginia that is leaving a whole bunch of geology stump. Maybe some of you who are on Science Circle give us some suggestions as to how to resolve it. I'm Bill Schmackenberg in real life. My email address is up there. Feel free to email me if you have further questions or comments that you want to do. Right. So, like I said, we're going to start off some real basic stuff. Magma that comes to the surface is considered lava inside the volcanic chain. It's considered magma. And I think there's an important distinction to be made between these two. Magma that forms on the outside of the earth cools relatively quickly creates fine grained igneous extrusive rocks like basalt. Magma that's inside the earth is like inside of a thermos jug. It cools very slowly forming coarser grained igneous rocks like granites. And it's the igneous rocks that tell us so much about what volcanoes were like in the past. I'll be saying more about them in a little while. Alright, some of the gases that have been measured from volcanoes include carbon dioxide, hydrogen sulfide, ammonia, what? Well, H2O, but not liquid form, but mostly in high pressure steam that's coming out. The explosive gas methane and cyanide, which is poisonous. One of the things that scientists have noticed is that we don't get any oxygen coming out of volcanoes. The intense heat inside the magma chamber forces the oxygen forms CO2 or sulfide gases. And this may have been important early in the history of the earth. It was probably volcanoes that formed our initial atmosphere and then later on as a result of terraforming processes and bacteria, the carbon dioxide is converted into oxygen. I'm going to give it a few minutes here to res. Alright, we also recognize a different solid material called pyroclastic material that shot out of volcano. The finest material is the size of flour, less than a quarter of a millimeter in diameter. Then the next size up is typically rice grains, a quarter to five millimeters cinders, which are the size of golf balls, and then anything larger than that are considered volcanic bombs. If you think of a volcano sort of like, yeah, that's true. If you think of some, think of volcanoes as sort of like a cannon. These things are fired out. They don't explode, but they're sort of like cannonballs. There are four types of volcanoes that me that geologists typically recognize. There are the shield volcanoes, which are very wide at the base, but they're not very tall. For example, Hawaii. These produce only a little bit of lava and are the least violent things. So just lava just sort of trickles down the side of the volcano. The fastest flowing lava is on the earth are only just a couple of miles an hour. So you can quickly and easily run away from them. Then we have the cinder cone volcanoes. They're the exact opposite. They're very narrow at the base and very tall. For example, some of the Mexican volcanoes are like that. They're a little more destructive. We're more violent. They shoot out rock particles. You get pumice coming out of them. When I worked at the University of Chicago, we did a field trip to the Southwest part of the United States to a cinder cone volcano. And it was sort of weird. I remember rolling in to the camp site. It was late at night. Couldn't see anything pitched to tent slept. Got up the next morning and the ground felt really weird and got outside walked around and the best I could describe it was like walking on on black popcorn is what the cinder cones are like. There's some of the most recent, by the way, and the southern part of or well Southwest part of the United States, in some case, only a couple of million years old. Then we have composite type of volcanoes, which are a mixture of rock and lava Mount St. Helens is an example. And then the fourth and probably the most violent type of the called areas are cauldron shaped volcanoes. The Greek islands and Melodia gene are a really good example of these. We typically have a bunch of vents that allow war to go through. It hits the hot molten magma inside pressure builds up and then boom, they explode outward. Other examples of called areas would be Yellowstone Park, for example, that's erupted 20, 30 times when they go off. They're extremely violent and that's something the USGS is concerned about is a eruption of a super volcano. And Vic says walking on cinders and why I felt like walking on glass and there's all the heat up your shoes. And that's not good. All right, so I have here pictures of four different types of volcanoes. So you see shield volcano in the upper left hand corner, very wide, not very tall. Cinder, I wish I had a different shot of this because it's looking down on the cinder cone volcano. And it really doesn't do the perspective right. Like I said, they're very, they went upside down ice cream cone. You got the idea of a cinder cone. And then there's Mount St. Helens as a composite example and then a caldera volcano in the lower right hand corner. All right, so one of the things that I think are really interesting that geologists and volcanologists have been discovering is we now understand why it is that some volcanoes are relatively mild and others are extremely violent when they go off. And there's a series of factors that we've identified dealing with volcanoes that tend to control how violent they are. The first one is gas pressure. So if you think of a volcano like a can of soda, if you pull the top of the can of so you. Okay, it's rapid release of carbon dioxide gas. And that's sort of what a volcano is like. And one volcanologist here in Virginia told me that the release of pressure is actually more important than temperature with dealing with volcanoes. So the higher the gas pressure, obviously that's inside the volcano, the more violent they tend to erupt. The second factor is the number of vents. We know that there are holes in the sides of some volcanoes, more vents, the less violent the eruptions like taking an ice pick and jamming it into a can of soda. You're going to release the gas pressure more slowly than if you don't. The third factor is viscosity, also known as resistance to flow. We've all seen different fluids flow. For example, if you look at water, if you pour it on an inclined plane, it tends to flow very quickly down the plane. If you think of something like molasses, if you pour that on inclined surface, it tends to move very slowly. So we say that molasses has very high resistance to flow, whereas water doesn't. And lava is very similar to that. Some lovers are, you know, are very runny and some are very sticky. Yeah, as some totes says, you can look at as the internal friction of a fluid, which is fine also. And even the fastest flowing lava is like I say on the earth, they're only a couple of miles an hour. You can just easily walk away from them. So it turns out volcanologists are more concerned about the viscous lava flows because they can form dangerous volcanic plugs on the top of a crater of gas pressure can build up. And then that's when you get these very explosive discharges. Mount Pinatubo that erupted in the 19 days is a really good example of that of a pyroclastic flow with a material just flowed out very quickly. Those are probably the most dangerous pyroclastic flows can travel over 100 miles an hour. And the very hot 600, 700 degrees Celsius, and they hit you that, you know, it's certain death. And the question then becomes, and here's to me is one of the most exciting discoveries that volcanologists have made is that you can determine how violently a volcano erupt based purely on the mineralogy of an igneous rock. I thought this was fascinating when I was a graduate student, I heard volcanologists in Chicago talk about this. It turns out that you if you have light colored, what are known as the felsic murals, things like quartz, that's in fells bar say must bite Micah. If those are the predominant minerals that are present in the magma or lava. Those tend to be very thick and be very viscous flows. But those are the most dangerous. So light colored igneous rocks to believe when they erupt are very dangerous. On the other hand, if you have a lot of dark colored minerals, for example, all of the period scenes ampoules, the so called mafic minerals that are present in igneous rock. Those are the ones that tend to be very running. For example, you tend to see those in the Hawaiian flows. And the last thing I have here is temperature. So what we've noticed is that in general, the higher the temperature. Well, you could argue it one or two ways. And I actually, when I do this as a PowerPoint in my, in my, in my classes, I have students vote on this. And I sometimes have students say, well, the higher the temperature, the more violent is higher the temperature, the more gentle it is. Yeah, I mean, a couple of ways of looking at and it depends upon the other factors, right? If gas pressure is the most important factor, right? Then it becomes a matter of gas laws. I'll make Mike show happy about this. Obviously, if you've got complying gases inside the crater, and you start increasing the temperature, you're going to, you're going to pump up the pressure. All right. On the other hand, if that's yeah, I just said that. Okay. If on the other hand, this is the more important factor in a volcano. As I bump up the temperature, what's going to happen is I'm going to make the law, the magma is runnier. It's the analogy I sort of like to make there and think of it this way. When I got up this morning, I had waffles. So my wife keeps the maple syrup in the fridge to keep it fresh. But I took it out. I think as hard as it rock. So what do I do? I nuke it. Okay. I heat it up and that becomes nice and running. And the same thing is true. Okay. With temperature inside a volcano. Okay. The higher the temperature, the runny it is and the more gentle it tends to erupt. And you sort of see that, you know, you look at the flows and why you're talking about 1200 degrees Celsius. So when they come out there, they're pretty running sort of a lot of us. If you look at the ones in Italy, Japan, those are the more business flows. They're a lot cooler, maybe 500, 600 degrees Celsius. Or right. Yeah, somewhere in that range, I would say. Right. So it is sort of interesting that we're getting a feel as to the factors that control volcanic violence. All right. And we've got a question from Astrid. How does the gas permeability of the gas through the rock come into this and the gas escape from the rock? That's a good question. And sometimes it does. And sometimes it doesn't. There are the silver salts. Okay. In which case. In which case, you know, the gas has clearly escaped from it. There's pumice. Okay, which is fired out at very high speeds from volcanoes where the gas is actually trapped inside the air pockets of the rock. There was an interesting study that I saw that he was done at the University of New Hampshire. And when their volcanologist presented this years ago in Chicago, and what they did was they wanted to know the altitude of the Rockies. And the way they did it was very clever. They went out. They went, first of all, they went to Hawaii. Okay, that must have been a tough job. Getting the grant for that. So they go to light and they measure the air pressure at the top of different volcanoes. And they get a relationship between the amount of trapped gas in the vesicular basalt versus elevation. And they found a relationship. And then they got basalts from the Rockies in the past. And they were able to determine how high the Rockies were based on the gas pressure in the vesicles. I thought it was a really clever use of using sort of pressure elevation changes. Okay, let's see. That was a part of the trivia question, right? Okay, so next thing I want to talk about is how volcanoes form. And there are multiple ways that we now recognize that volcanoes can form. Probably the most common way and the one I'm going to start with, as Rick has just said, is subduction. All right. And here you see a diagram of a typical subducting situation. So you have on the left-hand side of the slide a mid-ocean ridge. New seafloor material is being produced at the ridge. Agma is welling up like that. Seafloor material is moving to the side. As it moves to the side, eventually it gets denser and it's taken back down into the crust. And actually mid-ocean ridge or rifting tends to occur in the Atlantic, whereas subduction tends to happen mostly in the Pacific in terms of what's going on. And then what happens, if I can continue, what happens is water is taken down into the subduction zone or the trench. And as the water goes down, what it does is it lowers the melting point of the rocks. And rocks that are on the bottom of the crust tend to melt very easily. And as they're coming up, it forms the volcanoes. Typically the melt that comes from, they call this partial melting, is rich in more of the felsic minerals they melt at lower melting points. So things like quartz, potassium, phallospora, and the mycas. They crystallize out first, whereas the denser minerals, for example, your pyroxene soils and all of the enriched segments tend to be solid. So this is one way that we get it. So volcanoes around the Pacific, things like the Aleutian Islands off of Alaska and Indonesian islands, New Zealand. Any of the islands in the northwest part of the United States, such as Mount St. Alan's or in the Andes in the western part of South America, all really good examples of subduction. And I think scientists quickly grabbed onto this as one of the main mechanisms of which volcanoes. But there are other ways of doing it. So you can either form volcanoes as a result of rifting or by a subduction. And Bergen says, yeah, it's kind of nutty if the earth has a zipper. Bergen, it's funny you say that, I wasn't going to bring this up, but yet there are actually places where the earth is ripping apart. If it's town of Mid-Ocean Ridge, what happens is that magma wells up and fills the holes that are in between. There are other places on land where it's also unzipping. And my favorite example, really the only example that I know of that's doing that is if you look at Ethiopia in northeastern part of Africa, literally what's happening is Africa is being ripped apart. There's a rift zone that goes right through there. And as it proceeds, you're forming this valley. The technical term for it is called the lockogen or sort of a land sort of rift system, but there are places on land where you can actually see continents ripping apart. And that's important because sometimes I get asked, well, how do we know Pangea is superconduct ripped apart while it's happening today. Let's see, Vic says there's also an oceanic ridge extending from Iceland all the way around into the ocean. Oh yeah, the Mid-Ocean Ridge is extremely long. Iceland is the main part of it that's exposed above sea level. But yeah, it goes right down the middle of the Atlantic Ocean to the southern Azores. And then you're right, it wraps around Antarctica. All right, so next guy here. All right, when I was in college, one of the things that was being heavily debated is what do we do with Hawaii? Geologists really were bothered by Hawaii. It's a huge, long volcanic island chain. There are five islands that are most of all sea level now. You can also face the volcanic island chain all the way coast to Japan. There's a whole bunch of underwater seamounts that are on the bottom of the Pacific Ocean. And I remember as an undergraduate at Cornell going from geology class to geology class and the professors there just were heavily debating this. Some people wanted what was called a propagating rift. They thought there was a split in the Pacific sea floor, and Magma was welling up inside there. That one sort of, I think, fell by the wayside. The leading theory now is that we've got some kind of hot spot that's going on underneath the Pacific sea floor. There's some concentration of heat that's down there that's melting its way through the bottom of the Pacific plate. And it forms little seamounts on the bottom of the ocean that in turn works its way up to form volcanic islands. And we're not sure what's down there. I think it is that some kind of concentration of radioactive material that's down there. But again, nobody really knows as the Pacific plate drifts to the West. It drags these islands off of the, that's right. And we're going to say, Dallas forms the plate moves away from the hot spot. And you, in fact, there's a new one that's forming to the east of the big island of Hawaii. As of dot says, are there other examples of mid plate hotspots? Yes. And the best example of that that I can think of is Yellowstone. Yellowstone we think is sitting right on top of another hotspot as well. And you can, you can trace a series of volcanoes from Northwest Wyoming across Idaho. It's called the craters in the moon. The series of volcanoes that are millions of years old. And the cool thing about this hotspot is that we can use it. That's right. It's fair the path of the color of the river. We can use this to measure the, the rate at which the continents are drifting. So I just had my students do it and we did the Hawaiian island chain, for example. And students found out that it's drifting at a rate of about, I think the average was 3 inches a year, which is very high for a plate. Moving normally plates move maybe a couple of centimeters a year and inch a year. So for some reason we're getting a very high drifting rate off the line plate. All right. So we've got a couple of different models here. Okay. For how that forms. We've already talked about how Vic just brought up Yellowstone. So here's an example of how Yellowstone works. Basically it's a big volcanic crater system. The super volcano that's been erupted maybe 20, 30 times in the past. And mostly rhyolitic lava. That's why it's called Yellowstone. All right, let's see. Hawaiian chain is linear until you get back tens of a minute heads north all the way to the top of Chatscope. It's very evident from the sea mounts. Hey, maybe the plate moves because the hotspot reduces viscosity on the plate. That's an interesting idea. I never thought of that very gone. Right. We do know the plates move at different rates. We know the transform force allow them to move at different rates. It sort of decouples them from one spot to another. All right. And since you were bringing up Yellowstone, here's another graphic showing the Yellowstone volcano in red. And I wish I had a pointer here, but you can see it in there. And then there's a series of volcanoes that goes to the Southwest. So we can date them and measure their speed of movement. Okay. So those that's a modern plate tectonic theory. And now what I want to do is talk about some of the more ancient volcanoes. And here's one of my favorite ones I like to go to. This is ball knob that was that I took on a field trip. I just ran in my high school with my students. I'm fortunate being in Southwest Virginia that this structure is right behind the high school. It takes about 15 minutes to hike to the top of ball knob. I think I've got some other couple of pictures here. Yeah. All right. Yeah. Here's an example of a rock that we got off that I got off the top of ball knob. So you can see it's a classic sort of vesicular basalt. We've done a number of studies on this on this structure. We found that in terms of mineralogy, it's rich in amphiboles. And we're also starting to get some dates on it about 600 million years old. I'll say a little bit more about this history in a minute. And here's another picture that I took on the field trip just about a month ago. And this is a shot. I'm standing on the basalts that are here looking out over the valley. And in the background, you see grassy hill that's there. The class spent a night on bold mountain. No. Okay. Tagline. We're, it's like I said, it's a 15 minute hike to the top. We look around for about 15 minutes and then we come right back down. But it really is an outstanding example, an excellent way of doing field based science in the high school campus. We're very fortunate to have these schools have this opportunity. I've been running field trips to ball knob for about 30 years now. And when I first came to the high school, very little was known about this structure. I thought it was some kind of old volcanic stock, which was just pure guesswork. And over the years we've been learning a little bit more about each of these. All right. This is, this is a rock. This is a granite that was taken from Martinsville, which is south part of Virginia. Very different type of mineralogy, mostly quartz. And I see some dark minerals, maybe some pure scenes in there. Ball knob is about 600 million years old. This granite is called from what's called the Leatherwood granite. It's about 500 million years old. All right. And here are some samples of igneous rocks that I obtained from James Madison University. They were, they're cleaning up Memorial Hall. And they said, well, we've got all these rock samples left over. Do you want samples of them? I said, oh absolutely. So they sent me samples of these and I took some pictures. I also have some of my students go through and analyze them. This one was very interesting from going to Virginia. It's a rhyolite, which I didn't even know existed in our state. And it's more similar to what you see out in Yellowstone Park. Here are some examples of some other specimens. This is from molehill. This is about 50 million. Both the rhyolite and molehill samples are 50 from their ESEAN age and about 50 million years old. And again, the question is, you know, how did these rocks form? Some of them we're starting to understand others we're still having trouble with. And one of the things I had my students do was we went through and I had students use online gifts. And they clawed up the samples. And I don't know if you can read this, you may have to zoom in a little bit. I'm going to have to do it as well. But the first letter, we have about data from nine or 10 samples. Actually, Jamie, you has more, but they only gave us data on none. The first letter of the symbol that's next to each stops refers to the age. So if it's an E, it's ESEAN. It's about 50 million years old. If it's a late Jurassic, it's about 150 million years old. So we have volcanic rocks in Virginia that range widely in age and composition as well. The oldest English rocks that we have in Virginia go back about a billion years. And the youngest ones are about 50 million years old. All right, so what have we learned from this? You know, what do we know and what do we don't know? Okay, that's what I want to try and get into here. The, what do we know? All right, let's start off with ball knob. I'm going to go back here a little bit. Oops. Go back forward. Okay. Let's see. So we have a question from tagline. So Virginia area has been above sea level for at least a billion years old. Yeah, actually, the paleogeography of Virginia is very interesting. To the west of Virginia, you have the Laurentian super Laurentian Crayton plate. All right, so that's been around for you have millions of years. And what I tell my students and I think what I would suggest to you as well tagline is don't think of Virginia as it is part of North America today. If you want to try and visualize it, think about Japan. Think about how there's a volcanic island arc off the coast of a continent. That's what Virginia was like. In fact, we probably had several volcanic island arcs off the coast of Virginia in the past. And getting a little bit off of track here though. All right. So what happened was that a billion years ago, North America and South America slam into each other. And you're all familiar with the Pangea story, right? Okay. That 200 million years ago, North American Africa slammed together and formed the superconduct Pangea. And what we've learned over the last couple of years is that there were other supercontinents prior to Pangea. If you go back a billion years, geologists are now speculating that there was a superconduct known as Rodinia. There was a different arrangement of the continents, though Virginia was right in the middle of North American, South America. Then what happens Rodinia forms a billion years ago, 600 million years, Rodinia starts to rip apart. Okay. And the crack formed right behind my high school. My high school was actually in the crack of the, we want to call it the rifting zone and want to be fancy. They call it the late protozoic rifting zone. That zone can be traced all the way, at least as far as Southern Virginia, right in a diagonal line, right through Maryland, all the way up to New York. Some of the rocks there are very similar. And over the last year or two, we're learning a lot more about how North and South America split apart. One of the things that we learned is as the crack develops, okay, the initial rifting involves very shallow volcanism, extremely violent volcanism. Right. So what happens is that you start firing out pyroclastic bombs in my neighborhood. As one geologist said, if you had been around when that initial rifting, there's no way you would have been able to survive that you would have been able to get away from that pyroclastic material. Right. Then as rifting progresses, what happens is the shallow rifting goes deeper and deeper. Okay, into the earth and you go to deeper sort of volcanism and you form the salts that you see around here. As I said before, if you have a lot of dark minerals in it, those are relatively quiet sort of eruptions. You form ball knob and grassy hill. Right. Keep in mind that Virginia was a lot narrower than it is today. Okay. I'm about 20 miles south of Roanoke to give you an idea in terms of geography. We were the edge of, we were Virginia Beach if you went back 500, 600 million years. Okay. Then what happens, let's go pay this. Okay, we've got this grand here. Then what happens is volcanic island arc sets up off the coast of Virginia. Right. And starts firing off ash material. In fact, we can find some of those layers in the Appalachian Mountains. And that arc gets slammed into North American welded onto the North American continent. In fact, that's how I got this salt was by sampling from that old volcanic island arc sequence that you see. And then after that, you form Pangea or the continents come together. Africa slams in the North America. You form the Appalachian Mountains. And then rifting occurs. Pangea rips apart, North America pulls apart away from Africa. And you start finding the salts that are formed that are. I would say early Jurassic and age, maybe 200 million years ago. If you go around Southern parts of Virginia around Martinsville where the museum is that I like to work, you can find the salts from that era. What's really tricky, and this gets to sort of the question that we have. Are these igneous rocks in Northern Virginia? Okay, these rhyolites that are 50 million years old. And these basalts that are similar in age. And we don't have a model right now to explain these rocks. All right. It's an enigma because what's happening is at this time, North America is splitting apart. We call it passive tectonic margin. Okay, North America, Africa, Europe, they're just pulling gently apart. And there's no reason why volcanoes should have been triggered from. Jurassic time, late Jurassic 150 to 50 million years. And yet they are, and it's not just like one, like I said from this map, we've got about 10 different locations in Northern Virginia. Where you can find these volcanic deposits. And there seems to be a pattern for some reason. You've got high silica. Orts and potassium fells for rich samples in the West. And then to have the more mafic. Amphiboles purexings and so on in the East. So I'm having a discussion right now with some of the geologists at James Madison University. And quite a few are where these could have come from. So asymptote says, but if land tears apart, doesn't that produce a deep riff that releases magma? That's a good question. There should be the most of the rifting though is in the mid-Atlantic Ridge. Okay, it's confined mostly to there. So certainly middle of Iceland, for example, or down the middle of the Atlantic Ocean, you get this crack. And then magma is welling up and filling it in. Could you get cracks further? And that's, that's sort of an interesting question. If you did, then, you know, why is it salt? So we're, why aren't we getting just the salts? Where are the, right? Look, one's coming from that seems to suggest some kind of partial melting, almost like subduction is going on. But in order to have subduction, you have to have the collision of plates, not the ripping apart of plates. It's in my mind, it's sort of, this almost brings me back to the 70s, late 70s and 80s, when I was sitting in Cornell, we were debating about Hawaii. And the question in my mind is, you know, do we need a third mechanism for generating igneous rocks and volcanoes other than mid-ocean rifts, subduction, and hot spots? All right. So, I asked, but in ancient Rodinia, wasn't there rifts that are gone now? Oh, absolutely. Rodinia, by the way, up with this, a local chef is spelled like that. And I was told it's a Russian, is KT still here? I was told that Rodinia is a Russian word. So maybe KT, do you know is Rodinia, is it a place in Russia? Is there a translation from Russian into English? Because I ran into one of the guys, one of the geologists that was asked where Rodinia comes from. And Rodinia, from the Russian, being to beget or give birth, meaning motherland birthplace. There we go. Vic is faster. Okay. Interesting. I'm not like, Pangea means all lands. I get that. All right. But nobody is really sure about what Rodinia meant. But anyway, to get back to the question. Yeah, there are certainly rifts. Okay, from Rodinia. You go back 600 million years ago. Absolutely. Balnab is an example of rifting basalts that are there. If you go to the Catocta Mountains in Maryland, same thing, they are Rodinia rifting. Maybe some of the rocks around New York City are as well, although that's a little more questionable. But they're 600 million years ago. The ages don't work out here for the rifting of Rodinia. They're too young. The basalts and rhyolites we see in northern Virginia are only 50 to 150 million years ago. They're way younger than the rifting event of Rodinia. And even somewhat millions of years younger than the rifting of Pangea, even. Vic is putting in some Rodinia. Look at, what's the YouTube video Vic? Oh, Mark's Brothers. Okay. I have talked with other people. Some people have suggested that maybe this is not a geologic event. Maybe it's more of an extraterrestrial event. Some people said this could be a result of an impact event. Where some extraterrestrial object is slamming into the crust, fracturing it and causing these igneous rocks to come to the surface. That seems sort of unlikely to me. You'd expect to see some kind of cratering. Alright, so as some notes says, couldn't there have been a recent hotspot that's moved elsewhere? I remember when I took geophysics, we talked about moving hotspots. And the evidence that the geophysis told me is that most hotspots, once they set up, tend not to move. You know, the assumption that we make is that the hotspots stay in one place. And it's the plates that move over them. And I think, yeah, I don't know whether that's assumption or it's been proven. We sort of assume that because it makes it a lot easier to measure plate movement. If the hotspots are moving around on us, then we don't have a clue as to how fast plates are driving. But like I said, I remember this was discussed back in geophysics in the 80s and people were pretty clear that it wasn't moving around. Alright, couldn't that explain those rocks? What explains them? Moving hotspots? You want to move a hotspot around, ask them to explain the movement of the, or the placement of the igneous rocks? They kind of moved away from that spot. One of the things that I played around with is I sort of noticed that some of the youngest basalts are in the east and they get somewhat older in the west. So I tried to figure out if a simple plate movement could explain the location of those igneous rocks. If, for example, we had a hotspot or something. And the plate movement that you get when you play around with the scale is just way too high. Okay, to try and explain this away with just hotspots. I originally thought molehill, for example, was a hotspot. And I was quickly told by others that no, it can't be a hotspot. So it's sort of some kind of mystery that we have going on here. Anybody else have any other questions or comments? What is the main argument against molehill being a hotspot? I'm not exactly sure. It was one of the volcanologists that said that it might be based on mineralogical evidence. Jim Beard, I took to Jim Beard who was a volcanologist down at the museum and he didn't like the idea of a hotspot. He may have some mineralogical evidence. My concern, I still said, all right, maybe it is. But like I said, I tried doing some simple math and measuring the rate of North America and I got numbers that are way too high. Could they have been transported from somewhere else where the igneous rocks that are in northern Virginia, is that what you're asking, asymptote? Yeah, I don't think they are. Well, the structure of molehill is this. Basically, northern Virginia is mostly limestones. And what we found is that these basalts that make up molehill form the core of molehill. These basalts go right into the base of the mountain there. So we're pretty, in fact, we know for sure that they came from deep inside the earth. I had a chance to look at the rocks on molehill and not only do you find basalts, but you get all of the class that are in these basalts, which tell me that these things came up not from the crust. They're coming from the mantle. These are very deep-seated volcanoes that are coming up and could be as deep as 2,000 miles under the surface of the earth. So that's why I'm a little leery about saying that it's a great impact. How else would you make a basalt? And again, we get back to, you know, this involves the deep part of the earth. You know, it's not like you're saying, well, it's a meteorite, an asteroid impact, and these are melts from the impact event. Yeah, if somebody else has some other idea, please let me know. Because, like I said, there are a number of volcanologists in James Madison University. There have been geology conferences that have been held about these volcanoes where geologists get together and kick around ideas. But at this point, there's no consensus as to what formed them or why they're there. All right, Astrid says, continental plates and oceanic plates have different compositions. If that's true, can the plates move so that a hot spot can shift from an oceanic plate to a continental plate? Salt and olivine seem like ocean. Yeah, absolutely. Definitely, we know basalt. Oceanic plates are made out of basalt. Continental plates are made mostly from granites. And again, not so sure about shifting hot spots. The rhyolitic volcanoes that we're seeing in the west, Benton suggests that there's some kind of, at least to me, there's some kind of partial melting that's taking place. It just feels to me like there's some other mechanism, some other plate tectonic mechanism at play here, other than just hot spots and rifting and subduction. What's going on? Any other thoughts or ideas? Some upward movement from below. I'll be interested to create a 3D map of the sphere of energy in the Earth. Okay, thanks, Katie, for coming. Sure, no problem. Yeah. Trimble knob is, I have samples from Trimble knob as well. And I think they're also basaltic. They're right next to molehill. But yeah, JMU sent me some samples from there as well. Sure. Thank you all for coming. I appreciate your time. I hope I've made this interesting. And like I said, if you have another ideas, then let me know. Oh, okay. See Bay has a question about the Hawaiian islands. All right, basically what happens is that as long as the Hawaiian island is on top of the hotspot, the hotspot can continue to generate magma and build the island up. So they start as sea mounts and then eventually when they get high enough, they get above sea level. Some of them get built high enough that they can withstand weathering erosion for millions of years. Then as the island moves off of the hotspot, weathering erosion processes start to kick in and the islands get eroded. Like I said, the five Hawaiian islands we have now are the remnants of probably about 20 or 25 Hawaiian islands that existed in the past. Most of them though have just been broken down by weathering and erosional processes that are going on. And what else we were saying? Oh, I want to talk a little bit more about Kilauea. It got really bad this summer. The eruptions that are current in Kilauea and there was a lot of damage done to houses and so on. Some of them Kilauea was erupting a lot more violently than people have expected in the past. And we think what's going on there is that sea level was getting into the magma chamber of Kilauea and pressure was being built up and you get these more violent explosions that are going on. But for some reason Kilauea was much more violent this summer than it was in the past. Could be. Yeah, Vic, you raise a really good point. And this is a topic that people have been asking about as well is, is it possible that a volcano could erupt in Virginia? And we do know that volcanoes can appear in the ocean. They want to appear off the coast of Japan, fishermen spied it and lasted for just a couple hours and that was destroyed. There was a farmer in Mexico that reported a volcano coming up in his farm. That must have been scary. And so I've been asked and I've asked some volcanologists is it possible that a volcano could erupt and some geologists starting to say yes. We do have volcanoes. We do have earthquakes in Virginia where there are earthquakes. You tend to see volcanoes. In fact, they're getting worse. The most violent earthquake that went off was in 2011 in mineral Virginia. And it was a magnitude 5.8 somewhere around there. There's also there are also some earthquake studies that are being done at Virginia Tech. And they found some very interesting results the last time I was at the conference at a conference there. What they're doing is looking at earthquake waves. And there's three types of earthquake waves P, S and L. Those earthquake waves travel have no trouble flowing through the earth right down practically to the core under southern Virginia, which is where I live. What they're finding though is that when they monitor earthquake waves under northern Virginia, E and L get through but not S. All right, low depth of 100 kilometers. Let's say that they're saying the S waves are stopping. And the question is what's stopping those earthquake waves from moving through northern Virginia. And when it comes to S waves, which are like shear waves, the only thing that geologists can think of is liquids. So that, yeah, exactly as I'm told. Okay, we're starting to get evidence that below 100 kilometers under northern Virginia, there's liquids down there. And 50 million years ago, those liquids came to the surface. They brought all the salt to the surface three miles away from Harrison Berg and James Madison University. So could have all came to rough. The answer is yes. Okay, it might take another 50 million years, but at least we know there's some magma that's down underneath there. In fact, in some spots, I'm wondering if it's a lot shallower like we have hot springs, northern Virginia. That's sort of interesting as to why there are hot springs under northern Virginia, but not southern Virginia. Can hotspots move vertically, not that I know of. Yeah, power cuten, that's right. Well, I guess if you're on a spherical earth, vertical and radial mean the same thing. Okay, gotcha. Oh, that's cool. Where do you live, S and T? Where's, I can even try and pronounce that. Awesome. Oh, that's interesting. Yeah, I heard. One of the things I talk about in my classes is the Mexico City Earth, Mexico City earthquake that happened, I believe it was back in 1985 was a magnitude 8. You know about that, S and T. We can talk about later. Oh, cool. Do you worry about, S and T, do you worry about a volcano coming up under your house? Good. Sorry about that. Yeah, that's very true as much as we think we're pretty much safe. Even in Virginia, I don't tend to worry about earthquakes and whatnot, but Florence came pretty close to our area. In fact, the initial forecast for Hurricane Florence put my county dead center in the middle of it and people started freaking out over it. School started to close early. College is closed early. It ended up that it went south of us through North Carolina and swept right around us, but it could have been close. I mean, we could have had the flooding that North Carolina had. Yeah, North Carolina is still flooded and Richmond got slammed with some really nasty tornadoes that spun out of that. So the earth is is a dynamic place. You just don't know what to expect. All right, I'm about, let's see, 11, 11 a.m. Pacific Daylight Time. I'm going to be logging off. I'm going to head off to the college. I've got lesson plans to get ready, but I thank you all for coming. And for the questions that you've come up with in real life class this week, we lost like 11 instructional hours from Hurricane Florence. Most of you have my email address. If you don't, I'm going to put it in local chat. Yeah, feel free to email me. I check that every day. Bye, everyone. Hope you have a good day or a good night depending on where you are.