Geology 1 (Geoscience and the Origins of the Earth)


Hey guys, welcome to your very first
lecture. Before we start I wanted to do a
quick note. We’re gonna be covering the science of geology. In order to really get the most out your video experience, you want to
make sure that you understand that all these videos are being recorded in high definition Um, we have an image of the Earth right here in front of you, and if you have a high definition, you’ll actually see very small
wisps of cloud, and little tiny islands but if
you’re on a lower setting on your YouTube channel you want to make sure that you go ahead
adjust it, otherwise the features will appear blurry, you might
not even see them. So…anyways…at this point I just want you
to go ahead and learn how to toggle between
high definition and low definition on your YouTube
channel. High-definition means 720 points or higher lower than 720 is no longer
considered high definition. Sometimes it defaults is set at about 360, so that’s only
about half the definition you can get you you want to get as much definition
possible. Now if it slows down your computer so much that it doesn’t load up very rapidly, obviously you can reduce
the resolution. Anyways, just wanted you
to kinda know that would be the best way to go. So…anyway…learn to toggle it… you can actually pause the video and watch maybe how the definition changes on this planet. But anyways, pause the video then quickly
toggle over to high-definition if necessary. So in our very first lecture, we’re gonna
be introducing the science of geology. Geology is the science that pursues an understanding of Planet Earth. We all have an intimate understanding of
what the earth is. The earth is what we live on Some people refer to it as Mother Earth. There are numerous religious deities, there are
numerous approaches, culturally, to the earth’s
history. So it’s really close and important to us. Now, the way that scientists look at the earth is a little different so we’re
going to introduce the science of geology, what we’re actually doing. We’re going to be taking ourselves
away from the metaphysical approach of looking at our environments and actually
start looking at it from a scientific view point. And the way that we do this is
usually by splitting geology into two subdisciplines. There’s something called physical geology and that examines the materials
composing earth and seeks to understand the many
processes operate beneath and on its surface. This
is the main thing we will be discussing in this class. The second group is historical geology,
or the second discipline is historical geology, It seeks an
understanding of the origin of Earth and its development through time. So, in other words, we would tell the story of Earth. That’s usually taught as a different class
than the one that we’re teaching here. This will be predominantly physical
geology. We will do some historical at the end, however, for those you are interested in
that big picture question. So what do we see here? Well, here we see, this is actually from the University of Hawai’i website, this
is one of their young, budding, geology students that is taking a class in igneous rocks. And you could see that the student is
coming down and having the experience of putting the rock
hammer in the lava and covering their face because the
heat is extremely hot… …about three times hotter than
your hottest oven setting… ever could be. You can see how close the
student is [to the lava]. Up here, this is two hikers in the Grand Canyon. What I really like
about these hikers coming through the Grand Canyon, this is a place called Hidden Canyon, in the bottom the Grand Canyon, is these
sandstone layers right here. Each one of these layers is almost like
a layer of history. This really fits into historical geology. We’ll be talking about where these layers
come from right here. But not just that, what about these
boulders down here. These boulders aren’t made out of the same stuff as the walls.
The boulders came from somewhere very distant and it’s a very different
story for this than it is for these walls. In fact, the rocks down here, even though the rocks themselves might be a billion years old and maybe the wall rocks are 200 million years old, this deposit is being deposited today.
But this one is quite ancient. So there’s a lot of history going on, all
just in a couple of picture slides right here. And these hikers are just kinda coming up right along side it. We also need to be aware that geology is
really the science of people in the environment. So it’s kinda the original
environmental science. There are many important
relationships between people and the natural environment. For example, here we see Salt Lake City,
Utah. Salt Lake City… here’s, a matter of fact, the capitol building of Salt Lake City right here… We might marvel at man’s wonderful
architecture… here we see these tall buildings in
downtown Salt Lake City… some of them housing business
enterprises that do billions of dollars worth of work every single year. But, what do we see behind them? As tall and beautiful as these things are, we have these hills in the background, we
have a canyon that comes right down here and we even see a little dam that’s
covering this section…if you have sharp eyesight and you have it high definition on your video, you can see these things. The question is..is what’s more important… or what’s a more powerful
force here? Well, in the short term, man has been able to convert all the surface area into a city, but over the long term, eventually what is causing these hills behind Salt
Lake City to rise will continue to do so, and usually that
is accompanied by an earthquake. So it turns out that in Utah there
are lots of earthquakes. There’s something called an earthquake-fault…those of you that might eventually develop a trained eye for these things… turns up the fault is actually running
right here behind these buildings and it’s right in front the
legislative offices located right here. In the event of a major
flood, we’d see a debris flow that would come right down and distribute itself all over
inside the city which is why they built this dam here. So
eventually, in the short term, humans can actually do tremendous
progress but in the end, nature wins. It always wins. What causes
earthquakes? What causes these mountains rise in the first
place? That is, of course the subject of this class. Some of the problems and issues
addressed by geology involve natural hazards, resources, world population growth, and
environmental issues. Probably the most important thing that
people argue over, worldwide, isn’t necessarily land or clean air or access to food. Number one point of conflict isn’t even religion…
even though religion is usually brought in as a
justification for the conflict… the main thing that people fight over
worldwide is water. And here we can see this gentleman
is looking at a water well that’s been drilled. And the water’s actually under natural pressure, so it’s actually coming right out of the ground…out of this pipe. This is called an artesian well. When you have artesian conditions, you wind up having water that comes right
out, almost like oil, out of the ground if you can imagine an old oil well spraying
oil up into the air in the 1920’s and 1930’s. This is what we see here as well. So, the science of geology has come a long way. There were a lot of different ways
that we looked at the world and, basically the first people to look at it were called naturalists. There were no real scientists. There was nobody to teach science in
the traditional way that we do it now. Back in the days of ancient
Greece, there was a serious famous writers,
the most famous of which is a gentleman by the name of Aristotle. He was a philosopher and naturalist. He
spent a lot of time talking about origins of mountains and where fossils came from…in addition to the fact that he’d
worked out Formal Logic. He actually looked at human thinking and worked out how logical systems
operate. He was an absolutely brilliant
person. He made a lot of critical mistakes, but at least he took a swing at some of these
questions. And he approached them from a non-religious viewpoint, even though he himself had made some religious statements and a lot of people generally believe that he was a believer in the Greek
pantheon of gods and goddesses. Ultimately, he was kind of the father of science as we know it. And he spent a lot of time looking at Earth science. The first way people looked at things was
through something called castrastrophism. Castrastrophism is basically were catastrophes are responsible for earth’s creation and features. This is a way of thinking that dominated science and dominated our approach to on almost all Earth Sciences until about 1900 or so. By about that time, we began to give up on
that idea, because some other new philosophies had
come online regarding science. And some discoveries
had been made that actually demonstrated that it’s probably not the best way to approach
the problem. So catastrophism is the idea that… you know…major events such, as a major
flood, created the Grand Canyon and it also created all the river valleys all at the same time. Or, major ice sheets came in and did
it all kinda almost in a miraculous sense. And of course it was used, castrastrophism was used by a lot of
religious institutions as justification for a lot of their theological beliefs. Uniformitarianism is a little bit
different. Uniformitarianism is basically the philosophy that things
are changing gradually over time. It’s sometimes referred to as gradualism. Uniformitarianism, basically gave rise to the modern
geological sciences as we know it. So, instead of
looking necessarily at what a rock is, sometimes we spend more time looking at the
processes that created the rock in the first place. The gradual evolution of systems. OK? So here we see kinda the main players in this, here we see Aristotle. Here’s…I can’t even say his
last name…I think it’s Velikovsky… but he was the last catastrophist.
There are none of these left. I think he passed away in the 1950’s or 60’s, right around in there. He was the last one. Still a very good
scientist. I’m not saying that he wasn’t. He had some really good observations, but his interpretations were largely incorrect. And of course we now know, in the light of things called
plate tectonics that his ideas certainly don’t hold up.
But his observations are still useful to us in some respects. Of course, the guy that got it all started was gentleman by the name James Hutton, and
he is an English scientist. He was not the most popular person amongst his peers. He was considered a very abrasive and difficult person to get along with, and as a consequence, even
though he had the idea and actually wrote a lot of the stuff down
about, uniformitarianism, people didn’t want to deal with him. And so his ideas were slow to take hold. It wasn’t really until a guy by the
name of Charles Lyell, who was a good friend of Charles Darwin
actually, before the field of geology really got its
first textbook and we started actually seeing cohorts of
students that were studying in a formal way. Another idea that we need to
introduce early, because it’s one of those
things that were not accustomed to as human beings, thinking about…which is geologic time. You
know, when we go from place to place we’re used to thinking in terms of minutes. If you’re thinking about human lifespans
were thinking in terms of decades maybe, and in some tragic cases only years. But we’re not certainly… even in historical terms we’re
thinking about we might think about millennia… but we don’t necessarily think in
geologic time scales. Right? We don’t think about what one million years means. or what a billion years means. A billion years is so much time you
can’t fathom it. It is something you can’t even imagine. A thousand years ago human beings were populating medieval
Europe, they were getting ready to build ships that would go across the the Atlantic Ocean. Polynesians had
settled all over the South Pacific and had conquered even as far as Madagascar. Genghis Khan’s armies were almost about
to go and basically unify all of Asia. That was a thousand years ago. Now it seems like
ancient history to us. But, a thousand years ago, what did the
landscape look like? Exactly the same as it does now. Almost exactly. But what about a million years ago? If we
think about it, a million years ago, the Island of Hawaii
the Big Island of Hawaii, didn’t exist. We think about what
happened a million years ago, the city, or where we now know as Los
Angeles, was a shallow inland bay. If we think about
things a million years ago, we find that a lot of things have
changed, and if we go even further… fifty million years ago…or a hundred
million years ago… a lot changes. When we look at rocks we
know that are a hundred million years old, and we’ll discover why…during the class…why we
know that they’re a hundred million years old, we find that the animals themselves…this
is a fossil, this is a dinosaur in here… had changed considerably. Right? So we need to develop what we call an
appreciation for the magnitude of geologic times. Right? This process of this animal…it might have gone extinct, a matter of fact, it’s species all went extinct very succinctly, very quickly, 65 million years ago…but
its evolution occurred over several 100 million years. And we are now
discovering through DNA analysis that we are very closely
related to a lot of what we’ve even seen the
dinosaurs. So, it means that there’s some common ancestry amongst us. Other things that we would see is we
can look at is maybe a landscape now and we can make some assessments about
how old things are. Well, obviously the things at the bottom , for example this orange layer, is going to be much much
older than this upper layer, this limestone. The Skinner Gulch is what this says here. So what’s at the bottom is gonna be older than what’s on top. And there’s another rule. Here we see a dike…a dike is a body
of magma that was injected into the rock through
tectonic processes or volcanic processes… and when we look at a dike, you’ll notice that the dike only comes up to the blue one, then it’s cut off. So we know that this orange had to be
here or the dike wouldn’t be able to go in it. Right? There’s an old axiom that we need to keep in mind: “you gotta make it before
you can break it”. But when we look up here in the gray area, it’s not there. So the dike is older than
the orange but younger than the this gray or this
blue, depending on whether you’re color-blind or not. Could be gray to you. Alright. And then of course, beneath all that we see these rock layers, and they’re all tilted, so the rock layers had to be made, again,
and then tilted before these other layers could come on.
So we you could see that we are able to put together a story. What’s the most recent part of that
story? Well, the limestone is obviously not the
top part (of the story) because it comes up here and it ends… and it’s found back over here again. So we
have a gully that’s actually formed in the meantime and now there’s a River. So the most recent story is this river
cutting through here. And so the way that, kind of the whole purpose of this little slide is, by looking at this we’re able to figure out relative dating. In other words, how
things happened in sequence. It’s almost… you don’t actually get a number…but you
might actually get a “this had to happen before this…before
this had to happen before this…and so on. But, we can sometimes put numbers to it. We actually know about how old a lot of the dinosaurs are. And if we find the fossils in the rocks we
know about how they old are. So you can put a number to it. You get the idea. And so these are concepts we’ll be bringing up throughout the rest of the semester. The geologic time scale, of course, has shown us that there’s tremendous
diversity of Earth history. What’s gone on. Now when I say tremendous, most of that
tremendous diversity has occurred, especially in the life sciences, really
only in the last half billion years. About 550 million years ago. Prior to
that, there was really a lot of boring stuff going
on. The largest part a earth’s history is something called the precambrian. Which is, if we look at this here…so this is
a bar and this all of earth’s history. this is from the
origin to the earth, which we will discover to be 4.5, or actually in here it’s 4.6, billion years old… to 542 million years ago. That’s 90% of earth’s history in
something called the Precambrian. This blue part over here, is the part that we live in. Something
called the phanerozoic. So what do these things mean here?
Well, the precambrian means “just before the cambrian”. Well, why would they call it that? That doesn’t mean anything. Well, if we look at the phanerozoic… the phanerozoic is broken up into three
groups: the cenozoic, the mesozoic, and the phanerozoic. and the earliest part of the phanerozoic, which is to say the most ancient part, is the cambrian. So the precambrian is
just everything before the cambrian, which is why you see cambrian and then precambrian
here, okay. So you might be saying “what does that mean?” Well, and by the way, these are a lot of fancy sounding words…they are Greek words… .Paleozoic means ancient life. Paleo—Zoic. Zoe meaning “life”. Mesozoic meaning “middle life” and cenozoic meaning
“recent life”. So, the Paleozoic, the time of ancient life, is when we actually
start seeing fossils in the rocks… with hard shells, and teeth, and
vertebrae. Fish, and by the time we get to the Devonian, we’re actually seeing
large sharks. In the mississippian, huge ferns forests living up on the land. But during the cambrian, everything was
just in the ocean. so between the Cambrian and the Devonian, there’s tremendous changes in life that’s
happening here over this 100 million year period. When you get into the Mississippian and
Pennsylvanian, which the europeans call the Carboniferous…don’t worry about it, you won’t have to memorize time scale so don’t worry about it…I’m just guiding you through it… we start seeing an explosion in the size of land animals as well as insects. During the Carboniferous, we…um, not mosquitoes… …dragonflies with wings that are
several feet across in the fossil record. And by the time
you get to the Permian we actually see animals that look almost
dinosaur-like. They’re very large, they have very sharp teeth, there’s
carnivores living both in the oceans and up on land. But between the Permian and the Triassic, at 251 million years ago, was a massive extinction and almost all the
things that live during this period time went extinct. Now, a few things did survive, of course, because we’re here, but our ancestors were hit at one point very strongly by an extinction. And we find
that fish survived, and that sharks survived, ferns, things like this
that we see today, but a lot of the other species died off.
Things like trilobites, which are an early type of
lobster-creature that looks like a giant pill bug that had dominated the
oceans…were extinct by the Permian. And then we go into the Triassic, the Jurassic, and the Cretaceous. This is the three subgroups of a group
called the mesozoic, or middle life. It’s also commonly referred to as the
age of the dinosaurs. So, from the Permian into the Mesozoic
is time of the dinosaurs, and they went extinct at sixty five and
a half million years ago. And that dumps us into the Cenozoic which is the age of mammals. And so the early mammals grew very, very large. We evolved whales and elephants but all that evolved
just right here. And they’re still evolving today. The most
recent period of time is the Quaternary and the Holocene, and that’s where human beings live. The pleistocene is when you think of cavemen, right, neanderthals and things
like this. This is all in the Quaternary, OK. But if we look at the time period, that’s only the last two million years or so. The earth is 4.6 billion years old, So we’ve gotta telescope into this to this
and then to this… to this telescopes into, again this timescale. But this tells us the
different life forms that we would expect. And here you can see the changes in body forms that we see in our
rock record. All the way up to human beings up here. Hopefully you didn’t get buried in the
timescale, but it’s interesting stuff. So the nature of scientific inquiry is…its one of those things that kinda cuts
across all boundaries. Its science that’s not just done in
the United States or in Europe or even by the Chinese. It’s
done by Mongolians, it’s done by Africans it’s done by South Americans, there’s
geological Institutes worldwide. The earth, like I said, is
something that almost all people consider that they have in common, unless of course, they’re floating around on a raft. You know, then in which case they
would be more interested in what the ocean is doing. But almost everybody recognizes the
supremacy of importance of the earth. OK. So when we apply science, remember the assumptions are that science assumes the natural world is consistent and predictable. That’s an assumption. It could be a
fallacy…it could be wrong. But so far we have seen no reason to
believe that that isn’t so. And the goal of science is to discover
patterns in nature. It’s not actually to get answers,
sometimes we don’t get the answers, we just see the pattern. Patterns in nature,
and use the knowledge to make predictions or generate
understanding a phenomenal. Alright. You might say “well, big deal”… well, it’s important. The reason why
it’s important is if you build a building, for example, say
a ten-story skyscraper, you’re hoping that the engineer that built the
building or designed the building, compacted the soil properly or built it
on proper substrate, so that the building doesn’t fall over. But
how does he know that in advance? He has to have the science right. The
science is going to tell him what the pattern is in nature and how to apply that understanding to a
problem. Scientists collect facts through observation and measurements. Another way of saying facts, in Latin, is data. So scientists collect data…you can think of it this way. So here we see a woman geologist
working on a microscope. Turns out that geology is not always
conducted exclusively outdoors. Its actually done frequently inside of the lab looking
through microscopes…being able to figure out what the minerals are telling us. One of
the growing fields right now where we are looking at minerals, is forensic geology. People that commit a crime, maybe an atrocious crime, and then they hide, say the weapon of the crime or
they hide a body or something like that, and then they get mud on their shoes. We
are now able to track dust and dirt from crime scenes back to individuals..if we have proper
training on how to do that. Of course, that doesn’t mean that we don’t
do old-fashioned field geology. These are two common things, a Brunton compass and a yellow field notebook…these are carried almost by all geologists in the field even when they are on vacation, quite
frankly. I take mine with me almost everywhere I
go. So how or why things happen are explained using
hypothesis. So the way that we go about the
scientific inquiry is to put together hypothesis which is a
tentative or untested explanation, right. You can have almost an unlimited
number of hypotheses. Charles Darwin, when he came up with his idea that we now call
evolution, he’d never came out and said I think
things are moving or life is evolving. What he did was he had a whole bunch of
hypotheses about what he thought was going on and he started eliminating them until he found one that he could no
longer eliminate. it was the one that we now look at as
kinda one of the principal axioms in biology…which is evolution. But a
theory is different from a hypothesis. So a “hypo-” means a pre-thesis or before you actually have a full understanding. A theory is a well-tested and widely
accepted view that the scientific community agrees best
explains certain observable facts. One of the most obvious
people we think about when we do theories is Albert Einstein and his theory of
relativity. It turns out that Einstein’s theory of
relativity basically piggybacks on some problems
that Sir Isaac Newton’s equations couldn’t explain. and Einstein’s ideas did come in and
actually explain some the inconsistencies and, kind of in some ways, replaced Newton. Doesn’t mean Newton isn’t valuable to us, but Einstein’s ideas are basically really good if you’re into
rocket science or studying particle physics. But it turns out that
it’s incompatible with others theories. And so
we still have a long ways to go on these things. So, certain theories…sometimes it’s like
a tool in a toolbox…we know that it works for this but it won’t work for
that. Geology is the same way. Einstein’s theory of relativity is the same way. Evolution is the same way. Sometimes it’s
really easy to get the “what”, but the “how” or the “why” can sometimes be painfully inescapable, or… ungraspable. So what is the nature of
this inquiry? Well, the scientific method is what we
utilize to, kinda, do this process. Right? You can’t just have
a hypothesis and go right to a theory, OK? There’s a process that falls out as we go through. So, the scientific method involves gathering facts or data through observations. Right? And we say “how do we do that?” We gotta take measurements, right? It usually means you’re taking a ruler or something that you can write down in your notebook. …[reading from page] and formulation of hypotheses and theories…right, so… Not only do we have, you know, we have
to have reasonable formulation of hypotheses and theories. it’s not something we could just say
well… …most people won’t say…well you know, there’ s a river here because God made it. Now people have in the past, have had that hypothesis, but the scientific method says let’s not
approach it that way. There might be a more
pragmatic or practical understanding of why that river exists where it does, alright. You’ll find that as I go through the
class I’m not…I’m most certainly not anti-religion But a lot of phenomenon that are usually
immediately chalked up as religion can be explained in a scientific way. With that said there’s no fixed path
that scientists follow that leads to scientific knowledge.
There’s many different paths. You’ll actually see scientists…those of you that wind up graduating with a degree in science… will observe yourselves that scientists
will sometimes look at the same problem and get completely different answers because they have different tool sets that they bring to bear. You know, maybe one is a chemist and
another one is a physicist and so they apply their own tools and come up with
different answers. But when they both get the same answer…that’s usually
pretty enlightening stuff. One of my things I’m kinda famous for saying is that “knowledge begets understanding, and understanding begets wisdom.” Right? So, this goes for everybody. You know,
this is one my science fiction heroes, Captain Spock… and he’s all into logic. Basically logic is what leads you down this path from knowledge to wisdom. So we kind of talked about what science is. And I’m gonna jump off that at this
point. If you’re interested in the scientific method, it’s probably better to take a
philosophy class that explains this in more detail or
you can you just send me an email and I’ll, of course, discuss it with you. But the four
connected parts of the earth… …I should say…the Earth is connected in four separate parts. The main part is
going to be the geosphere. That’s what we’re concentrating on. So
here’s the four connected parts, the geosphere is here. This is the Earth’s interior, its rocks, its soil. But there’s other spheres here
too. There’s the hydrosphere, which are Earth’s waters, right… here’s the hydrosphere…the biosphere,
Earth’s living things… and the atmosphere, Earth’s air. And they’re all interacting one with another. The geosphere is interacting with the
atmosphere all the time to create things like soil. The atmosphere is interacting with the
hydrosphere which creates clouds and distributes water and it’s actually the
source of rivers. The biosphere, of course, we’ve done drilling in some of the most remote places on the planet, to very deep depths, and even in those rocks when we’ve done analyses to try to find truly dead rocks where nothing’s
ever been, we still find, even there, viruses and
microbacteria. So the biosphere’s everywhere. The atmosphere is everywhere, and the hydrosphere and the geosphere. And they’re all going to be interacting. We’re going to be talking about those interactions throughout the class. But for the most
part we’re gonna be emphasizing here. So here we see the interaction of three
spheres. Actually, I altered the slide right before I put
it up. It should say actually the four spheres. This would be the atmosphere, the
hydrosphere, and the geosphere, here we can see the hydrosphere… the geosphere being these rocks, and of
course the atmosphere being the air, the mist in the air, but I added biosphere right at the last minute because the biosphere is actually residing in the rocks and in the
water. And if we were to look over here, you’d
actually see birds and crab and things like that. They’re all here. All four of them. And the best place to look
at this intersection, of course, is the coastline. If people wanted to have a
really good understanding of how healthy the earth is, and where, kinda, the environmental
frontline is, it’s to go down to the coast because
that’s where you see the four major spheres all interacting. So
forgive me, in future lectures, I’ll change the 3 to a 4. But all four spheres are being represented here. And so my own training…I’m a
coastal geologist by training… when I look at these things, I
immediately see all kinds of different things that need to be investigated to find out how healthy this coastline is, how healthy this ecosystem is, and how
sustainable the system is for future generations. So to understand the earth, we need to
understand what it is. The Earth is a planet. This is a picture of the earth taken by Apollo 8
astronauts,… Apollo 8 did not land on the moon, this
is the moon down here… but what they did was they did leave
the earth, they left Earth’s gravity, they actually were captured by lunar gravity, they orbited the moon, and then returned back to the Earth. …almost like a figure eight. But as they came back around the earth,
they’re the first persons, these astronauts, to ever see the
Earth rise above the moon. And quite frankly, nobody’s seen it
since the seventies. Humanity has not returned to the
moon, except by satellites, since. And this picture was taken of the earth from the moon. it’s one of
the most fascinating pictures if you think about it. There’s a lot of really interesting
things kinda said in here. First off, we can see weather patterns. We
can see the land. We can see oceans. Even from a distance, we can see those
spheres interacting from a very far distance. So the earth is a dynamic place, even
from an objective viewpoint. Even from the moon…by comparison the
moon is dead, the moon is boring and dead by comparison. So the Earth’s a dynamic planet with many
interacting parts, or spheres. Right? You know, I liked…I
don’t really like to say spheres so much, but that’s in the literature and in the jargon, so I’ll use it for
a little bit. But it has interacting parts, and the parts of the Earth system are
completely linked. And it is characterized by different
processes, so we’ve got to think about scales. Right. So they vary on spatial scales from fractions of a millimeter to thousands
of kilometers. So these are tiny crystals that are forming inside of a rock. Here we can see the crystals
originated here, and they blade out in every direction. These are visible only under a microscope. Here we actually see another one blading out like so… another one blading out like this… Beautiful rock, right? Beautiful minerals, under under a microscope. But we don’t actually see that with the
naked eye. We have to have the tools to look at them. And we’re going millions…or, I’m sorry… to millimeters…we’re going to
millimeters of a meter. Thousandths of a meter
to be able to see these things…and even smaller than that sometimes. By comparison, we can look at satellite
images… and here we see Western Europe, here’s North Africa, of course. Over here is, I believe, Greenland… …er, Iceland, I’m sorry…so here
we see North Africa, the straights of Gibraltar, this is the Mediterranean Sea. The distances here are thousands of kilometers of distance, right. Whereas, this is just
millimeters…very, very small. Here’s the Sahara Desert, right, at North
Africa there’s basically nothing out here. Libya’s located right about here. Right in this area here. Morocco, these mountains right here…we
see Italy. Why does the geography between
Northern Europe and Western Europe exist? Look at the
Alps. These are the Alp mountains that separate Italy from the rest of Europe. Which allowed separate cultures and
unique identities to flourish in this part of Europe versus this part. The same thing here. Why did French get
spoken here and Spanish get spoken here? What’s the big difference? Look at these
mountains. Right , we have the Pyrenees right here, that are blocking this whole area. What about England? Why did England separate itself and have its own culture? Again, the geology played a role. Look at
this right here. England, actually Britain, is an island on which England is a country on that island. And here’s Ireland over here, again, each one of them having separate
cultural identities. So, again we see the interaction of the
biosphere, which in this case is humans, having to deal with geographical barriers
that are thousands of miles, or thousands of kilometers long. They have tremendous effect on our
societies every day. This, of course, is Scandinavia and Russia
back over here. So the earth as a system is powered by the Sun, right? The
biosphere, the geosphere, well, the geosphere we’re gonna come to a little bit. It’s not always powered by the Sun. Some of it is. But largely the atmosphere, the biosphere, and the hydrosphere are powered by the Sun, right. The Sun gives
energy directly to the atmosphere, to the hydrosphere, and at Earth’s surface. So when we go outside, on a warm day, we can thank the sun for it. The Sun is always going to be life’s best
friend. Despite the fact that it has some effects, such as if you get too much
exposure you wind up getting cancer and things like this, but if you
don’t get enough you don’t have any survival either. You’ve got to be able to balance it. The earth, of course, being half in the Sun and half in the shade all the time, here’s night time and here’s daytime, is a great
regulator. It gives humanity the opportunity to rest for 12 hours out of the Sun. Amazing how are our humanity is linked so tightly to the
earth as a planet. The Earth’s systems are also powered by the Earth’s interior. So it’s not just solar power. Heat remaining from the earth’s
formation and heat that is continuously generated from radioactive decay powers the internal processes that
produce volcanoes, earthquakes, and mountains. Here we see a geyser, this
is Yellowstone National Park, the geyser is actually powered by
internal heat from the earth, some of it radioactive decay some of it from the heat of formation of the earth…when you take two things and you slam them together during the Earth’s formation, things heat
up. Here we a lava flow…this is coming out of
coming out of one of the principal vents right near Pu’u O’o, on the big island of Hawaii. So, where did all this come from? Our current understanding is that everything, all matter, all energy, and the forces that control all of these interactions, began with the Big
Bang. The Big Bang is believed to have
occurred 13.7 billion years ago. The big bang, and we’ve actually gotten a map of it… I mean science has gone so far with this. I’m not really gonna go into details on how they got this, but this is the big
bang a couple hundred thousand years after it happened. You might be saying “how did they get that?” So you can actually figured it out. There
are several web links that you can do. And some great videos that explain
it. But it’s basically background cosmic
radiation…or radio waves actually… as opposed to cosmic rays… but background radio waves that were emitted and pulled and extended as the
universe expanded. We’re able to actually use satellites
to map the distribution of the Big Bang. And
this is what they came back with. Now, how they know that that’s part of the Big
Bang, again, that’s a whole other science
class. But nonetheless, they do have a really good understanding
of what it looks like and so at 400,000 years ago after the Big Bang occurred,
they can get this picture. Before that they can’t get a picture,
this is kinda locked into the universe… this is kinda of our background…it’s almost like a flash going off in your eyes and you see the memory of the
flash in your eye, even though it fades over time.
That’s kinda what’s happening here. This is, kinda, the early cosmic flash right after the
Big Bang. So the Earth and the other planets formed at essentially the same time and out of the same material as the sun. So, you know, you have the birth of our star, you have a bunch of gases, rocks that are floating in space. And we call these these clumps of gas and rocks…nebula. One of the inherent properties of matter is that matter
attracts matter. Right? When we walk on the earth
there’s the force of gravity. The reason why the force gravity works is
because we are matter. We have mass and the earth has
massed and for reasons that…actually nobody knows… and no one been ever been able to understand…even though we call it gravity… we don’t really know what “it” is. And the
fact that you have mass and the fact that the Earth has mass means that you’re
drawn together. But that occurs with everything. So
you’re attracted to everything that has mass. And if you happen to have enough mass
around you, you’re attracted…everybody’s attracted everybody else. Everything is attracted everything else.
And so what’ll happen is it’ll eventually start to contract, or gravitationally collapse, right? So, when you have so much material all
close together it all starts to pull inwards. Now the nebula will contract into a flattened, rotating disk, and it’ll heat up. It’ll actually heat up because
of the transference of energy types…from gravitational energy
into thermal energy…that is a law of
physics called the conservation of energy.
There’s a lot of gravitational potential energy. It’s like
jumping… this rock right here has dropped into the nebula further, and so energy is
released. When that happens it’s converted from potential into kinetic
energy. Kinetic energy is the energy of motion, and it causes things to heat up. That’s really the point of all that. So if you didn’t understand what I’m saying, just put it in your back pocket. When things get smaller they heat up. OK. And they start to spin. Anybody who has ever, kinda, seen things contract…say you’re on a tire
wheel, and your you’re playing around and
as you spin around you put your arms in, things spin faster and faster and faster. OK…and things get a little stressful sometimes. Well, that’s kinda what’s happening here in the formation of solar systems. So these disk occur and then you wind up with these kinda rings that are traveling at different
velocities because the things out here can’t goes as fast as
things close to the the forming star. This would be early the protosun. And, overtime these rings will gravitational collapse
into planets, Here we see Saturn, Jupiter, and the inner planets Mercury, Venus, Earth, and Mars. So the nebular theory proposes that the bodies of our solar system
evolved from an enormous rotating cloud called the solar nebula. Right. And so it turns out Mars
is just as old as the earth. The Moon is almost as old as the earth,
Neptune, Venus, Jupiter, even the sun. And when we look
at meteorites we find that they’re actually the same age as the Earth as well. So, what was the solar nebula? What’s the theory? Well, the solar nebula consisted of hydrogen and helium, in addition to microscopic dust grains…
you know…things that we would recognize right away as being little
bits of dirt. A disturbance caused this the solar nebula too slowly contract and rotate. We don’t know what that disturbance is. We do know that the Sun had a sister sun that formed at about
the same time…but it’s actually quite far away from this now. And maybe it was interaction of those
two stars that brought about the formation. But who
knows, right? Science hasn’t answered that question yet. The solar nebula assumed a flat disk shape with a protosun at the center. The inner planets began to form from metallic and rocky substances. Large outer planets began to form from the
fragments of ices. So it turns out that in the inner part of the
solar system that we find lots of rocky planets…not unlike earth in
some ways. Mars is much smaller than Earth, but it has
rocks and volcanoes and all of that stuff. But when we go further out we don’t see
that so much. Instead we find that the moons that are surrounding
Uranus and Neptune and Jupiter have large amount of water, and
carbon dioxide, and methane, and things like that. You might be wondering
what this image is down here. You notice that it says Earth. This is a real picture taken from a satellite that had landed on Mars pointed up
towards Earth. And so if you can look right there to
the middle, it might look like a little piece of dust on
your screen. You have it in high resolution you should see it…or high-definition. That’s the Earth as
seen from Mars. And if you look really, really carefully…
and i’m looking kinda carefully right now… you may even convince yourself that you see the moon. but I’ve never heard that its visible. But anyway. But the Earth is really just a little white speck up in the sky from Mars’ perspective.
There’s some structure to the earth also. It’s just not a blue ball with water and land on it, right? There’s some
structure to it. And this internal structure is something we’re
gonna spend the next couple of weeks really hitting
hard. It’s important to understand that what happens on the inside is what’s
determining what’s going on on the outside. The Sun plays a role, But it’s a minimal role compared to the
internal heat of the Earth. So, Earth’s internal structure can be defined by the chemical
composition. So here we have three layers, or actually four layers…there’s an inner core, there’s an outer core, so the core of the earth, which is the center-most part. Here’s the mantle, which is the part that’s in-between us and the core. And it’s made out of rocky material. Actually, the core is metallic…it’s made out of iron mostly. But the mantle’s mostly rocky. And then, of course, we get up to the crust and that’s definitely rocky. We know it because we live on it. Right? We don’t find metal sheets coming out
of the coming out of the volcanoes that are active
today. We find rock…basalt that is being spewed
everywhere on the seafloor and on volcanoes. So, the layers are defined by their composition, the crust, the mantle, and the core. How did this come about? Why do we have a layered Earth? Well, it turns out that it’s really just
something called density that’s driving everything. So basically, the layered structure occurred when metals
sank to the center. Right. So here you have the earth the
metals, all the iron, all the magnesium, and even some oxygen in some cases, are
gonna sink down to the bottom. Because why? Because it’s heavier, or we should say denser. And if it’s more dense, that means gravity has a stronger pull on
it and it’s able to pull it down more readily
than it can the lighter things. So, greater gravitational force
pulling the heavy things towards the center. Things that are still heavy, but not as
heavy as that, wind up floating out to the edges. Chemical
segregation… I should say…molten rock rose to
produce a primitive crust… …so here we ave our primitive crust… right here in the image. Chemical
segregation established the three basic divisions of Earth’s interior. We talked about that. The core, the mantle, and the crust, But it also produced a primitive atmosphere from volcanic gases. It’s actually still
making… our atmosphere today…is still
being evolved by volcanoes. Largely, the
chemistry is controlled now by biological effects. Through interaction between animals and plants and the sea and
some other complicated process. That is more of an environmental science question. But, you get the idea. And the earliest
primitive crust was lost to erosion and geologic processes. So, there was so much turmoil occurring
early on, while this was occurring… when the iron’s going on to the bottom, or sinking towards the core, and the lighter, rocky material was floating near the surface and making an early crust. But that early early crust has been lost to us. And, of course…how has it been
lost to us? Well, something called the rock cycle. It
turns out that things on earth are constantly cycling
around. Nothing is really the same forever. The oldest rocks that we have on the
planet date to about three and a half billion years old. We do find minerals that are even older…almost as old as the earth itself…about 4.3 to 4.4 billion… it depends on who you ask…years old. That’s right after the earth formed and we
find those actually in Australia. But those minerals were recycled out of a previous rock and now we find them in a new rock. And that’s because earth is constantly
cycling minerals and rocks and stuff around. Materials always changing. And that is called the rock cycle. There
are three different kinds rocks on planet Earth. There’s igneous
rock, there’s sedimentary rock, there’s metamorphic rock. Igneous rock is rock that is brought from…literally igneous means “fire born” or “fire breathed”… rock. It means it’s actually from a molten
magma. It’s from a melted rock source. A liquid.
And it solidifies. And over time, it might get eroded or
attacked by weather patterns, and that causes it to break up into small
pieces. Maybe the igneous rock eventually becomes a sedimentary rock, which is like a sandstone, or a shale, or
a silt, or you know, dust. If you take those sediments and bury them long enough and you add water, you wind up getting a
sedimentary rock. Right, so you get loose sediment that becomes sedimentary rock. An actual rock that you can pick up, or you can polish up, or whatever, and put into a rock collection. Sedimentary rock rock can also be altered into igneous rock because I can melt it, right? I can heat it back up, or actually it would be this path…I could melt it and it would go into the magma chamber… and I can make igneous rock out of it again, or I could continue to put it under heat and pressure… so not just compaction and cementation…which is the process
of lithifying or making a rock out little particles of rock. I can then take sedimentary rock and
turn it into a metamorphic rock. “Meta” meaning “changing face” or “changing shape” rock. So, a metamorphic rock is one that is not
quite melted, but it’s at such high heat and high pressure
that the sedimentary rock gets altered into this. So it actually is kind of a hybrid in some ways, or not really a hybrid,
it’s a kind of mid-level stage between a sedimentary rock, which usually forms at the surface of the earth, and igneous rocks which form under
conditions which actually melt the rock. Metamorphic rocks exist in the
middle of those two. And they cycle around, a metamorphic rock can be melted, an igneous rock can be put under heat
and pressure made into a metamorphic rock, and… anyways, you get the idea. We’re going to
be talking about each type of rock in detail as we go through the
class. That’s the primary focus of the first series of lectures, actually. So we’ve been talking a lot about the earth,
about the rock cycle, about how things are constantly changing and turning over. We need to kinda understand what the face of the earth is. What does the earth look like? Several features that pop out. This, of course, is what is called a
physiographic map of the earth, and basically the color tells us how high something it. So something that’s red is actually quite high, it’s a mountain.
Something that is yellow or green is quite low. Right. Usually the green is actually the lowest. Blue is the oceans, but the light blue isshallow ocean, whereas the dark blue is the deep ocean. And we notice pretty rapidly there’s a couple of interesting things that happen. First off, we notice that we have continents. Right. We have deep ocean basins here and we have continents. The continents are these areas with large mountain chains, these are the Himalayan mountains, here are the Alps…the Alps are very small by comparison with the Himalayas…and of course, the Appalachian Mountains and the Rocky Mountains that extend all the way from Mexico into Alaska, the Andes Mountains here. Now you might notice there’s a lot
to red down here. But it doesn’t look like mountains. We’ll get into what that is. It
does turn out that it is very high, is very high elevation, but it’s also very flat. Here are the ocean basins, right? The ocean basins are these deep sections of the earth that are covered
largely by water. In almost all cases, it’s covered by
water. These green areas, here, are usually the
grassy plains, or, actually, tropical rainforest.
So here we see the Amazon rainforest is here in green. These are the grassy plains of western
Russia. Our Great Plains of the United States and Canada extend all through here. And you get the idea. Here’s, basically,
really good growing country for wine and things like this in
South America. And we have plains over here in Australia as well. We also have shallow oceans. Right. Not everything is a deep ocean basin like we see over here. Sometimes we get shallow oceans and those are mainly concentrated, not just up here on the top part of the
map, but they’re also located here off the
coast of Alaska, located in Hudson Bay, on and even along the eastern coast
of the United States, southern coast of South
America. But we also find something else…
that there’s these blue areas in the middle of the ocean. What is that? We’ll come to those here in a moment. Here we see the deep oceans here, these deep parts. We’ll notice that the Pacific Ocean has the deepest part actually located way over here…near… this is Japan… right near Japan, relative to the eastern part, what’s actually fairly
shallow. You’d think that the deepest part of the ocean is right in the middle, but it’s not. It turns out, actually, it’s near the
edge. Deepest part of the Atlantic is here and here. And the
same thing with the Indian Ocean…deepest part is here. We also have tall mountains. Right. Notice the tall mountains, I actually went through those in detail. But what about
these things? These turned out to be ice sheets. These are ice sheets that are several kilometers thick. If you think of a kilometer,
there’s 1.6 kilometers in a mile. So, these are ice sheets…these are big, thick layers of ice that are in some cases miles thick or kilometer thick. I’m going
to use the metric system in this class, so be accustomed to hearing kilometers, and if you need to, get out a calculator and learn how to convert between the two [systems]. But we also notice that here’s Greenland, and Greenland is nice and high, but it’s all smooth. Right. Unlike what we see over here in the Himalayas and the Rockies, this is all smooth. It’s covered in ice too. This is Antarctica, by the way, down here. It turns out that this shallow blue area is an undersea mountain
chain. So there’s large undersea mountain chains that zipper
all over the planet. Here’s the longest and tallest of them all, right here, the mid-atlantic ridge, which is a large undersea mountain chain. And the top part of it is Iceland. Iceland is part of
this undersea mountain chain that actually pokes up out of surface of the ocean. So with that said, I hope you got a decent introduction to what this class is about and what we’re gonna be looking at. I want
you to be interested in it and get an understanding. This is an
ice geologist that’s doing work in Greenland and… in case you can’t see him, this is him right up over here. And this beautiful lake…if he was to fall in here it would be instant death. He would die of the icy cold water… hypothermia…you get the idea. This is a way that a way of life
for a lot of people. Studying the Arctic in studying ice
geology and how these rivers form, what they mean for global warming, what
they might mean for global cooling, in some areas. Right. Some places heat up and other places
are actually going down. It’s complicated, and it takes scientists…those with really
good instruments, and goodwill, and somebody
who was the know-how to be able to solve these problems and to ask the right
questions to start solving them. So with that said, this concludes our
first lecture and I hope, if you have any questions, you know,
feel free to get onto the discussion board or send me an
email because I’m happy to answer your questions that you have. Or, you can always ask your
classmates on the discussion boards. So until next
lecture, have a good one.