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GEOLOGY
Credit: NASA
Credit: NASA
Orion Nebulae
Where did
the earth
come from?
Credit: Stardate.org
Most societies have creation stories (“myths”)
You can read some here
http://www.gly.uga.edu/railsback/CS/CSIndex.html
Much of this course can be thought of as the creation
story as told by the science of our civilisation.
Once upon a time (13.7 billion years ago,
approx.) there was a small lump of
tremendous mass and temperature in the
middle of nothingness… and then
This is called the
Big ____ Theory
http://www.astro.ucla.edu/~wright/cosmology_faq.html
Very rapidly, space-time comes into being and expands,
subatomic particles appear and form _____, great
clouds of matter roam the vast universe.
All stars form from clouds of gas and dust
which roam our universe. Eventually,
gravity causes the cloud to collapse; since
the cloud is _________, material falls in
along the "poles" faster than it does near
the "equator". This flattening results in a
disk-like object.
Material slowly wends its way into
the center of this disk, forming a
new star. While the star continues
to grow, lumps form in the disk
which will ultimately become
________.
Credit: NASA
The disk eventually thins as more
material falls onto the star and the
protoplanets. A hole in the disk near
the star forms as material is
completely incorporated into the
star and planets.
Now fully formed planets exist
within the hole, even as new planets
are still under construction in the
outer parts of the disk
Ultimately, the remaining dust clears completely, leaving a fully
formed _______________ like our own.
Credit: NASA
See video at http://cougar.jpl.nasa.gov/HR4796/anim.html
Credit: NASA
How do we know this???
Did anyone ever SEE this???
It sounds like somebody’s dream animated with
lame special effects.
Except that it comes from scientists (albeit
government scientists).
So, what is science?
Is it a thing, a person, a process?
Our definition for now – the accumulated ideas of
“modern” (our) civilization about how things work – what
causes what, why it rains, why we get sick, etc.
The “Scientific Method” – a codification of the process
of applying _________________ to answering
questions about how things work.
The scientific method is basically a repeating _____
of observing, questioning, hypothesizing,
experimenting, observing, etc.
observe
question
experiment
hypothesize
No one knows when this got started.
Or when it is going to end.
For example, why can’t you tickle yourself?
observe
You notice that you
can’t tickle yourself
question
experiment
hypothesize
You wonder why
you can’t tickle
yourself
Then, you think of an hypothesis, a ________ answer (reason
why you can’t tickle yourself).
Then, contrive an experiment to test your hypothesis - predict
a new observation and then arrange things so you can make
this new observation.
If the scientific method is a cycle, how does it
ever result in knowledge?
provisional answers
observe
question
experiment
hypothesize
Scientific knowledge is the accumulation of provisional
answers to questions, answers that have _______ the process
of repeated cycles of the scientific method – that have not
been ___________. Well tested answers become “______”.
This is what I LOVE about science, and what drives
many people CRAZY.
Scientists are always qualifying statements, equivocating,
defining terms, and in general avoiding whenever possible
drawing any definitive conclusions about anything that
matters.
Why?
I think it is because scientists are acutely aware that
KNOWING ≠ ______
Our knowledge about the world tells us we (humans) are
sentient beings on the planet earth that are collectively
constructing knowledge. That knowledge assumes there is
a world “out there” that we can know, part of which
includes that very knowledge and the brains (and books,
etc.) that generate and sustain that knowledge, but is much
more than that knowledge, that transcends it.
So I claim the scientific view assumes that the real world
is _________________________, and that our
knowledge is an attempt to create an imitation (“model”)
of it, and further that this model (“world view”) is
necessarily “under construction”.
Moreover, based on long hard experience, it is hard to
avoid the (provisional) conclusion that the real world is
very complex, and that our model of it is not only
incomplete, it is ________, and wrong in fundamental
ways, and perhaps can’t possibly be ______ (which
doesn’t prevent it from being fairly powerful - from our
perspective).
With this view, it is understandable why scientists
1. ________ about almost everything when questioned, yet
2. Devote their lives to persisting in this _________ quest to
perfect the model
Current scientific knowledge is
a great human achievement,
similar to a great pyramid. It is
vast, integrated structure and a
true collective creation.
Giza, Egypt
Tikal, Guatemala (Mayan)
Scientific knowledge should be internally consistent
For example, Biology* – study of life
Is built on and is a subset of
___________ – the study of atomic/molecular interactions
Is built on and is a subset of
_________ – the study of the fundamental components of reality
_________ in Biology should contradict anything in
Chemistry or Physics.
*including Medicine and Agriculture
Similarly, the earth sciences, like Geology, are based on
chemistry and physics and consistent with them.
The same is true for all the disciplines that focus on
humans, like Psychology, Anthropology, Sociology,
Economics, Political Science, etc. These fields are also
consistent with and increasingly tied directly to Biology,
Chemistry and Physics.
All are originally subsets of Philosophy – the
search for a rational explanation of everything.
In order to arrive at what you do not know
You must go by a way which is the way of ignorance.
-T.S. Eliot, “East Coker”
Some readers, I am afraid, will conclude from the title that I intend to
recommend ignorance or to praise it. I intend to do neither….There are
kinds and degrees of ignorance that are remediable, of course, and we
have no excuse for not learning all we can. But… our ignorance
ultimately is irremediable …some problems are unsolvable and some
questions unanswerable. The extent of our knowledge will always be,
at the same time, the measure of the extent of our ignorance.
Because ignorance is thus a part of our creaturely definition, we
need an appropriate way: a way of ignorance, which is the way
of neighborly love, kindness, caution, care, appropriate scale,
thrift, good work, right livelihood. Creatures who have armed
themselves with the power of limitless destruction should not be
following any way laid out by their limited knowledge and their
unseemly pride in it.
The way of ignorance, therefore, is to be careful, to know the
limits and efficacy of our knowledge. It is to be humble and to
work on an appropriate scale.
-from the preface
Now, back to our story….
See video at http://cougar.jpl.nasa.gov/HR4796/anim.html
Credit: NASA
Atoms and molecules within the
nebula combined to form larger
particles. The ___determined what
kinds of particles could exist. Close
to the Sun, solar heat vaporized ices
and prevented ________ elements,
like hydrogen and helium, from
condensing.
The inner zone was dominated by
____________, which clumped
together into ever-larger bodies,
called planetesimals, eventually
forming the______ inner planets:
Mercury, Venus, Earth, Mars.
Credit: Stardate.org & NASA
In the solar system's outer region, though, it was chilly enough
for ices to remain intact. They, too, merged into planetesimals,
which in turn came together to form the cores of the giant
planets. _______ and _______ contain the largest percentages
of hydrogen and helium, while Uranus and Neptune contain
larger fractions of water, ammonia, methane, and carbon
monoxide.
So, we really are the
__________________
And yes, we are now “seeing” many of the stages of this
The point is, the process of solar system and planet
formation determined basic aspects of the composition of
the planet – including the abundance and distribution of
____________.
This sets both the _________ as well as ______ on what
can occur on earth, along with many other factors.
As the earth formed it
congealed into layers, with
elements distributing into
the different layers
The hot inner ______ is
surrounded by a semisolid
______ below a thin, solid
outer _____ on the surface
2-9/2-8
Note: 1st number is text figure (9th)/second is number is 8th edition
As the earth enlarged during condensation, the
increasing mass resulted in increased _______, raising
the internal temperature (4000o C in core)
In this semi-liquid state, elements
distributed according to _______,
heavier elements to the core (Iron,
Nickel), lighter elements to the
surface (Silicon, Magnesium,
Aluminum) which formed the outer
crust.
Periodically, _________ from the interior
distributed core materials in layers on the
surface, so these elements also exist in the
crust today.
Recall – the elements are different kinds of atoms – each
made up of 3 types of particles – protons (big, positive
charge), neutrons (big, no charge), and electrons (small,
negative charge). For charge balance, the number of
protons and __________ is equal. “Weight” of an atom, as
well as its identity, is due to the numbers of protons and
__________.
Interesting that all elements are made of the same
ingredients, but have very different properties.
Gases were released also during
this densification stage and
further through the crust
through ________ venting,
producing the atmosphere.
The early atmosphere was
probably high in ___________,
hydrogen, carbon dioxide, carbon
monoxide, nitrogen, ammonia,
methane and other gases. No
_________.
There were no oceans until the
surface cooled enough for water
to stay in a liquid state.
At this point (4 BYA), the
surface of the world was
starting to look like a
place we would recognize
today – land, sea and sky.
And still a very dynamic
place geologically
The crust, the outer layer, is in two zones
1. The ________ crust – underlying the continents
2. The _______ crust – underlying the oceans (71% of surface)
Lithosphere – the crust plus the underlying solid layer of the mantle.
Asthenosphere – lower portion of mantle, melted rock – flows slowly
Heat from the core
causes the molten
rock of the
asthenosphere to rise
toward the surface.
This can create
__________ flows
below the lithosphere
__________ cells
result when cooler
rock near the surface
flows toward the
center
Movement in the asthenosphere induces movement in the
solid lithosphere, which is divided into huge sections called
___________ plates (15). The movement of the plates is
slow (a few cm. per year)
This movement is the cause of continental drift, the long term
changes in the position of the continents.
Where has Lexington been?
http://www.calstatela.edu/faculty/acolvil/plates.html
This movement
causes the plates
to interact with
each other in 3
ways – separate,
collide, slide past
each other. These
interactions cause
various geological
features, including
mountains, ridges
and trenches.
Oceanic ridge at a
divergent plate
boundary – material
from the mantle is added
to the plates
Trench and volcanic island
at a convergent plate
boundary. One plate rides
up and other is driven
down – subduction.
Transform fault
connecting two
t
divergent plate
boundaries. Most are
in oceanic plates
Note the mid-oceanic spreading trenches and multiple transform faults
Convergence of plates is an important cause of mountain
building, as the continental plate compresses and folds as it
rides up over the subducted plate. Also material scraped
from the overridden plate can accumulate. In addition,
volcanoes often occur in these zones. The Himalayas and
__________ mountain ranges were formed in this way.
extinct
volcanoes
Volcanoes occur
where molten rock
(magma) from the
earth’s interior
emerges through an
opening in the
lithosphere.
Ongoing volcanic activity
contributes gases to the
atmosphere, elements to the
lithosphere, and islands and
mountains to the landscape.
central
vent
magma
conduit
magma
reservoir
Solid
lithosphere
Upwelling
magma
Partially molten
asthenosphere
Beautiful & Dangerous
And creative
The ________ islands are
being formed by the
Pacific plate moving
across a “hot spot” –
volcanism in the middle
of a plate (rare).
Earthquakes are shock
waves generated by the
sudden movement or
”slippage” of plates at
boundaries and faults.
They can create strong
vibrations in the crust
and have secondary
effects on the land and
water.
Many of these
faults are in the
ocean, but some are
on land, including
the New Madrid
fault zone that
includes Western
Kentucky
Earthquakes under water can induce shock waves in the
water, called “tsunamis”, aka “tidal waves”.
Such an event
occurred Dec. 26
2004 in the
Indian Ocean
They can move
extremely fast,
more than 500
mph, and travel for
miles inland from
the coast.
Fake photo
Tsunami
Japanese term (literally meaning "big wave") now generally used for an
unusual, very large wave or series of waves. Tsunamis are generated
either by submarine earthquakes, by landslides or by effects of
volcanic eruptions (such as the collapse of a caldera in the sea).
Tsunamis have long wavelengths and small wave heights on the open
sea. As water depth decreases near land the wavelength diminishes
and the wave height increases dramatically which may lead to
catastrophic flooding of coastal areas. Tsunamis may deceive coastal
residents in that a wave trough may a arrive before the first wave
crest.
http://www.phuket-tourism.com/tsunami.htm
The Rock Cycle
The Lithosphere is made of Rock – the cooled surface crust of the
earth. It varies greatly from place to place in the world and is a
complex mixture of elements and compounds, especially minerals.
Minerals are naturally occurring compounds with a
_________ structure. More than 2000 have been
identified as distinct minerals. They can be very beautiful
and are the source of many of our “resources”.
http://www.wilenskyminerals.com/MINERAL_PHOTOS.html
Rock is formed directly in the cooling of the crust, but once
formed, it is subject to the dynamic forces already discussed,
and also weathering.
Weathering refers to the breaking
down of rock into small particles,
which results from physical and
chemical forces such as ________,
grinding, flowing water, oxygen etc.
Plants and __________ also
contribute actively to weathering.
These smaller particles are then subject to being washed or
blown away, a process called erosion. This process can wear
down mountains, and also build soil. The eroded particles can
be transported to a new location by gravity, wind or water,
and collect in areas of ___________.
Devil’s Tower, WY
Three rock types – based on method of formation –
igneous, sedimentary & metamorphic.
1. Igneous rock is the original rock, and the
bulk of the earth’s crust, resulting from the
________ of magma. It is continually being
formed by upwelling of magma, creating
granite, lava, pumice, basalt, etc.
2. Sedimentary rock is formed from deposition of ___________
particles, often underwater (sediments). As these deposited layers
get buried, they can become fused to form distinctly layered rock –
limestone, shale, sandstone (common in Kentucky).
3. Metamorphic rock, forms when rocks are
buried and experience ____ temperatures and
pressures.
Limestone => Marble
Shale => Slate
Sandstone => Quartz
Rock cycle – all of these rock types are subject to the dynamic action
of plate tectonics, volcanism, subduction, weathering, etc. As a result,
each type can be, and is transformed into the other types, creating a
cycle of transformation of rock in the lithosphere (see fig. 2-29).
Even rock is
ultimately a
dynamic process
2-29
Mining
Mineral resources are dispersed throughout the crust, some
places richer than others. They must be mined.
They are ____________
Large amounts of
crust must be
processed to obtain
relatively small
amounts of mineral –
solid waste and
disturbance of the
landscape
Often toxic chemicals
are released (acids,
mercury, arsenic)
Copper mine (open pit)
Coal mining shares many of these problems
A classic “tradeoff”
Paradise – John Prine
Then the coal company came with the world's largest shovel
And they tortured the timber and stripped all the land
Well, they dug for their coal till the land was forsaken
Then they wrote it all down as the progress of man.
When I was a child my family would travel
Down to Western Kentucky where my parents were born
And there's a backwards old town that's often remembered
Repeat Chorus:
So many times that my memories are worn.
When I die let my ashes float down the Green River
Let my soul roll on up to the Rochester dam
I'll be halfway to Heaven with Paradise waitin'
Just five miles away from wherever I am.
Chorus:
And daddy won't you take me back to Muhlenberg County
Down by the Green River where Paradise lay
Repeat Chorus:
Well, I'm sorry my son, but you're too late in asking
Mister Peabody's coal train has hauled it away
Well, sometimes we'd travel right down the Green River
To the abandoned old prison down by Adrie Hill
Where the air smelled like snakes and we'd shoot with our pistols
But empty pop bottles was all we would kill.
Repeat Chorus:
End