 Welcome everyone to Geo
105, Environmental Geology.
This is Dr. Inoka Widanagamage.
My office is located
118D Carrier Hall
in the School of Engineering.
The textbook for the
course is Introduction
to Environmental Geology
by Edward Keller,
5th edition is recommended.
As you all know this course
a web course and blackboard
enabled.
So weekly materials will
be uploaded to blackboard,
you can expect one
chapter or two chapters
every week depending on the
weight of the materials.
Each lecture or chapter will
have practice questions, quiz,
or board by the end of the week.
You can expect very similar
type of questions in your exams.
Quizzes and all
assignments are expected
to complete and
submit to blackboard,
following instructions.
Office hours are
online, that means
you can expect email responses
from me during that time.
Monday, Wednesday,
Friday 2 to 3 p.m.
Please make sure to write
your name, student ID,
course number in subject
line of your email.
Why do we study
environmental geology?
We live here, we live
in the environment.
When you think about
geology, it is the science
of processes related to
composition, structure,
and history of
Earth and its life.
When it comes to
environmental geology
it is more applied geology.
Especially it is the use
of geological information
to help us solve
conflicts in land use,
to minimize environmental
degradation,
and maximize the
beneficial results of using
our natural and
modified environments.
In this course you
will be learning
about natural resources,
geology hazards,
environmental protection.
All manufactured objects
depend on Earth's resources.
Most resources are
limited in quantity
and they are non-renewable.
For example, many of
today's medications
are derived from benzene,
and benzene in turn
is derived from petroleum.
Almost all over the counter pain
medications, such as aspirin,
are based on these
petrochemicals.
Mining.
Metals, industrial
minerals, gems.
These are major economically
important mining materials.
Inappropriate mining
can release acid wastes
into groundwater causing
environmental issues.
Petroleum exploitations .
Similarly, removal,
transportation and waste
disposal can damage
the environment.
So in this slide you can see
a picture of acid mine range.
Right hand side, you can see
very brownish yellowish water
transporting through this river.
So acid mine drainage
or acid rock drainage
refers to the run-off
form of acidic water
and frequently comes from
areas where metal mines or coal
mines are in practice.
This is a very large
environmental issue.
We'll talking about earthquakes,
landslides, volcanic eruptions,
floods when we talk
about geological hazards
in this course.
Water, soy, air.
The production of
these three components
is considered as the major
environmental protection.
Look at this picture.
Look for the
contamination in here.
Mixing of gasoline
with toxic chemicals.
To understand this
kind of process
and to identify this
kind of problem,
you will need the knowledge
of environmental geology.
For example, you
should know what
is the permeability of
the rocks surrounding,
what is the porosity of the
rocks and soil surrounding,
and how this contaminant is
going to move to your drinking
water or the ground water.
These things need
to be understood
very carefully and correctly.
Then you will need the knowledge
of environmental geology
in order to understand
these kinds of conditions.
Let's briefly look
at the solar system.
I'm pretty sure you have
learned about the solar system
before in your high school
science class, or maybe
any other geology class
if you have taken any.
Anyway, solar system is based
on nebula theory and protoplanet
hypothesis.
The Eagle Nebula, with its
intensely cold gas and dust,
figure like pillars
where new stars
are thought to be forming.
The solar system formed
around 4.5 billion years ago
from a huge swirling
cloud of dust.
You can see these
pictures and figures,
and see how our planetary
system has been formed.
How do we know this?
We know this because advances
in technology, such as Hubble
telescope, have
allowed us to look deep
into space to observe the birth
of stars similar to our sun.
Based on this information, we
do have terrestrial planets
versus Jovian planets.
I'm not going into,
explain too much on this
because this is not the
major focus of the course.
So I will let you read these
slides, and let me know
if you do have any questions.
All right.
So now let's look at the
differentiation of Earth.
Primitive Earth-- the first
Earth did not have any layers,
but now we do.
So what are these layers?
The based on chemical
properties we do have
three different layers mainly--
crust, mantle, core.
Core can be subdivided into
outer core and inner core.
This is based on chemical
properties, based on chemistry.
For example, crust will have
a lot of oxygen and silicon,
mantle rocks will have a lot
of iron and magnesium, core.
The outer core is
liquid, mostly iron.
Inner core, it's a solid.
It's mostly iron and nickle.
Based on physical or
mechanical properties,
Earth can be subdivided
into a couple of layers.
Mainly lithosphere,
asthenosphere, mesosphere,
outer core, inner core.
What Is lithosphere?
This is the rigid, brittle,
outer shell of the Earth.
This will be known as
the lithospheric slabs
in plate tectonics.
These other plates that you will
learn in plate tectonics class.
The lithosphere is composed of
both crust and the upper part
of the mantle.
Asthenosphere is
plastic, very weak.
It's ductile.
It's a very weak zone on
which the lithospheric slabs
are moving in plate tectonics.
Isostasy is another important
concept to understand.
What this means?
This refers to the
state of gravitation
and equilibrium between Earths
lithosphere and asthenosphere
are such that the
tectonic plates
at an elevation which depending
on thickness and density.
So the tectonic plates moving
on top of the asthenosphere
based on these principles.
What drives plate tectonics?
And what are the
plate boundaries?
The theory of plate tectonics
originally proposed in 1960
by Alfred Wegener.
Initially it was known
as Continental Drifting.
After certain years it was
known as plate tectonic theory.
This included new understanding
of the sea flow and explanation
of driving force.
This describes lithosphere
as being broken
into plates that are in motion.
This explains origin
and distribution
of volcanoes, earthquakes,
fault zones and mountain belts,
which you will be
learning in future slides.
The driving force
for plate tectonics
is thermal convection.
Circulation of thermal currents.
As you can see, warm
currents rise up.
Cold currents sink down.
The warm currents represented
by the red arrows,
cold currents represented
by these blue arrows.
The warm currents rise up
because of the less density.
Cold currents sinking down
because of high density.
Thermal convection, when it
comes to plate tectonics,
you can see the red arrow rising
up because of less density.
The cold arrows, or
the blue collar arrows,
represent the sinking of
the lithospheric slabs.
There are three major
plate boundaries
that you will learning
in this class.
Divergent, convergent,
and transform boundaries.
Divergent boundaries.
Plates move apart from
each other and magma rises
from the bottom, cools
and forms new lithosphere.
You can see the creation of
crust at divergent boundaries.
For the same reason,
these boundaries
are known as constructive
type of plate boundaries.
This is typically expressed
as mid-oceanic ridges.
Example, Mid-Atlantic
ridge where
you can see the
Atlantic Ocean expanding
because of these divergent
plate boundaries.
Convergent boundaries.
Plates move towards each other.
There are different categories
of convergent boundaries
where you will expect to see
oceanic-oceanic convergence,
oceanic-continental convergence,
or continental-continental
convergence.
In this diagram you're
looking at oceanic-continental
convergence.
Oceanic crust, or
oceanic lithosphere,
is sinking underneath the
continental lithosphere
because oceanic crust,
or oceanic lithosphere,
is higher in density compared
to the continental crust.
Oceanic plates may
sink into mantle
along subduction zone marked
by deep oceanic trench.
Transform boundary.
This is the third and the
last type of plate boundary.
Plates slide past one another.
There's no construction
or destruction
of the crust during
transform plate boundaries.
Fault zones, earthquakes,
mark boundary.
You can expect to see lots
and lots of earthquakes
at these type of plate boundary.
San Andreas fault
in California is
an example for transform
fault, or the transform plate
boundary.
