Hello everyone, I want to begin by welcoming
you all to the video course on engineering
geology.
My name is Debasis Roy, I can be or I am,
I teach in the department of civil engineering
of Indian Institute of Technology Kharagpur.
My contact address is on the screen there,
I can also
be contacted by email at this address 
that it is - debasis at civil dot iitkgp dot
ornet ernet dot in.
.
This course actually is going to be comprised
of about 40 sessions, 40 - 1 hour sessions
out of
which there will be about 35 or 36 sessions
of instructions in the class room and the
rest 3 or 4
sessions will be laboratory based instructions.
So, we will visit lab, we will try to identify
some
rock samples or try to identify different
features on a geology map; those things will
be taken
care of in the laboratory, rest of it for
that matter, most of the things are going
to be taken care of
in the class room.
In the first session of this video course,
we are going to cover some introductory topics
that are
of general interest in order to give you a
flavor about what to expect out of this course.
So, what
we are going to try to learn in this first
lesson?
..
We are going to try to learn what are the
general scope and approach used in engineering
geology, then what are the typical assignments
that one might expect while working as a an
engineering geologist, who might have to be
interacted with when you work as an engineering
geologist, who are the end users of this knowledge,
of this field of a knowledge and then finally
we are going to actually talk about a summary
of the historical developments that has led
to the
current state of knowledge in this field.
.
So, to begin with we want to, we want to understand;
what is actually engineering geology?
.What are the definitions?
What are the essential aspects considered
in engineering geology?
Now, as the name suggests, the field of engineering
geology is actually a sup-topic or a sub
branch of the field of geology.
Now, geology essentially involves studying
of different aspects of
or different processes involving different
parts of the earth.
.
Now, in order to understand what we learn,
what we cover generally in geology, we try
to
understand first of all, what is the structure
of earth?
Now, you all know that earth is essentially
a
spherical body, the diameter or the radius
of the earth; it is actually a little bit
of omelet, so the
polar radius is a little bit smaller.
This is the polar radius that is a little
bit smaller than the radius
or the diameter at the equator.
So, the polar radius actually or polar diameter
for that matter is
about 2 times 6356 kilometers and the diameter
at the equator is about 2 times 6378 kilometers.
So, there is the difference of about 22 kilometers
when you consider the, consider the diameter
at
the pole or that across the equator.
Now, geologists concern themselves with the
process that actually covers the entire earth
actually.
So, this entire sphere actually that is shown
on the screen is what is dealt with by
geologists and you can understand that this
is not a homogeneous structure and the sphere
the
oblate spheroid actually can be sub-divided
into several different shell like zones.
..
For instance there is a zone which has got
a thickness of between 5 kilometer and about
100
kilometer at the surface of the sphere that
is called the lithosphere.
Now, this one has got a
thickness of about 5 kilometer underneath
oceans and the thickness can go up to about
a 100
kilometers underneath where there are major
mountains chains and underneath the continents,
the thickness of this lithosphere is only
about 35 kilometers.
.
Now, underneath the lithosphere, there is
another shell thicker shell actually, that
is called the
mantle.
So, the one we talked about earlier was the
lithosphere are the crust 
and underneath the
crust, there is mantle that goes upto about
2500 to 3000 kilometers measured from the
surface
.and below the mantle is the other unit that
is called the core; all these different parts
of the sphere
of the spherical structure are different in
terms of their properties or in terms of their
density or in
terms of the chemistry.
So, the processes that are there in the lithosphere
are not essentially the
same as those one encounters in the mantle
or those that take place in the core.
Now, you all know that the construction, human
activity or the construction, I mean all the
human engineering projects; they are confined
within the top few tens of meters or at the
most
top few hundreds of meters from the surface.
So, these are the particular things that are
considered by all, that are considered by
engineering geologists.
So, engineering geologists deal
with all processes that affect human activity
or human habitat or human environment.
So, what we are going to be concerned with?
We are going to be concerned with the processes
that take place over the top at the most hundred
meters from the surface of the earth.
So, we look
at shallow crustal processes in engineering
geology, shallow crustal geologic processes
in this
subject.
What are those shallow crustal geology processes?
.
They could be mass wasting, something to do
with the slope failure or landslides, then
they could
be near shore processes like erosion of the
or erosion due to the action of sea waves
or waves
generated on the river bodies or on the other
water bodies, there are could be deposition
due to
these wave action or a fluvial processes that
is also taken care of by engineering geologists
in the
near shore area, then marine erosion and deposition;
another topic of interest of the subject and
then fluvial processes, deposition erosion
flooding, these kind of processes also are
studied in the
subject of engineering geology.
Now, we need to understand the essentials
of the approach taken of the problem solving
approach normally adopted in engineering geology.
Now, it needs to be highlighted that
engineering geologists are essentially geologist,
they are not engineers but they are geologist.
So,
they concern themselves only with engineering
aspects.
..
Now, you all know that mechanistic aspects
are normally handled by engineers and here
we are
looking at geotechnical or geological engineers
who are mainly concerned with the mechanistic
aspects of the geological processes.
Now, that does not say that engineering geologist
should not
have a good understanding of the mechanistic
aspect that drives this shallow crustal geologic
processes because if they do not understand
the mechanistic aspects, then they cannot
interact
effectively with the engineers, geotechnical
or geological engineers who are ultimately
going to
be responsible for the construction processes
of different projects.
.
.Now, we look at typical assignments that
one might encounter while working as an engineering
geologist.
First class of assignment that one needs to
handle as an engineering geologist is in
resource management.
What do you mean by resource management?
Resource management
essentially means that utilization of natural
resources without harming the environment.
Now,
what are the resources that we need to worry
about?
We need to worry about ground water
resources, mineral resources and forestry
resources to name a few.
For instance we need to exploit, I mean if
we need to exploit the ground water resource,
then we
need to be very judicious about the use of
ground water.
If the ground water use is too much
compared to the local geology or local meteorology,
then that could cost undue harm to the
environment.
We will look at an example problem in this
regard later on in this lesson.
Then we need to also look at how to exploit
minerals resources without judicious of course
to the
maximum benefit of the construction activities
or for the human livelihood.
Now, mineral
resources, you all know that mining activities,
they actually are concerned with the exploitations
of minerals resources.
We also should look at how to exploit other
types of resources to extract
construction materials for a particular type
of construction project.
And finally, forestry resources
also is a very major part that engineering
geologists deal with.
We need to, for instance, when we
are harvesting timber, then if there is an
over harvesting or clear cut operations, I
mean clear
cutting of huge areas huge swats of forest,
then that could lead to disastrous consequences
like
that could lead to enormous amount of erosion
which can have or that can have a chain reaction
to all aspects of human habitat, locally as
well as on a regional scale.
The second aspect, the second type of assignment
that we are going to deal with as engineering
geologists is natural hazard assessment and
risk management of course.
What do we do in that?
We actually try to quantify the hazard involved
in a particular area because of geologic
processes.
To give you a few examples, engineering geologists
sometimes have got the
responsibility of dealing with the hazards
arising as a result of terrain stability.
Out of terrain
stability, we can or by terrain stability
what we mean is that landslide, mudslide,
rockslide, debris
flow all these events are actually lumped
together in this sub-topic.
..
So, engineering geologists need to identify
the hazards of terrain stability, terrain
stability related
hazards and they need to quantify those hazards.
So, for instance, if they find, if an engineering
geologist finds that in a certain area there
is an undue hazard of land slide; then land
use
planners, they may decide that the particular
project or settlement cannot be located in
that
particular situation.
Earthquake hazard is another topic of interest
in this regard.
What do we do in that?
We try to
find out what is the likelihood of an earthquake
to occur in a certain area.
Engineering geologists
are mainly interested in this regard to find
out if there is a seismogenic source in the
vicinity of a
particular type of development, whether there
is any active fault or volcano that could
cause that
could actually pose earthquake hazard to a
particular development in the vicinity of
those
features.
The quantification of the hazards is normally
done by seismologists and that is we are
going to deal with that a little bit in the
later part of this course.
But in general, the details of those things
are within the scope of other branches of
engineering
and science.
So, in regards to earthquake hazard identification,
engineering geologists are
entrusted mainly with trying to identify whether
there is any earthquake source nearby.
The other
thing is of course as I mentioned just a little
bit ago that volcanism is another aspect that
one
need or engineering geologists look at whether,
by that what I mean is that whether there
is a
volcano that is active or dormant which might
actually become active during the life time
of a
project or the settlement that is going to
be constructed nearby.
So, these things are done by
engineering geologists.
Then, they also deal with submarine hazards
like likelihood of seafloor movement; whether
there
is any likelihood of turbidity current or
tsunami caused by seafloor instability or
earthquake
taking place very near the seafloor.
So, these are the assignments typically are
entrusted to
engineering geologists which involves assessment
of natural hazards and risk management.
.The other class of problems that engineering
geologists deal with is assessment of geologic
hazards and risks that arises because of human
activities.
So far, we were taking about geologic
risk or geologic hazards because of natural
processes.
Now, because of human activity also, we
could actually complicate or worsen the likelihood
of a geologic hazard.
Now, we will consider a
few examples in this regard, this kind of
problems may be posed because of any big construction
project like constriction of dams, construction
of railways or construction of highways.
We are
going to take an example like by considering
a dam project.
.
.
We all know that rock masses are comprised
of joint sets.
Now, let us consider a dam to be
.constructed on top on the rock mass that
has got a joint set identified to be aligned
like that is
shown on the sketch there.
So, these are the joints in between relatively
intact rock masses.
Now
say, we want to construct a dam, a gravity
dam which is going to the resist the pressure
due to
water primarily by its self-weight.
So, this is the dam and it is going to actually
retain water of
that much of height.
This could be depending on the dam height;
the height of reservoir would be
several hundred feet.
Now, this type of alignment, it is this type
of alignment is not really preferred by engineering
geologists because the pressure of water which
is going to act in that direction that has
got a
component which is going to cause which is
going to or which might actually trigger instability
in the rock joints in that which are aligned
as shown in this sketch.
So, this kind of movement
might be triggered if a dam is constructed
as shown on this sketch.
Now, if the dam on the other hand was to be
located such that the water was on the other
side of
the dam like let us modify this sketch to
show what I mean.
So, we just modified the sketch.
.
We kept the joint set intact but here we are
going to construct the dam in such a manner
that the
water is on the other side with respect to
the orientation of the joint set.
Now, in this case, the
pressure due to water is going to be aligned
in the other direction 
and the force aligned like this
is unlikely to trigger any instability along
the joint sets oriented dipping in that manner.
So, this
is a preferred orientation of the dam.
So, if an engineering geologist is entrusted
with a site selection for a dam site, he is
going to he
or she is going to look at these aspects of
rock characteristics of course.
I mean these are not the
only aspects; you should realize that in this
introductory topic, we are just trying to
get a flavor
of what is going to be generally expected
in this field in the subject of engineering
geology.
So,
we are not covering all the different aspects
that are going to be considered while selecting
a dam
site.
We are going to do that thing later on when
we take these subjects up in more detail in
due
.course of time.
So secondly, let us consider a railway project
or for that matter, a highway project.
These things
are called liner developments because they
have got a long, they are relatively long
corresponding to the lateral extent of the
right of way.
Now, let us consider a typical linear
development, it could be railway or it could
be a highway or it could be a pipeline for
that matter.
Now, what are the considerations that come
in selection of a route for a railway or a
highway or a
pipe line?
Now, what has been known for a long time is
that clayey sub-grade situation poses a
lot of problem in this kind of development
because clays tend to settle or they tend
to behave in a
problematic manner, they tend to develop uneven
deflections or deformations under load over
the course of the project life.
So, what is normally done is that if there
are clay pockets, they are generally avoided
while
deciding a route for the highway or a railway
or any other type of linear development.
What I
mean by that?
Say, you want to go from point A or you want
to construct a highway from point A
to point B. Now, there is a clay pocket; we
are actually looking at a map area in this
sketch.
So,
what we are looking at?
We are looking at a plan view.
As I was mentioning, we are trying to
construct a highway for point A to point B
and in between point A and point B, there
is a clay
pocket which is as shown on this sketch.
.
Now, the shortest route from A, point A to
point B is going to cut across the clay pockets.
Now,
as I was mentioning, the clay pockets are
normally notorious in terms of posing maintenance
problem over the course of the project life.
So, these things are normally avoided and
a route that
might be selected may be like this.
So, this is a preferred route perhaps whereas
this was the
shortest route.
Again, there may be other considerations depending
on a local terrain or
topography that may come up in this regard
like may be, over in this portion of the alignment,
there is an excessive hazard of landslide.
So again, the engineering geologist may actually
recommend that the route of the linear development
from A to B follow the outer periphery just
.outside of the land slide hazard zone.
So finally, what we end up with?
We end up with a route which is perhaps going
to be like this;
this is not the shortest route and how the
route is going to be aligned; it is going
to be decided in
a close consultation with the engineering
geologist.
So, that kind of gives a general idea about
what kind of assignment that you might expect
while working as an engineering geologist.
Now,
who are the end users of the expertise?
.
End users as was very clear from the discussion
that we had so far; the end users include
mining
and forestry industry, they are very heavily
reliant on the knowledge of engineering of
geologist,
then regulators and developers, they are also
heavily tapped into the expertise of engineering
geologists.
Land use planners, linear facility developers,
project engineers and designers; they
are actually some of the beneficiaries of
the knowledge of the engineering geologist.
Now, we are at a stage when we can take up
a couple of example problems that you might
actually have to deal with if you work, if
you decide to take a career of engineering
geologist.
One of those concerns is mass wasting.
..
What do you mean by mass wasting?
Mass wasting includes landslide, mudslide
or any other
kind of slope failure like rock slide or debris
flow, rock avalanche; any of those type of
problems
that is dealt will classify as mass wasting.
Now, mass wasting can be triggered by natural
cause
like heavy rainfall or earthquake or it can
be caused because of human activity like road
construction or deforestation.
What do you mean by that is for example 
if we actually, if there is
a hill slope which looks like that which is
originally stable and we are looking at section
here and
then we decided to cut steepen the hill slope
so as to accommodate a road way and this type
of
steepening of the hill slope may actually
trigger, may actually trigger a landslide
like in this, like
this manner.
.
.So, over steepening of slope because of any
construction activity may actually make an
area
susceptible to landslide or slope failure.
Similarly, if the hill side is afforested
and we actually
indiscriminately cut down the trees, that
is also going to increase the chances of slope
instability.
.
Now, in order to illustrate what we mean,
we actually consider a configuration of slope
which is
shown, which is shown on the sketch there
and what I actually … at the, before the
slope failure
and the alignment of the trees and other things.
So, you just have a close look at the sketch
that is
shown on the right-hand side of the slide
there.
So, all the trees are upright and we do not
have
any indication of slope failure as yet.
Now, we move on to the next slide in which
we are going to see an animation of slope
failure.
I
again, I want to you to see what happens to
the orientation or to the uprightness of the
individual
trees and you just take a close look about
what are the other features that you can identify
during
the mass wasting process.
..
Now, what we see here?
First of all, we saw that there was a crack
that developed near the top of
the slope.
That was kind of a precursor in the problem
of impending slope failure.
So, there was a
development of crack near the top of the slope
and then what we saw is that a crack that
actually
opened up again near the top of slope from
where the sliding mass actually came tumbling
down.
So, this is called the main scarp 
and then there were other scarps that developed
in the process of
slope failure.
We saw that this tree which was originally
upright got titled in the process of slope
failure.
We also saw that there was a bulge that appeared
near the bottom of the slope which is
also called the toe of the slope.
So, this thing is called, we could call it
toe bulge.
.
.So, what is the precursor then of the slope
failure?
If you see that a crack is starting to appear
near the top of a relatively steep slope,
then that that is considered sometimes as
a precursor to an
impending slope failure.
What is actually an indication of ongoing
slope instability?
All the other
features that I actually marked here like
presence of a main scarp which is on one side
is a
relatively flat slope in the other side the
slope is relatively steep and more steep compared
to any
other portion of slope; that is an indicator
of ongoing slope failure or a process that
has been
there that develop developed over the recent
past.
Now, if this feature is very old, then what
is going to happen of course because of erosion
is; the
steep portion, the steep portion of the main
scarp is going to flatten out and the area
is going to
be again vegetated.
So these things, this feature is going to
vanish, this is going to be erased,
erased by you know as the time progresses.
If you see toe bulge near the bottom of the
slope; not
one bulge actually, there could be hummocky
topography comprised of several different
bulges,
that is also indicative of an impending or
ongoing or earlier slope instability.
So, these are the things that geologists are
going to look for to find out whether a slope
is going
to be stable or it has got some likelihood
of getting mobilized by I mean, there is the
possibility
of slope instability.
Now, this is what we discussed just a little
bit back; the precursors to slope instability
is that if
there is appearance of crack or if there is
a seepage coming out near the bottom of slope,
that is
an indicator of the impending slope instability.
Then other indicators of ongoing or slope
instability in the recent past includes uneven
ground surface near the bottom slope, then
there are
scarp like features along the slope face or
tilted tree or tilted telegraph poles or any
other type of
man-made thing that got tilted that was constructed
originally in an upright geometry which is
now tilted; so these all things are considered
as indicators of slope instability or mass
wastage.
Now, the other problem, another example problem
that we are going to consider here is ingress
of salinity.
..
What actually causes ingress of salinity?
Ingress of salinity is caused in the coastal
area because
of heavy tapping of ground water resources.
If ground water is tapped more than the
replenishment of ground water because of rainfall
or other types of precipitation that causes
a
draw down in the ground water and when the
ground water gets drawn down, then in the
coastal
area, saline water gets into the I mean, it
gets further inland and that actually makes
the ground
water wells and other things, brackish; I
mean, all the ground water resources that
can be tapped
become brackish.
So, we are going to look at how these things
develop over the next couple of
slides.
.
.So, what we begin with?
We begin with geometry like that, again we
looking at section here
where we have got a coast line; this is the
coast line 
and that is the sea level.
So, this water here,
this one, this is actually saline water and
the water on the right hand side is fresh
water.
So, what
we consider here?
We consider that a well, water well, irrigation
well is installed at that location
and in the next slide we will try to see,
how the initial extent of salinity progresses
to a location
which is farther, quite a ways on the inland.
.
So, you can see what happens actually?
What is the outcome of this is that the water
well is
going to actually start taping brackish water
in this kind of situation because the entire
water
from the sea coast to this much far inland
has become saline.
How does it happen?
This actually shows an animation which will
let you see how saline water which was initially
at
that location there, it progresses in land.
Now, water table has drawn down upto that
level
because of ground water taping.
Now, what happens actually?
Let us start it again.
What happens
actually?
Because of the draw down, the slope of the
top of the ground water actually pulls the
saline water further inland and because of
the fact that brackish water is heavier than
fresh water,
the water that gets on top of the fresh water
that actually pushes the fresh water out and
in that
process, the brackish water is going to make
an advance upto the extent that is shown on
this
particular slide.
..
Let us look at it again; pay a careful attention
to the sequence of events.
So, this was the original
configuration.
.
This is when the water was pushed on top of
the original refresh water.
..
And now, it is going to push everything down
because of gravitation, because of gravity.
.
And finally, we end up with brackish water
upto that location.
So initially, so this is the final
extent, if you recall, this is final extent
of salinity 
and as I mentioned earlier, this was the initial
extent of salinity.
Once again the water that is being tapped
by this water well is tapping into
brackish water only.
So, whatever area this water well is going
to start irrigating that is going to
be affected by salinity.
..
So, salinity ingress; what the precursors?
A precursor is that if you have got seasonal
or
temporary salinity showing up in irrigation
water that could be considered as a precursor
of
salinity ingress.
Now, what are the fixes?
The fixes are restricted groundwater use of
course and
facilitation of recharge.
Now, how much groundwater one could safely
tap in this kind of
situation is often quantified by engineering
geologists.
In the final segment of this particular
lesson, we are going to look at what are the
historical developments that have led to the
current
state of understanding of the subject of engineering
geology.
.
.Now, use of geological resources and heavy
construction actually dates back to several
thousand
years.
One could, for example, given is example of
mining and metallurgy, then religious or
ritualistic facilities, ports, lighthouse
and bridges construction.
Occasional knowledge of what
works and what does not works was there for
development of this particular heavy construction.
But what was not there is a scientific understanding
of why a certain thing works and why some
other things do not work.
So, what I want to highlight here is that
there has been history which dates back several
thousand
years of heavy construction, I mean extremely
large civil engineering project we can think
about;
like for example pyramids of Egypt or Taj
Mahal I mean, we can take about several different
heavy construction activities over the history
of human kind.
But most of the time, these things
relied on the knowledge on rules of thumb
that told the construction people whether
something is
going to work or something is not going to
work.
So, what I mean by that is that say, you have
got a, in several different occasions what
was found
that mid ways into the construction project,
one had to actually change the entire sequence
or
entire drawing, entire details of project
in order to make the project a success.
This was quite
primarily because of the fact that there was
no knowledge, no scientific knowledge that
from
which one could predict, the engineers could
predict whether a certain type of construction
can
be successfully implemented or not.
.
Now, other thing is the next bit of development
took place after the eighteen hundreds and
this is
when the transition from the approach based
on the rule of thumb to the scientific approach
began and this was primarily pushed by the
advancement I mean by the advancement of the
human civilization into areas which was not
inhabited for the most part.
So, what happen
.because of those spreading of human settlement
is one of which was railway construction.
Railways, railway construction was a prime
investigation of the developments of that
we get to
see today about of many different aspects
of engineering geology.
Then this happened, actually
this thing actually happened between eighteen
hundreds to early ninety hundreds.
Then early
nineteen hundreds to mid nineteen hundreds,
what happened actually were development of
several analytical techniques and emergence
of geotechnical and geological engineering
in the
process.
Scientific knowledge, quantified I mean, calculative
approaches to implement different
scientific knowledge was actually started
to develop in this particular time frame.
Now, after mid nineteen hundreds to present,
the development is mainly in the area of
instrumentation or different ways of investigation
process and remote sensing; these are the
different types of, different areas that actually
developing since the mid nineteen hundred
and in
this process, the sensitivity of human kind
towards environmental protection also increased.
So,
another branch of engineering that actually
bifurcated from the general area and that
was geoenvironmental engineering.
So, that was, in a nut shell was the historical
development that led to
the current state of the practice in engineering
geology.
.
So, now we try to summarize actually, what
was discussed in this lesson.
So, we actually
presented an outline of the scope of engineering
geology; what is the definition and what are
the
different types of problems that we consider
in engineering geology, what is the approach
typical
approach and end users that we encounter while
working as an engineering geologist, then
we
actually considered two problems of engineering
geology to give a flavor really about the
general
nature of problem that you might actually
come up with or you might actually encounter
during
this of course and finally we considered a
very brief point form summary of the historical
developments that actually let to the present
state of practice in engineering geology.
..
And to conclude, we actually leave you with
a question set and just note down these questions
and try to answer these questions in your
leisure.
Some of the answers were very obvious from
what was presented in this lesson and some
of which you have to think a little bit.
Try to develop
all the answers yourselves and we are going
to actually give you brief answers when we
meet in
the next class of this series of lectures.
Thank you very much.
.
.Hello everyone, welcome to session 2 of the
series of presentations on engineering geology.
In
this session, we are going to talk about geologic
structures; different types of land forms
and will
try to recognize what are the various land
forms that one might have to encounter while
working
as an engineering geologist.
(Refer Slide time: 54:06)
But before we get into the subject matter
of today’s presentation; I am going to take
up the
question set that I gave in the first of this
series of lectures and I am going to try to
provide you
the answers of the question set.
The first question that we had in the last
presentation was; how engineering geology
differs from
geotechnical and geological engineering?
Now, the difference is essentially very tenuous.
Only
thing that I can think about is engineering
geology is more inclined towards the geologic
maters;
while, geotechnical and geological engineering
deals primarily with the mechanical aspects
of
the different problems that are encountered
in engineering geology.
Then the second problem, the second question
that I asked was that what are the key factors
that
may trigger slope failure?
Two of the major factors that cause slope
failure are loss of strength,
loss of shear strength of the material of
which this slope is comprised.
The major reason for the
loss of shear strength is basically
We now try to understand try to get an idea
about different types of lands forms that
one might
have to have encounter in a fluvial
Set of questions that you should try in your
leisure and again as we did in the last presentation;
I
am going to provide brief answers when we
meet for the next lesson.
You should try to explain
the dip, strike, anticline and trust fault
and loess and you should explain
Whereas dunes are generally underlain by sand
grain deposits; we could also have glacial
.deposits.
.
Glacial deposits are listed here and they
are generally laid by ice.
So, if they are directly laid
underneath ice, they are called till.
There could be glacial fluvial deposits, melt
water that
originates from melting of glaciers like drumlin,
esker or glacial out wash.
Now these things,
typically are elongated in the direction of
the ice flow with their slope in the direction
of ice
flow; in the up ice direction is generally
gentler compared to or generally steeper is
comparison
with the down ice direction.
There could be glacial outwash deposit that
are comprised of basically sand and gravel
deposits
or there could be glaciolacustrine deposits
that are find grained deposits underneath
glacial lakes.
That in a nut shell summarizes different types
of land forms.
(Refer Slide time: 57:42)
.We looked at descriptions of different stratigraphic
units, we looked at how to define them
geometrically and we looked at, we tried to
list a number of landforms that are encountered
often
in the branch of engineering geology.
(Refer Slide time: 58:08)
We finally end the session with the set of
questions that you should try in your leisure
and again
as we did in the last presentation, I am going
to provide brief answers when we meet for
the next
lesson.
You should try to explain the dip, strike,
anticline and trust fault and loess; you should
explain the slope on the windward and the
lee side whether the slope of the dune is
likely to be
steep on the windward or on the downwind directions
that is the lee side and you should also try
to say, try to answer whether a drumlin, what
is going to be an orientation of a drumlin
visa ice
movement.
So, you try to answer those questions and
I am going to provide the solutions when I
meet you
again for the third of the series of presentations.
Thank you very much.
.
