This document outlines the methods and practices involved in geological surveys and mapping, covering topics such as geochemical and geophysical surveys, remote sensing, and the skills required for a geologist. It emphasizes the importance of geological mapping for resource exploration, safety, and environmental considerations, and details the necessary equipment for effective fieldwork. The document serves as a comprehensive guide for students and professionals in earth sciences to understand geological mapping techniques and their applications.

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Course Title: Earth Science
Paper Title: Earth’s Structures,
Surveying & Mapping
Geological MappingGeological Mapping
By
Prof.A. Balasubramanian
Centre for Advanced Studies in Earth Science
University of Mysore, India

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Table of ContentsTable of Contents
 Introduction
 Kinds of Geological Surveys
 Geological Maps and Mapping
 Remote Sensing for Geological
mapping
 Geological observations
 Geochemical Methods
 Geophysical surveys
 Geological investigations
 Basic skills of a Geologist
 Field Equipment and tools
 Exposure mapping
 Test Drilling
 Interpreting geological
maps
 Conclusion

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 The objectives of studying this module are to
understand the methods employed in conducting
geological surveys, mapping geological bodies, skills of
geologists, interpreting the geological maps and
preparing geological reports.
 It is necessary to follow a set of precautionary
measures while conducting geological surveys and
mapping works, by a student of earth science. All
details are highlighted in this module.
Objectives

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 A geological survey is the basic professional work
normally done by the geologists. A geological survey is
a systematic investigation of the geology of an area. It
reflects the geology and structure beneath a given
piece of land.
 Surveys are conducted for the purpose of preparing a
geological map. Any geological surveying method
employs several techniques including the traditional
traverses, walk-over surveys, studying the exposures,
outcrops and landforms.
Introduction
(…Contd)

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 Geological surveys also adopt some intrusive
methods, like hand augering and machine drilled
boreholes.
 Geological surveys also use the geophysical
techniques and remote sensing methods, such as
aerial photography and satellite imagery.
Introduction
(…Contd)

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 Geological surveys are normally undertaken by
private agencies, state government departments of
mines and geology, and national geological survey
organizations.
 They maintain the geological inventory of various
formations, mineral deposits and resources.
Introduction
(…Contd)

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 They keep all records for the advancement of
knowledge of geosciences for the benefit of the
nation.
 Geological mapping are parts of a geological survey.
 It involves certain procedures. This lesson highlights
the methods and procedures of geological mapping.
Introduction

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 A geological survey can be undertaken using a
number of methods depending on the size of a
region and the amount of information that are
required.
 Different types of methods are involved in
geological surveys. The first method is Remote
Sensing.
 It is used in some geological mapping works. This is
done using satellite remote sensing methods.
Kinds of Geological Surveys
(…Contd)

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 While most of these methods rely on geophysical
rather than pure geological data, the use of this
method can give a broad scale view of surface
geological structures such as folding, faulting,
igneous intrusions, etc.
Kinds of Geological Surveys
(…Contd)

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 The next method is the Airphoto interpretation
method.
 This can give a broad overview of the geological
relationships of an area with no detailed knowledge of
the mineral composition or fabric of the rocks.
 The third method is the outcrop surveying method.
Kinds of Geological Surveys
(…Contd)

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 This is normally done by geologists by conducting
traverses along the fields and mapping the
outcropping rock types.
 The last part is the Geology interpretation surveys.
 These are more detailed outcrop surveys, where the
geological boundaries are established and interpreted
in a small area.
Kinds of Geological Surveys

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 Geological methods rely on the identification of rocks
and minerals.
 They are done for getting an understanding of the
environment in which they are formed.
 Geological surveys aim to find what rock types occur
at or close to the surface and how these rock types
are related to each other.
Geological Maps and Mapping
(…Contd)

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 The surveys orient to know about the disposition
of rocks and minerals, their boundaries, ages, and
structures. At the end of the surveys, geologists
prepare the geological maps. The geological maps
are prepared for three major purposes. They are:
 For smaller scale reconnaissance works
 For large scale underground mining
 Engineering site plans.
Geological Maps and Mapping

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 There are several reasons based on which a
geological field mapping is carried out.
 They are all entailed in collecting variable amounts
of field data.
 The basic reason is to delineate the natural mineral
and other resources.
 Mineral and oil exploration proceed always in this
way.
Objectives of Geological Field Mapping
(…Contd)

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 Geological mapping is usually the first task in any
reconnaissance study.
 Geophysical investigations are carried out to answer
the question of the extent of the system under the
subsurface.
 Geochemical investigations are also used to
estimate parameters such as the temperature of
the system.
Objectives of Geological Field Mapping
(…Contd)

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 Exploitation of all mineral resources requires the
appreciation of basic geology and optimum utilization
of a potential area. This requires the mapping of the
resource.
 In addition, the understanding of the spatial
distribution and deformation of rock units, at the
surface, is critical in order to develop a 3-
dimensional model of the subsurface geology.
Objectives of Geological Field Mapping

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 Geological mapping is done to obtain and provide
basic knowledge about the prevailing field
conditions, not only through direct observations
but also by collecting and analyzing rock, mineral
and sediment samples.
Geological mapping
(…Contd)

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 A geologist conducts field surveys and prepare
accurate geological maps by collecting samples and
measuring the geometrical aspect of outcrops.
 There is no substitute for a geological map.
Geological mapping
(…Contd)

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 Geological mapping is normally done in a project
mode with people in a team, a set of special
equipment, and a topographic base map.
 Careful observations are done during the
geological mapping.
Geological mapping

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 Today, the availability of aerial photography and
remote sensing from satellite imagery, and the
computer capability for storage, recovery, and
evaluation of data are used for geologic mapping and
other purposes.
 These methods have almost replaced many old
methods of geologic data collection, plotting, and
interpretation.
Remote Sensing for Geological mapping
(…Contd)

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 The Remote sensing technology and satellite
products provide the fast access to all geospatial
data.
 Also, a greater and finer resolution of data and
images are readily available in planimetric and 3-D
mode at any desired scale and time.
 These data can be integrated with Geographic
Information Systems (GIS) for vertical and
horizontal comparison.
Remote Sensing for Geological mapping
(…Contd)

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Maps can be combined with layers of information on
 topography
 minerals
 water
 energy and the environment.
These technological advances have increased the
usefulness of and public access to geologic maps.
Remote Sensing for Geological mapping

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 The three basic reasons why geological field work
is carried out include exploitation of natural
resources, as a requirement of the government and
for academic purposes.
 Good geological mapping should be executed in
three phases; planning, data collection and
reporting.
Geological observations
(…Contd)

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 The data collection phase involves detailed
observations.
 All geological observations are marked on the base
maps for future compilation and interpretation.
 Base maps are used to locate the positions of people
objects and structures in the field.
Geological observations

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 Geochemical methods involve the measurement of
the chemistry of the rock, soil, stream sediments or
plants to determine abnormal chemical patterns
which may point to areas of mineralisation.
 When a mineral deposit forms, the concentration of
the ore "metals" and a number of other elements in
the surrounding rocks is usually higher than normal.
 These patterns are known as primary chemical
halos.
Geochemical Methods
(…Contd)

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 When a mineral deposit is exposed to surface
processes, such as weathering and erosion, these
elements become further distributed in the soil,
groundwater, stream sediments or plants and this
pattern is called a secondary chemical halo.
Geochemical Methods
(…Contd)

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 Secondary halos aid in the search for deposits as
they normally cover a greater area and therefore the
chance of a chemical survey selecting a sample from
these areas is greater than from a primary halo area.
Geochemical Methods
(…Contd)

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 Different elements have different "mobility" in the
environment based on their readiness to dissolve in
water, their density, their ability to form compounds
with other elements and the acidity (pH) of the
environment.
Geochemical Methods
(…Contd)

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 Subsequently, the secondary halo may not contain
the "metal" for which a geochemical survey is
searching but other "marker" elements.
 These are commonly employed during geological
surveys.
Geochemical Methods

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 Geophysical prospecting method are employed when
there are no exposures and the entire region is
covered with soils and regoliths.
 These are indirect methods of finding out the hidden
rock types and structures.
Geophysical surveys
(…Contd)

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 Geophysical survey refers to the systematic
collection of geophysical data for geospatial studies.
 Geophysical surveys are conducted using a great
variety of sensing instruments.
 The data are collected from above or below the
Earth's surface. Sometimes the data are collected
from aerial, orbital, or marine platforms.
Geophysical surveys
(…Contd)

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 Geophysical surveys have many applications in
 Earth science
 archaeology
 mineral and energy exploration
 oceanography and
 engineering.
 Geophysical surveys are part of the geological
surveys.
Geophysical surveys

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 During the preliminary phase, all existing data and
maps of the area of study are to be collected and
analysed.
 All suitable maps available like the physical, political,
relief, road, physical, and topographic maps are to be
seen first.
 These are to be carried to the field as it is possible
that details in one may not be present in another.
Base maps and other Maps
(…Contd)

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 Most importantly, for a geological fieldwork, a
handy base map is expected to be used as a
reference.
 Depending on the areal extent of the field and the
detail required, the scale of the map is to be chosen
as it is an important aspect to be considered.
Base maps and other Maps

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 Geological investigations normally start with base
maps, run through the field areas and end in
laboratory analysis of samples.
 The ultimate aim is to explain the geology and
structure of the area.
 The approach is highly practical.
Geological investigations
(…Contd)

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 The first geologic map was prepared, in the world,
to solve a practical problem involving the
distribution of different types of rocks at and near
the Earth’s surface.
 Most building materials, except wood, are from
various specific rocks and rock products.
Geological investigations
(…Contd)

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 Geological investigations are the basic needs for a
country.
 A geologic map graphically communicates important
information about the distribution of rocks and
unconsolidated materials at and near the Earth’s
surface.
 All are done by the geologists.
Geological investigations

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 Geologists spend most of their time in the field and
also in the laboratories.
 Their mind should be conservative and sympathetic
to country-side environment and people of rural
areas.
Basic skills of a Geologist
(…Contd)

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The flowing are areas of concern to a geologist:
 Field behavior
 Safety
 Ancillary skills
 Courage to carryout independent mapping.
Basic skills of a Geologist

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 When conducting surveys in some enclosed areas
the gates should not be left open, people should
avoid climbing dry stonewalls; should not leave
litter or disturb communities of plants and animals.
Field Behaviour
(…Contd)

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 While collecting specimens do not strip or spoil
sites, where type fossils or rare minerals occur.
 People should take only what is needed.
 It is necessary to ask permission to enter a land
from land owners or authorities.
Field Behaviour

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 Any geologist must be physically and mentally fit to
work in the field, even in a rugged area,
mountainous terrain, poor weather, difficult climate
and challenging situations.
Safety
(…Contd)

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 Geological works are prone to have physical
hazards which are to handled with care and safety.
 Experience is the best teacher but commonsense is
a good substitute during field mapping.
Safety

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 A geologist should be able to draw, swim, drive ride
and record in any type of conditions.
 He should be able to ride horses, in some areas, and
walk slopes, they should clamber up and conduct
surveys on cliffs and escarpments.
Ancillary skill

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 Every geological mapping project is time-consume
and mind depressing, especially when carry out
alone no matter how many hours are spend on the
compilation of all little information collected from
the field, it will certainly make an outstanding
contribution to the knowledge of geology of the
area.
 People should not lose heart at the begining. They
should not be frustrated.
Independent mapping ability

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 Geological mapping requires a lot of small field
equipment . Tools are
 Hammer and chisels
 Compasses, clinometers and camera
 Lenses and Tapes
 Map cases and Field note books
Field Equipment and tools
(…Contd)

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 Scales and Protractors
 Acid Bottles and Hand gloves
 GPS, pedometers and altimeters
 Stereo net and stereoscopes
In addition to these pencil, erasers and a jack-
knife are needed in the field.
Field Equipment and tools

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 Geologist need a hammer and some chisels. These
are used to break the rock and get samples.
 1Kg hammer is the most use full one in a resistive
hard rock, Hammer should be fitted with a good
wooden or fiber glass handle or a steel shaft.
 Normally a 45cm chisel with 2.5cm cutting edge is
used in the field. Chipping a rock samples should
be done carefully. People should wear safety
glasses.
Hammers and Chisels

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 Geologist use Brunton compass or a clinometers
compass which is an instrument helpful to detect
the directions using a magnetic needle that swings
freely on a pivot, is a horizontal plane.
 One end of this needle always points to the
magnetic north,
Compasses and clinometers
(…Contd)

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 The compass is normally made of brass or an alloy, so
that it is not susceptible to any magnetic influence the
circular dial of the compass is graduated into 360
degrees.
 In normal equipment this graduation is in clock wise
direction. In Brunton compass, it is drawn in reverse
direction.
 The east –west cardinal points are juxtaposed in order
to enable the user to get direct bearing of readings.
Compasses and clinometers

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 The Brunton compass is composed of a non-magnetic
cylindrical body as the base in which a graduated (360
degree) scale is fixed in circular form.
 At the center of this circle, a pivot holds the magnetic
needle which is marked with red point to denote the
north direction.
Parts of a Brunton compass
(…Contd)

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 The compass is attached to a mirror lid with a hinge.
 There is an axial line marked in the mirror. At the
opposite end of the mirror, there is a sighting arm
equipped with a slit and a Peep sight.
 The compass is also containing a Bulls-eye level to
denote horizontality of the equipment.
Parts of a Brunton compass
(…Contd)

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 There is a clinometers to denote the vertical drop
provision which helps to detect the angle of
inclination of the axis of the Brunton compass
oriented along the axial line, which can indicate the
direction of elongation and measurement.
Parts of a Brunton compass

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 In the Brunton compass, the sighting arm and the
mirror containing the axial line are raised
perpendicular to the cylindrical body of the main
equipment.
 The folding sight on the top of the mirror and the
peep site in the opposite sighting arm are used
together to align the direction is which the bearing
are decided to be determined.
Method of using the Brunton compass
(…Contd)

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 All object, axial line and peep slit should align in the
same line to determine the direction of the object.
 This helps to decide the forward measurement (as
forward bearing) or is marking the reverse direction
detection (as backward bearing ) works.
Method of using the Brunton compass

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o Brunton compass is useful in determining the dip
direction of any dipping strata.
o The clinometers kept inside the case is a free-fall type
unit denoting the vertical position always, By orienting
the axis of the Brunton along the dipping strata, the
dip angle between the vertical plane and direction of
the strata could be determined.
Method of measuring the dip

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 Clinometer is a simplified model of a Brunton compass
containing the very essential parts for determining the
dip of the strata inclination of joints, angle of slope of
an embankment and or determining the direction and
location of objects through forward or backward
bearing.
Clinometer
(…Contd)

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 All readings are made with reference to the north
direction.
 In all geological mapping, a high degree of accuracy is
recording the directions or bearing is essential.
 Dip, strike and direction are the three major
measurements made using the Clinometer.
Clinometer

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 Every geologist must have a hand lens with a
magnification of between 7 and 10 times.
 A short roll-up steel measuring tape is always needed
during the field work.
 It should help in measuring everything from grain size
to bed thickness.
 Sometimes a 10m or a 30 m linen tape may be of
much use for small surveys.
Hand lenses and Tapes

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 At the time of conducting a geological survey and
carrying out geological mapping there is a need to
use map cases, field notebook, scales, Protractors,
stereonets, pedometers and hand gloves.
 Acid bottles are also carried to test and distinguish
carbonate minerals or limestones.
 10% HCl is the normal or acid used in the field, kept
in tiny dropping bottles.
Other tools

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 Sample bags which best suit for keeping all the
geological samples like a canvas in fabric is an
essential item during surveys.
 Plastic bags may be used where the sample is soft,
disintegrated or wet.
 Safety clothing is a necessity.
Sample bags and safety clothing
(…Contd)

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 These include sturdy shoes, clothes that are tough
in fabric preferably jeans or khaki, hat and
sunglasses.
 Safety glasses and gloves are important especially
when hammering rock samples.
Sample bags and safety clothing

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 Safety in the field is always a priority; nevertheless
accidents cannot be ruled out.
 There is a need to be prepared with a first aid kit.
 It is crucial that at least one person in the field crew
should have been trained in basic first aid techniques.
First aid kit

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 A Global Positioning System is needed for conduction
geological surveys, It helps in detecting the latitude,
longitude, altitude and other Geospatial parameters with
precision and accuracy.
 A GPS needs a line-of-sight to several satellites for getting
the way-points.
 Grid references of toposheets are accurately indicated
with other benchmarks for locating the outcrops during
geological mapping works.
GPS

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 Geological mapping is the process of making
observations of geology and structure in the field
and recording them on a base map and reproduce
in the form of a geological map.
Method of surface geological mapping
(…Contd)

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 The information recorded must be factual and
thorough based on objective examination of rocks
and exposures.
 There are several methods adopted during this
process as traversing, following contacts and
exposure mapping is the methodology adopted.
Method of surface geological mapping
(…Contd)

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 This involves mapping of poorly exposed region
with indications of rocks from soils, vegetational
guides, topography and geomorphology and
structure.
 Contours are the major lines of trace involved
during surface geological mapping.
Method of surface geological mapping

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The features recorded are the following:
 Rock types and contacts
 Shape of the rock bodies
 Note on the sequence and relative ages
 Note on the primary porosity and permeability
 Note on the weathering and their patterns
 Note on the depositional or magmatic flow features
What to map during Geological mapping
(…Contd)

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 Structures including
a) Folding - dip, strike, deformation, orientation of
grains
b) Joints – attitude, size, open or closed
c) Faults – look for slickensides, fault gouge, breccia
and their visible displacements.
What to map during Geological mapping

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 Traversing is a method of making observation of
outcrops along a path across a country.
 It is a method to be repeated in roughly parallel
alignment with the earlier traverse.
 This method helps in covering the ground in detail.
Traversing
(…Contd)

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 Traverses are pre-determined routes, where
contacts and other geological features are
extrapolated between the traverses and the map of
the geology of the area is prepared. The major
traversing methods adopted during geological
mapping are:
a. Cross-section traverses
b. Stream and ridge traverses and
c. Road traverses.
Traversing

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 These are done in structurally complex geological
terrain by plotting a set of cross sections and
compiling them.
 Streams and ridge traverses give excellent semi-
continuous exposures and in places where the
slopes are partly covered by colluvium.
Cross-section traverse
(…Contd)

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 Locating a position on a stream is relatively an easy
method from the shape and direction of bends,
position of islands, waterfalls and junction of streams.
 In a dense and thick mountainous forest, the only
way to locate on the base map is to find out the way
along the river courses.
Cross-section traverse

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 Ridges and the spars are excellent traverse locations
during geological mapping.
 They can be indentified easily on a map or aerial
photograph. Exposures are normally clear in ridges .
 Since, ridges are more erosion-resistant rocks, they
tend to follow and indicate the strike directions
clearly.
Ridge Traverses

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 A very rapid reconnaissance of an unmapped area can
be made along tracks and roads and by following
paths between them.
 Road cuttings in mountainous exposures for mapping.
 Several stratigraphic successions can be easily
mapped and traced along such road cuttings.
Road Traverses

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 A primary purpose of mapping the geology of an
area is trace the contacts between different rock
formations, groups and types and to show them on
a map where they occur.
 One way of doing this is to follow the contact on
the ground and trace it on the map.
Following contacts and Exposures
(…Contd)

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 In some places contacts may be visible and easy to
trace.
 In some places, the contact may not be
continuously exposed or the contacts may be
beneath superficial deposits.
Following contacts and Exposures
(…Contd)

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 In such cases, the stratum contours are considered
for tracing, using geometric alignments and visual
interpolations.
 When a contact is concealed by alluvium or scree,
it should be shown by a dotted line.
Following contacts and Exposures

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 Mapping by exposures is the major method of
geological mapping. It is done at the scales of 1:10000
and larger.
 Exposure mapping shows the factual evidence on
which interpretations are made. It shows what has
been seen and inferred.
 A form line map is prepared based on the
interpretation of the form of geological structure.
Exposure mapping

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 In some places, rocks are poorly exposed.
 They are mostly covered and hidden by vegetation.
 They may show poor exposures due to coverage
by weathered regolith’s of all rocks.
Poorly exposed Regions
(…Contd)

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 Mica schist forms the poorest exposure but show all
evidence along the footpaths.
 In some places, when trees are uprooted due to
storm events, rocks are exposed for observations.
 In addition, road cuttings, railway cutting and in other
man made /animal–made excavations, rock types are
expected to be exposed for mapping.
Poorly exposed Regions

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 Soil, if they are not transported, reflect the parent
rocks existing beneath them. Sandy soils are
indicative of rocks containing more quarts. Clayey
soils are from Kankar and weathered rocks.
Dolerites and other basic rocks tend produce
distinctive red-brown soils.
Soil as an Indicator
(…Contd)

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 More acidic igneous rocks form lighter colored soils
in which mica may be visible.
 Any soil depend on parent rock, climate age and
other factors.
 Their association with specific rocks may help in
mapping the rock bodies.
Soil as an Indicator

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 Plants are good indicators of some elements
present in the rocks between them.
 Some are typical around limestones, on some acid
rocks and on serpentinous rocks.
Vegetational guides
(…Contd)

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 Flora are capable of indicating the varieties of rocks,
in an indirect way, when they are natural. Some
plants can indicate metallic ores too.
 There are many copper indicative plants, uranium
indicative plants and even gold indicative plants.
Vegetational guides

86. MHRD
NME-ICT
 Geomorphology is the science of landscapes.
 Geologist always look into the rock and relief
exposed in various places.
 In many places, resistive rock bodies stand well above
the land surfaces.
Topography and geomorphology
(…Contd)

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NME-ICT
 Remnants, residual hills, pediment zones, flood
plain deposits, alluvial cones and fans, drumlins,
dunes, boulder clays, and other fluvio-marine
deposits show typical relief feature as landforms.
Topography and geomorphology
(…Contd)

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NME-ICT
 Volcanic rocks always show very unique exposures.
 Typical drainage patterns exist in different rock types
and relief zones.
 Landslides bring down a major land mass and expose
the basement rocks.
Topography and geomorphology

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NME-ICT
 When it is essential to investigate the rock lying
beneath any overburden, pits and trenches are made
to study them.
 Many contacts could be best indentified from
trenches.
Pitting, Trenching, Augering and Loaming
(…Contd)

90. MHRD
NME-ICT
 In many cases, identifiable fragments of weathered
rocks can be from shallow anger-hole drilling
method loaming is a method of mapping in poorly
exposes and deeply weathered regions.
Pitting, Trenching, Augering and Loaming

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 Test drilling are commonly employed to locate
formation at depths.
 They are also done to confirm their presence when
there is a gap in other information, and also when
there is a need to find out the details of structure
and their geometry.
Test Drilling
(…Contd)

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NME-ICT
 There are two kinds of drilling methods adopted as
percussion and rotary drills.
 In percussion drills, rocks are fully crushed and
powdered or drilled using a ring like drill bit to
obtain a core sample.
 In rotary drills, only crushed products will come up
for identification.
Test Drilling

93. MHRD
NME-ICT
 Drilling is used to obtain very detailed information
about rock types, mineral content, rock fabric and
the relationships between rock layers close to the
surface and at depth.
 Drilling is only used in areas that have been selected
as "targets" from geological, geophysical and/or
geochemical methods.
Types of Drilling Methods
(…Contd)

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 Four drilling methods are widely used, each
depending on the type of information required
and/or the rock types being drilled.
 Air-rotary drilling : This is a quick and economical
method of producing a sample.
Types of Drilling Methods
(…Contd)

95. MHRD
NME-ICT
 This method is used in soft rock materials to about
25m deep, or to drill through the top layer of
decomposed rock and soil to get a fresh rock sample
from the bedrock below.
 Air-percussion drilling : This method is used for
penetrating hard rock types to a depth of around
300m.
 As in air-rotary drilling, rock chips are brought to the
surface by the returning air.
Types of Drilling Methods
(…Contd)

96. MHRD
NME-ICT
 Mud-rotary drilling method is used for drilling
through soft rocks, sand and clay layers especially in
the search for coal, oil or gas.
 This method is used for holes up to 3km deep and
can be done from ships or offshore platforms
especially in the search for oil and/or gas.
Types of Drilling Methods
(…Contd)

97. MHRD
NME-ICT
 Diamond core drilling method is employed using
industrial diamonds for drilling through rock layers.
 This provides a "core" of rock being left in the
centre of the pipe.
 This core is recovered and gives information not
only about the rock types, but also about the
relationships between the rock layers in detail.
Types of Drilling Methods

98. MHRD
NME-ICT
 A geological map is a spatial representation showing
the distribution of rock units and structures across a
region.
 It is drawn on a plane surface.
 A map showing the occurrence of structural
features across a region, the distribution of rock
units, and their type and age relationship is termed a
geological map.
Preparing a Geological map
(…Contd)

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NME-ICT
 A geological map is expected to show all the rock
types of a region, their structures, geological
formations, geothermal manifestations, age
relationships, distribution of mineral ore deposits
and fossils.
Preparing a Geological map
(…Contd)

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NME-ICT
 All these features are to be super imposed over a
topographic map or a base map.
 The amount of detail shown in a map depends
largely on the scale and a smaller scale will naturally
disclose finer detail.
Preparing a Geological map

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 Geologic reports and maps are prepared to assist in
public decision making.
 Geologic maps and reports can be used in regional-
scale environmental and resource management
planning documents to assist geologists, engineers
and land-use planners in making decisions that affect
public health and safety, critical environmental
habitats, water quality, uses of public lands, and help
identify areas where more detailed geologic studies
are needed.
Reporting
ReportingReporting
(…Contd)

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 It is often said that a report is as good as its data
collected from a field work.
 It is necessary that there is a need to collect very
clear and accurate data.
 Nothing can be overemphasized.
Reporting
(…Contd)

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 Ultimately when all possible available data are
collected, then they are taken back to the laboratory
for sorting, interpretation and analysis.
 This phase is the most challenging phase.
 Any wrong analysis or misinterpretation of data can
lead to an inaccurate report and in consequence
misinformation.
Reporting

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NME-ICT
 Once a geological map is complete, then the most
important task is interpreting it correctly.
 A map is basically a visual summary of an entire
report and the two should complement each other.
Interpreting geological maps
(…Contd)

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NME-ICT
 When the interpretation process is at hand, it is
crucial to have group discussions with all those
involved in the actual fieldwork.
 It is also deemed important to have discussions with
those who are experienced in the field of geology as
well as other related scientific fields of the area.
Interpreting geological maps

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 Basically, the quality of a geologic map will depend
upon the accuracy and the precision of the field
work.
 The interpretation of a geological map depends on
adequate training, interest and the techniques used.
Quality and Interpretations
(…Contd)

107. MHRD
NME-ICT
 It is necessary to visualise the scenarios that might
have been involved during the formation processes
of geological features displayed in maps while
analysing the geological maps.
 The ability to form a three- dimensional image from
a two dimensional map, is in real sense, a major
part of the geologic map interpretations.
Quality and Interpretations

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NME-ICT
 A Geologic map helps to protect groundwater
resources.
 The geologic maps are also used for habitat
prediction.
 Geologic maps are used to evaluate the mineral
resources.
 Geologic maps are also used to delineates the
landslide prone areas.
Uses of Geological Maps
(…Contd)

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NME-ICT
 Geologic map guides to delineate the earthquake-
prone areas and help in damage prediction.
 Geologic map delineates volcanic hazards and aids
in the mitigation of earthquake damage, cyclone
damage, tsunami damage, etc.
Uses of Geological Maps
(…Contd)

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NME-ICT
 Geologic maps show the locations of exploring
sand and gravel resources.
 Geologic maps identify the economic resources and
mining areas.
 A Geologic map guides transportation planning.
Uses of Geological Maps

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 Geologic maps are useful tools. They provide many
information for economic resource discovery and
development.
 The are useful in the design of buildings, canals,
roads and drainage of farmland, environmental
planning and development.
Conclusion
(…Contd)

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NME-ICT
 It is essential to know the procedures of conducting
geological surveys and mapping the earth’s surfaces.
 There are lot more aspects to learn in this topic
alone.
 Geological mapping is fundamental to every earth
scientist.
Conclusion

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Thank You