This document provides information about geology and the geological timescale of Bangladesh. It begins with definitions of geology and describes Bangladesh's geology as being characterized by rapid subsidence and the deposition of thick deltaic sediments. It then discusses the geological timescale and maps the major eras, periods, and epochs represented in Bangladesh. The major geological formations in Bangladesh are also outlined, including alluvium, Pleistocene terraces, and Miocene and Paleogene formations. Finally, the importance of geology and geological timescales to geography is discussed, in terms of understanding resource distribution, land usage, and environmental and planetary history.

1. Presentation on
geology & Geological timescale of Bangladesh
PRESENTED BY:
ROLL- 875, 884, 892, 905, 917, 1856
COURSE NO- 301
GROUP -C

2. QUESTIONS
1. What are geology & geology 0f BD?
2. What is Geological Time Scale ?
Show the Time Scale of BD with
map?
3. What Are Geological Formations?
4. Show the Geological Group
Formation of BD.
5. Why Geology & Geological Time
Scale are so important in
Geography?

3. Preface
Geological evolution of Bangladesh is basically related to the uplift of the
Himalayan Mountains and outbuilding of deltaic landmass by major RIVER
systems originating in the uplifted HIMALAYAS. This geology is mostly
characterized by the rapid SUBSIDENCE and filling of a basin in which a huge
thickness of deltaic sediments were deposited as a mega-delta out built and
progressed towards the south.
The DELTA building is still continuing into the present BAY OF BENGAL and a
broad fluvial front of the Ganges-Brahmaputra-Meghna river system gradually
follows it from behind. Only the eastern part of Bangladesh has been uplifted
into hilly landform incorporating itself into the frontal belt of the INDO-
BURMAN RANGE lying to the east. All the above has been the result of the
Indian plate colliding with the Asian plate as explained by the universally
accepted theory of PLATE TECTONICS.

4. 1.What is geology & geology 0f BD?
Geology
 Geology is the study of the Earth, the materials of which it
is made, the structure of those materials, and the
processes acting upon them. It includes the study of
organisms that have inhabited our planet. An important
part of geology is the study of how Earth’s materials,
structures, processes and organisms have changed over
time.
 Geology is The study of the planet Earth & the materials of
which it is made, the processes that act on these materials,
the products formed, and the history of the planet and its
life forms since its origin.
4

5. Geology of Bangladesh
Bangladesh occupies the delta plain of the Ganges
(Padma) and the Brahmaputra (Jamuna) rivers. The
country’s geological history is covered by several
kilometers of 2-million-year-old sediments.

6. 2. What is Geological Time Scale ? Show
the Time Scale of BD with map?
Geological Time Scale
The geologic time scale provides a system of chronologic measurement relating
stratigraphy to time that is used by geologists, paleontologists and other earth
scientists to describe the timing and relationships between events that have
occurred during the history of the Earth.
The geological time scale divides the total time span of earth's 4.6 billion years
of existence into units and sub-units on the basis of rock records. It basically
includes four eras, such as,
01. Precambrian Era
02. Paleozoic Era
03. Mesozoic Era
04. Cenozoic Era
These eras are subdivided into periods and the periods into epochs.

7. The Geological evolution of Bangladesh is shown by time scale
(source –Banglapedia)

8. Source: Himalayan
Research
Laboratory.
Auburn University;
Alabama; USA.

9. Source: Geology of Bangladesh, By F. H. Khan. P:33
In Geological Time Scale
ERA PERIOD EPOCH GROUP FORMATION
C
E
N
O
Z
O
I
C
QUATERNARY
Holocene
Pleistocene
Pliocene
Late Miocene
Middle Miocene
Lower Miocene
Oligocene
Late Eocene
Middle Eocene
Early Eocene
Lower –Cretaceous
Late Jurassic
Late Permian
Early Permian
Alluvium
Madhupur Clay
St. Martin’s
Limestone
T
E
R
T
I
A
R
Y
N
E
O
G
E
N
E
Dihing
Dupitila-Claystone
Dupitila-Sandstone
P
A
L
I
O
G
E
N
E
Tipam Girujan Clay
Tipam Sand Stone
Surma
Barail Renji?
Jenum?
Jaintia Kopili Shale
Sylhet Limestone
Tura Sandstone
MESOZOIC CRETACEOUS
JURASSIC
PERMIAN
Rajmahal Sibganj
Rajmahal
PALEOZOIC Gondwana Raniganj
PRECAMBRIAN

10. 3. What Is Geological Formations?
• Geological formations are groupings of rock with similar characteristics. In
geology, the term refers specifically to geological strata, while laypeople
may refer informally to outcroppings of rock or interesting geological
features as geological formations, even though this is not technically
correct.
• Visualizing geological formations is easiest to do when one things about
the landscape in cross section. If a hillside is sliced in two, layers of
geological material will appear. When materials in a layer are of similar
age or composition, they can be termed a geological formation. Geological
formations can be bundled together in large groups, or broken down into
smaller segments called members, to help geologists describe, explore,
and study them. When a geologist finds a formation which he or she
thinks is new, the information is presented to the authority which handles
naming conventions in the area, and if the formation is verified as a new
discovery, the geologist may have the honor of naming it.

11. • Many geological formations are made from sedimentary rock, although
other types of rock can also be found in a formation. The type of rock can
be important, as it may provide information about the conditions in which
the rock formed, and the geologic history of an area. Multiple deposits of
limestone formations, for example, indicate that an area was once covered
in an ocean, while a layer of volcanic flow would suggest that there was
volcanic activity in the region at some point in history.
• Identifying, describing, and naming geological formations is part of
stratigraphy the study of layers of rock in geology. Geologists can prepare
maps showing various formations in an area and their relationship to each
other, and they can use these maps to learn about geologic history.
Sometimes events may be more readily apparent when a map is examined
than when people are out in the field, because the map distills the
information in the landscape into small chunks of useful information.

12. 12
 Firstly: “Alluvium, Stream deposits” Delta plan deposit, FLood plain deposits.
 Secondly: “Pleistocene terrace” (Madhupur clay)
 Thirdly: “Pleistocene, Dupi Tila formation”
 Fourthly: “Pleistocene Tipan sand stone formation” Girujan clay formation
 Fifthly: “Miocene, Surma group”.
 Sixthly: Paleogene (Sylhet lime stone, Renji formation).
 Seventh: Lower Miocene - Pleistocene
4. Show the Geological Group Formation
of BD?

13. 13
FIRSTLY: “Alluvium, stream Deposits” is the
largest geological group formation. Except
Chittagong and Madhupur track some all
are this types. Maximum parts of
Bangladesh are formed with alluvium,
stream deposits. That is also called plain
land. This region is differ from any other
region of the world.
Source: Banglapedia

14. 14
SECONDLY: “Pleistocene
Terrace”(Madhupur clay) this regions are
placed in Dhaka, Gazipur and
Moymensingh. This region is called
Madhupur and Vawal tract.
Source: Banglapedia

15. 15
THIRDLY: “Pleistocene, Dupi Tila
formation” It is found normally in
the hilly area of sylhet and
chittagong. it is composition of
some hillock.
Source: Banglapedia

16. 16
FOURTHLY: “Pleistocene Tipan Sand
Stone Formation” this types of region is
marked as high land. Composition of
high area of the hill is under this
condition. It is found highly in
Chittagong, Khagrachari & Bandarban.
Source: Banglapedia

17. 17
Fifthly: “Miocene, Surma group”
Geologist belive that this region is very
old. It also assume that it is the result of
Plate Techtonic. This region is very high
and formed with many hillocks. But it is
found the presence of plain land.
Source: Banglapedia

18. 18
Sixthly: “Paleocene” (Sylhet
Limestone, Renji Formation)
mainly this types of region is
very little in Bangladesh. A
small area of Sylhet district it is
found the presence of it.
Source: Banglapedia

19. 19
Seventhly: “Paleocene” mainly
this types of region is very little
in Bangladesh. A small area of
Sylhet district it is found the
presence of it.
Source: Banglapedia

20. 5. Why Geology & Geological Time Scale is so
important in Geography?
The science of Geology is significant in locating water
supplies, mineral resources, understanding the development
of life on earth, developing predictive models for earthquake,
volcano and tsunami activity and adding fundamental
knowledge to the field of earth and planetary science.
Geology is important in determining building placement,
discovery of resources such as gravel , stone , oil , coal, water
and mineral deposit, knowledge of rock and mineral
properties, landslide avoidance , erosion control,
determining planetary histories, and earthquake and volcano
eruption prediction.

21. Geography deals with time, space, environment and human
beings.Geological Time scale tells a vast history in short of
these.
Suppose, if we want to identify the formation of rocks or
emerged the life evidence or plants, then Geological time
scale must be required. Beside this, to know the origin of the
earth, different age of environment we need this.

22. CONCLUSION
Geological structure is very important for development of any region. The
economical, social, political and cultural progress of a country depends on
its Geological structure. For the development of Bangladesh we have to
acquire proper knowledge about geology and geological history of
Bangladesh. In contrast we can say that bengal basin originally formed
from gondowana.

23. THANKS TO ALL……