Stratigraphy of Bangladesh

1. Lecture#06
Stratigraphy of Bengal BaSin

2. Stratigraphy of Bangladesh
One primary task for a petroleum geologist is to understand
the nature of rock layers beneath and to subdivide the pile of
sedimentary layers into rational and convenient units and
name the units.
Stratigraphy-
Branch of geology deals with the formation, composition,
sequence and correlation of stratified rock.
Basic objective of stratigraphy is to reconstruct geological
history using rock and their sequence studies.

3. Stratigraphy of Bangladesh
Unit
Rock units are called stratigraphic unit.
How the rock units are subdivided?
-The sedimentary rock sequence on and beneath the surface of
Bangladesh has been subdivided into stratigraphic units based
on lithology of the rock (i.e. type and nature of rock layers)

4. Stratigraphy of Bangladesh
How the rock units are subdivided?
-Under the lithostratigraphic method, rock layers are
subdivided into fundamental units called “Formation”.
Formation is defined as a unit of layers of uniform rock
types mappable at the surface and traceable in the
subsurface.
Formation may be composed of single rock type like
sandstones or may be composed of two ore more rock types.

5. Stratigraphy of Bangladesh
Two or more “Formations” together form a “Group”.
Example-Surma group consists of Bokabil and Bhuban
formations.
Group
Formation
Unit

6. Correlation
-Process of relating rocks at one
site with those at another site.
Type area
-Area where a particular
stratigraphic unit was first studied
and established is called the type
area for that unit.
Figure- Stratigraphic
subdivision and correlation

8. Figure- Stratigraphic succession of stable platform
area of Bangladesh

9. Figure- Stratigraphic succession of deep basin area of
Bangladesh

10. Stratigraphy of Bangladesh
The oldest sedimentary unit in Bangladesh is the Gondwana
group of permian age, resting on the precambrian crystalline
basement.
The thick coal seam and carboneous shale of the Gondwana do
not exhibits any oil or gas.

11. Reference
Energy Resources of Bangladesh
-BADRUL IMAM
Chapter-02