Chapter 1 and the related topics I have found that the most interesting to be constant in this presumption is the ability of the reservoir as well analysis for fluid

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International University Of Technology Twintech
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By
Mr. M. AL-Moalem
Stratigraphy & Structural Geology

2. Introduction to Stratigraphy
International University Of Technology Twintech
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‫للتكنولوجيا‬

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 Stratigraphy: The study of rocks to
determine the order, timing of events in
Earth’s history, and the study of origin,
relationship and extent of rock layers (Strata).
 Stratigraphy: the study of the 3-D spatial
and temporal relationships among rocks.

4. The stratigraphy record of sedimentary rocks is
the fundamental database for understanding
the evolution of life, plate tectonics through
time and global climate change.
Stratigraphy can be considered as the
relationship between rocks and time.
The stratigrapher is concerned with the
observation, description and interpretation of
direct and tangible evidence in rocks to
determine the history of the Earth.
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5.  Geologists usually learn the principles of
sedimentology and stratigraphy from
outcrop relationships in the field, and by
drilling a hole and bringing pieces of rock
back to the surface or by geophysical
techniques such as creating seismic reflection
profiles and the measurement of the
properties of layers in the subsurface.
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6. Concepts and Lithostratigraphy
 Our observations about rocks need to be set in the context of a
time framework if we are to use them to understand Earth
processes and history.
 Stratigraphy is primarily concerned with the following issues:
1- The recognition of distinct bodies of rock and their spatial
relationships with each other.
2- The definition of lithostratigraphic units and the correlation of
lithostratigraphic units with each other.
3- The correlation of rock units with a chronostratigraphic
standard, which is a formal time-framework to which all of
Earth geology can be related.
 Lithostratigraphy forms the basis for making geological maps and
by correlation lithostratigraphic units it is possible to reconstruct
the changing palaeogeography of an area through time.
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7. Geological Time
 A million years is a relatively short period in the history of the Earth,
which is about 4,5 billion years.
 The passage of time since the formation of the Earth is divided into
Geochronological Units and these are divisions of time that may be
referred to in terms of years or by name.
- The Permian Period, for example, was the time between 229 and 251
million years before present.
 Geological time is normally expressed in millions of years or thousands of
years before present, the abbreviations used for dates are:
- - ‘Ma’ for millions of years before present.
- - ‘Ka’ for thousands of years before present.
- - ‘Ga’ ( Giga-years) for thousands of millions of years before present.
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8. Geological Time Units
 Geochronology ( Time Unit ) is concerned with
geological time units.
- An interval of time that is expressed in years, for
example, Cretaceous Period.
 Chronostratigraphy ( Rock Unit ) is concerned with
stratigraphic units.
- A unit of rock, for example, Chalk strata.
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9.  The terms for the geochronological units are:
1- Eons:
These are the longest periods of time within history of
the Earth, which are divided into three eons:
- the Archaean Eon up to 2,5 Ga.
- the Proterozoic Eon from 2,5 Ga to 542 Ma.
(together these constitute the Precambrian)
- the Phanerozoic Eon from 542 Ma up to the present.
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2- Eras :
are the three time divisions of the Phanerozoic:
- the Palaeozoic Era up to 251 Ma.
- the Mesozoic Era from 251 Ma until 65,5 Ma.
- the Cenozoic Era from 65,5 Ma up to the present.
3- Periods / Systems :
The basic unit of geological time is the Period.
The Mesozoic Era, for example, is divided into three periods, the
Triassic Period, Jurassic Period and the Cretaceous Period.
The term System is used for the rocks deposited in this time, e.g.
the Jurassic System.

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4- Epochs / Series :
Epochs are the major divisions of periods :
Some have names, while others are Early, (Mid-) and Late (e.g.
Early Cretaceous and Late Cretaceous).
The chronostratigraphic equivalent is the series, but it is
important to note that the terms: Lower, Middle and Upper are
used instead of Early, Middle and Late.
For example, rocks that belong to the Lower Triassic Series were
deposited in the Early Triassic Epoch.
5- Ages / Stages :
The smallest commonly used divisions of geological time are
ages, and the chronostratigraphic equivalent is the stage.

12. Stratigraphic Charts
 The geological time scale have
been constructed by integrating
information from biostratigraphy,
magnetostratigraphy and data
from radiometric dating to
determine the chronostratigraphy
of rock units throughout the
Phanerozoic.
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Era Age (Ma) Epoch
0.01 Holocene
1.8 Pleistocene
5.3 Pliocene
23.8 Miocene
33.6 Oligocene
54.8 Eocene
65 Paleocene
144
206
248
290
323
354
417
443
490
543
2500
3800
Pennsylvanian
Jurassic
Age of the Earth 4600 Myrs (4.6 Byrs)
Geologic Time Scale
Devonian
Silurian
Ordivician
Cambrian
Triassic
Period
Quaternary
Tertiary
Neogene
Paleocene
Cretaceous
Precambrian
Phanerozoic
Eon
Proterozoic
Archean
Mississippian
Cenozoic
Mesozoic
Paleozoic
Permian

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