Luminescence dating methods are used to determine the age of Quaternary sediments by measuring how long ago they were last exposed to sunlight or heated. Minerals like quartz and feldspar accumulate radiation damage over time since burial due to natural ionizing radiation in the environment. This radiation damage is measured as paleodose and compared to the dose rate to calculate the burial age. The seminar discusses principles of luminescence dating, methodology, case studies applying it in places like Australia, Africa, USA, Europe and Asia to understand past environmental changes. It concludes luminescence dating provides estimates of mineral crystallization or last sunlight exposure ages and is useful for reconstructing past wind patterns from dated dune fields.

1. Department of Geology Non-Thesis Seminar
USE OF LUMINESCENCES DATING FOR
QUARTERNARY SEDIMENTS
SOUMENDU SHEKHAR ROY
APPLIED GEOLOGY
POST-GRADUATE 2nd YEAR,2014-15

2. Department of Geology
Non-Thesis Seminar
Direct Age Estimation
Different Dating Methods of Quaternary Sediments
Age Equivalence Relative Age
• Radiometric Methods
• Incremental Methods
• Paleomagnetism
• Tephra-chronology
• Stratigraphic Correlation
• Pedogenesis
• Weathering Characteristics
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

3. Department of Geology
Non-Thesis Seminar
Radiometric Dating
• Radio Carbon Geochronology
• Uranium Series Method
• Luminescence Dating
• 40Potassium/40 Argon Geochronology
• Fission Tracks
• Electron Spin Resonance Dating
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

4. Department of Geology
Non-Thesis Seminar
Luminescence Dating Method
Luminescence methods are used to determine the age of
Quaternary sediments. The method was initially developed in the
1960's for dating pottery and since the 1980's it has also been
applied to dating geological sediments, based upon the fact that
naturally occurring common minerals such as quartz and feldspars
accumulate signals over time as a result of ionizing radiation in
their environment.
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

5. Department of Geology
Non-Thesis Seminar
Exposure to ionizing
radiation produces
free electron & holes
as electrons moves
from valenced band
to conduction band.
All Crystalline structure
have positive & negative
charge deficit sites-
TRAPS
The mean life time of such metastable Traps
t= S X Exp(E/KT)
An electron or hole gets
ejected by absorption of
photon of sufficient
energy or acquiring the
necessary activation
energy
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

6. Department of Geology
Non-Thesis Seminar
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

7. Department of Geology
Non-Thesis Seminar
Thermo-luminescence
Luminescence Dating
Thermally stimulated luminescence, or
thermo-luminescence (TL), is observed by
heating a sample at a constant rate to about
5008C and recording the luminescence
emitted as a function of temperature.
Optical-luminescence
Optically stimulated luminescence (OSL)
arises from the recombination of charge
which has been optically released from
electron traps within the crystal.
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

8. Department of Geology
Non-Thesis Seminar
Age Determination by Luminescence Dating
The radiation dose (paleodose, or P) accumulates in the
crystal in the form of electrons in excited states, of which
some are metastable and thus resident over periods of time
long enough to allow a dating application.
Dose rate (D),is the ionizing radiation per time
unit at the position of the sample within the
sediment. This dose rate provides the clock for
the dating application.
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

9. Department of Geology
Non-Thesis Seminar
The Dose Rate (D )
The denominator D of the
age formula consists of two
independent parameters,
the internal (D internal) and
the external dose rate (D
external).
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

10. Department of Geology
Non-Thesis Seminar
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology

11. Department of Geology
Non-Thesis Seminar
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology
Comparison Chart different Radiometric Dating Process

12. Department of Geology
Non-Thesis Seminar
Case Studies
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology
Australia. – The Late Pleistocene
environmental history of Australia’s
deserts was recently reviewed by Hesse
et al. (2005) and studies with
luminescence ages up to 2004 were
scrutinized and summarized by
Munyikwa (2005b).
Africa-The Late Quaternary environmental
history of the Kalahari Desert was recently
reviewed by Thomas & Shaw (2002) and
Shaw & Thomas (2005); both reviews rely
heavily on results from luminescence
dating.
USA-BERGER & EASTERBROOK
(1993) and BERGER & EYLES
(1994) dated glaciogenic and
water-lain sediments from the
Western Washington, British
Columbia and Toronto area.
Europe-PERKINS & RHODES (1994) used
multiple-aliquot methodology to date
sandy River Thames sediments and
achieved a good consistency with
independent age control.
Asia-The Thar Desert lies at the extreme
edge of the Sahara–Arabian belt, and
the location is such that minor
perturbations in monsoon conditions
result in an amplified change in
geomorphic processes including aeolian
dynamism.(Wasson et al. 1983; Singhvi
& Kar 1992; Juyalet al. 1998).

13. Department of Geology
Non-Thesis Seminar
CONCLUSIONS
Overview Principle Geological Scenario Conclusion
Case Study &
Comparison
Methodology
• Luminescence dating allows the dating of mineral crystallisation, heating to a few 100°C or the last
daylight exposure of sediment grains.
• Luminescence dating represents a suite of related techniques, all of which provide an estimate of
radiation history due to accumulation of trapped charges in mineral lattices.
• Recent research is focusing on improved and innovative procedures of both palaeo-dose and dose
rate determination. Furthermore, it is expected that it may be possible to extend the upper dating
limit using approaches such as thermally-transferred OSL in quartz or by using a more stable
luminescence emission, such as the red emission band of feldspars
• Combination of dune types, dune dynamic processes and dune orientation with luminescence
ages enables for the first time reconstruction of past wind direction on a regional scale,

14. Department of Geology
Non-Thesis Seminar