Sediment and fossils for C14 dating

Dating sediments by luminescence (OSL)

At CIRAM, we put our expertise in archaeometry at the service of archaeologists, museums, and institutions for reliable luminescence dating (OSL) adapted to the study of sedimentary deposits.

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Geological rock illustrating optically stimulated luminescence dating of sediments

Would you like to date sediments by luminescence (OSL)?

Optically stimulated luminescence (OSL) dating is an essential method for dating the last exposure of sediments to light. It allows for the reconstruction of the chronology of burial-related events, such as site occupation, ditch excavation, dune formation, or the use of a burial mound.

Unlike radiocarbon dating which applies to organic materials, OSL dates the minerals (quartz or feldspar)contained in sands or silts. It thus makes it possible to date contexts where organic remains are absent or poorly preserved.

At CIRAM, we're with you every step of the way, from advice on sampling to analysis and interpretation of results, guaranteeing rigorous protocols.

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Scientific apparatus for optically stimulated luminescence analysis of sediment samples

Our analysis techniques for dating sediments by luminescence

For dating sediments by OSL, we implement a controlled analytical chain:

  • Sampling in a dark environment: sediment grains must be sampled without exposure to light so as not to "destroy" their signal.
  • Laboratory preparation: separation of target minerals (quartz or feldspar), purification, calibration.
  • Optical stimulation: the grains are exposed to a controlled light source; the emitted luminescence allows measurement of the energy accumulated since their last burial.
  • Calculation of equivalent dose and annual dose: from this data, we calculate the age of the deposit.

Our facilities are specifically equipped to guarantee the reliability of results, with handling devices under red light, protected analysis chambers, and advanced calculation software.

Find out more about OSL dating

The steps in a CIRAM analysis

The OSL analysis process at CIRAM suit un protocole rigoureux :

01 - Contact and scientific exchange

We work with you to identify the objectives of dating and the specific features of the sedimentary context.

02 - Sampling instructions

We provide you with a detailed protocol to guarantee unimpaired sampling.

03 - Receiving and preparing samples

Laboratory processing under controlled conditions.

04 - Luminescence measurements

Analysis of light signals, determination of equivalent dose.

05 - Low background gamma-ray spectrometry measurement

Determination of annual dose.

06 - Calculations and interpretation

Calculation of burial age, drafting of a clear and documented report.

Why choose CIRAM for OSL dating?

Calling on CIRAM to date your sediments means benefiting from:

  • Recognized expertise: over 20 years of experience in physical dating applied to archaeology.
  • Expertise in complex terrain: funerary contexts, Paleolithic sites, alluvial or eolian deposits.
  • Specialized equipment: our laboratories are adapted for the preparation and OSL analysis according to international standards.
  • Tailor-made support: advice in the field, rapid response, analysis and explanation of results in their archaeological context.
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Are you asking yourself these questions?

What types of sediment can be dated by luminescence?

OSL applies to sands, silts or sediment layers rich in quartz or feldspar. It is used in alluvial, aeolian, colluvial or archaeological contexts.

How far back can we go with OSL?

The method is effective for periods ranging from a few thousand to several hundred thousand years (up to 700,000 years depending on the context).

How much sediment should be removed?

Approximately 100 to 300 grams of sediment are required. Samples should be taken in opaque tubes, in a dark environment.

Can OSL be combined with other dating methods?

Yes, OSL is complementary to carbon 14 or thermoluminescence and enables chronological data to be cross-referenced.

How long does an OSL analysis take?

It takes between 3 and 5 months from receipt of the samples to delivery of the report, depending on the age of the samples.

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