Liverpool Luminescence Laboratory

The Liverpool Luminescence Laboratory was established in 2003 and is a key research facility of the Environmental Change research group. 

What is luminescence dating?

Luminescence dating is a geochronological technique that can determine the timing of sediment deposition using quartz or feldspar. It relies upon the fundamental principle that mineral grains can store and release energy produced by radioactive decay. The radioactive decay of K, Rb, U and Th emits energy in the form of alpha and beta particles, and gamma rays, which exposes grains to an environmental dose-rate, in addition to the dose provided by the cosmic rays. This energy recharges the battery over time during burial. Defects or impurities in the crystal lattice of quartz or feldspar grains trap electrons, which are then excited and released when stimulated by light or heat. We can then determine the time elapsed since the grain was last exposed to light or heat by measuring how much energy is stored in the grain today and dividing it by the environmental dose-rate it was exposed to throughout burial.

Luminescence dating is a versatile technique and can be advantageous over other geochronological techniques as: (1) it directly determines the timing of sediment burial or exposure; (2) it can be used in many depositional settings (e.g. aeolian, fluvial, glacial, lacustrine); (3) it can used for grain sizes ranging from silt up to boulders; and (5) it has the potential to cover the full Quaternary timeframe, from 0 to 2 Ma, depending upon the materials and signals used for analysis. New innovations in luminescence dating now mean that we can also determine rock surface exposure ages from boulders and burial dating of cobble- or gravel-sized clasts.

Quarry of Outwash Sediment

Quarry of outwash sediment sampled for luminescence dating near Esquel in NE Patagonia

Exposure of Sediment

Exposure of sediment sampled for luminescence dating at Lago Buenos Aires, east of the Northern Patagonian Icefield

Sampling for outwash

Sampling for outwash cobbles for luminescence dating near Epuyen in NE Patagonia

The laboratory

The Liverpool Luminescence Laboratory is a purpose-built facility for the preparation and analysis of samples for luminescence dating under subdued lighting conditions. It currently houses two Risø DA-15 automated TL/OSL readers and a HPGe Gamma-Ray Detector. The laboratory is capable of using both fine-grained and coarse-grains quartz and feldspars for dating.

Sample Prep Facilities

Sample preparation facilities in the Liverpool Luminescence Laboratory

Research

Main research interests:

  1. Developing new & innovative approaches to luminescence dating.
  2. Applying the luminescence dating technique to address key research questions in a variety of environments (e.g. aeolian, fluvial, lacustrine, glacial).
  3. Reconstructing former ice limits using luminescence dating, especially in Patagonia,  Britain & Ireland.
  4. Improving our understanding of the internal dose-rates of feldspar grains. 

Staff & Contacts

Dr Rachel Smedley, Lecturer in Physical Geography & Laboratory Director. E-mail: rachel.smedley@liverpool.ac.uk

Publications

Recent outputs can be found in the Environment Change publications.

Smedley, R.K. (2018). Telling the time with dust, sand and rocks. Elements: An International Magazine of Mineralogy, Geochemistry, and Petrology, 14 (1), 9-14.

https://doi.org/10.2138/gselements.14.1.9

Smedley, R.K., Chiverrell, R.C., Burke, M. J., Duller, G.A.T., Thomas, G.S.P., Clarke, C., Scourse, J.(2017). Internal dynamics condition millennial-scale oscillations of a retreating ice stream margin. Geology,45, 787-790. https://doi.org/10.1130/G38991.1

Smedley, R.K., Scourse, J.Small, D,Hiemstra, Duller, G.A.T., J.F., Burke, M. J., Carr, S.J., Chiverrell, R.C., Fabel, D., McCarroll, D., Clarke, C. (2017). New ages constraints for the southern limit of the British-Irish Ice Sheet on the Isles of Scilly. Journal of Quaternary Science, 32, 48-6. http://doi.org/10.1002/jqs.2922.

Smedley, R.K., Glasser, N.F., Duller, G.A.T. (2016). Luminescence dating of glacial advances at Lago Buenos Aires (~46 °S), Patagonia. Quaternary Science Reviews, 134, 59 – 73. https://doi.org/10.1016/j.quascirev.2015.12.010.

See also the special issue of Elements: An International Magazine of Mineralogy, Geochemistry, and Petrology, titled Luminescence Dating: Reconstructing Earth’s Recent History. Guest Editors: Dr Rachel Smedley & Prof. Ann Wintle. Link: https://pubs.geoscienceworld.org/elements/issue/14/1