Instrument Package for Luminescence Tomography of Rock, Sediment, and Soil Structures

Innovation in Focus

How old are the individual layers of a soil profile?

Which processes have shaped a landscape – and how will it continue to evolve?

Can the age of archaeological artifacts be determined with precision?

Questions such as these lie at the core of geoscientific and archaeological research. At the Institute of Geography at the University of Cologne (UzK), an innovative instrument package for luminescence tomography was established between 2022 and 2023 to address precisely these questions with novel methodological approaches. Funded by the German Research Foundation (DFG) and led by Professor Dr. Tony Reimann, this package opens up new methodological avenues for investigating rock, sediment, and soil structures. Specifically, it enables the development of 3D analyses of luminescence properties in rock, sediment, and soil structures within both spatial and temporal contexts.

Core Instrument: New Generation Luminescence Reader

At the heart of the package is a new generation luminescence reader (Figure 1), specialized in InfraRed PhotoLuminescence (IRPL; Prasad et al. 2017; Kumar et al. 2018). For the first time, this technique allows dosimetric luminescence information to be obtained non-destructively from natural minerals.

• With spatially resolved luminescence imaging (e.g., HR-IRPL, EMCCD), enhanced luminescence analyses of rock surfaces as well as saprolitic or volcanic material can be performed.
• At the same time, IRPL provides the foundation for advancing luminescence tomography as a novel method.

Complementary Instrument: micro-XRF Spectrometer

An associated micro-XRF spectrometer (Fig. 2) is integrated into the package. This instrument enables spatial mapping of elemental distributions on rock and soil surfaces, which can then be combined with luminescence data.

Objective: Luminescence Tomography

Through the combination of these instruments, the luminescence properties of mineral grains can be recorded in their spatial context (luminescence reader) and merged with elemental distribution maps (micro-XRF). The objective is to enable luminescence tomography, thereby capturing rock, sediment, and soil structures in three spatial dimensions and in relation to time. This makes it possible to reconstruct spatially resolved chronologies while simultaneously obtaining contextual and process-related information on landscape dynamics, soil formation, and archaeological artifacts.

Significance for Research and Networking

This project expands the internationally recognized Cologne Luminescence Laboratory (CLL) and strengthens the geochronological research focus at UzK. Importantly, the integration of internal and external users from geosciences and archaeology highlights the potential of the instrument package – both to advance innovative applications and to foster collaboration within the Department of Geosciences (UzK), the Geoverbund ABC/J, and the Institute of Prehistoric and Protohistoric Archaeology (UzK).

edited by Luisa Loers