Short communication: Synchrotron-based elemental mapping of single grains to investigate variable infrared-radiofluorescence emissions for luminescence dating

Sontag-González, M; Kumar, R; Schwenninger, J-L; Thieme, J; Kreutzer, S; Frouin, M

Journal article

Short communication: Synchrotron-based elemental mapping of single grains to investigate variable infrared-radiofluorescence emissions for luminescence dating

Abstract:: During ionizing irradiation, potassium (K)-rich feldspar grains emit infrared (IR) light, which is used for infrared radiofluorescence (IR-RF) dating. The late-saturating IR-RF emission centred at ∼880 nm represents a promising tool to date Quaternary sediments. In the present work, we report the presence of individual grains in the K-feldspar density fraction displaying an aberrant IR-RF signal shape, whose combined intensity contaminates the sum signal of an aliquot composed of dozens of grains. Our experiments were carried out at the National Synchrotron Light Source (NSLS-II) at the submicron-resolution X-ray spectroscopy (SRX) beamline. We analysed coarse (>90 µm) K-feldspar-bearing grains of five samples of different ages and origin in order to characterize the composition of grains yielding the desired or contaminated IR-RF emission. Using micro-X-ray fluorescence (μ-XRF), we successfully acquired element distribution maps of up to 15 elements (<1 µm resolution) of sections of full grains previously used for IR-RF dating. In keeping with current theories of IR-RF signal production, we observed a trend between the relative proportions of Pb and Fe and the shape of the IR-RF signal, namely that most grains with the desired IR-RF signal shape had high Pb and low Fe contents. Interestingly, these grains were also defined by high Ba and low Ca contents. Our study also represents a proof of concept for mapping the oxidation states of Fe using micro-X-ray absorption near-edge structure spectroscopy (μ-XANES) on individual grains. The high spatial resolution enabled by synchrotron X-ray spectroscopy makes it a powerful tool for future experiments to elucidate long-standing issues concerning the nature and type of defect(s) associated with the main dosimetric trap in feldspar.

Publication status:: Published

Peer review status:: Peer reviewed

Actions

Email

Email this record

Send the bibliographic details of this record to your email address.

Your Email
Please enter the email address that the record information will be sent to.

-
Your message (optional)
Please add any additional information to be included within the email.
Cite

Cite this record

APA Style

Sontag-González, M., Kumar, R., Schwenninger, J.-L., Thieme, J., Kreutzer, S., & Frouin, M. (2024). Short communication: Synchrotron-based elemental mapping of single grains to investigate variable infrared-radiofluorescence emissions for luminescence dating. Geochronology, 6(1), 77–88.

MLA Style

Sontag-González, M., et al. “Short Communication: Synchrotron-Based Elemental Mapping of Single Grains to Investigate Variable Infrared-Radiofluorescence Emissions for Luminescence Dating.” Geochronology, vol. 6, no. 1, Copernicus Publications, 2024, pp. 77–88.

Chicago Style

Sontag-González, M, R Kumar, J-L Schwenninger, J Thieme, S Kreutzer, and M Frouin. 2024. “Short Communication: Synchrotron-Based Elemental Mapping of Single Grains to Investigate Variable Infrared-Radiofluorescence Emissions for Luminescence Dating.” Geochronology 6 (1): 77–88.
Share
Print