Optical bleaching front in bedrock revealed by spatially-resolved infrared photoluminescence

E.L. Sellwood*, B. Guralnik, M. Kook, A.K. Prasad, R. Sohbati, K. Hippe, J. Wallinga, M. Jain

*Corresponding author for this work

    Research output: Contribution to journalJournal articleResearchpeer-review

    217 Downloads (Pure)

    Abstract

    Optically stimulated luminescence (OSL) dating of sediment, based on the accumulation of trapped charge in natural crystals since their last exposure to daylight, has revolutionised our understanding of the late Quaternary period. Recently, a complementary technique called luminescence rock surface dating (RSD), which uses differential spatial eviction of trapped charges in rocks exposed to daylight, has been developed to derive exposure and burial ages, and hard-rock erosion rates. In its current form, the RSD technique suffers from labour intensive sample preparation, uncertainties in the depth and dose rate estimates, and poor resolution of the luminescence-depth profile. Here, we develop a novel, 2D luminescence imaging technique for RSD of large rock slabs (3 × 5 cm) to overcome these challenges. We utilize the recently discovered infrared photoluminescence (IRPL) signal for direct, non-destructive imaging of the luminescence-depth profile in a sub-aerially exposed granitic rock, with an unprecedented spatial resolution of ~140 µm. We further establish a correlation between luminescence and geochemistry using micro X-ray fluorescence (µXRF) spectroscopy. Our study promises a substantial advancement in luminescence imaging and paves the path towards novel applications using 2D dating, micro-dosimetry in mixed composition samples, and portable instrumentation for in-situ luminescence measurements.
    Original languageEnglish
    Article number2611
    JournalScientific Reports
    Volume9
    Issue number1
    Number of pages12
    ISSN2045-2322
    DOIs
    Publication statusPublished - 2019

    Cite this