Lyoluminescence: a potential tool for dating evaporites up to the Middle-Pleistocene?

Abstract

Lyoluminescence (LL) is light emission during the solvation of previously irradiated crystals in the liquid-solid interface (Atari, 1980). Our aim is the breakthrough development of lyoluminescence as a dating tool on halite (here: sodium chloride and potassium chloride) for application in Earth Sciences. The positive correlation between radiation dose and LL light emission makes crystal lattice defects viable natural ionizing radiation dosimeters. With a saturation dose of ~10 kGy (e.g. Atari et al., 1973) for sodium chloride dissolved in pure water and for realistic dose rates of ~4 Gy/ka (e.g., Han et al., 2014), the LL signal from salt minerals potentially may determine an age up to 2.5 Ma. We hypothesize that LL, naturally observable in salt minerals, will allow dating the last recrystallization event significantly beyond the age limits of conventional luminescence-dating methods. In the past, the potential of halite as a material for optical luminescence dating had been suggested, e.g. Bailey et al., (2000); Zhang et al., (2005). However, LL may offer an additional luminescence-dating tool for routine use in geochronology but targeting the crystallization instead of heat or light exposure event. Moreover, it may enable tapping into different archives and subsurface processes where only the event of the last hydration is of interest. In our contribution, we present the first basic design of a measurement prototype using 3D printing and preliminary experimental results of salts easily soluble in water.ReferencesAtari, N.A., 1980. Lyoluminescence mechanism of gamma and additively coloured alkali halides in pure water. Journal of Luminescence 21, 305–316. https://doi.org/10.1016/0022-2313(80)90009-5Atari, N.A., Ettinger, K.V., Fremlin, J.H., 1973. Lyoluminescence as a possible basis of radiation dosimetry. Radiation Effects 17, 45–48. https://doi.org/10.1080/00337577308232596Bailey, R.M., Adamiec, G., Rhodes, E.J., 2000. OSL properties of NaCl relative to dating and dosimetry. Radiation Measurements 32, 717–723. https://doi.org/10.1016/S1350-4487(00)00087-1Han, W., Ma, Z., Lai, Z., Appel, E., Fang, X., Yu, L., 2014. Wind erosion on the north‐eastern Tibetan Plateau: constraints from OSL and U‐Th dating of playa salt crust in the Qaidam Basin. Earth Surf Processes Landf 39, 779–789. https://doi.org/10.1002/esp.3483Zhang, J.F., Yan, C., Zhou, L.P., 2005. Feasibility of optical dating using halite. Journal of Luminescence 114, 234–240. https://doi.org/10.1016/j.jlumin.2005.01.009