Often mineral grains that are fresh from a bedrock sources have significantly lower luminescence emissions per radiation dose in comparison to grains that have cycled repeatedly. (b) The luminescence for grains is zeroed by exposure to sunlight with erosion and transport.
OSL dating provides an estimate of the time elapsed with latest period of burial and thus, yields a depositional age (Fig. (c) With burial and exposure to ionizing radiation free electrons are stored in charge defects within grains crystal lattice.
(f) Careful sampling without light exposure and measuring of the natural luminescence, followed by a normalizing test dose (Ln/Tn) compared to the regenerative dose to yield an equivalent dose (De) (from Mellet, 2013).
The exposure of quartz and feldspar grains to sunlight for 60 seconds effectively diminishes the time-stored OSL signal to a low definable level.
Purity of the separate is accessed through microscopic inspection and point counting of grain mineralogy.
Thus, the population of stored electrons in lattice-charge defects increases with prolonged exposure to ionizing radiation and the resolved luminescence emission increases with time.
There is significant variability in the luminescence properties of quartz and potassium feldspar grains related to crystalline structure, minor and rare-earth impurities, solid-solution relations, number of luminescence cycles (Fig. Thus, because of this inherent variability in dose sensitivity of quartz and feldspar, analytical procedures for dating often need to be tailored for a specific geologic provenance.
The advent of single aliquot regenerative (SAR) dose procedures for quartz (Murray and Wintle, 2003; Wintle and Murray, 2006) has provided the needed analy tical flexibility to compensate for variable luminescence properties of quartz and feldspar grains and laboratory-induced sensitivity changes, particularly associated with preheat treatments and with laboratory beta irradiation.
This residual level is the point from which the geological OSL signal accumulates post burial.
Many types of sediment receive prolonged ( 1 hr) light exposure with transport and deposition, particularly in eolian, littoral and sublittoral sedimentary environments.
The recent development of charge transfer techniques for potassium feldspar (e.g. A common approach in OSL dating is to use SAR protocols on quartz aliquots with the protocols customized for a specific sample, a study site or area (Fig. The SAR approach is predicated on a number of assumptions.