Osl dating labs
Common silicate minerals like quartz and potassium feldspar contain lattice-charge defects formed during crystallization and from subsequent exposure to ionizing radiation.
These charge defects are potential sites of electron storage with a variety of trap-depth energies.
The radioactive decay of 40K releases beta and gamma radiation, whereas the decay in the U and Th series generates mostly alpha particles and some beta and gamma radiation.
Free electrons are generated within the mineral matrix by exposure to ionizing radiation from the radioactive decay of daughter isotopes in the 235U, 238U and 232Th decay series, and a radioactive isotope of potassium, 40K, with lesser contributions from the decay of 85Rb and cosmic sources.
The OSL signal of potassium feldspar is usually more resista nt to solar resetting than most quartz.
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.
This technique, as thermoluminescence, was originally developed in the 1950s and 1960s to date fired archaeological materials, like ceramics (Aitken, 1985).
Ensuing research in the 1970s documented that marine and other sediments with a prior sunlight exposure of hours to days were suitable for thermoluminescence dating (Wintle and Huntley, 1980).