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Males had a median income of ,714 versus ,361 for females. None of the families and 4.1% of the population were living below the poverty line, including no under eighteens and 21.1% of those over 64.
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| Calculating Age | Challenges for OSL | Case studies of OSL dating in glacial environments | References | Comments | Another way of dating glacial landforms is optically stimulated luminescence dating (OSL). The OSL signal is reset by exposure to sunlight, so the signal is reset to zero while the sand is being transported (such as in a glacial meltwater stream). Turnaround time is several weeks to several months and very dependent on the time taken to prepare the samples, with organic rich samples taking the longest. All sediments contain trace minerals including uranium, thorium and potassium.These slowly decay over time and the ionising radiation they produce is absorbed by other constituents of the sediments such as quartz and feldspar.A subpopulation of stored electrons with trap depths of ~1.3 to 3 e V is a subsequent source for time-diagnostic luminescence emissions.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.

OSL works because all sediments have some natural radioactivity, caused by the presence of uranium, thorium and potassium isotopes in heavy minerals such as zircons. The ‘quartz technique’ for limestone monuments containing traces of quartz enables their dating with Optically Stimulated Luminescence (OSL) techniques.The surface luminescence (thermoluminescence, TL or OSL) dating has been developed and further refined on various aspects of equivalent dose determination, complex radiation geometry, incomplete bleaching etc.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.