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- Optically stimulated luminescence (OSL) thermochronometry is a dating method used to determine the time since quartz and/or feldspar began to store charge as it cools through the effective closure temperature. The closure temperature for quartz and Na-rich K-feldspar is 30-35 °C and 25 °C respectively. When quartz and feldspar are beneath the earth, they are hot. They cool when any geological process e.g. focused erosion causes their exhumation to the earth surface. As they cool, they trap electron charges originating from within the crystal lattice. These charges are accommodated within crystallographic defects or vacancies in their crystal lattices as the mineral cools below the closure temperature. During detrapping of these electrons, luminescence is produced. The luminescence or light emission from the mineral is assumed to be proportional to the trapped electron charge population. The age recorded in standard OSL method is determined by counting the number of these trapped charges in an OSL detection system. The OSL age is the cooling age of the quartz and/or feldspar. This cooling history is a record of the mineral's thermal history, which is used to reconstruct the geological event. The sub-Quaternary period (104 to 105 years) is the geological age where OSL is a favourable dating technique because of low closure temperature of quartz and feldspar used in this technique. The Quaternary period is marked by intense crustal erosion particularly within active mountain ranges, leading to high exhumation rate of crustal rocks and formation of sub-Quaternary sediments. Previous techniques (e.g. Apatite Fission Track, Zircon Fission Track, and (Uranium-Thorium)/ Helium dating) could not adequately track the geological age records particularly in the last ~300 thousand years. OSL dating is currently the only dating method that has been successfully applied to understand the cooling ages of the geological events. (en)
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- Optically stimulated luminescence (OSL) thermochronometry is a dating method used to determine the time since quartz and/or feldspar began to store charge as it cools through the effective closure temperature. The closure temperature for quartz and Na-rich K-feldspar is 30-35 °C and 25 °C respectively. When quartz and feldspar are beneath the earth, they are hot. They cool when any geological process e.g. focused erosion causes their exhumation to the earth surface. As they cool, they trap electron charges originating from within the crystal lattice. These charges are accommodated within crystallographic defects or vacancies in their crystal lattices as the mineral cools below the closure temperature. (en)
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- Optically stimulated luminescence thermochronometry (en)
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