Terrestrial age measurements using natural thermoluminescence of a drained zone under the fusion crust of Antarctic ordinary chondrites

• Published in: Meteoritics & Planetary Science
• Main Authors: AKRIDGE, Jannette M. C., BENOIT, Paul H., SEARS, Derek W. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2000
• Subjects: Space and Planetary Science; Geophysics; Antarc*; Antarctic; Ice Sheet
• Online Access: http://dx.doi.org/10.1111/j.1945-5100.2000.tb01470.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1945-5100.2000.tb01470.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1945-5100.2000.tb01470.x

Abstract— Miono et al. (1990) and Miono and Nakanishi (1994) have proposed that the build‐up of natural thermoluminescence (TL) in a drained layer directly below the meteorite fusion crust can be used to determine terrestrial ages of meteorites in the 40 to 200 ka range. We have measured the natural TL of the drained layer of 15 meteorites. The data indicate that this technique could be used to determine terrestrial ages of meteorites with ages <200 ka, after which TL equilibrium is reached. Comparison of TL build‐up with terrestrial ages for a suite of Antarctic meteorites suggests that the meteorites have been exposed to temperatures of 0 to 5 °C. The close correspondence between natural TL levels and surface exposure TL growth curves suggest that Allan Hills meteorites with ages <200 ka have spent a significant portion of their terrestrial history exposed on the ice surface, rather than being buried in the ice sheet. The technique is, however, sensitive to thermal history; and, for Antarctic meteorites with terrestrial ages <200 ka, natural TL of the drained zone largely reflects exposure on the ice surface.