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Erosion of archaeological sites: Quantifying the threat using optically stimulated luminescence and fallout isotopes
Author(s) -
Huisman Hans,
Kort JanWillem,
Ketterer Michael E.,
Reimann Tony,
Schoorl Jeroen M.,
Heiden Menno,
Soest Maud,
Egmond Fenny
Publication year - 2018
Publication title -
geoarchaeology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 44
eISSN - 1520-6548
pISSN - 0883-6353
DOI - 10.1002/gea.21716
Subject(s) - erosion , optically stimulated luminescence , archaeology , radionuclide , geology , radioactive fallout , plutonium , centennial , environmental science , physical geography , earth science , geography , paleontology , chemistry , radiochemistry , quartz , physics , quantum mechanics
Although visible evidence shows that erosion has damaged many archaeological sites, especially when tilled, there has hitherto been scant attention to its quantitative assessment. Accordingly, the archaeology communities lack insight into whether long‐term threats to the stability and integrity of soils at these sites allow these cultural repositories to be preserved for future human generations. Of the techniques that are available to measure erosion rates, few have been tested on the timescales needed. We selected three archaeological sites with high expected erosion rates. We combined optically stimulated luminescence (OSL) dating with analyses of radioactive fallout isotope distributions to assess erosion patterns and rates. An age–depth representation of OSL single‐aliquot results was developed to determine past erosion, and to identify stable land surfaces on centennial to millennia timescales. Fall‐out isotopes of cesium (Cs) and plutonium (Pu) were suitable for shorter timescales: The 240 Pu/ 239 Pu ratios and a correlation between activities of 239+240 Pu and 137 Cs demonstrated the weapons testing fallout origin of these isotopes in the ~1952–1966 timeframe. Erosion rates in recent decades ranged from 2 to 6 mm/year on the studied sites. Our results indicate that erosion is not only tied to the past, but keeps on threatening archaeological sites.