Grand Archaeology IMG. Grand Canyon National Park: Museum of Northern Arizona geomorphologist Kirk Anderson collects a sediment sample at Furnace Flats for analysis via the optical stimulated luminescence technique (OSL), which reveals the time when the sediment was deposited. Dating techniques such as OSL and carbon-14 help researchers understand when sites were occupied. Sept 2007 Allyson Mathis

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Keywords: america, american, archive, arizona, canyon, coconino, conservation, country, county, grand, historic, history, land, lands, mohave, national, natural, nature, np, park, parks, preserve, public, service, usa, widlife, wilderness