Magnetic Susceptibility of Soils: Tephra, Erosion, and Fire on Columbia Plateau Landscapes


Sedimentation and soil formation on uplands of the Columbia Plateau are strongly influenced by climate, tephras, erosion of arid lands, and fire regimes. Magnetic susceptibility of in situ strata, and laboratory samples from arroyo profiles of the Yakima Upland Fold Belt can help untangle the interactions of these processes in shaping natural and cultural landscapes. Records from four profiles of overlapping age (500 to 9000 BP) are compared. Data for mass specific magnetic susceptibility are cross-evaluated between these four sites. The graphed results are compared for profiles with and without artifact bearing cultural strata. Several working hypotheses are outlined. High magnetism in these profiles appears to correspond with Mazama tephra and erosion during the arid post glacial maximum (8000 to 4000 BP). However, magnetism also peaks in buried A horizons during moist intervals (4000- 3000 BP). Some of these signatures can be attributed to the presence of Mount St. Hellen tephra, and/or burn layers as a result of natural and cultural fire episodes related to Native American management of sage-grass steppe communities. ​

Cite this Record

Magnetic Susceptibility of Soils: Tephra, Erosion, and Fire on Columbia Plateau Landscapes. Steven Hackenberger, Douglas MacFarland, James Brown. Presented at The 81st Annual Meeting of the Society for American Archaeology, Vancouver, British Columbia. 2017 ( tDAR id: 430493)

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Spatial Coverage

min long: -122.168; min lat: 42.131 ; max long: -113.028; max lat: 49.383 ;

Record Identifiers

Abstract Id(s): 17336