Variability in Bioavailable⁸⁷Sr/⁸⁶Sr in the North American Midcontinent

Creator(s)

Chris Widga, East Tennessee State UniversityFollow
J. Douglas Walker, University of Kansas, Lawrence
Andrew Boehm, University of Oregon

Document Type

Article

Publication Date

1-1-2017

Description

Strontium (Sr) isotope tracers are useful for understanding provenance and mobility in biological materials across multiple disciplines. However, the impact of these techniques is highly dependent on the construction of appropriate comparative baselines (i.e., an isoscape). We present the results of a systematic survey of87Sr/86Sr values from grasses in the North American Midcontinent with a particular emphasis on sedimentary systems. Although87Sr/86Sr values are highly variable across the region, the Sr isoscape shows ­multi-scalar patterns that are dependent on local-to-regional trends in surficial geology. High values are found in bedrock-dominated areas such as the Black Hills (SD) and Ozark Uplift (MO), or formerly glaciated areas where surface deposits are dominated by ice-transported Precambrian clasts. The lowest values are found in river valleys that incorporate eroded Neogene sediments into terrace formation. Intermediate values are found in upland loess and alluvial deposits which blanket much of the study area. We demonstrate trends in large-scale variability of the Midcontinent’s87Sr/86Sr isoscape and suggest that future refinement focus on sub-regional trends in Sr isotope variability.

Citation Information

Widga, Chris; Douglas Walker, J.; and Boehm, Andrew. 2017. Variability in Bioavailable⁸⁷Sr/⁸⁶Sr in the North American Midcontinent. Open Quaternary. Vol.3 https://doi.org/10.5334/oq.32