Campus Units

Agronomy

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

4-2018

Journal or Book Title

Aeolian Research

Volume

31

Issue

Part B

First Page

91

Last Page

104

DOI

10.1016/j.aeolia.2017.05.005

Abstract

Loess was first studied in Michigan on the Buckley Flats, where outwash, overlain by ≈70 cm of loamy sediment, was originally interpreted as loess mixed with underlying sands. This paper re-evaluates this landscape through a spatial analysis of data from auger samples and soil pits. To better estimate the loamy sediment’s initial textures, we utilized “filtered” laser diffraction data, which remove much of the coarser sand data. Textures of filtered silt data for the loamy sediment are similar to loess. The siltiest soils are found in the low-relief, central part of the Flats. Spatial analyses revealed that many silt fractions are nearly uniformly distributed, suggesting that the loess was not derived from a single source. The previous depositional model for the loamy mantle relied on loessfall followed by pedoturbation, but does not explain (1) the variation in sand contents across the Flats, or (2) the abrupt contact below the loamy mantle. This contact suggests that the outwash was frozen when the sediments above were deposited. Deep gullies at the western margins of the Flats were likely cut as permafrost facilitated runoff. Our new model for the origin of the loamy mantle suggests that the sands on the uplands were generated from eroding gullies and saltated onto the uplands along with loess that fell more widely. Sands saltating to the west of the Flats may have entrained some silts, facilitating loessfall downwind. At most sites, the loamy mantle gets increasingly silty near the surface, suggesting that saltation ended before loess deposition.

Comments

This is a manuscript of an article published as Nyland, K.E., R.J. Schaetzl, A. Ignatov, and B.A. Miller. A new depositional model for sand-rich loess on the Buckley Flats outwash plain, northwestern Lower Michigan. Aeolian Research 31 (2018): 91-104. doi: 10.1016/j.aeolia.2017.05.005. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Elsevier B.V.

Language

en

File Format

application/pdf

Available for download on Wednesday, April 01, 2020

Published Version

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