Late Quaternary Soil Development Enhances Aeolian Landform Stability, Moenkopi Plateau, Southern Colorado Plateau, USA

Abstract

The Moenkopi dune field in northeastern Arizona covers roughly 1250 km 2 , but most of the field is inactive. Dune deposits on the Moenkopi Plateau (MP) have remained inactive throughout the Holocene despite periods of elevated aridity or historical reductions of vegetation cover by livestock grazing. We argue that this inactivity is not because of any diminishment of driving forces in the aeolian system (e.g., insufficient winds), but rather because of increased cohesion due to soil development that enhances resistance to wind erosion. Abundant aeolian sediments were supplied to the Black Mesa region by the Little Colorado River and its tributaries during the late Pleistocene (MIS 2 and 3), which enabled the development of climbing dunes and transport of sand over the Adeii Eechii Cliffs and onto the MP. These deposits (Qe1) stabilized during the Pleistocene/Holocene climatic transition (~12-7.5 ka) because of reduced sediment supply and high dust flux which resulted in rapid soil formation. Erosion of climbing dunes/sand ramps from the Adeii Eechii Cliffs eliminated delivery of large quantities of new sand to the MP during the mid to late Holocene. Soil development within the Qe1 mantle increased sediment cohesion and prevented widespread aeolian reactivation during the Holocene, despite the occurrence of conditions (wind speed, climate, etc.) under which dune reactivation would be expected. Drylands comprise roughly 40% of the land cover of earth and climate models predict their expansion. Pedogenic stability is not commonly considered in climate-based models used to predict aeolian activity. To improve predictions of future dune activity in drylands, the degree of soil development in aeolian deposits should be considered when evaluating sediment availability in aeolian systems.

First Findings of Buried Late-Glacial Paleosols within the Dune Fields of the Tomsk Priobye Region (SE Western Siberia, Russia)

“…Many researchers, around the world, are finding that aeolian deposits are not necessarily associated with periods of increased wind speed or increased aridity. They can occur during periods of increased sand supply, which is associated with the hydrological cycles of water bodies [56][57][58]. In the first approximation, we can agree with these conclusions.…”

Geologic, geomorphic, and edaphic underpinnings of dryland ecosystems: Colorado Plateau landscapes in a changing world

“…The largest aeolian deposits in the present study are in the Island in the Sky district of Canyonlands National Park (Figures 8b and 9b), for which the biogeochemical and textural composition has been linked to the changing climate during the Pleistocene–Holocene transition (Reheis et al, 2005; Reheis et al, 2018). While we did not precisely determine soil age here, many of our study plots contain illuvial soil horizons with increased water‐holding capacity that likely can be linked to accumulation of carbonates and far‐derived, nutrient‐rich dust over thousands of years, akin to similar increases in fertility, water‐holding capacity, and productivity on stable aeolian soils in the region (Ellwein et al, 2018; Reynolds et al, 2001; Reynolds et al, 2006). Both global and local characterization of the impact of the time of soil formation on plant communities suggest that soil age is important for understanding local‐scale heterogeneity in soil properties as well as plant community distribution and dynamics (Browning et al, 2012; Delgado‐Baquerizo et al, 2020; Duniway et al, 2010; McAuliffe, 1994) and is thus likely important for understanding variation in soils and plants across the Colorado Plateau and the study parks.…”

A hybrid approach for predictive soil property mapping using conventional soil survey data

“…Much of the regional aeolian deposition is very fine sand–sized (0.05–0.1 mm) particles (Arcusa, McKay, Routson, & Munoz, 2019; Neff et al., 2008; Reheis et al., 2018), which may help explain why very fine sand models in this study were less accurate. Active local aeolian sand redistribution and transport has also influenced UCRB parent materials (Ellwein et al, 2018) but also appears to be relatively predictable using 30‐m resolution data (Nauman et al., 2018). This may explain why fine sand and total sand models have stronger performances in this study in contrast to very fine sands.…”