Soil formation on loess/sandstone toposequences in west-central kentucky: i. morphology and physicochemical properties
1991
KARATHANASIS, A. D. | GOLRICK, P. A.
Soil formation in loess/sandstone topo-sequences in west-central Kentucky is closely related to the stratigraphy of the parent materials and landscape position. Soils in summit positions have weakly developed modern argillic horizons underlain by a truncated paleosol with well developed paleoargillic horizons. The loess-derived modern argillic is separated from the fine-grained sandstone-derived paleosol by distinct partially cemented stone-lines in summit positions. Downslope, modern sola developed in mixed colluvium from loess and weathered sandstone are completely welded into the paleosol. Stone-lines are not well defined on these landscapes. Solum and argillic horizon thickness decrease with increasing slope gradient in summit, shoulder, and upper back-slope positions but increase downslope due to depositional processes and greater permeability of the coarser-textured paleosol. The comparable paleoargillic horizon development in the lower backslope and middle summit positions, as evidenced by fine/total clay ratios and free iron oxide data, suggests a more stable Pleistocence landscape position for the paleosols. Evidence from this study and extensive field observations suggests that all summit, shoulder, and upper backslope pedons could be classified as fine-loamy Hapludults in the range of the Riney series. Most mapping concerns should be associated with the lower backslope and foot-slope positions where variable colluvial accumulation, truncation depth, paleolandscape influence, or gravel content has formed a variety of soils ranging from clayey Hapludults to loamy-skeletal Paleudults.
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