Characteristics and Genesis of a Gravelly Brunizemic Regosol

Abstract

AbstractA Rodman gravelly, cobbly sandy loam profile was sampled in Wisconsin in a prairie “oak opening” at the crest of an eskerkame ridge of Woodfordian (Cary) age largely composed of gravel and cobbles of dolomitic limestone. Laboratory analyses reveal a shallow profile resembling a Brunizem soil with respect to distribution of organic matter. Distributions of pedogenic calcium carbonate and clay somewhat resemble those in the upper horizons of calcareous parent materials of some soil profiles in the North Central Region of the USA. The slight concentration of silt and clay near the surface of the Rodman soil may be largely aeolian in origin. The weathering mean of this shallow soil profile is 5.6 on the basis of the entire clay and 7.8 on the basis of noncarbonate clay. A depth function is suggested by the slight concentration of weathered ferromagnesian sand particles near the surface. Distribution and character of the carbonate crusts on the under surfaces of coarse particles exhibit a pronounced depth function by volume but not with respect to content of noncarbonate silt and clay.