THE K HORIZON

Abstract

The designation K is proposed for soil horizons so strongly carbonate-impregnated that their morphology is determined by the carbonate. Tough these horizons display a variety of macroscopic forms, and range in consistence from soft to extremely hard, they all have a peculiar and diagnostic soil fabric, the K-fabric. In material with K-fabric, fine-grained authigenic carbonate coats or engulfs skeletal pebbles, sand, and silt grains as an essentially continuous medium. The material breaks down or is markedly softened by acid treatment. The designation K2 is proposed for carbonate horizons of 90 percent or more, by volume, of K-fabric, and K1 and K3 designations are proposed for upper and lower transitional horizons containing 50 percent or more of K-fabric. Other soil horizons containing carbonate accumulations are noted by the ca symbol in combination with the appropriate master horizon designation. /Author/