Calcic and Petrocalcic Horizons - Soil Geography of the USA: A Diagnostic-Horizon Approach - page 107

Fig. 12.1 A calcic horizon
reacting to 10 % HCl ( top )
and a petrocalcic horizon in
a Petrocalcic Paleargids in
southern Nevada ( bottom ;
photos by J. Bockheim)
aridic/torric, ustic, and xeric soil-moisture regimes accounted for 44 %, 26 %, and
17 % of the soil series with a calcic or petrocalcic horizon. Seventy-eight percent of
the soil series with a calcic or petrocalcic horizon have a mixed mineralogy class,
and 16 % are carbonatic. Three-quarters of the soils are in loamy (includes fine-
loamy and coarse-loamy), or less commonly in loamy-skeletal, particle-size clas-
ses, and another 11 % were in silty particle-size classes.