Duripan Horizon and Durinodes - Soil Geography of the USA: A Diagnostic-Horizon Approach - page 141

(ii) younger surfaces in the arid Basin and Range province of NV and AZ
containing volcanic ash. However, there may be three groups of conditions that
lead to the formation of durinodes and duripans. The distribution of Mesozoic
granite rocks corresponds to the distribution of Durixeralfs in California's Central
Valley. The distribution of loess in southeastern WA and ID and volcanic ash bears
no relation to the distribution of duric soils. However, duric soils appear to be
concentrated if not restricted to the Basin and Range province where the dominant
vegetation in Great Basin shrub-grassland and desert scrub.
Parent material appears to be particularly important with regard to the distribu-
tion of duric soils (Table 14.4 ). In their micromorphologic analysis of cementing
materials in duripans of western USA, Flach et al. ( 1974 ) stressed the importance of
easily weathered noncrystalline parent materials. Volcanic glass and siliceous loess
have been implicated in the formation of duric soils (Chadwick et al. 1989 ; Blank
and Fosberg 1991 ; Harden et al. 1991 ; Othberg et al. 1997 ; Blank et al. 1998 ).
However, duric soils also occur on ancient alluvial fans derived from highly
weathered granitic materials in Australia (Chartres and Fitzgerald 1990 ) and in
areas to the west of the Sierra Nevada in the USA (Flach et al. 1969 ; Torrent
et al. 1980 ; Eghbal and Southard 1993a , b ; Munk and Southard 1993 ; White
et al. 2005 ). Melzer et al. ( 2012 ) showed that soils derived from basaltic materials
yielded greater silica for eventual silicification than those derived from granitic
materials in South African savanna ecosystems.
In the USA, 93 % of the 140 common soil series with duric properties are derived
from alluvium, again mostly in the Basin and Range province. The alluvium
commonly contains loess (34 % of pedons) and/or volcanic ash (34 %) or is derived

Table 14.4 Relation of soil-forming factors to the development of duripans

Role of soil-forming
factor Area Soil taxa Citations

Organisms

[Global] - Plants cycle Si,

especially grasses

Blecker et al. ( 2006 )
and Cornelius
et al. ( 2011 )

Owyhee
Plateau, ID

Argidurids Cryptogamic organisms

produce distinct
fabrics on duripan
surface

Blank et al. ( 1998 )

Mojave Desert,
southern
CA

Typic Haplodurids High bioturbation and

soil rejuvenation

Eghbal and Southard
( 1993a , b )

Southeast
Australia

Natric Durixeralfs Abundant opal

phytoliths

Chartres and Norton
( 1993 )

Merced, CA Abruptic Durixeralfs High evapotranspiration

of water in pores
precipitates Si

White et al. ( 2005 )

Eastern WA,
western ID

Argidurids Si precipitates in cicada

burrows

O'Geen et al. ( 2002 )

(continued)