Gypsic and Petrogypsic Horizons - Soil Geography of the USA: A Diagnostic-Horizon Approach - page 181

Table 17.3 Relation of soil-forming factors to the development of gypsic and petrogypsic
horizons
Area Role of soil-forming factor Citations

Organisms
Important in forming gypsic crusts
Climate

Central Asia Form in areas with 400 mm/yr Boyadgiev and Verheye ( 1996 )

<

MAP

Australia Form in areas with 250 mm/yr Chen ( 1997 )

<

MAP

SE Spain Form in areas with < 200 mm/yr

MAP

Canton et al. ( 2003 )

Utah, USA Form in areas with < 180 mm/yr

MAP

Nield et al. ( 2007 )

Iran Climate change yields argillic, cal-

cic, gypsic

Khademi and Mermut ( 2003 )

Relief

Central Asia Gypsic soils occur in depressions of

hill country ( < 8 % slopes)

Boyadgiev and Verheye ( 1996 )

Australia, Spain Gypsic soils dominant along salt
lakes (sahkhas)

Chen ( 1997 ) and Herrero et al. ( 1992 )

Oklahoma,
USA; Spain

Gypsic soils strongest developed in
footslope positions

Carter and Inskeep ( 1988 ), Mach´n and
Navas ( 1998 ) and Cant´n et al. ( 2003 )

Parent materials

Wyoming,
USA; Spain;
Syria

Alluvium most common parent
material

Reheis ( 1987 ), Herrero et al. ( 1992 ) and
Florea and Al-Joumaa 1998

Spain Mudflows remobilize gypsum Herrero et al. ( 1992 )

Oklahoma,
USA;
Kuwait

Pedogenic gypsum most abundant
in gypsum-rich parent material

Carter and Inskeep ( 1988 ) and El-Sayed
( 1993 )

Time

Australia Petrogypsic horizons may form in

thousands of years

Chen ( 1997 )

SW USA Gypsic develops in morphogenetic

stages similar to carbonates

Gile et al. ( 1966 ), Reheis ( 1987 ) and Buck
and Van Hoesen ( 2002 )

Tunisia Gypsum crust formed in 1,660 yr Drake ( 1997 )

17.6 Genesis of Gypsic Horizons

The dominant process occurring in soils with a gypsic horizon is gypsification;
ancillary processes are argilluviation, gypsiturbation, calcification, salinization, and
solonization.
Gypsiturbation results from the growth of microcrystals of gypsum and causes
“puffing” of the ground surface (puff solonchaks), desiccation cracks, polygons,
karst topography, and dissolution channels expressed as vertical and planar voids.