Kuti L., T. Tóth, J. Kalmár, and P. Kovács-Pálffy. 2003. Mineral composition of 
salt-affected soils and recent mineral formation in the neighborhood of 
Apajpuszta and Zab-szék. (Hung.) Agrokémia és Talajtan. 52:275-285.

The mineral composition of two 1m soil profiles was investigated at the 
Apajpuszta and Zabszék Experimental Stations. From the point of view of particle
distribution, the soil samples had silty (loamy) clay, clay silt (loam), clay
sand and silty (loamy) sand texture, with a substantial carbonate content and
high (9-10) pH. The sand fraction of the samples consisted of two types of quarz
(of volcanic and metamorphic origin), feldspar, muscovite, biotite and
associated minerals, rock debris (dolomite, limestone, metamorphic shale,
decomposed rhyolite and other volcanic rocks) and organoclasts (snail shell
debris). X-ray diffraction and thermic analysis of the samples demonstrated that
the clay minerals consisted of montmorillonite, chlorite, illite, kaolinite and
a mixed structure smectite-illite mineral, while there were also considerable
quantities of quartz, carbonate and feldspar, with a little amphibole, pyrite,
goethite, hematite, gypsum and 2-4% amorphous phase. The normative minerals
calculated from the two complete chemical analyses differ considerably from the
real composition, probably due to the Na nature of the montmorillonite, the
substantial Na+ adsorption of the extremely disperse and disorganized clay
minerals, and a high rate of SiO4-4 - AlO5-5 replacement. Within the framework
of the generally accepted salinization model, the paper wishes to shed light on
the "fine structure" of this process, including the role of clay minerals in the
initiation and development of the process. Assuming that in the initial state
the main clay mineral in the soil profile was Na montmorillonite of pyroclastic
origin, Ca2+ ions originating from the groundwater, which had normal pH and
contained Ca hydrocarbonate, or dissolved from the rock debris will have
replaced the interstitial Na+ ions in the smectite when the capillary pump went
into action. These then crystallized out on the surface in the form of various,
chiefly carbonate, Na salts. When the climate turned wet these salt excretions
were dissolved and  the high pH solution seeped into the soil, where the Na+
ions replaced the interlayer Ca2+, which was finally precipitated, forming a
crust on calcareous and non/calcareous particles in the proximity of the
groundwater level. Due to its periodic nature, this process will have been
repeated many times, with the result that a salt solution ``pillow`` developed
on the surface of the groundwater, while clay minerals progressively decayed ,
leading to structural disorganization. On the basis of these data it is 
possible to determine whether salinization is in the initial, evolutional or 
mature stage. The data indicated that the sampling areas in Apajpuszta and 
Zabszék are now in the developmental stage. From the point of view of mineral 
genetics, salinized alkaline soils can be regarded as the cradle of new 
minerals. It is here that various water-soluble Na salts, Mg-containing calcite 
and gypsum are formed, while the clay minerals decompose into lattice fragments 
with the size and properties of colloids, which re-form into clay minerals with 
a regular sturcture in the course of sedimentation or diagenesis.