Abstract form

Changes of salt minerals of soil surface efflorescences in space and
time: a case study in Hungary
Géza SZENDREI* 1 , Tibor TÓTH 2 , Péter KOVÁCS-PÁLLFY 3 , Sándor SZAKÁLL 4
1 Department of Mineralogy and Petrology, Hungarian Natural History Museum,
Budapest, Hungary
2 Research Institute for Soils Science and Agrochemistry, Hungarian Academy of
Sciences, Budapest, Hungary
3 Hungarian Geological Survey, Budapest, Hungary
4 Department of Mineralogy and Petrology, University of Miskolc, Hungary
*Corresponding author’s e-mail: szendrei@miner.nhmus.hu
In the European prairie ecological division (term after Bailey 1996) mineralogical
investigations of soil surface efflorescences have not been published. As there are more
minerals with sodium sulphate or sodium carbonate chemical compositions, more
details were expected from the mineralogical study than from the chemical
compositions alone.
176 spots were visited for surveying and characterizing salt minerals in soil surface
efflorescences, and on 39 localities (at 29 villages) were found salt efflorescences
between 1995-2005.
The soil profiles were described and sampled by the Hungarian soil survey manual and
were analysed by international standard methods. The salt minerals were mainly
determined by X-ray diffractometry.
There were differences in the geographical distributions of salt mineral associations in
surface efflorescences: sulphate mineral associations were only found in salt affected
areas West of the Danube and North of Tisza river. Other salt mineral associations:
carbonate, carbonate-chloride, carbonate-sulphate and carbonate-sulphate-chloride
minerals were found in Danube-Tisza interfluve and in Trans-Tisza river region. Except
for gypsum, salt minerals were dominantly sodium salts, sodium-magnesium salt
minerals were found only at one site.
Concerning long-term changes in salt efflorescences more occurrences were recorded in
the past (1817-1995) than at present (1995-2005): 107 sites compared to 39 spots. The
extent of salt efflorescences became much less than they were in the past.
The geographical distribution also changed, in the past more occurrences were observed
in the Danube-Tisza interfluve and Nyírség region, and less in Hajdúság region than
today, and sodium-carbonate minerals were more frequent.
Attempts were made to observe short-term changes by repeated sampling (six sampling
in 2001) at Nyírőlapos (Hortobágy). Only thenardite was determined in springtime. In
addition to this, mineral gypsum, sodium carbonate minerals (mainly trona) were
identified in summer, termonatrite, thenardite and halite in autumns were found. This is
likely due to increasing salt concentrations in the solutions.
The relationship between the chemical composition of groundwater and occurrence and
nature of salt efflorescences has already been well-known. In our study we tried to find
relationship of groundwater levels and the distribution of salt minerals in soil surface
efflorescences.
Reference Bailey, R. C. (1996): Ecosystem geography. New York. Springer.
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