Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 13. 1987. (Budapest, 1987)

.Ë^i-EL^il?-.?-!!' Locality: Mezőnagymihály, Gajla-tanya. Humous alluvial soil. The upper part of the profile is dark-brown adobe soil, turning lighter downwards and turning into a loess-like substance. The lowermost part of the profile is carbonate-spotted, fine grained sand (Fig. 6). ^^iPL^Î!?-^.?-* Locality: Mezőnagymihály, Potornya-tanya. Flat, somewhat wet area of north-south directions. Alluvial meadow soil (of slightly sodic character). The top of the profile is reddish brown to greyish brown hard adobe soil, turning into yellow clayey adobe soil then to greenish grey clay. The lower half of the profile contains much carbonate and limonite concretions and limonitic spots (Fig. 7). ANALYTICAL DATA The results of analyses are shown for each profile in Figs 2-7 (pH, DTA, trace element concentrations determined by optical emission spectrometry and atomic absorption spectrophotometry). pH determinations Suspension was made of 20 g air-dry average sample and 50 ml distilled water, and pH was determined after 6 hours and after several stirrings. Results are shown in Table 1. Table 1 pH data arranged by depth mber Depth Profile number cm 24 25 26 27 28 29 1. 0- 20 7. 55 7. 3 6. 1 6. 5 5. 8 6.0 2. 20- 40 7. 7 8. 2 6. 2 7. 8 7.25 8. 5 3. 40- 60 7. 9 9.0 8. 1 8. 3 8. 55 9. 2 4. 60- 80 8. 1 9. 65 8. 2 8. 35 8.8 9. 3 5. 80-100 8. 4 9. 7 8. 1 8. 5 8.7 9. 0 6. 100-120 8. 4 9. 7 8. 3 8. 25 8. 6 9. 2 7. 120-140 8. 4 9. 6 7. 8 8. 4 8. 5 9. 1 8. 140-160 9. 6 7. 5 8. 4 8. 5 8. 7 9. 160-180 8. 85 7. 8 8. 3 8. 5 8. 4 10. 180-200 8. 9 8. 35 8. 3 Columnar diagram of average pH of A, B and C soil levels (Fig. 8) shows that level A is generally acidic. pH reaches its highest values in level B, while in level C it somewhat decreases, but remains alkaline. Differential thermal analysis DTA was applied to determine clay mineral quality, organic matter, carbonate and clay mineral quantity in the soil samples, 50 g air-dry, averaged sample was pulverized in a ball-mill, then averaged again and 1 g of it was filled in the container of the derivatograph. Heating was continued up to 1000°C, by 10°C per minute. Sensibility of the photoemulsion registration galvanometer was 1/10 for DTA and DTG as well; sensibility of the ball-pen registration instrument was 250./uV for DTA and 2. 5 mV for DTG. Quantitative and qualitative interpretation of DTA, DTG and TG curves was carried out. The quantitative interpretation can be applied to the determination of the most important ratios of the components due to overlap of peaks. For the purpose of interpretation we have divided the DTA curves into four main parts. 1. Adsorptive water fixed on clay minerals, organic matter and different colloids. It is