Former Wansleben Salt Lake is located in Central Germany, 20 km west of Halle/Saale, in the middle of a vast loess area (Fig.1). The length of the lake was 6 km, its maximum width 2 km, its total area nearly 9 km2 and its mean depth 7 m (Seyfert, 1919). Because occasional floodings in nearby copper mines were supposedly connected with the lake's existence, the lake was reclaimed in 1896. Since then the lake's bed has been used agriculturally.
The origin of the lake, as well as its elevated Na+, Mg++, SO4- - and Cl - concentrations, are attributed to Permian salt formations in the underground (see Fig.2). The former lake is also located in the middle of the largest contiguous Chernozem region in Germany. Chernozems in Central Germany are considered to be relicts that developed during an early stage of the Holocene (Boreal, see Table 1).
In the course of a regional soil survey in the sixties, a buried soil profile was discovered in the former Wansleben Salt Lake, below a calcareous lake sediment of 0.5 m thickness (Altermann and Mania, 1968). In 1995 this buried soil profile was described in detail and sampled, and the samples were analyzed. Figure 3 shows the soil profile (with German horizon designations, according to AG Boden, 1994). Tables 2a and 2b contain the profile description (according to Soil Survey Division Staff, 1993) and Table 3 gives the results of the analysis, in the format of Soil Survey Staff (1975). Additionally to samples taken for standard physical and chemical analysis, the IIAb1 and IIAb2 horizons (see Fig.3) were sampled for 14C-analysis.
|Geological Classification||Period (approximately)||Climate||Botanical and Prehistoric Classification|
|Subantlantic||600 BC - Present||Present temperate-humid climate (oceanic)||Fagus sp., Quercus sp., Picea sp., Clearing during Iron Age and Present|
|Subboreal||2500 - 600 BC||Warm, some dry periods (continental)||Mixed forest of Quercus sp. with Fagus sp. and Picea sp., Bronze Age|
|Atlantic||5500 - 2500 BC||Warm, humid (oceanic)||Mixed forest of Quercus sp., Clearing since begin of Neolithic|
|Boreal||6800 - 5500 BC||Warm, arid (continental)||Forests of Betula sp. and Pinus sp. with maximum of Corrynus sp.|
|Preboreal||8500 - 6800 BC||Cool (continental)||Forests of Pinus sp. and Betula sp. Begin of Mesolithic|
|Younger Dryas||9000 - 8500 BC||Cold||Park tundra with Betula sp. End of Palaeolithic|
|Alleröd||9800 - 9000 BC||Temporarily warmer||Sparse forest with Betula sp. and Pinus sp.|
|Older Dryas||10300 - 9800 BC||Cold||Tundra|
|Bölling||10800 - 10300 BC||Moderately warm||Park tundra with Betula sp.|
|Oldest Dryas||14000 - 10800 BC||Cold (arctic)||Tundra|
|End of Weichselian Pleniglaciation (Pommeranian)|
Classification: Palaeosol (Chernozem) below a Lithic Haplustoll. Location: In former Wansleben Salt Lake ("Salziger See"), 0.3 km north of the road between the villages of Wansleben and Amsdorf, just outside of Wansleben (Topographic Map 4536; R=4481740.0, H=5703660.0; 20 km west of Halle/Saale in the State of Sachsen-Anhalt). Physiographic pos.: On the bottom of the former lake (depressional). Topography: Nearly level. Drainage: Upper soil is well drained; lower soil is apparently affected by artesian water. Vegetation: Field is in agricultural use. Parent material: Marly lake deposit overlying loess of Wisconsin age over glacial till of Illinois age. Lake deposit (Holocene) is a medium textured sediment derived from surrounding mesozoic formations, with some fine gravel and shells of molluscs. The loess ist medium to fine textured and the glacial till is irregularly alternating loamy, sandy or clayey, with some medium sized pebbles. The upper seven horizons all contain gypsum. Sampled by: G. Machulla, H. Ringe, R.R. van der Ploeg, M. Volkmann, Sept.13th, 1995. Soil No.: A 674 (Altermann notation).
Colors are for the moist soil unless otherwise indicated.
0 - 25 cm. Dark gray (10YR 4/1) sandy loam; coarse blocky and coarse to very coarse granular structure; many fine and very fine roots; slightly fine gravelly; mollusc shells; abrupt smooth boundary.
25 - 40 cm. Dark grayish brown (10YR 4/2) sandy loam; very thick platy and coarse blocky structure; few very fine to fine nonmatrix pores; few fine roots; slightly fine gravelly; mollusc shells; clear wavy boundary.
40 - 50 cm. Very dark gray (10YR 3/1) silt loam; very coarse blocky structure; few very fine to fine nonmatrix pores; common tubular pores; many fine roots; very fine gravelly; with bands of fine gravel and sand; shells of molluscs; clear wavy boundary.
50 - 75 cm. Black (10YR 2/1) silt loam; very coarse blocky structure; few very fine to fine nonmatrix pores; common tubular pores; common fine roots; in the upper part of the horizon some mycelial carbonate is observed; diffuse boundary.
75 - 90 cm. Black (10YR 2/1) silt loam; very thick platy and coarse blocky structure; common very fine to fine and medium to coarse non- matrix pores; common tubular pores and few krotovinas; common fine roots; irregular diffuse boundary; common large crystals of gypsum.
90 - 110 cm. Very dark gray (10YR 3/1) silt loam; structureless; common very fine to fine and few fine nonmatrix pores; few tubular pores and common krotovinas; few fine roots; diffuse boundary.
110 - 140 cm. Grayish brown (10YR 5/2) silt loam with common yellowish brown and gray distinct mottles; structureless; few very fine to fine nonmatrix pores; very few fine roots; clear smooth boundary.
140 - 200 cm. Brown (7.5YR 5/4) sandy loam with common yellowish brown distinct mottles; subangular fine to medium blocky structure; slightly medium gravelly.
|Depth (cm)||Horizon||Size class and particle diameter <2mm|
|Sand (2-0.063)||Silt (0.063-
|Clay (<0.002)||Coarse (2-0.6)||Medium (0.6-0.2)||Fine (0.2-
|Depth (cm)||Org. Carbon Pct.||Nitrog. Pct.||C/N||Carbonate as CaCO3||Bulk density||Water content||Hydr. cond. Ksat
|1/3- to 15-bar
|Depth (cm)||Extractable bases||Sum of bases||Ext.acidity||Cation exch. capacity||Base saturation|
|Ca||Mg||Na||K||Sum of cations||Sum of cations
|Depth (cm)||a) Clay fraction mineralogy||a) Mineral Code:
VR = vermiculite
KK = kaolinit
MI = mica
QZ = quartz
|40-50||MI4, VR+++, KK2, QZ2|
|50-75||MI4, VR+++, KK2, QZ2||b) Approximate weight fractions:
4 = one-third to half
2 = one-twentieth to one-fifth
+++ = strong (X-ray)
|110-140||MI4, VR+++, KK2, QZ2|
The buried soil below former Wansleben Salt Lake resembles the Chernozem of the surrounding upland in many aspects. Additionally, the 14C-analysis provided for the IIAb1-horizon an age of 2355 years (±60) and for the IIAb2-horizon 4120 years (±105). Hence, it is likely that both soils developed simultaneously and that both are of Boreal age. Consequently, Wansleben Salt Lake must be Postboreal age, but, in view of the 14C-data, at least 2355 years old. In one respect however, both soils differ considerably. Whereas the A-horizon of the upland Chernozems around Wansleben shows pH-values near 7.0, the pH-value of the A-horizon of the buried profile is below 5.0 (see Table 3). To explain this low pH-value, the following hypothesis is postulated.
The Holocene climate in the Wansleben area was predominantly warm and dry. Even today the mean annual amount of precipitation is less than 500 mm. Consequently, soils hardly have been leached and in most soils gypsum has accumulated. In the IIAb2-horizon of the buried Chernozem even 1-cm large gypsum crystals can be found, but they are lacking in the IIAb1-horizon. It is likely that after the lake's bottom became flooded (2500 years or more ago), anaerobic conditions and low redox values developed in the A-horizon of the flooded Chernozem. Under such conditions sulfates became reduced and sulfides were built. These sulfides existed until the lake was reclaimed at the end of the last century. Since then oxidative weathering of the sulfides may have lead to the low pH-value that presently is observed. Additional research is needed to check this hypothesis.
Letzte Änderung am 03. Februar 1998