Climate and soil moisture content during development of the first palaeosol in the southern Loess Plateau
2018
Zhao, J.‐B. | Luo, X.‐Q. | Ma, Y.‐D. | Zhou, Q. | Chen, B.‐Q. | Yue, Y.‐L.
The scientific problems concerning Quaternary soil water content and the water cycle have not been researched. This study examined the soil water content and depth of distribution of gravitational water in the south Loess Plateau during development of the first palaeosol layer (S₁) by methods such as field investigation, electron microscopy, energy spectrum analysis, chemical analysis, and so on. The purpose was to reveal the climate, water balance and vegetation type at the time when S₁ developed. The depth of migration of CaCO₃ and Sr were 4.2 m below the upper boundary of the S₁ palaeosol, and the depth of weathered loess beneath the argillic horizon was 4.0 m. Ferri‐argillans developed well in the argillic horizon and their depth of migration was 1 m below the argillic horizon. These findings suggest that the climate during the last interglacial was subtropical and humid, and the soil‐water balance was positive. Gravitational water was present to a depth of least 4.2 m from the top of S₁, and the water content was adequate for tree growth. The chemical weathering index showed that this palaeosol has been moderately weathered. HIGHLIGHTS: We studied the palaeo-water content index during development of the first palaeosol. Soil water balance during development of S₁ palaeosol in the south Loess plateau was positive. Available water content was 14% during development of S₁ palaeosol. We suggest that a subtropical climate and forest vegetation prevailed.
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