Paleo-pedological record of the Rocourt Pedosequence at Veldwezelt–Hezerwater (Belgian Pleistocene loess belt): Part 1 — Evolution of the parent material

Abstract

As the environment influences soil formation, loess–paleosols are important archives of former climatic conditions. However, this record is highly complex and all features need to be evaluated in order to obtain consistent information on soil formation. This study revises the pedological record of the Rocourt-paleosol complex, an important pedo-stratigraphic marker for the Eemian and Early Weichselian, at an exceptionally well-preserved in-situ sequence (Veldwezelt–Hezerwater, Belgian loess belt). Contrasting hypotheses exist considering the evolution of the parent material after the deposition of the Saalian loess and on the importance of aggrading aeolian deposition. In this study, soil morphological features and depth functions of X-ray diffraction, grain-size distribution, CEC, base saturation, total Fe, Al, K, Na and Ca content, pH and electrical conductivity were established to reconstruct deposition dynamics, weathering and carbonate content of the parent material. Texture analysis confirms the petrostratigraphic homogeneity of the parent material and suggests that it developed under a regime of fluctuating rates of primary dust deposition intermixed with periods of (fluvial) reworking of the dust. Strong weathering was identified in the lower stratigraphic unit, supporting the general consensus that it formed during the Eemian in Saalian loess. Less information is present to confirm the origin of the upper, less developed illuvial units, which may have formed by welding or by pedogenesis in locally redistributed or aeolian material. The overlying A-horizons are clearly less weathered, and evidence for early recalcification indicates that deposition of unweathered, calcareous sediments gained importance during the formation of these horizons.