(Re)deposition of loess in southern Limbourg, The Netherlands. 1. Field evidence for conditions of deposition of the lower silt loam complex

Abstract

AbstractThis is the first of five papers on a study clarifying conditions and processes during and between the periods of loess accumulation in the southern Netherlands. The research approach involves studies of the stratigraphic, sedimentological, and paleopedological frameworks, micromorphological and analytical characterization of the deposits, and interpretation of micromorphological data in the light of independent process simulating experiments conducted on comparable test materials.Lower or Middle Pleistocene Maas terrace Sands and Gravels overlie Middle Miocene Sands, and are separated by a stoneline complex, consisting of four components, from various silt loam units, which have been grouped into the Lower, Middle and Upper Silt Loam complexes. There is also one intra‐silt loam stoneline. The stonelines range from pre‐Saalian to early Middle Pleniglacial Weichselian in age and variably represent periods of deflation, hillslope erosion, and channel erosion. The present paper reports the results of a macroscopic field study of the Saalian, Eemian, and Early Weichselian Lower Silt Loam stratigraphical units and provides a brief overview of the remaining units, which will be detailed in a future paper. The lateral variability of the units is drawn to scale in a profile 475 m long.The Lower Silt Loam complex comprises an early Saalian channel deposit and a Saalian eolian unit with penecontemporaneous reworking by sheetflow. It is surmounted by the Eemian Rocourt paleosol. This is followed by a Lower Silt Loam unit consisting of older local silt loam material reworked and redeposited by sheet and shallow channel flow, which is in turn surmounted by a paleosol that may be the Early Weichselian (Warneton) or late Eemian in age. The last and largest Lower Silt Loam unit was deposited from channel, and subsequently sheetflow on a major erosional surface, which bevels all older silt loam units. Above this are calcareous Middle Silt Loams.The geomorphic evolution of a dry valley or del can be traced to an early Saalian channel. But, various paleochannels are no longer evident in the present landscape.