Late Weichselian (fluvio-)aeolian sediments and Holocene drift-sands of the classic type locality in Twente (E Netherlands): A high-resolution dating study using optically stimulated luminescence

摘要

The Late Weichselian and Holocene (fluvio-)aeolian sands of the type locality Lutterzand in the E Netherlands have been the focus of many palaeoclimatic, palaeoenvironmental and geochronological studies. In the present study, an accurate and detailed chronological framework has been established using radiocarbon and optically stimulated luminescence dating. Additionally, the sedimentological characteristics of the fluvio-aeolian and aeolian sequences have been reinvestigated.Four main phases of (fluvio)aeolian sedimentation have been differentiated in the Lutterzand sections, consistent with the Late Pleniglacial, the pre-Aller?d Lateglacial, the Late Dryas, and the Late Holocene. From at least 25.2 ± 1.9 ka up to 19.9 ± 1.6 ka, the area was marked by a transition from fluvial to aeolian deposition under continuous permafrost conditions (Older Coversand I). The Beuningen Gravel Bed is considered as the lithostratigraphic marker for permafrost degradation, shallow channelling and aeolian deflation associated with the formation of a desert pavement. Localised fluvial sedimentation in shallow channels took place in two phases, a first from ~20 ka to ~23 ka, and a second at around 16 ka; the desert pavement formed in between ~16 ka and ~14 ka, but probably shortly after 16 ka. The aeolian sediments overlying the Beuningen Gravel Bed were deposited as sand sheets and low dunes, and yielded ages between 15.8 ± 1.4 ka and 12.2 ± 0.9 ka. Although the OSL ages seem to point to fairly continuous coversand sedimentation during the Lateglacial, the intercalated Usselo Soil allows distinguishing a pre-Aller?d phase (resulting in the Older Coversand II and the Younger Coversand I between 15.8 ± 1.4 ka and 12.3 ± 1.0 ka) from a post-Aller?d phase (with deposition of the Younger Coversand II between 13.6 ± 1.1 ka and 12.2 ± 0.9 ka). During the major part of the Holocene, (podzol) soil formation occurred in the top of the aeolian sediments. Probably due to human activities, local erosion of the upper part of the Lateglacial sequences and redeposition took place. These drift-sands were dated between 0.40 ± 0.04 ka and 0.20 ± 0.02 ka.