Multi-method study of the Middle Pleistocene loess–palaeosol sequence of Köndringen, SW Germany

Abstract

Abstract. Loess–palaeosol sequences (LPSs) remain poorly investigated in the southern part of the Upper Rhine Graben but represent an important element to understand the environmental context controlling sediment dynamics in the area. A multi-method approach applied to the LPS at Köndringen reveals that its formation occurred during several glacial–interglacial cycles. Field observations, as well as colour, grain size, magnetic susceptibility, organic carbon, and carbonate content measured in three profiles at 5 cm resolution, provide detailed stratigraphical information. Only minor parts of the LPS are made up of loess sediment, whereas the major parts are polygenetic palaeosols and pedosediments of varying development that are partly intersected, testifying to a complex local geomorphic evolution. The geochronological framework is based on 10 cm resolution infrared-stimulated luminescence (IRSL) screening combined with 18 multi-elevated-temperature post-IR IRSL ages. The luminescence ages indicate that two polygenetic, truncated Luvisols formed during marine isotope stages (MISs) 9(–7?) and MIS 5e, whereas unaltered loess units correspond to the last glacial (MISs 5d–2) and MIS 8. The channel-like structure containing the two truncated Luvisols cuts into > 2 m thick pedosediments apparently deposited during MIS 12. At the bottom of the LPS, a horizon with massive carbonate concretions (loess dolls) occurs, which may correspond to at least one older interglacial.

Loess formation and chronology at the Palaeolithic key site Rheindahlen, Lower Rhine Embayment, Germany

“…Sabelberg et al, 1976;Meijs et al, 2013;Lehmkuhl et al, 2016;Antoine et al, 2021). Such stratigraphic gaps may represent short phases of the past like in the exceptionally well-preserved Last Pleniglacial records of Remagen Schwalbenberg (Schirmer, 2016;Fischer et al, 2021) and Nussloch (Bibus et al, 2007;Antoine et al, 2009) or cover whole glacial periods as postulated for the LPS at Rheindahlen (Schirmer, 2002) or supported by chronometric evidence at Köndringen (Schwahn et al, 2023). In the Lower Rhine Embayment, LPSs have been exposed in several brickyards and large-scale lignite open cast mines, partly in very broad lateral extent (e.g.…”

“…The first fossil Bt horizon below land surface would then have the same chronostratigraphic position as the Mautort I or Grâce I Soil of the global sequence for northern France (Antoine et al, 2021), the Harmignies and Rocourt soils in Belgium (Haesaerts et al, , 2019Meijs, 2002;Meijs et al, 2013), or the Erbach Soil in the general loess stratigraphy of Germany (Schönhals et al, 1964;Semmel, 1989;Zens et al, 2018). Pedostratigraphic correlation of the first fossil Bt with the Eemian has recently been corroborated by luminescence dating at the LPS of Garzweiler-Elsbachtal and Inden-Altdorf (Fischer et al, 2012), Kitzingen and Holzkirchhausen (Rahimzadeh et al, 2021), and Köndringen (Schwahn et al, 2023).…”