Weichselian phases and ice dynamics of the Scandinavian Ice Sheet in northeast Germany: a reassessment based on geochronological and geomorphological investigations in Brandenburg

Abstract

How to cite:Hardt This thesis presents new geochronological and geomorphological data concerning Weichselian ice dynamics of the Scandinavian Ice Sheet for the northeast German lowland area. The largest Weichselian ice extent in Brandenburg (Brandenburg phase) occurred in the late marine isotope stage 3. The global Last Glacial Maximum is represented by the Pomeranian ice marginal position in Brandenburg ( ∼ 20 ka). Therefore, a 2-fold Last Glacial Maximum in Brandenburg, as previously proposed by Lüthgens and Böse (2011), is confirmed.For the first time, we determined optically stimulated luminescence (OSL) ages of glaciofluvial deposits associated with the Weichselian Frankfurt phase at a site in Ladeburg (central Brandenburg; Fig. 1). Furthermore, we report new OSL ages of glaciofluvial deposits from the lignite mine Jän-schwalde (southern Brandenburg), a key site regarding the Weichselian maximum extent during the Brandenburg phase. In combination with cosmogenic nuclide surface exposure ages of glacigenic boulders, which were collected from literature and recalibrated with an updated 10 Be production rate, a consistent process-based model of the Weichselian ice dynamics in Brandenburg was developed (Fig. 1).The ice advance of the Brandenburg phase was dated to 34.1 ± 4.6 ka. For the formation of the Brandenburg ice marginal position, a mean age of 30 ± 4 ka was determined at Jänschwalde. The succeeding meltdown during the so-called Frankfurt phase was dated to 26.3 ± 3.7 ka at Ladeburg. The subsequent landscape stabilization phase started at around 24 ± 2 ka in central Brandenburg, which was deduced by recalibrated exposure ages of glacigenic boulders (Hardt et al., 2016). These ages are corroborated by other published OSL ages from the region (Fig. 1).The recalibration of previously published cosmogenic exposure ages from glacigenic boulders with an up-to-date 10 Be production rate (Heyman, 2014) resulted in a considerable increase of the ages (9-15 %; Hardt and Böse, 2017). In combination, the OSL ages and the cosmogenic nuclide exposure ages now provide a consistent geochronology of the Weichselian ice dynamics in Brandenburg. The largest Weichselian ice extent during the late marine isotope stage 3 (Brandenburg phase) corresponds with the so-called Klintholm advance in Denmark (Houmark-Nielsen, 2010) and a possible ice advance in central Poland (Marks, 2012).Published by Copernicus Publications on behalf of the Deutsche Quartärvereinigung (DEUQUA) e.V.

Thresholds for the presence of glacial megafauna in central Europe during the last 60,000 years

“…The connection between England and the European mainland developed during this time. Simultaneously, the landscape of Scandinavia and Russia must have changed in front of the expanding continental ice sheets, which were recently dated to the stage of the “Brandenburger ice advance”, after 30,000 yr b2k 41 . A well-known archeological site for the millennia after GI4 is the Czech Site of Dolní Věstonice, which is at the southern Russian corridor, where mammoths were hunted extensively from 31,000 to 29,000 yr b2k 42 , 43 .…”

A submerged pine forest from the early Holocene in the Mecklenburg Lake District, northern Germany

“…). A considerably long time period comprising thousands of years passed between the decay of the inland ice (in this part of northern Germany between 26–20 ka; Hardt & Böse ; Hardt ) and the formation of dead ice lakes. While the majority of the basins formed during the Lateglacial (mostly Allerød, i.e.…”

Proposing a new conceptual model for the reconstruction of ice dynamics in the SW sector of the Scandinavian Ice Sheet (SIS) based on the reinterpretation of published data and new evidence from optically stimulated luminescence (OSL) dating

“…Lüthgens et al (2010a, b) and provide ages for proglacial outwash sediments attributed to the maximum extent of the Weichselian Glaciation, here called the Brandenburg Stage, between younger than 34 and 30 ka, as determined by optically stimulated luminescence (OSL) dating of quartz single grains and small aliquots (quasi-single grains). Brauer et al (2005) report that OSL ages from Stolzenhagen using single aliquots of quartz from outwash sediments associated with the advance of the SIS to its maximum extent at ∼ 33 ± 2 ka (Lüthgens et al, 2010a;Hardt, 2017) provide similar ages from correlate outwash sediments at the Ladeburg site of ∼ 34±5 ka based on small aliquot (quasi-single-grain) quartz OSL. These ages are in good agreement with surface exposure ages (recalculated using the global 10 Be production rate of Heyman, 2014) for erratic boulders, indicating the initial down melting of the ice in the area north of the maximum position of the Weichselian Glaciation in northeastern Germany at about 24-21 ka based on Rinterknecht et al (2006), Heine et al (2009), and .…”

“…Thus, the measurements were done on a quasi-single-grain level, which is an important prerequisite when working on poorly bleached (glaciofluvial) material (Thrasher et al, 2009). Of the nine samples, seven were suitable for age calculation (see Hardt, 2017, andNitzsche, 2015, for a full sample report). Owing to the observed incomplete bleaching, we applied the three-parameter Minimum Age Model (MAM; Galbraith et al, 1999) and obtained a mean age of 30 ± 4 ka (n = 3) for the Weichselian formation of the Taubendorfer sandur in Jänschwalde and a mean age of 31±4 ka (n = 4) for the proglacial outwash sediments ascribed to the advancing ice in Müncheberg (Table S1 in the Supplement).…”