The Quaternary geology and landscape of Brandenburg, comprising wide areas of the northern German lowlands, were basically shaped by the last three glacial and interglacial cycles during the Middle and Late Pleistocene (Schroeder et al., 2001; Lippstreu et al., 2015; Böse et al., 2018; Stackebrandt, 2020). Roughly about 95 % of Brandenburg is covered by loose sediments of glacigenic, fluvioglacial, alluvial, limnic, and palustrine origin, reaching thicknesses of more than 500 m in deeply incised troughs of the Elsterian Stage. These deep valleys were generated not solely by exogenic erosion but also by preceding neotectonic movements that prepared troughs for the accommodation of thick preglacial soft sediments, easily eroded by glacial action (Stackebrandt, 2009). The present landscape of Brandenburg from south to north is occupied by morainic belts and meltwater deposits of maximum advancing and decaying ice masses of the Scandinavian Ice Sheet during the Saalian and Weichselian stages, separated by large ice-marginal valleys (Urstromtäler) that drained the proglacial meltwaters from northerly directions as well as the rivers from the south towards the northwest (Fig. 1).

Figure 1Geomorphological units of Brandenburg (modified after Stackebrandt and Franke, 2015; Stackebrandt, 2020). Insets show the positions of the maps in Figs. 2 and 3.

A reliable understanding of the right chronological order of the ice-marginal stages still suffers from contradictory dating results. Traditional approaches invoked morphostratigraphic correlations and the dating of organic matter included in interglacial and interstadial sediments under- and overlying sediments of morainic materials (Cepek, 1965; Lüthgens and Böse, 2012; Lippstreu et al., 2015). With growing progress in exposure dating techniques, such as optical stimulated luminescence (OSL) and surface exposure dating (SED), it became possible to also date glacigenic and glaciofluvial deposits directly related to the timing of ice-sheet dynamics (Brauer et al., 2005; Lüthgens and Böse, 2012; Hardt and Böse, 2016). The latest findings show that ice margins were not a static feature in time, as suggested by morphostratigraphic interpretations, but revealed marked diachronous behaviour both at a regional scale (Böse et al., 2018; Lüthgens et al., 2020) and for the entire Scandinavian Ice Sheet (Hughes et al., 2015).

The hills of the Fläming region together with the Lusatian border wall (Lausitzer Grenzwall), situated about 50 km south of Potsdam, reach the highest elevations in Brandenburg (140 to 200 m a.s.l.) and represent the morainic remnants (Altmoränenlandschaft) of the Warthe Stage (Marine Isotope Stage (MIS) 6) of the Saalian glaciation (Lippstreu et al., 2015; Meschede and Warr, 2019). Although the morainic surface is very smooth, lobes of differing end moraines and block chains appear beneath the periglacially formed ground layer. Exposure dating suggests formation of the Saalian ice margin between 170 and 150 ka (Krbetschek et al., 2008; Rinterknecht et al., 2012). In contrast to younger glacial belts, the Fläming landscape is barren of any lakes but was covered by aeolian sandy loess, creating a NW–SE-striking belt.

The area around Potsdam was basically shaped by glacial advances during the late Weichselian Brandenburg Stage, corresponding to the local Last Glacial Maximum around 24 ka (Böse et al., 2012; Hughes et al., 2015). The latest OSL data from meltwater sediments challenge this dating and provide older ages of between 34.0 and 27.0 ka (Lüthgens et al., 2010a, b, 2020).

The Frankfurt substage ice margin north of Berlin likely is represented by several younger recessional stillstands of the Brandenburg advance (Hardt et al., 2016). The youngest glacial advance in Brandenburg is documented by the Pomeranian ice margin that occupies the northeastern part of Brandenburg. Dating results range between 15 ka (Litt et al., 2007) and 20 ka (Lüthgens et al., 2011; Hardt and Böse, 2016).

Situated between the wide glacial spillways of the Berlin and Baruth ice-marginal valleys, the area around Potsdam lies in the reaches of the Brandenburg ice-marginal stage. The area is characterized by a complex mosaic of morphological plates, morainic ridges, and lowland valleys (Weiße, 1991; Stackebrandt and Manhenke, 2004; Hermsdorf, 2005; Lutze, 2014) (Figs. 2, 3). This morphological configuration is not consistent with a simplified glacial-series concept. Strong overprinting was generated by dead ice, meltwater, and permafrost, creating a kame topography (Weiße, 2012a, b). Likewise, it seems that Late Pleistocene glaciation was routed by the preformed underground structure, created by neotectonics and former glaciations (Stackebrandt, 2009; Lippstreu et al., 2015). In analogy to the southeast orientation of the Nuthe River valley and the southwest elongation of the modern Havel River, two prominent palaeo-depressions cut about 150 m below the surface into Neogene sediments at 120 m below modern sea level. Between the two palaeo-depressions a common Quaternary sequence can be found (Fig. 4). Depositional infills of the depressions comprise sediments of the last 440 kyr, with glacial tills and meltwater sediments of the Elsterian, Saalian, and Weichselian stages, as well as intercalated organic muds and peats of the Holsteinian and Eemian interglacials and of the Holocene. Mainly late Weichselian and Holocene sediments cover the modern landscape around Potsdam. Locally, outcrops of older deposits occur in morphological plates, which often include a core of basal tills of the Saalian glaciation (Fig. 3).

Figure 2Geological map of the wider surrounding of Potsdam (modified from Lutze, 2014). Inset shows position of the map in Fig. 3.

Figure 3Geological map of the area southwest of Potsdam, redrawn from the 1 : 100 000 geological map of Hermsdorf (2005). The map is underlain by relief obtained from a DGM (Digitales Geländemodell, i.e. digital elevation model) of the Brandenburgviewer (LGB, 2020). Red numbers indicate the stops of the field trip. The white line shows the approximate location of the geological profile depicted in Fig. 4.

Figure 4Generalized geological profile through the Quaternary sedimentary section of Potsdam (unpublished after Norbert Hermsdorf​​​​​​​, Landesamt für Geowissenschaften und Rohstoffe Brandenburg, LGRB). Location of profile is shown in Fig. 3.

During the late Weichselian glacial maximum, the ice sheet reached 125 to 200 m thickness north of Potsdam (Weiße, 2012a). Bulldozing processes by the advancing ice lobes created a set of lateral and terminal push moraines, made up of compressed, imbricated, and folded proglacial sands and older tills. Today, they represent the highest morphological ridges and peaks around Potsdam (80 to 125 m a.s.l.), often fringing the margins of the plates. In places, thin, up to 4 m thick layers of basal till of this advance are preserved as ground moraines on the plates. Glacial advance around Potsdam was driven by two ice lobes. One of those traversed the Nuthe Valley in a westward direction; another one filled the Havel River valley and moved in a southward direction (Weiße, 1991; Hermsdorf, 2005). During its maximum extent, the ice sheet with its different lobes reached nearly the northern slopes of the Fläming Hills south of the Baruth ice-marginal valley and then retreated to the north (north of the then active Baruth ice-marginal valley), where they formed a stagnating ice margin, which nonetheless was not persistent in space and time (Juschus, 2010; Böse et al., 2018). During that time, the ice lobe filling the Havel depression scoured the underground down to 60 m below the present-day surface, by both glacial exaration and strong subglacial meltwater erosion. Sediment-laden meltwater from subglacial tunnels of that lobe fed a huge, 70 km² proglacial outwash cone (sandur, Sander in German), which passes over at its marginal fringe into the Baruth ice-marginal valley. The so-called “Beelitz Sander” is located about 20 km south of Potsdam (Figs. 2, 5).

Figure 5The outwash cone of the Beelitz Sander at the Weichselian ice margin south of Potsdam (modified from Stackebrandt, 2020).

During deglaciation, ice-sheet retreat and disintegration led to the isolation of motionless ice fields and blocks in the northern hinterland of the former ice margin (Weiße, 1991, 2012a, b). The collapse of subglacial valleys sealed meltwater channels by dead ice (Juschus, 2010). The glacial sediments carried by meltwaters were deposited on and between the ice remnants. During final deglaciation, they left behind kame hills and kame terraces with ancient ice-contact slopes. Except for a few dead ice relics preserved by overlying sediments, ice decay was likely completed at the latest during Bølling–Allerød warming, roughly between 15.0 and 13.0 ka. This time was characterized by boreal climate conditions and the growth of birch and pine woodlands (Rowinsky, 1995; Wolters, 1999; Brande and Rowinsky, 2017). Glacial decay significantly changed the drainage path of meltwater flow away from the Baruth ice-marginal valley towards the northern hinterland of the former ice margin (Juschus, 2010). With its height of 70–80 m, the Beelitz Sander became a topographical barrier and diverted meltwater discharge to the neighbouring Kanin Valley (Kaniner Tal; 40–60 m a.s.l.) (Böse and Brande, 2002) (Fig. 3).

With ongoing unsealing of the local lowlands, other meltwater routes followed the Nuthe depression to the northwest, the Havel depression to the southwest, and in a westward direction the valleys west of Potsdam (Weiße, 2001, 2012a). During the late glacial Younger Dryas, climate deterioration caused a return to subarctic conditions, dominated by waterproof permafrost ground and periglacial processes (Weiße, 2001). Dry valleys and screes formed along steep slopes, while surficial soils and sediments were affected by cryoturbation and ice-wedge growth. Dryness and a sparse vegetation cover gave rise to aeolian sediment remobilization and the transformation of dune fields (Kaiser et al., 2009). Nevertheless, as a consequence of medieval German settlement and deforestation, a reactivation of sands by aeolian processes caused the formation of dunes on the southern part of the Glindow plate close to Bliesendorf, burying the Holocene brown soil (Brande et al., 1999; Böse et al., 2002).

Today's temperate climate and modern environment developed during the Holocene. The last remains of dead ice finally melted out. Lake basins, modern river courses, floodplains, and wetlands occupied the valleys, while small hollows were filled with ponds and mires (Wolters, 1999; Weiße, 2001; Brande and Rowinsky, 2017). Mixed pine and deciduous forests expanded at the expense of pine woodlands (Wolters, 1999).

Anthropogenic land use in the Late Holocene changed natural landscape, vegetation, and hydrology around Potsdam (Böse et al., 2002; Viehrig, 2002; Rubin et al., 2008; Lutze, 2014). In particular, deforestation, pasture farming, the expansion of hunting grounds, fruit and wine growing, and damming, as well as peat and clay mining, left their tracks in the modern cultural environment.

After the slavonic settlements mainly founded from the 4th to the 8th century, a major rural transformation changed the aspect of the landscape with the German settlement from the 11th century onwards. The plates were widely cleared for agricultural purposes, using new ploughing techniques. The area southwest of Potsdam was predominantly influenced by the foundation of the Lehnin monastery in 1180 and the related villages in the surroundings (Böse et al., 2002). A major transformation in the river system and the adjacent lowlands was induced by the medieval German construction of watermills and consequent damming. The Potsdam area was mainly influenced by the dam built in Brandenburg in 1309, which induced a water-level rise of more than 1 m in the Havel system and a groundwater-level rise in the adjacent flat areas (Kaiser et al., 2017).

From the 17th century the Prussian regency started to design the landscape around Potsdam, characterized by parks and forests for hunting, the intensification of agriculture, development of infrastructure (canals, roads), and the expansion of settlement areas (Viehrig, 2002; Rubin et al., 2008; Lutze, 2014; Lange, 2016). The increasing demand for wood in industry, for building timber, and for firewood in the cities led to an acute shortage of wood in the 18th century. Soils became impoverished in nutrients such that they only allowed for the cultivation of pine trees. Efforts for reforestation increased in the late 19th and early 20th centuries and in particular after World War II, leading to the widespread presence of pine forests in Brandenburg (MLUL, 2015).

Today, a variety of landscapes, geomorphology, soils, and hydrology are reflected in different forms of land use (Brande et al., 1999; Knothe, 1995; Lutze, 2014). Agriculture and fruit growing mainly take place on the plates with their glacial tills and sands that are covered by brown earth and para-brown earth soils with leak waters. The steep terminal moraines, outwash plains, and dune fields are mostly covered by forests; exposed southern slopes are partly covered with vineyards.

The valleys with groundwater fluctuations are used for agriculture or are covered by green land. Parks in and around Potsdam are often located on river terraces with sandy substrate underneath. The Beelitz Sander represents a famous environment for the cultivation of asparagus. The use of raw materials from natural substrates, such as peat, clay, and sand, play a role today and have done in the past.

In addition to raw materials, other resources relate to water management and the utilization of geothermal energy. Infiltration water of the Havel River including especially water from the second groundwater level located beneath an impermeable layer provides a rate of 8000 to 10 000 m³ of potable water per day in each of the five waterworks, sufficient for the whole Potsdam community (180 000 inhabitants). The use of near-surface groundwater is influenced by saltwater brine, which is often bound to Elsterian glacial erosion zones as deep valleys (e.g. Nillert et al., 2008). Thermal influx from depth is already used for numerous geothermal heat pumps installed for the heating of single-family houses. Complex geothermal probe fields are being implemented or planned, which will also meet higher performance requirements.

No data sets were used in this article.

Under the coordination of BD as corresponding and leading author, WS, RW, MB, UR, BB, and AB have contributed text and their expertise on regional geology to the article. Contributions to illustrations are specified in the captions of the figures.

The contact author has declared that none of the authors has any competing interests

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