Saalian Research Articles

Mazovian Interglacial sites in the Sosnowica Depression and the Parczew-Kodeń Heights (Western Polesie, SE Poland), and their stratigraphic, palaeogeographic and palaeoenvironmental significance

We describe the geological context of the Pleistocene strata in the Sosnowica Depression and the Parczew-Kodeń Heights, as well as the main geological processes taking place in that area during the Middle Pleistocene. The stratigraphy of the Pleistocene succession is based on the analysis of new sites with Mazovian Interglacial deposits (MIS 11c) with age determinations obtained from palaeobotanical and palaeofaunal proxies, at Zahajki, Wygnanka, and Sytyta in the Sosnowica Depression, and Podedwórze and Gęś 3 in the Parczew-Kodeń Heights. The interglacial deposits documented occur in the direct subsurface and are not overlain by glacial deposits, which indicates that the study area was not covered by the ice-sheet of the Middle Polish Glaciations (Saalian, MIS 6). They are overlain by Early Liviecian (Fuhne, MIS 11b) lacustrine and bog deposits, or upper Vistulian (MIS 2) clastic and bog deposits. Holocene strata lie above. Therefore, the glacial deposits building the Parczew-Kodeń Heights are considered to derive from the Sanian 2 (Elsterian, MIS 12) Glaciation and not from the Saalian (MIS 6) Glaciation as previously thought. Palaeolakes formed in the late part of the Sanian 2 (Elsterian, MIS 12) Glaciation and remained open during the Mazovian Interglacial (Holsteinian, MIS 11c), with some still existing until the Early Liviecian (Fuhne, MIS 11b) Glaciation. The palaeolakes described were part of an extensive palaeolakeland of the Mazovian Interglacial, stretching from the southern part of Podlasie to the northern part of Western Polesie. The last ice-sheet in Western Polesie represented the Sanian 2 Glaciation. Downloads pdf Published 2024-07-20 — Updated on 2024-07-23 Issue Vol. 68 No. 2 (2024) Section Articles License Authors who publish with this journal agree to the following terms: Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal. Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal. Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as this can lead to productive exchanges and earlier and more frequent citation of the published work (See The Effect of Open Access).

The Pleistocene ice-sheet dynamics in north-central Poland based on magnetic fabrics of tills and landform analysis

Abstract This research was carried out in north-central Poland, which was occupied by the ice sheet of the Saalian (Marine Isotope Stage [MIS] 6) and Upper Stadial of the Weichselian (MIS 2) glaciation. The application of the anisotropy of magnetic susceptibility (AMS) method supported by a digital elevation model (DEM) analysis of the orientation of glacial landforms allowed for the reconstruction of ice-sheet extent and ice movement directions of these two Pleistocene glaciations. The research used an innovative method of collecting AMS till samples from the glacial plateau areas. Based on the research, it was found that during the general recession of the ice sheet of the Saalian glaciation, a previously undescribed glacial transgression occurred, characterized by a different direction of ice-sheet movement. On the basis of detailed geomorphological studies of the area of terminal moraines, previously described in fragments, the maximum extent of the ice sheet during the Weichselian glaciation was clarified. The recession of the ice sheet of the Weichselian glaciation from the area of north-central Poland took place in four regressive or transgressive–regressive stages with variable directions of ice-sheet movement. The results obtained indicate the great potential of the AMS method in paleoenvironmental studies of glaciated areas.

Ventifacts and wind deflation surfaces in context with glaciofluvial sediment successions in southern Sweden – Their age and implication for glacial history

Recent suggestions propose that the glacial landscape in southern Sweden is primarily a relict from the Saalian glaciation (>130 ka). The arguments for this standpoint are the assertion that the majority of glaciofluvial deposits in this region are till-covered, and that wind-abraded clasts are observed at the contact between glaciofluvial sediments and till at numerous locations. Furthermore, it has been posited that this wind abrasion occurred during periglacial conditions during the Early Weichselian, preceding the Last Glacial Maximum (LGM). If this hypothesis holds true, it would necessitate a significant shift in our understanding of the Quaternary geological history for this region. To test this claim, we conducted an extensive examination of the purported stratigraphic conditions within 54 gravel pits situated south of the Middle Swedish End Moraine Zone (MSEMZ). The presence of a covering till bed on top of glaciofluvial sediments could only be confirmed in 22% of the gravel pits, and these sites were almost exclusively associated with ice-margin standstills/oscillations during the Late Weichselian deglaciation. In all other gravel pits where covering till could not be verified, ventifacts occur in several stratigraphic positions: at the contact between glaciofluvial and overlying littoral sediment, redeposited ventifacts within littoral sediment, and ventifacts at the contact between glaciofluvial or littoral sediments and overlying aeolian sediment. We conducted an extensive luminescence dating program (comprising 74 samples) in 22 of the gravel pits to determine the age of the ventification by dating underlying and overlying sediments. We conclude that wind abrasion across southern Sweden was not a single simultaneous event but rather a time-transgressive or recurrent process. It occurred in close conjunction with local deglaciation in some instances, while in others, it transpired later, extending into the Early Holocene. Notably, none of the encountered ventifact surfaces are of a pre-LGM age. For sites along the west coast, the evidence indicates a first wind abrasion event during periglacial conditions roughly between 17 and 16 ka. In upland sites, ventifact formation either occurred immediately after deglaciation, during the Bølling−Allerød interstadial complex (14.7−12.8 ka), or during the Younger Dryas. Even though the ice margin was situated far to the north of these sites during the latter event, concurrent patterned ground formation suggests a harsh climate with reduced vegetation cover, leading to sand drift and ventifact formation in both coastal and upland areas. In some locations, the sand drift and subsequent aeolian sediment deposition persisted into the Early Holocene. Based on our stratigraphic investigations and dates, we reject the idea that southern Sweden's glacial landscape was shaped primarily during the Saalian.

The relationship between the loess stratigraphy in the Vojvodina region of northern Serbia and the Saalian and Rissian Stage glaciations – a review

The regional loess stratigraphy in the Vojvodina region, in the southeastern Carpathian Basin, has often been successfully correlated to the global palaeoclimate. This is a quasi‐continuous sedimentary record that provides detailed environmental reconstruction during the last four glacial/interglacial cycles. In this study, we present a standardized loess stratigraphy and illustrate how it correlates with the marine oxygen isotope and Chinese loess stratigraphical records. We argue that the loess stratigraphy in Vojvodina region is an important link in the integration of European terrestrial stratigraphical schemes and the deep‐sea stratigraphical model. We highlight how the loess record can better illustrate terrestrial environmental change through multiple glacial cycles than other records, such as glacial records. The investigated loess record enables direct links to be made between the loess sediments and their glacial sources. This reveals evidence of glaciations during every glacial cycle of the Saalian Stage complex, equivalent to Marine Isotope Stage (MIS) 10, 8 and 6. Therefore, Serbian loess has the potential to provide a direct link between terrestrial glaciations and wider records of global climate change, which is an enigma for many other continental records. These loess records display a strong relationship with the intensity of European glaciations during different glacial cycles. Loess sedimentation rates are highest in the most intensive European glaciation of the Saalian complex (MIS 6) and much lower during the weaker ‘missing’ glaciations equivalent to MIS 8 and 10. A key observation from the Vojvodina loess is the gradual increase in interglacial aridity through the late Middle Pleistocene. The explanation for the progressively increasing aridity in the investigated region at this time is still unclear. However, this trend is consistent with the idea of the Saalian complex as representing a 400 ka mega glacial cycle modulated by shorter classic 100 ka glacial cycles.

The Grasshopper Paradigm in damselflies: evidence for phalanx-like postglacial recolonization of Europe from a Balkan refugium in Platycnemis pennipes Pallas (Odonata: Zygoptera: Platycnemidae)

We explore haplotype diversity, phylogeography and phylogenetic relationships of the damselfly Platycnemis pennipes in Europe based on 618 bp DNA from the mitochondrial gene COI. A haplotype network analysis shows that the species is divided into two haplotype groups. One is restricted to the Italian Peninsula, while the other is found from the Black Sea region across eastern and central Europe to Scandinavia, England, and southwestern France. This pattern is recovered in a Bayesian phylogenetic analysis. Genetic distance (K2P) between the two groups is approximately 1.5%, while within-group variation is an order of magnitude lower. An analysis of the molecular variance (AMOVA) shows that variation between the two groups account for more than 96% of the total variation within the dataset, adding to the evidence that they have been isolated for a considerable amount of time. The pattern we find is similar to the so-called Grasshopper Paradigm in European phylogeography, where a species has recolonized Europe after the last glaciation from a glacial refugium in the southeast, while other refugial populations in the Iberian and Italian peninsulas have remained isolated to this day. In P. pennipes there is only an isolated refugial population in Italy as the species does not have current populations in the Iberian Peninsula. By comparing the genetic distance between the two groups to a previously published divergence time analysis of European Odonata we estimate that they have likely been isolated since the onset of the Saale Glaciation ca 400 ky ago.

Penultimate interglacial palynology of Flanders: A revised river evolution model

There are no Saalian Stage pollen records in Northwest Europe that not only cover an entire interglacial complex but also have been successfully correlated down to marine isotope substage level. The presented pollen record fills this knowledge gap. Three pollen sequences, sampled from a well-preserved Saalian Stage river terrace near Brussels (Belgium), together span most of an interglacial complex: two interglacial cycles and one interstadial separated by colder intervals. To date the pollen data, the authors present a multi-proxy supported river evolution model through which the correlation of the pollen record with the penultimate interglacial complex (Marine Isotope Stage (MIS) 7) becomes apparent. The authors further illustrate homotaxis—defined as the similarity between pollen diagrams that are not necessarily contemporaneous—by comparing MIS 7 with MIS 5 pollen data from the same area, convincingly curve-match the pollen record with marine isotope data, and point to similarities between Southern and Northwest European vegetation dynamics and climate variability during MIS 7.

An examination of the glaciomarginal fan of the Odranian glaciation at the Mokrzeszów site, Sudetic Foreland, SW Poland

The article presents the results of research from the Mokrzeszów site in the Sudetic Foreland. Lithopetrographic and sedimentological analyses of sediments from the Middle Polish Glaciations (Early Saalian, Odranian, MIS6) in this area indicate the overrepresentation (90–95%) of large Scandinavian erratics. The deposits, representing a repetitive sequence of Gp-Gms-Sp-Sh/Sr(Dmm) lithofacies, accumulated during at least two episodes of glacial outburst floods and six sedimentary cycles. High-energy flows are estimated for the Gms and Gp facies at about 5 m∙s−1 and low-energy flows indicate 0.8 m∙s−1 for the Sp/Sh/Sr facies, to the lack of flow (Fm). The sedimentary sequences confirm the existence of a fan, which may have originated as a subaqueous steep coarse-grained fan in glacial-flow-lake-outburst floods that formed between the ice sheet front and the morphotectonic edge of the Sudetic Marginal Fault line and within the Roztoka-Mokrzeszów Graben, or as an aerial, piedmont fan on the Sudetic Marginal Fault edge. The sediments show discontinuous deformations – gently sloping faults and fractures from glacioisostatic stresses. The fault activity is probably related to the reactivation of the faults due to ice loading during or after the older Saalian glaciation.

The near-surface structure in the area of the Børglum fault, Sorgenfrei-Tornquist Zone, northern Denmark: Implications for fault kinematics, timing of fault activity and fault control on tunnel valley formation

Previous studies showed evidence that the Sorgenfrei-Tornquist Zone (STZ) in northern Denmark is seismically active and fuelled the demand for further analyses of the fault structure and its seismic hazard potential. We focus on the area of the Børglum fault, which represents the northern boundary fault of the STZ and extends at least 250 km from the western Baltic Sea across Jutland into the southeastern North Sea. The Børglum fault has previously been interpreted to represent a glacially-triggered fault. Two shear-wave reflection seismic sections were acquired to image the near-surface structure in the vicinity of the Børglum fault. Detailed insights into the acquisition, processing and interpretation of the seismic sections will be provided. The seismic sections indicate that the Børglum fault in the study area is not an isolated fault, but most likely represents a complex fault system with a strike-slip component. The fault interpretation is based on systematic vertical reflector offsets, the observation of steeply dipping thin transparent zones that separate the offset reflectors, abrupt lateral changes in the reflector pattern and in some cases, the presence of a fault shadow (a diffuse zone on a seismic section below a fault). This interpretation is mainly based on the identification of positive flower structures on the seismic sections, and supported by the presence of elongated sedimentary mini-basins and topographic depressions in the study area, which are partly interpreted to represent strike-slip basins. A WNW-ESE striking tunnel-valley system is imaged on the seismic sections. The spatial relationship between the faults and the tunnel valley suggests a fault-control on tunnel-valley system formation in this area. The seismic sections indicate that faults in the study area were probably active at the end of the Saalian glaciation (MIS 6). In addition, soft-sediment deformation structures and shear-deformation bands developed in Late Pleniglacial to Lateglacial sediments point to repeated phases of fault activity. The reflector pattern on one of the seismic sections indicates that a major fault nearly reaches the Earth's surface. A step in the topography above the fault probably represents a fault-scarp. Because the ongoing glacial-isostatic adjustment will lead to a change in the stress magnitude in this area, future movements along the faults are possible.

Landform mapping used to identify glaciations in the multi-glaciated landscape of Yorkshire, U.K

Landform mapping, coupled with luminescence dating, has confirmed two glaciations in the Vale of Pickering in northern England: a Late Devensian (MIS 2) glaciation and a Drenthe stage late Saalian (MIS 6) glaciation. In addition, mapping of strandlines around the margins of proglacial Lake Humber has suggested a parallel evolution for the Vales of York and Pickering with synchronous flooding in both regions during the Late Devensian. This mapping also confirms a lack of recognisable glacioisostatic rebound post-MIS 2, while a review of the literature indicates the spacing regularity of the strandlines, recorded during the drainage of Lake Humber, can be attributed to cyclical climate changes. In contrast, the penultimate glaciation that is represented by a North Sea glacial incursion into the Vale if Pickering as far as the Wykeham Moraine, records post-glacial rebound of up to 30m. It is also probable that a proglacial lake, which has been given a tentative late MIS 7 date, impounded in the Vale of York could be indicative of an MIS 8 or early Saalian glacial blockage of the Humber.

Sedimentary and structural record of the Scandinavian Ice Sheet margin dynamics at the SE part of the Głubczyce Plateau, a foreland of the East Sudetes Mountains (S Poland)

A sedimentological and structural study is presented of a push-moraine formed in front of the Scandinavian Ice Sheet margin on the Głubczyce Plateau located at the forefield of East Sudetes Mountains. The glacial succession, which is composed of basal and flow tills, and sand/gravelly-sand deposited mainly from sheet flows at the surface of the glacier's marginal fan, developed in the culmination zone of an inter-valley hill, the base of which constitutes tectonic horst built of Carboniferous sandstones. In the central part of the hill, glacial deposits form a set of up-thrust slices, on the basis of which the succession is interpreted as thrust-block moraine. It was formed most likely during the maximum extent of the Saalian (Drenthe) glaciation. The substratum's topography and geology strongly determined the moraine development. Resistant Palaeozoic bedrock formed a rigid surface along which overlying unconsolidated sediments were pushed in front of the advancing ice sheet margin. The diamicton, lying above the bedrock and beneath the glaciofluvial sand, was of key importance for glaciotectonic shortening and development of the push moraine. It underwent ductile shearing, and a décollement surface developed within it, possibly because of thin permafrost, which caused high pore-water pressure within underlying unfrozen diamicton during the ice sheet advance. The ice-marginal deformation was induced by compression forces developed within the ice sheet margin moving against a reversed bedrock slope. A complete understanding of the process of this glaciomarginal form development and its paleoclimatic meaning requires a three-dimensional analysis of the ice sheet behaviour during the time over a much larger area also outside the Głubczyce Plateau. The varied topography of the ice sheet substratum induced time-transgressive changes of the ice distribution within the marginal part of the ice sheet. High friction in some elevated areas resulted in progressive concentration of ice flow in lower lying areas, such as valleys, where friction was much lower. This phenomenon essentially influenced the ice sheet margin dynamics and thus could determine the distribution and scale of glaciotectonic deformations.

Soil-development differentiation across a glacial–interglacial cycle, Saalian upland, E Poland

Three soil profiles at the Koczery site (E Poland), studied through soil and sediment evaluation, reveal a polygenetic development of soils in areas unglaciated during the Weichselian glaciation (MIS 2) period. Pedogenesis had developed on glacial till (till) in period from the Saalian glaciation (MIS 6) to the Holocene (MIS 1). Wide-spectrum analyses demonstrate that the profiles represent a Planosol. Four stages (I–IV) of soil formation were distinguished in the study area. Stage I, comprising of a nutrient- and element-rich material, correlates to the accumulation of Saalian glacial till (MIS 6). Stage II, that took place during the Eemian Interglacial (MIS 5e), corresponds to the initial development of Cambisol as a result of carbonate leaching process. This was followed by the development of a Luvisol through the processes of illuviation of clay minerals and iron components. Stage III bears evidence of intensive frost weathering processes along with a development of sand-wedge cast that occurred under permafrost conditions of Weichselian glaciation (MIS 2). Further, the formation of an aeolian pavement along with erosion and removal of upper portions of the Eemian soil took place. An accumulation of coeval-age coversand led to a restart of the pedological clock, which resulted in the development of cryogenically-altered soils. Stage IV ushered the Holocene (MIS 1) delivering a progressive development of pedogenesis together with plant-succession modifications under temperate-climate conditions. Brunic or luvic horizons are formed within the coversand deposits. Pseudogleyic conditions developed along the lithological discontinuities. Of note, sand-wedge casts (SWCs) occupy specific locations in the profiles that provide the vertical migration of water, base components and iron. Reducing conditions that occurred along the bottom of ice-wedge casts favour the formation of gleyic horizon. SWCs that have been ultimately modified into ice-wedge and acted as sand-wedge-affiliated geochemical corridors (SWGC) for shallow groundwater forming natural tile drains.

Sediment sequence at Muhos, western Finland – a window to the Pleistocene history of the Scandinavian Ice Sheet

In this study, we analysed a ~54‐m sediment core consisting of Quaternary sediments overlying the Neoproterozoic Muhos Formation in central western Finland, adjacent to the Gulf of Bothnia. The sediments recovered were logged, and their sedimentological characteristics defined. Two fine‐grained sediment units were subjected to biostratigraphical studies using pollen and diatom analyses. In addition, two sand‐rich units and a wooden stick were dated by the optically stimulated luminescence (OSL) and 14C‐AMS methods. The core sediments were divided into six units, where several diamicton, sand and gravel, and silt‐and‐clay‐dominated beds were studied. The results indicate that the sediment succession of the core beneath the Holocene Litorina Sea and the Ancylus Lake sediments of the Baltic Basin were deposited in glacial and lacustrine environments that existed in the Oulu River valley during the time period between the Saalian glaciation (MIS 6) and the Holocene. The stratigraphical evidence, supported by the OSL ages, suggests that the Scandinavian Ice Sheet (SIS) entered the Muhos area during the Saalian glaciation, and at least during three separate time intervals in the Weichselian stage. Stratigraphically controlled and age‐bracketed evidence shows that the first Weichselian SIS advance extended further south in the eastern part of Fennoscandia than previously estimated, and that this ice growth phase occurred during the Early Weichselian Herning Stadial (MIS 5d). The subsequent ice growth phases occurred during the Middle (MIS 4) and Late (MIS 2) Weichselian substages. The lacustrine and littoral sediments of the Muhos core were correlated with the late Eemian interglacial (MIS 5e) and two Weichselian interstadials (MIS 5c and MIS 3).

A melting pot in the Arctic: Analysis of mitogenome variation in Arctic char (Salvelinus alpinus) reveals a 1000‐km contact zone between highly divergent lineages

AbstractAnalysing the geographical distribution of evolutionary linages can reveal the potential locations of past refugia and colonisation routes and thus can improve understanding of current patterns of genetic variation and adaptive potential. We analysed 94 full mitogenome sequences to assess phylogeographic relationships amongst ten Arctic char (Salvelinus alpinus) populations, from western Greenland, eastern Greenland, Iceland and Norway. In addition, we excised D‐loop sequences, which were combined with previously published data in order to provide a circumpolar phylogeographical overview. In western Greenland, a secondary contact zone between Arctic and Atlantic evolutionary lineages was identified, spanning >1000 km, which geographically parallels a similar contact zone in Labrador, Canada. In eastern Greenland, Iceland and Norway, the Atlantic lineage was exclusively observed, whereas the northernmost western Greenland populations belonged to the Arctic lineage. The Arctic and Atlantic lineages were estimated to have diverged ca. 400,000 years BP, corresponding to the onset of the Saale glaciation, whereas the time of the most recent common ancestor (TMRCA) of the Arctic lineage was ca. 15,000 years BP. The Atlantic lineage comprised two subclades, with an estimated TMRCA of 60,000 BP, suggesting a complex history involving cryptic refugia or multiple recolonisations. Codon‐based tests revealed no evidence for positive selection within the 13 coding genes, indicating that there are no mitochondrial genetic adaptations within or between lineages. Higher genetic diversity observed within the contact zone likely correlates with higher standing genetic variation that could contribute to adaptive responses and morphological diversification, which Arctic char is renowned.

Repetitive Late Pleistocene soft‐sediment deformation by seismicity‐induced liquefaction in north‐western Lithuania

AbstractLiquefaction can cause deformation of unconsolidated sediment, but specific processes involved and the trigger mechanisms often remain obscured. This study describes multiple deformed sediment layers in a succession of lacustrine sand, silt and clay deposited during the Marine Isotope Stage 5d in north‐western Lithuania. The deformation structures (load casts, pseudonodules, ball‐and‐pillow structures, broken‐up laminae and injections) are embedded in ten separate layers of fine‐grained, laterally continuous sediments. Detailed mesoscale sedimentological analyses suggest that each deformation event consisted of numerous successive stages of sediment advection facilitated by liquefaction. Low‐permeability fine‐grained laminae contributed to localized pore‐water pressure build‐up and lowering of sediment strength. Erosional top surfaces that truncate layers with soft‐sediment deformation structures suggest that at least seven deformation events were separated by successive periods of initial erosion and then uninterrupted deposition in the lake. The most likely trigger of the deformation was recurrent palaeoseismic activity possibly linked to a late glacial isostatic adjustment following the Scandinavian Ice Sheet melting after the Saalian glaciation. This study emphasizes the potential role of seismic processes in shaping the sedimentary record of the intraplate region of north‐eastern Europe and contributes to constraining the depth of liquefaction, regardless of the actual trigger mechanism.

Reconstruction of the geological history of the Lithuanian Maritime Region from MIS 6 to MIS 3

The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called Lithuanian Maritime Region (LMR) – a belt several tens of kilometres wide along the Baltic Sea coast – is characterised by a complicated Quaternary structure and many of unsolved problems related to stratigraphy and palaeogeography. The inter-till lacustrine sediments widespread in the middle part of the Pleistocene thickness play a key role in solving the mentioned problems. The primary inter-till sediments were attributed, as a single lithostratigraphic unit, to the late Saalian Glaciation (MIS 6, Pamarys Sub-Formation; according to the Lithuanian Quaternary Stratigraphic Scheme). Subsequent detailed investigations show that the investigated inter-till succession represents a more complicated sediment complex formed over a wide time interval from the Saalian ice sheet decay at the very end of MIS 6 to the beginning of severe climate cooling during MIS 4. This standpoint is confirmed by the results of a few series of OSL and IR-OSL datings of inter-till sediments, as well as by data of pollen and diatom analysis. The more detailed stratigraphic subdivision of the inter-till sedimentary complex offers a new significant insight into the regional stratigraphic scheme of the Quaternary. As a result of the mentioned investigations, a new original reconstruction of the palaeogeographic situation in the LMR during the MIS 6 – MIS 3 time span was carried out. The lowermost part of the investigated inter-till sediments, attributed to MIS 6, could be correlated with the third MIS 6 warming in Northern Eurasia about 155 ka ago. The reconstruction of the palaeoenvironmental changes starting from MIS 6 and lasting to MIS 3 shows that the Eemian Sea MIS 5e in age was absent in the LMR, while part of the south-eastern Baltic Sea region was covered by a continental ice sheet during MIS 4 and, possibly, the very beginning of MIS 3.

Possible new evidence for Mid-Pleistocene glaciation in the Vale of Pickering, North Yorkshire, UK

Whilst the Late Devensian glaciation (MIS2) of the Vale of Pickering is well-documented, earlier glaciations within it are not. A proposed limited glaciation in the Mid-Pleistocene, thought to be of Marine Isotope Stage 8 (MIS) age is not well constrained. This paper aims to obtain preliminary ages for two of the most prominent geomorphic features in the Vale of Pickering to see if they related to pre-Devensian glaciations. New luminescence dating by infra-red stimulation of feldspars from sand accumulations near the summit of Gallows Hill, part of the Wykeham Moraine, and from a section through poorly sorted fluvial sand and gravel on the flanks of the Hutton Buscel Terrace in Yedman Dale gave ages of 176 ± 14 ka and 156 ± 12 ka, respectively. Evidence suggests they represent a glacial incursion (MIS 6) into the Vale of Pickering blocking its eastern end and forming a pre-Devensian Glacial Lake Pickering. Whilst they could be older, this style of glaciation is very different to the limited plateau ice-field proposed for MIS 8 at the western end of the Vale of Pickering. Taken at face value, these preliminary ages suggest that the Vale of Pickering was partially glaciated in MIS 6 as part of a wider ice sheet and contemporary with the Saalian glaciation in Europe.

Morphology, function, petrography and provenance of ground stone tool assemblage from Niemczańska, Poland in the light of late Bronze Age lithic production in the Odra basin

This paper presents results of morphological and petrological analyses of ground stone tool assemblage acquired from late Bronze Age settlement site at Niemczańska, Wrocław, Poland. The collection of six tools is functionally and petrologically diverse but comparable in terms of physical and mechanical properties, i.e. hardness and wear resistance. Exclusively hard and quartz-rich rocks were selected for tools production (granites, gneisses and sandstones). We applied complementary approaches: polarizing optical microscopy with modal mineralogical analyses, scanning electron microscopy and electron probe microanalyser for the petrographic and raw material provenance study. The results of our observations lead to the conclusion that raw material was collected locally from the surface deposits associated with glacial erratics brought to the area during MIS-16 to Saalian glaciations from Sweden and Åland Islands. Our observations confirm that erratics were a common source of raw material for the Odra Basin populations during the Bronze Age instead of autochthonic Sudetic or allogenic materials. Agricultural (grinder and grinding disc) and non-agricultural (whetstone, pad/fragment of a grinding disc, grinder and smoother) functions are recognised, based on morphological observations and use-wear traces. Three activity zones are distinguished at the site – production, habitation and possible cult zone with lithic tools spread within production and habitation zones.

An exceptionally preserved conulariid from Ordovician erratics of Northern European Lowlands

A conulariid preserved in three dimensions from Ordovician fluvioglacial erratics of the Northern European Lowlands (North German Plain) is described under open nomenclature. It is assigned to the genus Conularia with similarities to Baltoscandian conulariids. The lithology of the erratic boulder and fauna contained in it provide important information on the origin and transport direction of the sediment preserved in a kame from the Saalian glaciation. This paper deals with the site of origin of the boulder in Baltoscandia analysing the comprised palaeofauna, from a palaeostratigraphic and palaeogeographic point of view, from its deposition in Ordovician times until its arrival at its current location in the Late Pleistocene. It also reveals for the first time the internal structure of the conulariid aperture.

Morphometric indicators of insular and marginal morainic uplands (based on LiDAR data) of the Last and pre-Last Glaciations, case of Lithuania

The LiDAR-based digital elevation models of representative sample areas of morainic uplands of the Last (Weichselian) and pre-Last (Saalian) Glaciations in Lithuania were selected, and the terrain ruggedness index (TRI) and slope angles (SAs) were calculated. Former hypsometric studies of the topography in Lithuania were mainly dealing with the indication of maximum, minimum or average altitudes of relief derived from topographical maps. The SAs and TRI were calculated for the pattern areas (16 × 16 km) and their central smaller parts (5 × 5 km). In order to test how much morphometric parameters are dependent on the size of a sample area, smaller areas (located in the central parts of all five patterns) were analysed in a similar way, calculating SA and TRI values. The same order of the mean values of SAs was determined: the steepest slopes are characteristic of the Tauragnai, Plateliai and Vištytis patterns, and the gentlest slopes of the Varniai and Medininkai patterns. The steepest slopes and the highest TRI were determined for the marginal morainic uplands of the Last (Late Weichselian) Glaciation. The age of the insular Žemaičiai (Samogitian) Upland is under discussions so far. It was proposed by other researchers earlier that the core of the insular Žemaičiai Upland height formed during the Saalian Glaciation and this core is covered by a thin cover of Weichselian deposits. The morphometric parameters display that the highest maturity of the relief is characteristic of the southern slope of the insular Žemaičiai Upland and the Medininkai Upland of the Saalian age. This indicates a likely similar age of both uplands.

Differentiation of subglacial conditions on soft and hard bed settings and implications for ice sheet dynamics: a case study from north-central Poland

We reconstruct patterns of subglacial processes on a hard bedrock and a soft bed under the southern sector of Scandinavian Ice Sheet (SIS) occurring in the basal till of the Late Saalian Glaciation at the Wapienno, Barcin and Młodocin sites (north-central Poland). Based on detailed sedimentological studies, two phases of SIS transgression were recognised. In the initial phase of the transgression, the SIS advanced onto a frozen substrate (continuous permafrost). The low permeability of the substratum led to a high subglacial water pressure (SWP) and increased basal sliding. The local increase of SWP led to the development of different types of structures and sediments. On a hard bedrock, with low SWP, abrasion predominated and linear structures were developing, while in the case of high SWP, the ice was decoupled from the hard substrate, pressurised liquefied sediment flowed, and structures of the p-form and s-form type developed. On a soft bed, the ice-bed contact was of a mosaic type and the ice movement had an ice-stream character. The ice-stream developed towards the east in the marginal zone of the SIS and used a W-E oriented valley filled by the Wapienno Formation fluvial complex. During a later phase, the ice movement was slower and did not have a stream character. Its direction changed to SE. The deposition of the main part of the diamicton occurred mainly as a result of the lodgement process.