Towards a revised model of Late Quaternary mountain glaciation in the Krkonoše Mountains, Czech Republic

Abstract

Reconstructing the nature of Quaternary mountain glaciation of the Krkonoše region is critical to improving our understanding of former regional climate systems in the region between the Scandinavian and Alpine ice sheets. Geomorphological, sedimentological and micromorpho-logical data is presented from sites in the Úpa Valley to derive a new model of mid-Late Qua-ternary glaciation of the Krkonoše mountains. A combination of Schmidt-hammer and 10Be dating is used to infer a Late Weichselian age to preserved moraine systems in the upper valley, whilst sedimentological and micromorphological analysis implies two earlier glaciations, with the earlier (Saalian ?) extending beyond the mountain front. �e implications of these find-ings are discussed, with reference to the possible factors driving glaciation of the Krkonoše, and suggestions are made for further analysis to validate the model and to provide links with the broader European stratigraphic record.

key words: Quaternary glaciation, the Krkonoše mountains

1. Introduction

Quaternary mountain glaciation of the Krkonoše (Giant) mountains of the Czech Republic / Polish borders has been recognised since the early work of Partsch (1878). !e location of these mountains as part of Bohemian Massif is highly significant, as they lie in the corridor unaffected by continental Scandinavian ice sheets or the Al-pine ice-field during the Quaternary. As such, locations such as the Krkonoše moun-tains may preserve a unique record of glaciation, and provide significant information regarding atmospheric circulation within this part of central Europe during the Quaternary (cf. Florineth, Schluchter 2000). Such data are essential for understand-ing climatic forcing of glaciation in these regions, and identifying whether the Last Glacial Maximum (LGM) in the Krkonoše was synchronous with that of the large continental ice sheets or not, as found in other regions (Gillespie, Molnar 1995).

!ere have been a number of geomorphological investigations of the Krkonoše mountains, identifying erosional and depositional landforms suggested to reflect a number of glacial episodes (Sekyra 1964, Šebesta, Treml 1976, Traczyk 1989), but

Towards a revised model of Quaternary mountain glaciation in the Krkonoše Mountains, Czech Republic

simon carr, zbyněk engel, jan kalvoda, adrian parker

254 simon carr — zbyněk engel — jan kalvoda — adrian parker

almost no litho- or biostratigraphic evidence has been reported from this region. Re-cent geomorphological and sedimentological investigations in the Úpa Valley (Carr et al. 2002) suggest that the number and likely extent of Quaternary glaciations is more extensive than previously considered. Unlike many glaciated upland areas of northern and western Europe almost no studies have been conducted coupling glacial sedimentological work with paleoecological studies in the Krkonoše region. Although pollen stratigraphic work has a long tradition in the Czech Republic (see Rybníčková, Rybníček 1996), most studies comprise only Holocene sequences. A number dated sequences exist in the Krkonoše region (Hütteman, Bortenschlager 1987, Speranza et al. 2000, Jankovská 2001, Svobodová 2002) but these are typi-cally of mid to late Holocene age. Radiocarbon dated sequences of early Holocene exist only at Łomnica and Labe valleys (Engel et al. 2004). Sedimentation at these sites started during the Lateglacial period probably, however, this hypothesis has not been confirmed by numerical-age dating until now. !erefore, it is currently dif-ficult to establish the stratigraphy, timing and nature of Quaternary glaciation in the region. !is paper presents the initial findings of a project investigating the Lategla-cial of the Krkonoše mountains, coupling geomorphological sedimentological and micromorphological analysis of a number of sites in the Úpa Valley.

2. Study area

!e area under investigation is the upper Úpa (Obří důl) valley in the eastern Krkonoše mountains, extending south-eastwards from Sněžka (1,602 m), to the town of Trutnov (Fig. 1). !e Krkonoše mountains are made up of two contrasting lithologies, with the north of the range consisting of Middle Carboniferous granites, whilst the southern part of the range consists mainly of Proterozoic mica schists, gneiss and phyllites, and Silurian schists, shales, limestones and phyllites. To the south of the mountain front, in the Trutnov area, the bedrock consists of Permian and Upper Carboniferous sandstones and conglomerates.

Within this region, a number of sites have been investigated (Fig. 2). A well-documented series of moraines have been identified in the upper Úpa Valley and the tributary valley of Zelený důl (Partsch 1894, Šebesta, Treml 1976). Natural sedi-ment exposures were investigated at a number of localities along the Úpa river, as well as some temporary sections in Pec pod Sněžkou and Svoboda nad Úpou.

3. Age of the Úpa Valley moraines

Previous investigations of the glacial history of the Krkonoše mountains have focused almost exclusively on the arcuate moraine systems located high in the valleys of the Krkonoše. A total of 11 cirques and valley heads have been identified as containing belts of moraines thought to reflect Quaternary glaciation (Engel 1997). In the Úpa valley, preserved moraines have been attributed to Riss and Würmian glaciations

255towards a revised model of quaternary mountain glaciation

respectively (Partsch 1894). !e lowermost (and consequently oldest) moraines ex-tend down to 820 m a.s.l., just above Pec pod Sněžkou. One of the key implications of the traditional model is that if valid, there should be a significant difference in weathering characteristics of boulders exposed on the surface of the three moraine belts, preserved in the Obří důl.

¹⁰Be exposure dating of glacially abraded bedrock surfaces in the upper part of the Obří důl (Fig. 3) has been presented by Mercier et al. (2002) and subsequently revised on the basis of new ¹⁰Be production data (Kubik, Ivy-Ochs 2004) by Braucher et al. (2006). Although the ¹⁰Be sites are all located well within the inner-most moraines, these show that the earliest exposure of bedrock within the upper cirque of Obří důl occurred at around 12.45 ¹⁰Be kaBP (Fig. 4). However, this data provides little evidence that may be used to infer the ages of the moraines lower down the valley.

Schmidt-hammer assays have been commonly used to provide relative age esti-mates for geomorphological features in glacial forelands, typically for landscapes thought to date from the Little Ice Age (Evans et al. 1999). However, Schmidt-hammer assays have also been successfully used to discriminate between weathered surfaces of much greater age, principally to separate surfaces exposed since the LGM from those covered by Younger Dryas glaciation (Anderson et al. 1998). On each of the preserved moraines in the Obří důl, 150 Schmidt-hammer assays were undertaken on embedded granite boulders, to record average rebound (r-) values to provide a relative index of surface hardness, considered to be a proxy for degree of surface

Fig. 1 The cirque of the Obří důl valley and the Sněžka mount (Photo M. Křížek).


weathering. In addition, 75 assays were undertaken at ¹⁰Be sampling site G08, on the abraded surface of the stoss-and-lee granite bedrock form at the site, to provide an analogue site by which surface weathering could be tested against a radiometric age. Mean r-values and standard deviation data is presented in Fig. 4.

!e Schmidt-hammer data presented in Fig. 4 demonstrates that there is no signif-icant difference in the degree of weathering between the preserved moraine belts in Obří důl. !is may be explained by suggesting that the moraines are so old that the

Fig. 2 Overview topography of the Úpa Valley, showing the location of the study sites.


relative differences in weathering are too slight to be identified by this technique. However, the data from the sample location for ¹⁰Be dating at G08 would appear to reject this idea. !e mean r-value for G08 is only slightly higher than the moraine samples, and well within standard deviations of the whole dataset. !is suggests that the moraines are close to the same age (or perhaps slightly older) as the exposed rock surface at G08, implying a Weichselian Lateglacial age to all moraine systems.

On this basis, it can be suggested with some confidence that the preserved mo-raine belts identified in the Úpa valley reflect a single phase of glaciation, terminating around 12.5 ¹⁰Be kaBP. !is finding is echoed by Engel et al. (2004) who find evi-dence only for Late Weichselian to early Holocene deglaciation from the nearby Labe valley. !e only evidence for earlier glacial episode within the upper Úpa valley was suggested by Sekyra (1964) who described allochthonous granite boulders 50 to 100 m above confluence of Úpa and Zelený potok rivers as erratic material. As a conse-quence, a fundamental re-investigation of the Quaternary stratigraphy of this region is timely, especially with a view to identifying pre-Late Weichselian glaciation.

4. Evidence for extensive glaciation of the middle Úpa Valley

Previous investigation of the middle and lower reaches of the Úpa valley has focused mainly on the identification and survey of the stacked terrace sequence of the Úpa, and how it relates to the Labe (Elbe) system (Balatka, Sládek 1962, Kunský 1966).

Fig. 3 The trough of the Obří důl valley (Photo Z. Engel).


!is has resulted in a broad chronology of Quaternary incision and terrace forma-tion that allows limited correlation with the German and Scandinavian Quaternary stratigraphy. !ese terraces can be traced up to Mladé Buky (Král 1949), above which the Úpa valley narrows, and no terrace remnants are identified, resulting in a major problem relating the geomorphological record of the upper Úpa with the broader Quaternary terrace stratigraphy of the middle and lower Úpa. However,

Fig. 4 The head of the Úpa Valley (Obří Důl), with the locations of the three moraine belts, and summary data of 10Be dating (Mercier et al. 2002) and Schmidt-hammer assays on granite.


reconnaissance of the area between Pec pod Sněžkou and Mladé Buky identified a series of natural and artificial exposures containing un-litihified sediments, which have been the focus of subsequent research.

Seven sediment exposures were selected and described, adopting a lithofacies approach to describe the basic sedimentary characteristics of each constituent unit (Figs. 2 and 5). Individual lithofacies were identified on the basis of sediment tex-ture and support, matrix colour, clast form and lithology, clast fabric (a-b ratios of > 1.5 : 1), consolidation, nature of unit contacts and internal structural character-istics (c.f. Evans, Benn 2004). Particle size analysis was carried out by wet sieving of the > 63 micron fractions. Oriented samples of undisturbed sediments have been collected from key localities for preparation of thin sections for micromorphological analysis. Detailed description of sites 1–6 are presented in Carr et al. (2002), and the focus here is therefore on description of a further site at Mladé Buky, and micromor-phological analysis of samples from both sites 6 and 7.

Site 1: Bouda pod Studniční horou:!is section through part of the lowest moraine identifies the till that comprises the lowest preserved moraine belt in Obří důl. A massive, matrix supported diamict underlying a carapace of coarse, poorly-sorted gravels is identified by Carr et al. (2002), and interpreted as a subglacial till and associated glacifluvial outwash. !e till rests directly on local bedrock.

Sites 2, 3, 4, 5: Pec pod Sněžkou – Svoboda nad Úpou:!e matrix supported diamictons identified at sites 2,3 and 4, beyond the lower-most moraines of Obří důl reflects subglacial till deposition of a glacier extending from the cirques of Obří and Zelený důl (Carr et al. 2002). Glacitectonised bedrock at Pec pod Sněžkou is also identified (Fig. 5). Site 5 (Svoboda nad Úpou) preserves a large body of poorly sorted gravels, that comprise the lowermost (most recent) aggradation of the Úpa terrace sequence, which is currently being eroded into by the present river channel. !ese gravels have been interpreted by Carr et al. (2002) as proximal glacifluvial gravels associated with the till at the earlier sites, deposited as bedload in episodic flood-type conditions. !is suggests the ice limit for glacia-tion of the till facies lies between sites 4 and 5.

Sites 6 and 7: Mladé Buky:Two sites, on opposite sides of the valley, provide evidence of a further glaciation of the Úpa valley, during which glaciers extended beyond the mountain front, pos-sibly as a piedmont lobe. Site 6 (Mladé Buky Sports Field) has already been de-scribed by Carr et al. (2002), and only new micromorphological data from this site is presented.

Site 7 is located at the foot of the Mladé Buky ski school (50º 36' 04.4" N, 15° 50' 42.5" E) at an altitude of 475 m a.s.l. !e site is an exposure eroded by the present channel of the Úpa river, and the sediment section, comprising three litho-facies, lies directly upon tectonised local Permo-Carboniferous sandstone shales


(Fig. 6). !e direction of exten-sional tectonic movement recorded in the bedrock is down-valley, characterised by a series of brittle failures aligned in a generally W-E orientation.

Lithofacies 7:1 comprises a mod-erate to over-consolidated clast supported, massive diamicton, with a matrix of red (10YR 4/6) fine sand. !e lithofacies seems to largely comprise comminuted local bedrock, an observation supported by the sheared/interdigitated con-tact between the two units, and numerous ra6s of the underlying sandstone shales incorporated into the diamict. !e upper contact be-tween this and the overlying sedi-ment (LF 7:2) is gradational. LF7:2 is a dark red (2.5YR 4/6) sandy, massive, matrix supported diamic-ton, with relatively low (< 5 % by volume) clast content, and ap-pears to be very similar to LF6:1 at Mladé Buky sports field. !e unit coarsens upwards slightly, associ-ated with a progressive increase in clast content by volume. Clast lithology is a combination of very angular local sandstone shales and sub-angular to sub-rounded gran-ites and gneisses from the upper Úpa valley. Co-variance analysis of clast shape and form (Benn, Bal-lantyne 1994, Benn 2004) based on C40 and RA indices suggests that the clasts within LF7:2 have undergone some abrasion through active transport, although the data is skewed with the granites gener-ally displaying evidence of sig-nificant active transport (low RA values, intermediate C40 values),

Fig. 5 Summary lithofacies descriptions for the 7 sections described from the Úpa valley. Details of sections 1–6 are presented by Carr et al. (2002).


whilst the less far-travelled component has undergone less abrasion and modifica-tion (higher RA and C40 indices). Clast fabric is indecisive, but indicates a preferred down-valley, rather than local slope orientation. At the top of the section, LF7:3 is a clast supported diamicton that displays substantial evidence of human disturbance, probably associated with the hard-core used to provide foundations for the adjacent access road to the ski-school.

Micromorphological analysis of vertical thin sections recovered from LF6:1 (Mladé Buky Sports Field) and LF7:2 (Ski School) is presented in Fig. 7, and fol-lows the procedure outlined by Carr et al. (2003). !e textural characteristics of both samples are very similar, with the medium to fine sand dominating both thin sections. Larger grains (> 0.5 mm diameter) tend to be sub-rounded in shape, whilst smaller grains are more angular and flake-like, implying the edge abrasion of larger grains (Carr et al. 2003), supporting the clast co-variance analysis noted above.

Structural analysis of both thin sections demonstrates that abrasion has been a key process in sediment formation at both sites, with ample evidence of larger sand-stone grains being progressively disaggregated with individual sand grains being lost (Fig. 7b). It is evident that the sediment in both thin sections have undergone deformation, with rotation/turbate features common, sometimes associated with

Fig. 6 Lithofacies description, particle-size, clast form and clast fabric data from Site 7 (Mladé Buky Ski School).


asymmetric pressure shadows where fine grains have been ‘injected’ into the lee of larger grains undergoing rotation (Fig. 7b). !e asymmetric pressure shadows can typically be traced as the end-points of grain lineations, where the long axes of elongate grains are aligned parallel to one another, o6en indicating a shear plane within the sediment. It is apparent that there has been some ‘cannibalisation’ of pre-existing sediments during the production of the two diamicts sampled. In both sam-ples, there are concentrations of iron-rich, birefringent sediments preserved within embayments in larger grains that may be the remnants of a weathered land-surface or soil that has been subsequently been entrained into the diamict. In LF7:2, a small number of so6 sediment intraclasts are observed, consisting of a fine silt/clay which displays a strongly birefringent ‘kinking’ plasmic fabric (Bordonau, van der Meer 1994).

Plasmic fabric development is limited in both samples, possibly partly masked by the large number of highly birefringent mica platelets in both thin sections. However, at higher magnifications (> 40×), a skelsepic plasmic fabric is observed, suggesting that clays are aligned parallel to the surfaces of larger grains. Where grain-packing

Fig. 7 Micromorphological description of samples from the till identified in the vicinity of Mladé Buky. A: Summary description of micromorphological structures indicating deformation in both samples. The presence of a structure is marked with a single dot, with two dots indicating nume-rous examples and three dots suggesting the structure is very common. B: Annotated photomicro-graph of thin section from Mladé Buky sports field (plane polarized light). A range of structures are evidence on the sample, indicating both rotational and planar deformation of the sediment, with some indication of high confining stress during deformation resulting in the abrasion and comminution of sandstone gravel particles.


permits, this has developed into a more lattice-like plasmic fabric (lattisepic), where two distinct domains of oriented clays are observed.

!e data from site 6 (Carr et al. 2002), when combined with the new data re-ported above strongly supports a subglacial origin for sediments found in the vicin-ity of Mladé Buky. Both LF6:1 and LF7:2 comprise a mix of local and far-travelled (up-valley) lithologies, some preserving striations, and with clast form indicative of active transport and abrasion, rather than passive transport. !e structural data ob-tained from micromorphological investigations further supports this interpretation, with sand grains being removed or abraded from larger particles in a sediment body that is undergoing rotational deformation, perhaps with some evidence of planar failure along distinct shear planes. Turbate features, asymmetric pressure shadows and skelsepic/lattisepic plasmic fabric all point to pervasive rotation of the sediment body. !e size and distribution of rotation features would suggest that these have not been produced by slope or debris-flow deposition (Lachniet et al. 2001, Menzies, Zaniweski 2003). During deformation, pre-existing sediments have been incorpo-rated into the sediment, in the form of perhaps a soil horizon, but more significantly some fine-grained sorted sediments. !e small intraclasts observed in LF7:2 are most probably remnants of a small pond-infill which has undergone compressive defor-mation (hence the kinking plasmic fabric) before being brecciated and incorporated into the deforming till body. !is is consistent with compressive proglacial deforma-tion (c.f. Hart et al. 1990) followed by extensional subglacial deformation associated with an advancing glacier.

5. Discussion

5.1 Glacial history of the Krkonoše mountains

As noted above, understanding the timing of glaciation of the Krkonoše mountains has historically been limited to the identification of two generations of moraines, classically associated with Riss and Würm glaciations (Partsch 1894, Sekyra 1964). However, more recent research (Carr et al. 2002, Mercier et al. 2002) and the data presented in the current paper strongly refute this classical model. It is evident from ¹⁰Be dating of exposed rock surfaces, combined with Schmidt-hammer assays of the moraines in the upper Úpa valley that the preserved bands of moraines are most likely all Weichselian in age, and probably record progressive deglaciation subse-quent to the regional LGM.

!e sediments identified from macro-scale and micromorphological analysis as subglacial tills at Mladé Buky are evidence that at least on one occasion during the Quaternary, glaciers extended beyond the main mountain-front of the Krkonoše, possibly forming piedmont glacier lobes. !e glacier producing the till identified at the Mladé Buky Ski School must have been substantial to have been able to cause brittle failure of the underlying bedrock, and to create the comminution till that forms the base of the till body at site 7. Whilst it is difficult to establish lateral limits


to the till identified at Mladé Buky, it would appear that glaciation was regionally significant at this time, with ice extending some 20 km from the head of the Úpa valley.

!e Úpa terrace sequence (Král 1949, Balatka, Sládek 1962) provides some in-dications of the likely age of glaciation in the Mladé Buky area. Carr et al. (2002) tentatively suggest that the till at Mladé Buky forms the eroded face of the second terrace in the valley, and propose that if terrace formation and erosion follows the model of Bridgland (2000), the till at Mladé Buky possibly reflects the penultimate (Saalian: OI Stage 6) glaciation. At present there is no evidence for glaciation prior to this stage, and the much more complete terrace stratigraphy down-valley would imply that mountain glaciation never extended more than a few kilometres beyond Mladé Buky.

5.2 Nature of pre-Late Weichselian glaciation

!e identification of subglacial till at Mladé Buky has implications for the style and controls over pre-Late Weichselian glaciation in the region. To enable a valley glacier to extend approximately 25 km down-valley, a significant depression of equilibrium-line altitude (ELA) would have been required. Research is ongoing to identify plausible climatic scenarios to permit steady state glaciation of the Úpa val-ley to the vicinity of Mladé Buky, but initial results suggest that the ELA of the Úpa glacier would need to be lower than at 900 m a.s.l., a drop of 200 m from probable ELA’s during Late Weichselian glaciation. !is change in ELA reflects mean summer temperatures perhaps 3 °C colder or increased net accumulation at the ELA in the order of 1,000 mm than conditions at the local LGM. As such, this demonstrates the climatic sensitivity of glaciation in the region, whereby relatively small changes in climate may have had a more dramatic effect on glaciation.

Part of this sensitivity arises from the regional scale geomorphology of the Úpa Valley and its tributary systems. !ere are a number of high altitude cirques and tributary valley-heads that could have acted as accumulation basins to feed an ex-tended Úpa valley glacier, notably the Zelený důl and Jelení důl valleys, where there are significant areas above 1,000 m elevation. In addition, adjacent to Obří Důl are significant mountain plateau areas above 1,400 m that could have provided per-manent snowfields or even plateau ice-fields to dramatically increase the potential accumulation area of the glacier (Fig. 8).

!is discussion highlights critical areas for future fieldwork to validate the pro-posed model:

1. Identification and description of glacier evidences in the Malá Úpa valley.2. Examination of weathering/exposure ages of rock surfaces close to Horní

Maršov. !e mountains of Špičák, Stará hora and Červený vrch may provide key evidence of glacier thickness at one or more stages of the Late Quater-nary.

3. Identification of glacigenic sediments in the vicinity of Mladé Buky, to provide more detail of the extent of ice beyond the mountain front.


5.3 Glaciological and climatic considerations for Late Weichselian glaciation

If the glacial history presented above is valid, there are a range of implications for the dynamics of glaciation, and the climatic controls over glaciation during both the Weichselian and previous glaciation. By comparison with the ‘classic’ stratigraphy (Partsch 1894, Sekyra 1964), glacier fluctuations in the Úpa Valley during the Late Quaternary have been significant, with a more dynamic record of glaciation during the Weichselian than previously considered. Rather than restricted glaciation within the upper part of the valley head, it seems that a Weichselian valley glacier extended beyond the lowermost preserved moraines. Subsequent to an as yet undated local glacial maximum, there is a detailed picture emerging of active glacier retreat during the Lateglacial, with at least three substantial still-stands or readvances, prior to the Úpa becoming largely ice-free by 12.45 ¹⁰Be kaBP. It is possible that small niche glaciers and firn fields persisted at the head of Obří důl until the early Holocene, but at present there is no strong evidence to support re-occupation or readvance of glaciers during a possible Younger Dryas event. !ese findings support the conclu-sions made by Engel et al. (2004) for the upper Labe valley.

!e identification of more extensive and dynamic glaciation in the Úpa Valley during the Weichselian has significance in the context of palaeoclimatic inferences that may be made for the region. !e assumption implied within the ‘classic’ model of glaciation is that the region was cold and arid during glaciation, resulting in

Fig. 8 The plateau of the Luční louka Meadow above the cirque edge of the Úpa valley (left) at 1,400–1,450 m a.s.l. (Photo Z. Engel).


shallow mass-balance gradients, limiting the growth of ice, and resulting in fairly static glaciers with slow response times (cf. Johannesson 1989). Whilst permafrost and niveo-aeolian evidence from the region (such as Pawelec 2006) support the idea of low temperatures and increased aridity at the peak of the Weichselian, the identification of quite dynamic variation in Late Weichselian glaciation in the Úpa implies that there could have been substantial seasonal to millennial variation in temperature and precipitation, operating a major control over glacier mass-balance gradients and behaviour. It is therefore interesting to speculate whether Late Weich-selian expansion and subsequent retreat in the Krkonoše mountains was controlled by local topoclimatic factors, or regional temperature and precipitation gradients, resulting in asynchronaiety by comparison with the major continental ice sheets and the global ∂¹⁸O₂ record within ice and marine cores. Such asynchronaeity has been seen elsewhere across the Earth (Gillespie, Molnar 1995, Garcia-Ruiz et al. 2003), usually controlled by regional atmospheric patterns, with the interplay between Atlantic westerly and Mediterranean southerly systems critical within the context of this study (Florineth, Schluchter 2000).

In the absence of a reliable detailed Lateglacial palaeo-environmental record with associated AMS ¹⁴C chronology for the region, any attempt at correlating local events in the Krkonoše with wider NW European event stratigraphy, or to reconstructed atmospheric circulation is purely speculative. !e mire in the upper Labe valley, to the west of the study area preserves a complex sequence of organic and minerogenic sediments overlain by Holocene peats (Jankovská 2004), and may provide a suit-able record for such palaeoenvironmental and chronological analysis.

6. Conclusions

!e key findings of this project so far are:• !e classic Quaternary morpho-stratigraphy of moraines reflecting glaciation

during the Würm, Riss and ‘Middle Pleistocene’ is rejected in favour of a shorter sequence of Late Weichselian glaciation of the Upper Úpa (Obří důl).

• Sediments in the vicinity of Pec pod Sněžkou suggest more extensive glacia-tion of the Úpa Valley, terminating beyond the lowermost preserved moraines. Tentative comparison with the Úpa terrace sequences suggests that this glacia-tion occurred during the Weichselian.

• Sedimentology and micromorphology identifies a further till deposit in the Mladé Buky area that probably represents pre-Weichselian glaciation, possibly during the Saalian (OI stage 6), in which ice extended to the mountain pied-mont.

• It is suggested that glacier advance and retreat was more dynamic than previ-ously considered, and possibly reflects local and regional climatic influences.


Acknowledgements

�is paper was written during a research sabbatical (S.C.) at the Department of Geography, University of Reading in 2006. Fieldwork in 2000 and 2002 was funded by an Oxford Brookes University School of Social Sciences and Law Scholarship Fund (S.C. and A.P.) and by the Centre for Earth’s Dynamics Research, Czech Republic (J.K. and Z.E.). Regional geo-morphological analysis was also elaborated (2005–2006) as a part of activities of the research project of the Faculty of Science, Charles University in Prague, MSM 0021620831. �e Krkonoše National Park Authority is thanked for providing permission to work in the region. Finally, the authors would like to thank Howard Stimpson for assistance in the laboratory analysis and Vít Vilímek for research assistance in the field.

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Documents

Towards a revised model of Late Quaternary mountain glaciation in the Krkonoše Mountains, Czech Republic