Geomorphology 293 (2017) 130–142 Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph 10Be exposure age chronology of the last glaciation of the Roháčská Valley in MARK the Western Tatra Mountains, central Europe ⁎ Zbyněk Engela, , Pavel Mentlíkb, Régis Braucherc, Marek Křížeka, Markéta Pluháčkováb, Aster Teamc a Charles University, Faculty of Science, Department of Physical Geography and Geoecology, Albertov 6, 12843 Praha, Czech Republic b University of West Bohemia, Center of Biology, Geoscience and Environmental Education, Klatovská 51, 30619 Plzeň, Czech Republic c Aix Marseille Université, CNRS, IRD, Collége de France, 13545 Aix-en-Provence cedex 4, France ARTICLE INFO ABSTRACT Keywords: 10Be exposure ages from moraines and bedrock sites in the Roháčská Valley provide chronology of the last Quaternary glaciation in the largest valley of the Western Tatra Mts., the Western Carpathians. The minimum apparent Cosmogenic nuclides exposure age of 19.4 ± 2.1 ka obtained for the oldest sampled boulder and the mean age of 18.0 ± 0.8 ka Glaciation chronology calculated for the terminal moraine indicate that the oldest preserved moraine was probably deposited at the Western Tatra Mts. time of the global Last Glacial Maximum (LGM). The age of this moraine coincides with the termination of the Carpathians maximum glacier expansion in other central European ranges, including the adjacent High Tatra Mts. and the Alps. The equilibrium line altitude (ELA) of the LGM glacier in the Roháčská Valley, estimated at 1400–1410 m a.s.l., was 50–80 m lower than in the eastern part of the range, indicating a positive ELA gradient from west to east among the north-facing glaciers in the Tatra Mts. Lateglacial glacier expansion occurred no later than 13.4 ± 0.5 ka and 11.9 ± 0.5 ka, as indicated by the mean exposure ages calculated for re-advance moraines. This timing is consistent with the exposure age chronology of the last Lateglacial re-advance in the High Tatra Mts., Alps and lower mountain ranges in central Europe. The ELA in the Roháčská Valley estimated at 1690–1770 m a.s.l. in this period was located 130–300 m lower than in the north-facing valleys in the High Tatra Mts. 10Be exposure ages obtained for a rock glacier constrains the timing of this landform stabilization in the Salatínska Valley and provides the first chronological evidence for the Lateglacial activity of rock glaciers in the Carpathians. 1. Introduction confidently dated. Despite the wide application of cosmogenic nuclide dating in the Reconstructions of the past glacier variability are among the most field of glacial geology over the past three decades (Ivy-Ochs et al., useful records of paleoclimate changes during the Quaternary. In 2014), the chronology of glaciations remains poorly constrained in mountain regions, glacier history is often the primary proxy for climate many mountain regions. A large data set of exposure ages on glacial during glacial periods. Mountain glaciers are a particularly important deposits exists from the Andes (e.g. Rodbell et al., 2009 and references paleoclimate proxy for two reasons. First, glaciers are the key climate therein; Fernández and Mark, 2016), the Cordilleras in the western U.S. indicators, retreating and advancing in response to changes in the (Balco, 2011; Rood et al., 2011; Young et al., 2011), High Asia glacier mass balance, which is mainly determined by snow accumula- (Chevallier et al., 2011; Heyman, 2014; Owen and Dortch, 2014) and tion (precipitation) and glacier melt (air temperature) over a year (e.g. Scandinavia (Hughes et al., 2016; Stroeven et al., 2016), but other Winkler et al., 2010). Second, geomorphic evidence of glacier advances ranges are yet underexplored. Limited chronological data are available such as ice marginal landforms, polished bedrock surfaces and trimlines for the Carpathians, the largest mountain region in mainland Europe. is the only well-preserved palaeoclimate proxy for glacial periods in The glaciation history of this range has been an object of glacial studies many mountain systems, which generally retain poor sedimentary since the mid-19th century when Zejszner (1856) recognized the records. Glacier history is considered a reliable indicator of climate existence of former glaciers in the Tatra Mts. (Fig. 1, inset), the Western changes in those ranges, where glacier deposits are widespread and Carpathians. There were a number of geomorphological investigations ⁎ Corresponding author. E-mail address: [email protected] (Z. Engel). Maurice Arnold, nk> http://dx.doi.org/10.1016/j.geomorph.2017.05.012 Received 10 November 2016; Received in revised form 15 May 2017; Accepted 19 May 2017 Available online 24 May 2017 0169-555X/ © 2017 Elsevier B.V. All rights reserved. Z. Engel et al. Geomorphology 293 (2017) 130–142 Fig. 1. Overview of the Western Tatra Mts. range and its position in the Carpathians of central Europe (grey shade, inset map). The LGM extent of glaciers in the Tatra Mts. and central Europe (blue shades, inset map) is after Zasadni and Kłapyta (2014) and Ehlers et al. (2011), respectively. The valleys cited in the paper are indicated by full names or abbreviations (DK: Kondratowa, DSK: Sucha Kasprowa, DG: Gąsienicowa, DPSP: Pięciu Stawów Polskich Valley, DM: Za Mnichem). A red box indicates the outline of Figs. 2 and 6 and a dashed line marks the water divide. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.) of the glacial landscape within the Carpathians during the next decades glaciers and a bedrock surface in the Roháčská Valley, the largest area (e.g. Sawicki, 1911; Lukniš, 1964; Sîrcu, 1964), but no chronological of Quaternary glaciation in the Western Tatra Mts. We thus establish a evidence was reported from this region until the beginning of the 21st new glaciation chronology for the valley spanning the LGM and century (Reuther et al., 2007; Urdea and Reuther, 2009; Rinterknecht Lateglacial. We compare the derived chronology with published et al., 2012; Kuhlemann et al., 2013; Gheorghiu et al., 2015; chronological data on local glaciations in both the Western and High Ruszkiczay-Rüdiger et al., 2016). Tatra Mts. and we interpret our findings with respect to the results of The Tatra Mts. have been the most extensively glaciated part of the the recent paleoclimate studies from the Carpathians and Alps. Carpathians during the Quaternary. The large extent of local glaciations resulted from high topography of the range (the maximum elevation of 2. Study area 2655 m a.s.l.) and their location in the north-western part of the Carpathians exposed to humid air masses moving in from the Atlantic The Western Tatra Mts. (49°08′–49°17′ N, 19°34′–20°00′ E) are a Ocean. A number of cirque and valley glaciers formed along the divide 30 km-long and 16 km-wide range in the northernmost part of the (Zasadni and Kłapyta, 2014) leaving a strong erosional imprint on the Carpathians. The range extends between 790 and 2248 m a.s.l. (Bystrá landscape. The strong geomorphological evidence left by former ice Mountain; Fig. 1). The range extends from the western part of the High masses makes the Tatra Mts. a primary focus of palaeoglaciological Tatra Mts., the highest part of the Carpathians. The southern part of the research in the Carpathians. In this region, the first reconstructions of range is built of Proterozoic gneisses, schist and amphibolite while the the spatial extent of local glaciers were achieved (Partsch, 1882; Dénes, main ridge consists of polygenetic Variscan granitoids (Jurewicz, 1902) and different palaeoglacial histories have been suggested (Dénes, 2007). The crystalline basement is overlain by Mesozoic sedimentary 1902; de Martonne, 1911; Partsch, 1923; Romer, 1929). sequences which consist of an autochthonous sedimentary cover, the The number and likely age of Quaternary glaciations in the Tatra High-Tatric and Krížna nappes in the western and northern part of the Mts. were initially assessed based on geomorphologic criteria (Halicki, range (Putiš, 1992). In the topographic sense the Tatra Mts. emerged 1930; Lukniš, 1959; Klimaszewski, 1960) or weathering characteristics due to a Miocene rotational uplift that resulted in an asymmetric horst of moraine material (Lukniš, 1973). Krupiński (1984) and Baumgart- structure of the massif (Králiková et al., 2014). The massif is deeply Kotarba and Kotarba (1993, 1995, 1997) published the first radio- incised by glacial valleys and cirques with headwalls up to 600 m high carbon data from moraine-dammed lakes, providing minimum age (Křížek and Mida, 2013), displaying the most pronounced glacial constraints on the termination of the last glaciation. Further progress morphology within the Carpathians. However, glacierization at present was made when glacier advances were constrained in selected valleys only consists of glacierets or firn-ice patches below north-facing rock using thermoluminescence (Prószyńska-Bordas et al., 1988; Butrym walls (Gądek, 2008). et al., 1990; Lindner et al., 1990, 1993; Lindner, 1994) and optically The climate in the Western Tatra Mts. is transitional between stimulated luminescence techniques (Baumgart-Kotarba and Kotarba, maritime and continental influences. The range represents an oro- 2001). Exposure-age dating applied to glacial landforms since the end graphic barrier to air masses moving in from the Atlantic Ocean, which of 1990s allowed for reconstruction of the glaciation history in selected results in higher precipitation on the northern flank compared to the sites within the range (Dzierżek et al., 1999; Baumgart-Kotarba and southern slopes (Konček et al., 1974). Mean annual precipitation Kotarba, 2001; Dzierżek, 2009; Makos et al., 2013a, 2013b, 2014; Engel generally increases with altitude from 900 to 960 mm at the southern et al., 2015). Makos et al. (2016) published the first exposure ages from foothills (Vido et al., 2015) up to ~1800 mm at Kasprowy Wierch the Kondratowa, Sucha Kasprowa and Bystra Woda valleys in the summit (1991 m a.s.l.; Żmudzka, 2011).