Was the Last Glaciation of the Black Forest (Southern Germany) Synchronous with the Alpine Glaciation?
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Was the last glaciation of the Black Forest (southern Germany) synchronous with the Alpine glaciation? Felix Martin Hofmann, William McCreary, Frank Preusser Institute of Earth and Environmental Sciences, University of Freiburg, Germany Key site Scienti�ic context and approach 420000 440000 Coordinate system: ETRS 1989 • During the last glaciation maximum, the southern Black Forest was µ Schauinsland UTM Zone 32N (1284) 2 # r covered by a 1000 km large ice cap dominated by radial ice �low from cie gla ach eb Titisee 0 5 Feldberg (Fig. 1) Se # km Haslach g • Due to multiple moraines (Fig. 1) inside the last local glacial maximum Feldberg lacier (1493) → Belchen se glacier extent, its limited size and the lack of signi�icant topographic 5300000 e (1414) Wi er # ci S Schluchsee la ch g lu control, the ice cap of Black Forest is a valuable palaeoclimatic archive e c es h i se W e g la • According to Monegato et al. (Fig. 2): growth of North American Ice Sheet # ci er → southwart shift of the North Atlantic jet stream → advection of A Kö hlgarten l A b lb r g (1224) e i l a c c a l i moisture from the Mediterranean Sea → enhanced ice build-up in the Alps e g r a r h e 80° W 60° W 40° W 20° W 0 ° W Eurasian Ice 26-24 ka Sheet North American Ice Sheet µ (expanding) Polar front 50° N Alpine France Black Forest ice cap (starved?) glaciers t ! Strasbourg s e r 5280000 o Elevation(ma.s.l.) # Summit (m a.s.l.) F 40° N Jet stream k c <100 River 0 1000 km a l Freiburg B ! Germany 100-200 Lake Fig. 2: Palaeoclimatic context at ca. 26-24 ka (Monegato et al. 2017) # Feldberg 200-500 Prominent moraine 500-1000 Glacier extent during the • Black Forest in a leeward position to the glaciers in the Alps; ! last glaciation maximum Basel Switzerland 1000-1500 (Hemmerle et al. 2016) Hypothesis: Last glaciation maximum in the Black Forest out of phase? Fig. 1: Location of the study area, last local glacial maximum extent in the Black Forest and prominent terminal moraines Key site: Sankt Wilhelmer Tal Future directions • Geomorphological mapping with particular emphasis on moraines • Geomorphological mapping of further sites based on new �ield evidence and high-resolution remote sensing data • Application of modern geochronological methods to numerically date data the last glaciation maximum and periods of glacier variability during the subsequent deglaciation: 10Be surface exposure dating of moraine boulders (Ivy-Ochs & Kober 2008) and dating with luminescence depth- pro�iles from boulders buried inside terminal moraines (Rades et al. 2018) • Palaeoglacier modelling, equilibrium line altitude reconstructions as well as determination of palaeo-precipitation and temperature together with data from the lake Bergsee record (southernmost Black Forest; Duprat-Oualid et al. 2017) Acknowledgements This research is undertaken during the 'Geometry, chronology and dynamics of the last Pleistocene glaciation of the Black Forest' project (funded by the German Research Foundation) References Duprat-Oualid F., Rius D., Bégeot C., Magny M., Millet L., Wulf S., Appelt O. 2017. Vegetation response to abrupt climate changes in Western Europe from 45 to 14.7 k cal a BP: the Bergsee lacustrine record (Black Forest, Germany). J. Fig. 3: Moraines in (a) Sankt Wilhelmer Tal and in (b) Katzensteig (numbering: morphostratigraphical position). Coordinate system: Quaternary Sci., 32, 1008-1021. ETRS 1989 UTM Zone 32 N Hemmerle H., May J.-H., Preusser F. 2016. U� bersicht ü ber die pleistozänen Vergletscherungen des Schwarzwaldes. Ber. Naturf. Ges. Freiburg i. Br., 106, 31-67. Fig. 4: The prominent M13 moraine in Ivy-Ochs S., Kober F. 2008. Surface exposure dating with cosmogenic nuclides. E&G Quat. Sci. J., 57, 179-209. Sankt Wilhelmer Tal viewed from NW (Photo: Felix Martin Hofmann) Monegato G., Scardia G., Hajdas I., Rizzini F., Piccin A. 2017. The Alpine LGM in the boreal ice-sheets game. Sci. Rep-UK , 7, 2078. M13 N Rades E.F., Sohbati R., Lü thgens C., Jain M., Murray A.S. 2018. First luminescence-depth pro�iles from boulders from moraine deposits: Insights into glaciation chronology and transport dynamics in Malta valley, Austria. Rad. Meas., 120, 281-289. .