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Abstract Climate is currently warming due to anthropogenic impact on the Earth’s atmosphere. To better understand the processes and feedbacks within the climate system that underlie this accelerating warming trend, it is useful to examine past periods of abrupt climate change that were driven by natural forcings. Glaciers provide an excellent natural laboratory for reconstructing the climate of the past as they respond sensitively to climate oscillations. Therefore, we study glacier systems and their behavior during the transition from colder to warmer climate phases, focusing on the period between 15 and 10 ka. Using a combination of geomorphological mapping and beryllium-10 surface exposure dating, we reconstruct ice extents in two glaciated valleys of the Silvretta Massif in the Austrian Alps. The mountain glacier record shows that general deglaciation after the Last Glacial Maximum (LGM) was repeatedly interrupted by glacier stabilization or readvance, perhaps during the Oldest Dryas to Bølling transition (landform age: 14.4 ± 1.0 ka) and certainly during the Younger Dryas (YD; 12.9–11.7 ka) and the Early Holocene (EH; 12–10 ka). The oldest landform age indicates a lateral ice margin that postdates the ‘Gschnitz’ stadial (ca. 17–16 ka) and predates the YD. It shows that local inner-alpine glaciers were more extensive until the onset of the Bølling warm phase (ca. 14.6 ka), or possibly even into the Bølling than during the subsequent YD. The second age group, ca. 80 m below the (pre-)Bølling ice margin, indicates glacier extents during the YD cold phase and captures the spatial and temporal fine structure of glacier retreat during this period. The ice surface lowered approximately 50–60 m through the YD, which is indicative of milder climate conditions at the end of the YD compared to its beginning. Finally, the third age group falls into a period of more substantial warming, the YD–EH transition, and shows discontinuous glacier retreat during the glacial to interglacial transition. The new geochronologies synthesized with pre-existing moraine records from the Silvretta Massif evidence multiple cold phases that punctuated the general post-LGM warming trend and illustrate the sensitive response of Silvretta glaciers to abrupt climate oscillations in the past. 

Abstract. Glaciers preserve climate variations in their geologicaland geomorphological records, which makes them prime candidates for climatereconstructions. Investigating the glacier–climate system over the pastmillennia is particularly relevant first because the amplitude andfrequency of natural climate variability during the Holocene provides theclimatic context against which modern, human-induced climate change must beassessed. Second, the transition from the last glacial to the currentinterglacial promises important insights into the climate system duringwarming, which is of particular interest with respect to ongoing climatechange. Evidence of stable ice margin positions that record cooling during the past12 kyr are preserved in two glaciated valleys of the Silvretta Massif in theeastern European Alps, the Jamtal (JAM) and the Laraintal (LAR). We mappedand dated moraines in these catchments including historical ridges usingberyllium-10 surface exposure dating (10Be SED) techniques andcorrelate resulting moraine formation intervals with climate proxy recordsto evaluate the spatial and temporal scale of these cold phases. The newgeochronologies indicate the formation of moraines during the early Holocene (EH), ca. 11.0 ± 0.7 ka (n = 19). Boulder ages along historical moraines (n = 6) suggest at least two glacier advances during the Little Ice Age (LIA; ca. 1250–1850 CE) around 1300 CE and in the second half of the 18th century. An earlier advance to the same position may have occurredaround 500 CE. The Jamtal and Laraintal moraine chronologies provide evidence thatmillennial-scale EH warming was superimposed by centennial-scale cooling.The timing of EH moraine formation coincides with brief temperature dropsidentified in local and regional paleoproxy records, most prominently withthe Preboreal Oscillation (PBO) and is consistent with moraine depositionin other catchments in the European Alps and in the Arctic region. Thisconsistency points to cooling beyond the local scale and therefore aregional or even hemispheric climate driver. Freshwater input sourced fromthe Laurentide Ice Sheet (LIS), which changed circulation patterns in theNorth Atlantic, is a plausible explanation for EH cooling and moraineformation in the Nordic region and in Europe.