Palaeoclimatic reconstruction from Lateglacial (Younger Dryas Chronozone) cirque glaciers in Snowdonia, North Wales

摘要: Abstract The cirques of Snowdonia, North Wales were last occupied by glacier ice during the Younger Dryas Chronozone (YDC), c. 12.9–11.7 ka. New mapping presented here indicates 38 small YDC cirque glaciers formed in covering a total area 20.74 km 2 . Equilibrium line altitudes (ELAs) for these glaciers, calculated using an area–altitude balance ratio (AABR) approach, ranged from 380 to 837 m asl. A northeastwards rise ELAs across Snowdonia is consistent with southwesterly snow-bearing winds. Regional palaeoclimate reconstructions indicate that was colder and drier than at present. Palaeotemperature annual temperature range estimates, derived published palaeoecological datasets, used reconstruct values accumulation ‘winter plus summer precipitation’ degree-day model (DDM) non-linear regression function, respectively. DDM acted as best-estimate stadial precipitation yielded between 2073 2687 mm a −1 (lapse rate: 0.006 °C m ) 1782–2470 mm a 0.007 °C m ). Accounting potential input windblown avalanched snow onto former surfaces, dropped 1791 2616 mm a 1473–2390 mm a spatial pattern suggests steep gradient provides verification ELAs. Glaciers nearer coast most responsive fluctuations climate YDC, responding sea-ice enforced continentality coldest phases abrupt warming end stadial.