Origins of the divergent evolution of mountain glaciers during deglaciation: Hofsdalur cirques, Northern Iceland

The aim of this work is to study the process transformation debris-free mountain glaciers into debris-covered and rock glaciers, examine factors driving diverging evolution in similar glacial systems. area Hofsdalur valley, Tröllaskagi peninsula (northern Iceland), where several cirques host a great diversity as well various landforms. Four adjacent have been analysed through multidisciplinary approach: geomorphological analysis, boulder surface displacement tracking, quantification recent glacier changes, three dimensional palaeoglacier reconstruction, equilibrium-line altitude calculations relative direct dating methods applied boulders. Dating included situ 36Cl cosmic-ray exposure dating, Schmidt hammer weathering measurements lichenometric dating. results confirm that followed an pattern observed other peninsula. During Younger Dryas (12.9–11.7 ka) many those hosted whose retreat started early Holocene. Distinct dynamics cirque floor elevation conditioned subsequent evolution. In some cirques, ice completely covered headwalls, which consequently did not supply debris onto surface, remained debris-free. most these however, enhanced paraglacial processes ice-free walls generated high surface. As result, evolved towards or depending on local topographical setting. lower they collapsed immediately after their formation. At higher altitudes, above permafrost limit, ice-cored landforms survived until present day, but stagnant since Holocene Thermal Maximum, while heads during Late