Investigation of a cold-based ice apron on a high-mountain permafrost rock wall using ice texture analysis and micro-¹⁴C dating: a case study of the Triangle du Tacul ice apron (Mont Blanc massif, France)

Abstract The current paper studies the dynamics and age of Triangle du Tacul (TDT) ice apron, a massive volume lying on steep high-mountain rock wall in French side Mont-Blanc massif at an altitude close to 3640 m a.s.l. Three 60 cm long cores were drilled bedrock (i.e. wall) 2018 2019 TDT apron. Texture (microstructure lattice-preferred orientation, LPO) analyses performed one core. two remaining used for radiocarbon dating particulate organic carbon fraction (three samples total). Microstructure LPO do not substantially vary with along axis Throughout core, irregularly shaped grains, associated strain-induced grain boundary migration strong single maximum LPO, observed. Measurements indicate that deforms under low strain-rate simple shear regime, plane parallel surface slope Dynamic recrystallization stands out as major mechanism growth. Micro-radiocarbon indicates becomes older depth perpendicular surface. We observed ages than 600 year BP base lowest 30 3000 years.