Spatial and climatic characterization of three glacial stages in the Upper Krnica Valley, SE European Alps

Abstract

The southeastern European Alps represent the spot where mean annual precipitation is at its highest in the entire Alpine chain. Accordingly, the glacial evolution here might have a different spatial and chronological pattern if compared with other alpine areas. This paper discusses geomorphological evidence of three glacial stages from the Krnica Valley in the Julian Alps of Slovenia, and is the first step towards a comprehensive palaeoglaciological studies in this alpine sector. Very well-preserved glacial landforms in the Upper Krnica Valley allowed the reconstruction of glacier surface topographies and corresponding equilibrium line altitudes (ELAs) by means of field-based geomorphological and sedimentological data and by using geospatial analysis. The uppermost frontal moraines belong to the Little Ice Age (LIA) and the corresponding ELA is estimated at 1973 m a.s.l. Other two stages with the ELA depressed by 50 m and 161 m compared to the LIA ELA, suggest early Holocene and Younger Dryas ages of the palaeoglaciers, respectively. This assumption ensues from absolute age datings and related ELA depressions observed elsewhere in the European Alps. The presence of buried ice under the debris in the Krnica cirque, imaged through geophysical investigations, point to peculiar microclimatic conditions able to preserve relict glacier ice. This is favoured by the recursive presence of snow on the ground caused by the extreme summer shading and the significant winter snow-recharge triggered by snowblow and avalanche feeding. The possible evolution of such relict ice under the ongoing climate warming is also discussed.

Holocene climate variability in Slovenia: A review

“…Colucci and Žebre (2016) analysed the system of frontal moraine ridges of the Triglav Glacier identified by Šifrer (1963) and proposed that it was formed during the LIA; they consequently calculated the extent of the glacier to be about 44.2 hectares (compared to 0.7 hectares in 2022; Pavšek 2023) with a volume of 13.83 km³ (compared to 2.455 m³; i.e., 2.455 × 10 −9 km³ in 2022; Pavšek 2023). The presence of the LIA glacier extent could be also expressed by the moraine ridges in the Upper Krnica Valley (Kozamernik et al 2018), but this is also uncertain due to the absence of ages of moraine ridges. The radiocarbon ( 14 C) analysis of the organic material sourced from a non-vegetated moraine located approximately 500 m below the present-day ice mass of the Triglav Glacier (as observed in 2022) produced an age range of 5.6 to 5.4 ka, indicating the extent of the glacier at that time similar to the LIA period and possibly suggesting another period of apparent colder climate (unpublished research conducted by Karsten Grunewald and associates; Lipar et al 2021).…”

Recent evolution of Marmolada glacier (Dolomites, Italy) by means of ground and airborne GPR surveys

“…GPR surveys are applied in glaciology with different objectives, including ice volume estimation (Binder et al, 2009;Gabbi et al, 2012), imaging of the internal structure of a clean ice body (Arcone, 1996; or covered by debris (e.g. Kozamernik et al, 2018), determination of the thermal regime (Baelum and Benn, 2011;Gacitùa et al, 2015) and quantification of snow seasonal melting and the characterization of the snow cover (Godio, 2009;Gusmeroli et al, 2014;Zhao et al, 2016). Moreover, there are several other specific glaciological applications spanning from sub-glacial lakes detection (Siegert et al, 2004), discovery and characterization of brines (Forte et al, 2016), to ice cave imaging (e.g.…”

Geometry and paleo-ice content of rock glaciers in the southeastern Alps (NE Italy – NW Slovenia)

“…In the southeastern Alps, the exact timing and extent of Lateglacial glaciations are still largely unknown (Kozamernik, Colucci, Stepišnik, Forte, & Žebre, 2018). On the other hand the onset and decay of rock glaciers have been related to the Younger Dryas (YD) cold phase event and the subsequent climate amelioration of the early Holocene (Colucci et al, 2016b).…”