The recent evolution of Liligo glacier, Karakoram, Pakistan,and its present quiescent phase

Abstract

Liligo glacier, in the central eastern Karakoram, Pakistan, is a small, south-to-north-flowing glacier situated in a transverse valley on the left (south) side of Baltoro glacier. New processing of satellite imagery enables a better quantification of terminus oscillations over the past 30 years. From the beginning of the 1970s to the beginning of the 21st century, Liligo glacier advanced about 2 km (60 m a -1 ). The progress was characterized by a significant evolution of terminus morphology, similar to that observed on the same glacier during the advance event near the beginning of the 20th century, and to those of many other Karakoram glaciers. This suggests indications of a surge-type mechanism. Field observations performed in 2004 indicated there was probably no confluence at that time between Liligo and Baltoro glaciers and that a quiescent phase had started in the early years of the 21st century.

Changes in glacier surface cover on Baltoro glacier, Karakoram, north Pakistan, 2001–2012

“…The distribution of the debris unit succeeds the ultimate advance of the glacier, likely to result from slumping of the debris into the depression in the proglacial area as the tributary glacier commences its quiescent phase and decouples from the main Baltoro Glacier tongue. The associated supraglacial pond identified by Belò et al (2008) Geomorphological features present on TG12 (Inset A) also suggest that a surge event has occurred recently and that the glacier is now in a quiescent phase. This tributary glacier has not been documented to surge previously.…”

“…Omitting lithological variation is a potential error in the resultant ablation rates calculated by the study, as differing thermal capacity and rates of heat transfer for different debris lithologies were not incorporated into calculations. Other studies focused on different aspects of the Baltoro Glacier system; Quincey et al (2009a) investigated the changing velocity of the glacier between 1993 and 2008 and linked their observations to climatic variability, while both Diolaiuti, Pecci, and Smiraglia (2003) and Belò, Mayer, Smiraglia, and Tamburini (2008) identified the surging nature of the confluent Liligo Glacier (TG 7) ( Figure 1) and reconstructed its recent dynamic history.…”

“…Retreat of the debris unit is, however, unlikely, as movement of rock debris upslope would have had to occur. Therefore, the changes in debris unit boundary between 2001 and 2012 are attributed to dissipation and reorganisation of the debris, as the surface morphology changes following the active surge phase of Liligo Glacier between 1973 and 2001 (Belò et al, 2008;Diolaiuti et al, 2003). The distribution of the debris unit succeeds the ultimate advance of the glacier, likely to result from slumping of the debris into the depression in the proglacial area as the tributary glacier commences its quiescent phase and decouples from the main Baltoro Glacier tongue.…”

Integration of classification tree analyses and spatial metrics to assess changes in supraglacial lakes in the Karakoram Himalaya

“…After the first successful attempt to climb K2 peak, the first large-scale (1:12,500) map of the Baltoro Glacier was produced by another Italian team in 1954. In the latter half of the twentieth century and early twenty-first century, a plethora of climbing and scientific expeditions continued to traverse and map the region at various scales and for very different purposes (Belò et al 2008;Mihalcea et al 2008). Satellite imagery now provides synoptic views and analytical capabilities unavailable to earlier explorers of the Karakoram Himalaya.…”

“…Wherever the glacier debris cover is thick, it protects the ice underneath from solar radiation and subsequent melting (Mihalcea et al 2006(Mihalcea et al , 2008Belò et al 2008). On the other hand, thin debris cover, or variable debris cover due to crevasses and ice-cliffs, increases the melting rate of the glacier ice (Mihalcea et al 2006(Mihalcea et al , 2008Belò et al 2008). Such increased melting and calving of ice, coupled with downwasting of glaciers, increases the formation of supraglacial lakes.…”