ROCK GLACIERS (Syllabus: GS Paper 1 – Geography)

News-CRUX-10     10th January 2024        

Context: The Kashmir Himalayas are dotted with permafrost structures called ‘rock glaciers’, with significant ice volumes within, a new study mapped.

Rock Glaciers/Permafrost

  • About: A rock glacier is a mass of rock, ice, snow, mud, and water that moves slowly down a mountain under the influence of gravity. It typically form in mountainous regions where there is a combination of permafrost, rock debris, and ice.
  • Composition: It consist of a mass of ice covered by rock debris, or it might consist of a mass of rock with interstitial ice.  A gradient of compositions between these two states also exists.
  • Appearance of Rock Glaciers: Unlike ice glaciers, rock glaciers often exhibit minimal visible ice at the surface, making them inconspicuous when observed from a short distance. 
  • Subtle Movement: The gradual movement of rock glaciers, typically ranging from a few centimeters to a few meters per year, plays a crucial role in camouflaging their true nature. This slow motion effectively conceals the rock glacier's identity, especially when viewed from the ground at a close proximity.
  • Characteristics: Rock glaciers often originate in cirques or at the periphery of expansive talus slopes, conforming to the contours of their valleys and terminating in tongue-shaped ends. 

oThe presence of arcuate and linear ridges, particularly behind the tongue, serves as indicators of the underlying moving ice.

  • Despite their variability, rock glaciers typically exhibit modest dimensions, with a large one measuring around fifty meters in thickness and a few kilometers in length.