Ninetyeast Ridge: Formation, Composition, and Significance

Introduction: Rock Glaciers in the News

A recent study has highlighted the significant presence of over 100 active permafrost structures, commonly known as rock glaciers, within the Jhelum basin of the Kashmir Himalayas. This discovery carries substantial implications for the region's hydrology and presents potential risks, particularly as the global climate continues to warm.

What are Rock Glaciers?

Rock glaciers are unique landforms composed of a mixture of rock fragments and ice. They are typically found in mountainous regions where specific environmental conditions prevail.

One common formation scenario involves a pre-existing glacier that accumulates substantial amounts of debris and rocks during its movement. If this glacier subsequently recedes or thaws, the debris-covered ice can gradually transform into a rock glacier.

To the unaided eye, rock glaciers often resemble ordinary ground. Their proper identification necessitates a specialized geomorphological view, distinguishing them from other landforms.

Understanding Permafrost

Permafrost is defined as a layer of ground that remains permanently frozen for at least two consecutive years. It can be found either on or beneath the Earth's surface.

Classification of Rock Glaciers

Rock glaciers are broadly categorized based on their internal ice content and movement characteristics:

• Active Rock Glaciers: These structures contain significant amounts of ice and exhibit ongoing, albeit slow, movement. They are considered more dynamic and potentially hazardous.
• Relict Rock Glaciers: These are more stable and inert, having little to no ice and showing no significant movement. They represent past periods of permafrost activity.

Importance of Rock Glaciers

Rock glaciers serve as crucial indicators and reservoirs in high-altitude environments:

• Mountain Permafrost Indicators: They are vital indicators of mountain permafrost, the permanently frozen ground underlying many high-altitude regions. Their presence signifies specific cryospheric conditions.
• Water Storage: Rock glaciers store substantial volumes of water within their frozen cores. This stored water could become a valuable resource, especially in regions facing increasing water scarcity and rapid glacial retreat.

Potential Impacts of Active Rock Glaciers

The presence and potential thawing of active rock glaciers pose several significant environmental and societal risks:

Glacial Lake Outburst Floods (GLOFs)

GLOFs are sudden and catastrophic floods resulting from the failure of a natural or artificial dam containing a glacial lake. This releases large volumes of water and debris downstream.

Landslides

Landslides involve the rapid downward movement of soil, rock, or snow along a slope, often triggered by events like earthquakes, heavy rainfall, or human activities.

Thermokarst Formation

Thermokarst refers to a distinctive type of terrain characterized by irregular surfaces, marshy hollows, and small hummocks. These features form due to the thawing of ice-rich permafrost.

The presence of water bodies near Kargil-Zanskar in Jammu and Kashmir suggests the existence of underground permafrost, resembling ‘thermokarst lakes’. This phenomenon poses further risks due to the potential for collapse.

The melting of ice beneath the Earth's surface carries a high risk of ground collapse. This collapse creates a unique landscape featuring sinkholes, hummocks, caverns, and tunnels.