Aravali Range and its geophysics "EMPOWER IAS"

In news:

• The Supreme Court has ordered the Haryana government to take “all essential measures” to remove encroachments, including some residential constructions, in the ecologically fragile Aravali forest land near a village.

 

 

Key Points

 

 

About the Aravalli Range:

• • Location:
    • They stretch for a distance of about 720 km from Himmatnagar in Gujarat to Delhi, spanning Haryana, Rajasthan, Gujarat, and Delhi.
  • Formation:
    • The Aravallis date back to millions of years when a pre-Indian subcontinent collided with the mainland Eurasian Plate.
  • Age:
    • Carbon dating has shown that copper and other metals mined in the ranges date back to at least the 5^th century BC.

Characteristics:

• • The Aravallis of Northwestern India, one of the oldest fold mountains of the world, now form residual mountains with an elevation of 300m to 900m.
  • Guru Shikhar Peak on Mount Abu is the highest peak in the Aravalli Range (1,722 m).
  • It has been formed primarily of folded crust, when two convergent plates move towards each other by the process called orogenic movement.

 

Extension:

• •  
• The mountains are divided into two main ranges – the Sambhar Sirohi Range and the Sambhar Khetri Range in Rajasthan, where their extension is about 560 km.
• The hidden limb of the Aravallis that extends from Delhi to Haridwar creates a divide between the drainage of rivers of the Ganga and the Indus.

 

Checks Desertification:

• •  
• The Aravallis act as a barrier between the fertile plains in the east and the sandy desert in the west.
• Historically, it is said that the Aravalli range checked the spread of the Thar desert towards the Indo-Gangetic plains, serving as a catchment of rivers and plains.

 

Rich in Biodiversity:

• •  
• Provides habitat to 300 native plant species, 120 bird species and many exclusive animals like the jackal and mongoose.

 

Impacts Climate:

• •  
• Aravallis have an impact upon the climate of northwest India and beyond.
• During monsoons, it provides a barrier and monsoon clouds move eastwards towards Shimla and Nainital, thus helping nurture the sub-Himalayan rivers and feeding the north Indian plains.
• In the winter months, it protects the fertile alluvial river valleys from the cold westerly winds from Central Asia.

 

Recharges Groundwater:

• •  
• Aravallis also functions as a groundwater recharge zone for the regions around that absorb rainwater and revive the groundwater level.

 

Checks Pollution:

• •  
• This range is considered the “lungs” for the polluted air of Delhi–National Capital Region (NCR).
• For Haryana, having the lowest forest cover at around 3.59% of the total forest cover in India, the Aravalli range is the only saving grace, providing the major portion of its forest cover (2017 Report).

 

Threats:

•  
• The Aravalli hills are an ecologically sensitive zone but have for years borne the brunt of quarrying and environmental degradation.
• A 2018 report by a Supreme Court-appointed Central Empowered Committee (CEC) found out that 25% of the Aravalli range has been lost due to illegal mining in Rajasthan since 1967-68.
• The consequences of the mining has been a destruction of aquifers and deforestation. Many rivers originating in the Aravalli like Banas, Luni, Sahibi and Sakhi, are now dead.