Gilbert Hill: Geological Significance of Mumbai

Category: Geography / Geological Heritage

UPSC Notes

Gilbert Hill is a prominent geological formation in Andheri, Mumbai, Maharashtra. It consists of a steep-sided rock mass formed from ancient volcanic basalt.

The hill is known for its columnar structure, which developed through the cooling and contraction of volcanic rock.

Geological formation

  • Basaltic lava was emplaced during ancient volcanic activity.

  • As the rock cooled, it contracted.

  • Contraction produced joints that created column-like structures.

  • Erosion and subsequent landscape changes exposed the formation.

Key Pointers for UPSC

  • Location: Andheri, Mumbai, Maharashtra.

  • Rock type: Basalt.

  • Geological feature: Columnar jointing.

  • It is associated with the Deccan volcanic province.

  • Columnar joints form through cooling and contraction, not through the growth of mineral crystals into literal columns.