Gilbert Hill, Mumbai

Category: Geography — Geomorphology and Geological Heritage

Gilbert Hill is a geological formation in Andheri, Mumbai, consisting of a steep, near-vertical rock mass made of basalt.

Key facts

  • Location: Andheri, Mumbai, Maharashtra.

  • Rock type: Basalt, an extrusive igneous rock.

  • Geological origin: Associated with volcanic activity during the geological history of the Deccan region.

  • The formation is a prominent example of columnar jointing in basalt.

  • Columnar joints develop when cooling lava contracts and fractures into polygonal columns.

  • Gilbert Hill is also important as a geological landmark within a densely urbanised landscape.

Geological significance

  • Basalt forms from the cooling of lava at or near the Earth's surface.

  • The Deccan Traps represent one of the world's major flood-basalt provinces.

  • Geological landmarks provide evidence of past volcanic processes and help explain regional landscape evolution.

UPSC key pointers

  • Gilbert Hill is located in Mumbai, Maharashtra.

  • Basalt is an extrusive igneous rock.

  • Columnar jointing results from contraction during cooling.

  • Do not confuse Gilbert Hill with Gilbert Peak or Gilbert's geological classifications.