DECCAN TRAPS

 

A view of the Ajanta Caves excavated in the gorge wall of the Waghur/Waghora River. The caves, listed as a World Heritage Site, are excavated in compound lava flows. The Buddhist cave monuments date from 2nd century BCE to 6th century CE 

(Photo courtesy of Francesca Lugeri)

At the end of the Cretaceous, the western part of peninsular India underwent numerous volcanic eruptions that resulted in the formation of the Deccan Traps. A total of 48 lava flows have been identified within the Deccan Traps, with a maximum thickness of about 2.5 km on the western side of the plateau near Mumbai. The Deccan Traps are spread over half a million square kilometers in the west-central parts of India, and they occupy huge areas of the states of Maharashtra and Karnataka. India also has the longest lava flows known to be preserved. They are estimated to be 1500 km long and drain out into the Gulf of Bengal near Rajahmundry in Karnataka.

Many archaeological monuments like the Buddhist, Hindu, and Jain temples of Ajanta, Ellora, and Elephanta are the oldest in-situ basalt cave temples, dating back to the second century. They also have the oldest known cave paintings on the Indian subcontinent. However, this title could be snatched by the recent discoveries in Mangar Bani, near the outskirts of Delhi.

At least 4 of the UNESCO World Heritage Sites in India, like the Ajanta, Ellora, and Elephanta cave temples, and the Chhatrapati Shivaji Maharaj Terminus (formerly Victoria Terminus), is made of this basalt.

Deccan basalts are in high demand worldwide and are mined for a variety of purposes including masonry stone, road metal, and as a raw material for corrosion-resistant basaltic pipes and basalt wool.

Quarrying of Deccan basalt is done in the western Deccan Plateau region, especially around Navi Mumbai, Aurangabad, Jalgaon, Nashik, and Kolhapur.

Basalt is a dark-colored, fine-grained, extrusive igneous rock (i.e., the molten rock or lava cooled on the surface) 

Basalt flows cover about 70% of the Earth’s surface and huge areas of terrestrial planets.

They come from the mantle. When rocks melt under pressure and temperature, they then make their way up to the surface via ducts and feed fissure volcanoes on the surface.

Future studies could gather more evidence about the environmental conditions that led to the mass extinction of non-avian dinosaurs and gigantic reptiles. 

The massive Deccan volcanic mountain ranges of the Western Ghats (east of Mumbai) reach up to a height of 3500 m and consist entirely of layered lava flows. (photo courtesy of G. Keller)