The Deccan Traps were formed as a result of which geological event?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer
Volcanic eruptions
Explanation
The Deccan Traps of western and central India were formed as a result of massive volcanic eruptions, specifically a series of catastrophic fissure eruptions. This geological event occurred around 66 million years ago, at the end of the Cretaceous period, coinciding with the mass extinction event that wiped out the dinosaurs.
As the Indian tectonic plate drifted northward over the Réunion hotspot (a volcanic hotspot in the Earth's mantle), the crust fractured, causing colossal amounts of highly fluid basaltic magma to pour out onto the surface. This type of broad, large-scale volcanic activity is known as flood basalt eruption. The lava spread horizontally across vast areas, cooling down to form multiple flat-topped, stepped layers of basalt rocks. The word 'Trap' is derived from the Swedish word trappa, which means 'stairs,' referencing the step-like landscape of the region. Over millions of years, the weathering of these volcanic basalt rocks created the highly fertile black soil (regur soil) characteristic of the Deccan Plateau.
Key Points
The Deccan Traps constitute one of the largest volcanic provinces or Large Igneous Provinces (LIPs) on Earth, covering an area of nearly 500,000 square kilometers today.
Tectonic plate collision is responsible for the formation of the Himalayan mountain range (collision of the Indian and Eurasian plates), not the Deccan Traps.
Glacial movements shaped northern high-altitude landscapes and valleys but had no role in creating the basaltic layers of the peninsular Indian plateau.
Important Questions and Answers
Question: Which specific type of highly fertile soil is produced by the long-term weathering of the Deccan Trap basaltic lava rocks?
Answer: Black soil, also widely known as Regur soil or Black Cotton soil, is produced.
Question: Over which deep-mantle volcanic hotspot did the Indian plate pass during the Late Cretaceous period to trigger the Deccan Traps eruption?
Answer: The Indian plate drifted over the Réunion hotspot.