Deccan Volcanism and Its Impact on Tropical Flora

Syllabus: GS1/Geography

In Context

• A recent study highlights that the Deccan Volcanism, despite its catastrophic effects on terrestrial fauna (such as the extinction of dinosaurs), caused only regional and short-term impacts on tropical flora.

Key Findings

• The volcanic activity primarily led to a latitudinal shift of the Indian Plate within the Inter-Tropical Convergence Zone (ITCZ).
• Dormant phases of the Deccan Volcanism witnessed a humid climate, fostering rapid development and diversification in tropical rainforest ecosystems instead of leading to their extinction.
• The findings offer hope that tropical rainforests, if left undisturbed, can recover quickly under favorable climatic conditions.

Inter-Tropical Convergence Zone (ITCZ)  – ITCZ is a belt of low pressure around the Earth, typically located near the equator, where the trade winds from the Northern and Southern Hemispheres converge. – Its position shifts slightly with the seasons, based on the position of the sun. – Weather Characteristics: The ITCZ is known for heavy rainfall, thunderstorms, and high humidity due to the warm air rising, leading to condensation and cloud formation. – Significance: It plays a key role in global weather patterns, especially in tropical regions, influencing rainfall, monsoons, and seasonal weather changes.

What is Deccan Volcanism?

• Deccan Volcanism refers to the extensive volcanic activity that occurred in the Deccan Plateau of India, primarily during the Cretaceous-Paleogene transition, around 66 million years ago. 
• This volcanic event is believed to have played a significant role in the mass extinction event that wiped out the dinosaurs, though other factors, such as an asteroid impact, may have contributed as well.

Key Features of Deccan Volcanism

• Formation of the Deccan Traps: The Deccan Traps are a vast, layered region of flood basalts (solidified lava flows) covering large areas of central and western India. These volcanic eruptions led to the formation of the Deccan Plateau.
  • The volcanic rock formations are characterized by horizontal layers of basalt and are among the largest volcanic provinces on Earth.
• Cause of Deccan Volcanism: It is believed that the Deccan volcanism was triggered by a mantle plume (a column of hot magma rising from deep within the Earth’s mantle), which caused widespread eruptions over a prolonged period.
• Impact on Climate: The massive eruptions released huge amounts of greenhouse gases (such as carbon dioxide) and sulfur aerosols, which likely led to global climate changes, including global warming and acid rain.
  • These changes are believed to have contributed to the extinction of many species, including the non-avian dinosaurs.
• Extent of the Deccan Traps: The Deccan Traps cover an area of about 500,000 square kilometers in India, with thicknesses of lava flows reaching up to 2,000 meters in places.

• The longest lava flows on Earth are found in the Deccan Traps; they are estimated to flow 1500Km across India and out into the Gulf of Bengal.

Source: PIB