34-million-year-old fossil leaves from Nagaland link Antarctic ice to Indian monsoon
A study by the Birbal Sahni Institute of Palaeosciences and Wadia Institute of Himalayan Geology, released by DST on 9 September 2025, used 34-million-year-old fossil leaves from Nagaland's Laisong Formation to link Antarctic ice formation with the early Indian monsoon.
Summary
A study led by researchers from the Birbal Sahni Institute of Palaeosciences (BSIP), Lucknow and the Wadia Institute of Himalayan Geology, Dehradun, autonomous institutes of the Department of Science and Technology, has linked the formation of Antarctic ice sheets about 34 million years ago to the early evolution of the Indian monsoon, DST said on 9 September 2025. Well-preserved fossil leaves from the Laisong Formation in Nagaland, about 34 million years old, showed that the region once had a warm, wet climate with very high rainfall and temperatures. The research, published in Palaeogeography, Palaeoclimatology, Palaeoecology, found that the growth of Antarctic ice reshaped global wind and rainfall patterns by shifting the Intertropical Convergence Zone (ITCZ), bringing intense monsoonal rain to Northeast India.
Key facts
- Fossil site
- Laisong Formation, Nagaland
- Age
- ~34 million years
- Institutes
- BSIP Lucknow and WIHG Dehradun (DST autonomous)
- Mechanism
- Antarctic ice growth shifted the ITCZ
- Journal
- Palaeogeography, Palaeoclimatology, Palaeoecology
Practice MCQs 2 questions
Fossil leaves from which geological formation in Nagaland helped link Antarctic ice formation to the early Indian monsoon, per a DST release of September 2025?
Show answer
Correct answer: B — Laisong Formation
The study used well-preserved fossil leaves, about 34 million years old, from the Laisong Formation in Nagaland.
According to the BSIP–WIHG study, how did the growth of Antarctic ice about 34 million years ago bring intense monsoon rains to Northeast India?
Show answer
Correct answer: D — By shifting the Intertropical Convergence Zone (ITCZ)
The research found that the growth of Antarctic ice reshaped global wind and rainfall patterns by shifting the Intertropical Convergence Zone (ITCZ), a major rain belt.