Bakhira Lake sediments reveal 25,000 years of Central Ganga Plain climate
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A study by the Birbal Sahni Institute of Palaeosciences, reported by DST on 10 September 2026, measured magnetic minerals in sediments of Bakhira Lake in Sant Kabir Nagar, UP, to track 25,000 years of Indian Summer Monsoon change. Bakhira is an oxbow wetland of the Rapti and a Ramsar site since 2022. The record can improve monsoon models.
- Released
- 10 Sep 2026, DST (PIB)
- Institute
- Birbal Sahni Institute of Palaeosciences (BSIP), autonomous under DST
- Lake
- Bakhira, Sant Kabir Nagar, UP; Ramsar Site 2022
- Record
- about 25,000 years, seven AMS radiocarbon dates
- Journal
- Palaeogeography, Palaeoclimatology, Palaeoecology
The Bakhira Lake sediment study: what happened?
Direct records of rainfall do not go back far. To see older change, scientists read lake mud. Magnetic minerals in the layers show how much rain, erosion and runoff there was.
- A study of magnetic minerals in sediments of Bakhira Lake, Sant Kabir Nagar (UP), tracked climate change over 25,000 years [PIB].
- It can improve monsoon models and water management in the Central Ganga Plain [PIB].
What climate phases does the record show?
| Phase | Approx. age (ka BP) | Monsoon |
|---|---|---|
| Last Glacial Maximum and Heinrich Stadial 1 | 25.3 to 18.1 | cold, dry, weak |
| Bølling-Allerød | 15.3 to 12.8 | warm, humid, stronger |
| Younger Dryas | 12.8 to 11.1 | cool, dry, weak |
| Holocene Climatic Optimum | 9.2 to 4 | warm, wet, strong |
| Late Holocene droughts | 4 to 2 | dry, weaker |
ka BP = thousand years before present. PIB, 10 Sep 2026.
Why is Bakhira a good archive?
- It sits in the Ghaghara-Rapti alluvial system; it formed when the Rapti migrated and a loop was cut off.
- Sediment from the lake and its catchment settles and is preserved.
- Most earlier Central Ganga Plain studies covered only the Holocene.
What can Prelims ask on the Bakhira Lake sediment study?
- Bakhira Lake: Sant Kabir Nagar, UP; oxbow of the Rapti; Ramsar Site 2022.
- BSIP is an autonomous institute of DST.
- Proxy used: environmental magnetic properties of sediments.
How to use this in Mains
- As per PIB (2026-09-10): A study of magnetic minerals in sediments of Bakhira Lake, Sant Kabir Nagar (UP), tracked climate change over 25,000 years.
- Paleoclimate records help predict monsoon variability.
Quotable data pointA study of magnetic minerals in sediments of Bakhira Lake, Sant Kabir Nagar (UP), tracked climate change over 25,000 years.
PIB: Science & Technology: Bakhira Lake sediment study, 10 Sep 2026
Exam angle
Prelims: places in news (Bakhira).
Practice MCQs
Original practice questions (not PYQs).
Bakhira Lake, a Ramsar site, was formed by the cut-off of a meander of the
Answer (b) & explanation
PIB, 10 Sep 2026.
Questions students ask about this
Where is Bakhira Lake?
In Sant Kabir Nagar district of Uttar Pradesh, in the Ghaghara-Rapti alluvial system.
How was Bakhira Lake formed?
As an oxbow or floodplain wetland, after the Rapti River migrated and a meander was cut off.
What did the study find?
A record of monsoon change over about 25,000 years, from the Last Glacial Maximum to the late Holocene droughts.
Keep studying
Go deeper
Official source: PIB: Science & Technology: Bakhira Lake sediment study, 10 Sep 2026
facts from cited sources only; faculty review pending