Jharkhand Coal Mine Reveals 290-Million-Year-Old Gondwana Ecosystem

Researchers investigated the Ashoka Coal Mine in the North Karanpura Basin of Jharkhand, where layers of coal and shale preserved a rich archive of ancient plant fossils and chemical signatures.

A multidisciplinary study of open cast coal mines in Jharkhand has uncovered remarkable evidence of a lost ecosystem that existed nearly 300 million years ago—long before dinosaurs or humans appeared on Earth. The discovery reconstructs dense swamp forests and interconnected river systems that once thrived when India was part of the southern supercontinent Gondwanaland.

The findings not only deepen understanding of Earth’s deep past but also offer critical insights into how marine incursions and sea-level rise can reshape continental environments—a question that resonates strongly in the era of climate change.

The study, led by the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institute under the Department of Science and Technology (DST), Government of India, has been published in the International Journal of Coal Geology.

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Reconstructing India’s Prehistoric Gondwana Landscape

Researchers investigated the Ashoka Coal Mine in the North Karanpura Basin of Jharkhand, where layers of coal and shale preserved a rich archive of ancient plant fossils and chemical signatures.

Around 280–290 million years ago (Permian Period), India was joined with Antarctica, South Africa, South America, and Australia as part of Gondwanaland. The new study reconstructs a lush, swampy ecosystem occasionally influenced by marine waters—suggesting periodic sea incursions into what was once considered an exclusively continental basin.

Earlier research had proposed multiple theories regarding the Permian Sea transgression, but fossil and sedimentary evidence remained sporadic and geographically limited. The new integrated approach combining palaeobotany and geochemistry provides stronger, location-specific proof of marine influence in the Damodar Basin.

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Fossil Treasure Trove: Glossopteris Dominance

One of the most significant outcomes of the study is the discovery of an extraordinary fossil record of Glossopteris, an extinct group of seed plants that dominated southern continents during the Permian.

Researchers identified:

• Fossils of at least 14 species of Glossopteris and its close relatives

• Delicate leaf impressions preserved in shale

• Fossilized roots

• Spores and pollen grains

A Globally Significant Discovery

Among the most important finds is the first-ever juvenile male cone of Glossopteris discovered in the Damodar Basin. This rare specimen represents a long-missing reproductive structure, helping scientists better understand how these ancient trees reproduced.

The discovery fills a crucial gap in Glossopteris biology and strengthens evolutionary links between Gondwanan plant assemblages across southern continents.

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Chemical Clues of an Ancient Sea

The team combined fossil evidence with advanced geochemical techniques to decode the environmental history of the basin.

Microscopic examination of coal and shale samples revealed:

• Framboidal pyrite — tiny raspberry-shaped mineral clusters

• Unusually high sulphur content in coal layers

These features are typically associated with brackish or marine-influenced conditions, rather than freshwater swamp deposits common in coal basins.

Further analysis using Gas Chromatography–Mass Spectrometry (GC–MS) identified organic molecular signatures consistent with marine incursions.

The data suggest that during the late Permian, seawater advanced into the Damodar Basin, possibly moving from Northeast India toward Central India, establishing a clearer pathway for the Permian Sea transgression.

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Why This Matters Today

The study’s implications extend beyond palaeontology and coal geology.

By reconstructing how ancient sea-level rise periodically flooded continental ecosystems, the findings provide a geological analogue for understanding modern climate challenges. Today, rising global temperatures and polar ice melt are contributing to accelerating sea-level rise.

The Gondwanan case study shows how:

• Marine waters can penetrate deep into continental interiors

• Ecosystems adapt—or collapse—under shifting salinity conditions

• Sedimentary basins preserve long-term environmental signatures

Such insights may help scientists model future risks of coastal and inland marine encroachment under ongoing global warming.

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Advancing India’s Geological Research

The research demonstrates the value of integrating:

• Palaeobotany

• Coal petrology

• Sedimentology

• Organic geochemistry

By combining fossil plant records with microscopic mineral and chemical signatures, scientists reconstructed a comprehensive picture of a vanished ecosystem that existed nearly three times older than the age of dinosaurs.

The findings significantly refine the sedimentation history of the North Karanpura Coalfield and add a critical marine dimension to the geological evolution of India’s Gondwana basins.

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Publication

The study is published in the International Journal of Coal Geology.DOI: https://doi.org/10.1016/j.coal.2025.104860