Researchers at Nagaland University have conducted a comprehensive geological study of the Sylhet Limestone formations in Anglong district, shedding new light on the region’s ancient marine environment during the Eocene period.
Lumami, July 20 (MExN): Researchers at Nagaland University have conducted a comprehensive geological study of the Sylhet Limestone formations in Assam’s Karbi Anglong district, shedding new light on the region’s ancient marine environment during the Eocene period. The findings, published in the Journal of Geosciences Research, offer critical insights into carbonate sedimentation and palaeoenvironmental reconstruction of Northeast India.
The study, led by Prof SK Srivastava and research scholar Tsenchumo Lotha from the Department of Geology, employed an integrated approach combining field observations, petrographic analysis, and micropalaeontological investigations. This marks a significant departure from earlier studies that relied largely on limited field data, stated a press release.
The researchers examined rock layers including limestone, shale, and sandstone, alongside sedimentary structures both physical and biological, and analysed microfossils (foraminifers) and mineral composition through microscopic examination. The evidence indicates that the Dillai Parbat area was once part of a shallow, warm, oxygen-rich marine environment, akin to a lagoon or near-shore sea under tropical to subtropical climatic conditions.
The study also documents fluctuations in sea level over time, varying energy conditions in the depositional environment, and evidence of storm events that left distinct imprints on the rock formations. The observed changes, the researchers noted, were linked to tectonic movements.
“We attempted to understand the depositional conditions by combining field observations and laboratory analysis. The evidence indicates that the limestone was deposited in a shallow marine, warm-water environment with favourable ecological conditions for microfaunal growth,” Prof Srivastava explained.
Lotha highlighted the significance of the interdisciplinary method, stating, “Things are not always clear when we are in the midst of fieldwork. But when we connected the same with lab results, the overall picture started becoming clearer. That process was really important for understanding the environment of deposition.”
The research is expected to aid future geological correlation and basin analysis in similar settings, while also contributing to the broader understanding of sedimentation processes, microfossil assemblages, and palaeoenvironmental conditions in Northeast India.
Congratulating the team, Nagaland University Vice-Chancellor Prof Jagadish Kumar Patnaik said, “Such high-quality research reflects Nagaland University's commitment to advancing knowledge through rigorous scientific inquiry and interdisciplinary collaboration. I hope this achievement will inspire our faculty and students to pursue impactful research that addresses fundamental scientific questions while contributing to national and global scholarship.”
The peer-reviewed study is available online at the Journal of Geosciences Research (DOI: 10.56153/g19088-025-0289-109), which publishes original work across geology, geophysics, geochemistry, palaeontology, hydrogeology, remote sensing, and environmental geology.
