Udupi's St Mary’s Islands on India’s tentative UNESCO World Heritage list

Udupi: The picturesque St Mary’s Islands, off the coast of Malpe, have moved a step closer to international recognition.

The island cluster has been placed on India’s Tentative List for UNESCO World Heritage Sites, marking it as a contender for global heritage status.

The four islands—Coconut, North, Darya Bahadurgarh, and South—form a chain stretching nearly six kilometres in the Arabian Sea.

Known for their breathtaking geological formations, they have long fascinated geologists and tourists alike. Their hallmark feature is the columnar jointing in rhyolitic lava, rare worldwide and virtually unique in India.

These striking rock columns, often mistaken for man-made sculptures, were formed some 88 million years ago during the Late Cretaceous period, when the Indian subcontinent drifted away from Madagascar.

As molten lava cooled and contracted, it cracked into vertical, polygonal pillars—nature’s own mosaic of stone.

Unlike the more common basaltic columns seen elsewhere, the St Mary’s formations are rhyolitic, making them scientifically rare and globally significant.

Dr Udayshankar, professor of Geology at Manipal Institute of Technology, highlights the importance of the site: “Spectacular columnar basalts fully cover this island, and these rock types are not seen on the mainland.

This is a volcanic island, 63 million years old, comparable with the Deccan volcanic rocks in Maharashtra, Gujarat, Madhya Pradesh, and northern Karnataka. It dates back to the Gondwana land break-up—Africa, Madagascar, India, Australia, and South America—continental drift.”

He added that palaeomagnetic studies conducted here have also deepened the understanding of India–Madagascar separation.

Tourism Department assistant director Vindya N M noted that the islands are relatively well-preserved.

Falling under India’s Coastal Regulation Zone, they enjoy legal protection, and tourism is regulated through short guided trips, she said.

Globally, the site finds parallels in Giant’s Causeway in Northern Ireland, a UNESCO site famed for its 40,000 basalt columns; Fingal’s Cave in Scotland, celebrated for its acoustics and legends; and Devils Postpile in California.

Prof Udayshankar, yet, stresses that St Mary’s Islands stand apart for their rhyolitic origin and tropical maritime setting, making them a rare geological spectacle.

For now, being placed on the tentative list is just the beginning. As India prepares its case for UNESCO inscription, the St Mary’s Islands are set to gain the global spotlight, celebrated not just as a tourist attraction but as a natural archive of Earth’s volcanic past.