Lonar Lake: Vidarbha’s Mysterious Meteoric Crater Lake

Pranay Arya
Jan 12
7 min read

Lonar Lake in the Vidarbha region of Maharashtra is unlike any other lake in India. It rests in a circular crater formed by a meteorite impact thousands of years ago, making it one of the world’s few known impact craters in basalt rock.

The lake’s waters are both saline and alkaline, so rich in minerals that locals once collected soda ash from its shores during dry seasons. In recent times, this crater lake even turned bright pink due to an explosive bloom of salt-loving microbes, a phenomenon that drew global attention.

Scientists were long baffled by Lonar’s origin and unusual chemistry, while local legends revered it as a creation of divine forces.

Today, Lonar Lake is recognised as a geological wonder and a protected site, though it faces modern challenges that threaten its delicate ecosystem and heritage.

Meteor Impact and Geological Puzzles

Lonar Lake’s story began with a colossal meteor strike in what is now Buldhana district of Vidarbha.

The impact on hard Deccan basalt rock carved out a crater roughly 1.8 km across and 150 m deep.

Early studies estimated that this cosmic collision occurred around 35,000 to 50,000 years ago, though newer dating research suggests the crater might be much older, perhaps up to about 570,000 years. Notably, the meteor is believed to have fragmented just before impact. Aside from the main Lonar crater, two smaller depressions nearby, locally known as Ganesh and Amber lakes are thought to have formed from the same event, though those minor craters have long dried up.

For decades, the Lonar crater perplexed geologists. When a British officer first documented it in 1823, many assumed it was volcanic in origin because it lies amid the vast volcanic basalt flats of the Deccan plateau.

It took more than a century of debate and a series of studies in the 1960s and 1970s to confirm the extraterrestrial origin. Researchers drilled into the crater floor and discovered telltale evidence of an impact, shocked basalt fragments and a glassy mineral called maskelynite, which forms only under the extreme pressure of a high velocity meteor strike.

In 1973, a landmark scientific study reported the presence of maskelynite and other shock metamorphic features at Lonar, finally establishing that the lake’s crater was created by a meteorite and not by any volcano.

Lonar is globally unique, often described as the only known impact crater in basaltic rock that still holds a lake.

This rare context makes it a valuable analogue for craters on the Moon and Mars, which also have basaltic geology. Scientists have been intrigued by Lonar for precisely this reason. The crater’s formation in volcanic rock mirrors conditions on the lunar surface.

Recent mineralogical studies have found that soil samples from Lonar contain minerals similar to those found in lunar rock samples returned by space missions.

The site’s otherworldly qualities are such that even compasses are said to behave erratically near certain parts of the crater rim, a quirk attributed to magnetic anomalies in the basalt or remnants of the meteorite. All these factors have put Lonar on the map as a natural geological laboratory, preserving evidence of an ancient impact amidst the Indian countryside.

A Unique Saline Ecosystem

Lonar Lake’s environment is as unusual as its origin. The crater’s closed basin traps water and minerals, resulting in a hyper-saline and alkaline lake unlike any other in India.

Tests have shown the lake water’s pH levels hovering around 10 far more alkaline than normal freshwater.

During hot, dry months, intense evaporation concentrates the salts to the point that the water can become seven times saltier than seawater.

Historically, villagers harvested the lake’s soda rich evaporites. Centuries-old administrative records noted that the Lonar area produced all the necessary ingredients for making quality glass and soap from these mineral deposits.

Two small streams periodically drain into the crater, and a freshwater spring emerges along the lake’s edge, but there is no outlet everything that flows in is either absorbed or evaporates within the bowl of the crater. This has created a caustic body of water that only specialised life can tolerate.

The lake’s extreme chemistry has fostered a niche ecosystem of microbes and algae found in few other places. Scientific surveys have identified multiple species of algae in the water, including blooms of Dunaliella salina, a green micro alga known to thrive in high salinity. More famously, Lonar is home to haloarchaea, salt-loving microorganisms that produce reddish pigments.

These microorganisms dramatically announced their presence in June 2020, when Lonar Lake’s green waters overnight turned pink. With human activity around the crater reduced, scientists observed an intense bloom of haloarchaea tinting the lake’s surface a reddish hue.

Analysis later confirmed that increased salinity and heat allowed the pigmented microbes to dominate the upper layers of the water. Once monsoon rains arrived and fresh water mixed into the crater, microbial levels dropped, and the lake gradually returned to its usual greenish colour. This rare episode highlighted how delicately balanced Lonar’s ecosystem is.

Beyond microorganisms, the broader crater habitat supports a surprising variety of life. The forested slopes around Lonar Lake are protected as a wildlife sanctuary and support several species of mammals and over a hundred species of birds.

Sightings of nilgai, chital, peafowl and barking deer are common in the surrounding scrub and dry deciduous forest.

More elusive animals, such as sloth bears and wolves, have also been recorded in the sanctuary. Migratory birds visit the lake seasonally, drawn by the algae and aquatic organisms in its waters.

Researchers have also identified microbes in Lonar that fix atmospheric nitrogen, a rare function in such alkaline environments. From microscopic life to large mammals, the crater supports a web of organisms adapted to its isolated mineral rich conditions.

Mythology and Historical Significance

For the people of Vidarbha, the Lonar crater has long been more than a scientific curiosity. Local folklore traces the lake’s origin to a battle in ancient times involving a demon named Lonasura.

According to the legend, a divine warrior defeated the demon and hurled him into the ground, forming the crater and filling it with the demon’s saline blood. This belief gives Lonar both its name and spiritual importance.

A medieval temple dedicated to Daityasudan, an incarnation of Vishnu, stands in Lonar town and remains an important religious site. Numerous ancient temples, some dating back over a thousand years, are scattered along the crater rim and slopes. Many are now partially ruined, overtaken by vegetation and time, though their stone carvings still reflect the craftsmanship of earlier dynasties that ruled the region.

Several of these temples are protected as archaeological monuments. Their architectural styles reflect regional traditions, particularly stone construction techniques common in early medieval Maharashtra. Religious festivals continue to draw pilgrims to the crater, reinforcing its cultural relevance alongside its geological importance.

Lonar Lake also played a role in historical economies. Its mineral rich waters supported the extraction of soda ash, which was used in soap and glass making for centuries. Historical records mention Lonar as a site where essential materials for glass production were obtained. The town surrounding the crater developed small scale industries based on these natural resources.

Even during the Mughal period, Lonar was noted for the quality of soap produced using its alkaline salts. These activities declined over time, but they form an important part of the lake’s historical identity. When colonial surveyors rediscovered the crater in the nineteenth century, its scientific importance was not yet understood, but its cultural and economic value was already well established among local communities.

Conservation and Current Status

In recent decades, Lonar Lake has received formal recognition for its ecological and geological importance. The crater and its surroundings were designated a wildlife sanctuary, bringing forested slopes and the lake under legal protection.

Later, Lonar Lake was recognised internationally as a wetland of importance, highlighting its rare ecosystem.

Geological authorities have also classified the crater as a national geoheritage site due to its status as a meteor impact structure preserved in basalt rock. These designations have encouraged scientific research and increased public awareness.

At the same time, Lonar faces growing pressures. Agricultural runoff from nearby fields introduces nutrients and chemicals into the crater. Waste left by visitors has accumulated along parts of the shoreline. Invasive plant species have spread across sections of the basin, altering native vegetation patterns.

Some historic temples have suffered from unscientific repairs using modern materials, damaging their original stonework.

Encroachments and construction near the crater rim have contributed to soil erosion and habitat disturbance.

Efforts to manage these challenges have included clean up drives, visitor guidelines, and ecological monitoring. Scientists continue to study changes in water chemistry, microbial populations, and biodiversity to better understand how the lake responds to environmental stress.

The closed nature of the crater means even small disturbances can have lasting effects, making careful oversight essential.

Lonar Lake stands as a striking reminder of natural forces that shaped the Earth long before human history began. The crater connects deep geological time with living ecosystems and long standing cultural traditions in Vidarbha.

Looking into its mineral rich waters is to confront a rare convergence of cosmic history and local life. Lonar’s continued survival depends on recognising its scientific value and cultural meaning while respecting the limits of its fragile environment.