In News:

600-million-year-old stromatolites in the Himalayas tell the story of an ocean lost and Earth’s first breath.

What are Stromatolites?

Stromatolites are organo-sedimentary structures formed by the entrapment of calcium carbonate precipitates by cyanobacteria (blue-green algae) in shallow marine environments. These layered, dome-shaped mounds represent some of the earliest evidence of life on Earth, with their formation driven by photosynthetic microbial mats.

• Composition: Typically found in limestone, shale, and sandstone.
• Structure: Characterized by laminated layers that may appear flat, dome-shaped, or columnar.
• Habitat (Ancient & Modern): Mostly marine; some ancient forms inhabited freshwater and intertidal zones. Today, living stromatolites survive in limited saline lagoons and bays.

Latest Discovery: Chambaghat, Himachal Pradesh

A major stromatolite outcrop, dating back 600 million years, was recently found in Chambaghat, Solan district, Himachal Pradesh. These structures lie within the Krol Group of sedimentary rocks — a part of the ancient Tethys Sea that existed before the Indian plate collided with Eurasia.

• Elevation: Found at 5,000–6,000 ft above sea level, showcasing tectonic uplift.
• Age Significance: Though not the oldest globally or in India, these are among the younger but well-preserved stromatolites, possibly from the Precambrian-Cambrian boundary (~543–548 million years ago).

Scientific Importance

• Geological Record: Stromatolites document Earth's atmospheric shift from a greenhouse gas-rich to an oxygen-rich environment — a transformation driven by photosynthetic cyanobacteria.
• The Great Oxidation Event (GOE): Occurred ~2.4 billion years ago, when oxygen produced by cyanobacteria began accumulating in the atmosphere, enabling the evolution of multicellular life.
• Tectonic History: Their presence in the Himalayas illustrates the story of the Gondwana supercontinent, India’s northward drift, and the closure of the Tethys Sea.

Global and Indian Context

• Oldest Stromatolites (Global): ~3.6 billion years old from Western Australia.
• Oldest in India: ~2.5 billion years old in the Dharwar Supergroup, Karnataka.

Prominent Stromatolite Sites in India:

Region                                                      Geological Feature

Chitrakoot, Uttar Pradesh                    Columnar stromatolites in Vindhyan limestones

Morni Hills, Haryana                            Preserved stromatolites in dolomite

Mussoorie & Nainital, Uttarakhand    Precambrian marine stromatolites in Krol Belt

Jaisalmer Fossil Park, Rajasthan         Protected Mesozoic marine fossil site

Dharwar Supergroup, Karnataka        Neoarchean stromatolites (~2.6 billion years old)

Bhima Basin, Karnataka                      Precambrian stromatolites in shallow marine limestones

Preservation and Geoheritage

Geologists and experts advocate for declaring Chambaghat as a Geoheritage Park, involving local communities and schools to foster awareness. The goal is to integrate science with tourism, conservation, and education.

• Challenge: Many stromatolitic sites across India face neglect or risk from mining and construction, despite their scientific and educational potential.
• Appeal: Proposal for UNESCO Geoheritage status to protect and promote this prehistoric legacy.