Scientists from the Indian Institute of Science (IISc), Bengaluru, and Niigata University, Japan, have unearthed remnants of an ancient ocean in the Himalayas. The team found water droplets trapped in mineral deposits dating back approximately 600 million years. The study suggests that the unique find could provide crucial insights into a significant oxygenation event in Earth’s past.
The encapsulated droplets, which the researchers described in a study published in Precambrian Research, offer a window into the conditions of paleo oceans. They are akin to “time capsules for paleo oceans,” said Prakash Chandra Arya, a Ph.D. student at IISc and lead author of the study.
According to the researchers, the pristine ocean that existed between 700 and 500 million years ago — one of the significant glacial periods in Earth’s history — was a water-rich environment that may have boosted oxygen levels in the atmosphere and triggered the emergence of complex life forms on our planet. The discovery of the pristine ancient marine rock deposit in the Himalayas could help answer questions about the links between these events, researchers said.
Only now, the connection between these significant events remained elusive due to a lack of well-preserved fossils and the disappearance of past oceans, scientists noted. But the exposure of ancient marine rocks in the Himalayas, like the one uncovered by the researchers, provides new clues.
The Indo-Japanese team of scientists spent over five years searching a vast area of the western Kumaon Himalayas in India for this particular sea sediment. The deposits they stumbled upon are a tidbit of the pristine ocean that existed during a period known as the Snowball Earth glaciation era, PTI reported. The team analyzed the sediments and traced them back to their origin in the Himalayan mountain chain.
They also did experiments in their specially designed labs to confirm their findings. They tested the samples’ chemistry and isotopic composition and found they were consistent with the presence of water droplets.
Finding these deposits was like playing hide-and-seek with nature, the researchers say. “We looked across a super-duper long stretch of the Himalayas, like searching from one side of your school playground to the other,” said Sajeev Krishnan, a professor at IISc and a co-author of the study. “We did all sorts of cool experiments to ensure we had uncovered a tiny piece of the ancient Himalayan ocean.”
The pristine marine sediments, rich in calcium and magnesium carbonates, contain droplets most likely left behind by an ancient, oxygen-rich sea. In the past, these sea organisms would have dissolved copious amounts of oxygen into the atmosphere through their photosynthetic activities, triggering a global increase in oxygen levels known as the Second Great Oxygenation Event, they noted. This oxygen-rich atmosphere is believed to have paved the way for the emergence of complex living organisms. This is the first time these ancient oxygenated waters have been identified on Earth.