Scientists of Indian Institute of Science (IISc) and Niigata University, Japan, have discovered droplets of water trapped in mineral deposits in the Himalayas that were likely left behind from an ancient ocean which existed around 600 million years ago.
The scientists believe that the 600-million-year-old ocean water from the Himalayas can provide the evolution of oceans, and even life, in Earth’s history.
Snowball Earth glaciation
IISc said that scientists believe that between 700 to 500 million years ago, thick sheets of ice covered the Earth for an extended period, called the Snowball Earth glaciation (one of the major glacial events in Earth’s history).
What followed this was an increase in the amount of oxygen in the Earth’s atmosphere, called the Second Great Oxygenation Event, which eventually led to the evolution of complex life forms.
So far, scientists have not fully understood how these events were connected due to the lack of well-preserved fossils and the disappearance of all past oceans that existed in the Earth’s history. Exposures of such marine rocks in the Himalayas can provide some answers, the institute said.
A time capsule
“We have found a time capsule for paleo oceans. We don’t know much about past oceans. How different or similar were they compared to present-day oceans? Were they more acidic or basic, nutrient-rich or deficient, warm or cold, and what was their chemical and isotopic composition? Such insights could also provide clues about the Earth’s past climate, and this information can be useful for climate modelling,” said Prakash Chandra Arya, Ph.D. student at the Centre for Earth Sciences (CEaS), IISc, and first author of the study published in Precambrian Research.
The deposits found by the team – which date back to around the time of the Snowball Earth glaciation – showed that the sedimentary basins were deprived of calcium for an extended period, probably due to low riverine input.
The long hunt
IISc said that the team hunted for these deposits across a long stretch of the western Kumaon Himalayas, extending from Amritpur to the Milam glacier, and Dehradun to the Gangotri glacier region.
Using extensive laboratory analysis, they were able to confirm that the deposits are a product of precipitation from ancient ocean water, and not from other places, such as the Earth’s interior (for example, from submarine volcanic activity).
