Scientists From India, Japan Uncover Ancient Ocean Water In The Himalayas — And Clues To Earth's Past

Researchers from the Indian Institute of Science (IISc) and Japan's Niigata University have made an intriguing discovery high up in the Himalayas.

They have found droplets of water trapped in mineral deposits, believed to have originated from an ancient ocean that existed approximately 600 million years ago.

This finding provides valuable insights into the Earth's history and its paleo oceans.

The deposits, containing calcium and magnesium carbonates, have also presented an opportunity for a potential explanation for a significant oxygenation event in the past.

Prakash Chandra Arya, a PhD student at the Centre for Earth Sciences (CEaS) in IISc, says "We have found a time capsule for paleo oceans."

He is part of the study, which is published in the scientific journal Precambrian Research.

Scientists speculate that between 700 and 500 million years ago, the Earth experienced a period of intense glaciation known as the Snowball Earth glaciation.

During this time, the planet was covered by thick sheets of ice for an extended duration. This event is considered one of the major glacial occurrences in the Earth's history.

What followed was an increase in the amount of oxygen in the Earth's atmosphere, known as the Second Great Oxygenation Event. This event eventually led to the evolution of complex life forms.

Scientists have yet to fully understand the connection between these events. The lack of well-preserved fossils and the disappearance of past oceans make it challenging. However, the exposure of marine rocks in the Himalayas may provide some answers, according to IISc.

The mysteries surrounding past oceans remain. Questions about their similarities or differences compared to present-day oceans, their acidity, nutrient content, temperature, and chemical composition still need answers. Such insights could also offer clues about the Earth's past climate and be valuable for climate modeling, says Arya.

The team discovered deposits dating back to the time of the Snowball Earth glaciation. These deposits revealed that the sedimentary basins experienced a prolonged calcium deficiency, likely due to low riverine input.

During this period, the oceans lacked flow, resulting in a lack of calcium input. As a consequence, the precipitation of calcium caused an increase in the amount of magnesium, explains Sajeev Krishnan, a Professor at CEaS and an author of the study.

The researchers propose that the magnesium deposits formed during this time were able to store ancient ocean water in their pore space as they crystallised.

The deprivation of calcium also likely caused a deficiency in nutrients, creating an environment suitable for slow-growing photosynthetic cyanobacteria. These cyanobacteria may have started releasing more oxygen into the atmosphere.

According to Arya, an increase in oxygen levels in the atmosphere leads to biological radiation (evolution).

To locate these deposits, the team searched a vast area of the western Kumaon Himalayas, ranging from Amritpur to the Milam glacier, as well as from Dehradun to the Gangotri glacier region.

Through extensive laboratory analysis, it has been confirmed that the deposits found are a result of precipitation from ancient ocean water rather than from other sources like submarine volcanic activity.

These deposits hold the potential to provide valuable information about past oceanic conditions such as pH, chemistry, and isotopic composition.

Previously, this information has only been theorised or modeled, so it could greatly contribute to our understanding of the evolution of oceans and even life on Earth.