Scientists from the Indian Institute of Science (IISc) and Niigata University, Japan, have made a significant discovery high up in the Himalayas. They found droplets of water trapped in mineral deposits, indicating the existence of an ancient ocean around 600 million years ago. The deposits, containing calcium and magnesium carbonates, have also shed light on a major event in Earth’s history – the oxygenation of the atmosphere.
Prakash Chandra Arya, a PhD student at IISc and the study’s lead author, describes this finding as a “time capsule for paleo oceans.” According to their research, between 700 and 500 million years ago, Earth experienced the Snowball Earth glaciation, where thick ice sheets covered the planet for an extended period. This was followed by the Second Great Oxygenation Event, leading to the development of complex life forms.
The connection between these events has been a mystery due to the lack of well-preserved fossils and the absence of past oceanic remains. However, the exposure of marine rocks in the Himalayas has offered some answers. The researchers believe that studying past oceans can provide valuable insights into their characteristics, chemistry, and isotopic composition, which, in turn, can help us understand Earth’s past climate and aid climate modeling.
The deposits discovered by the team date back to the time of the Snowball Earth glaciation. During this period, the sedimentary basins lacked calcium due to minimal riverine input. As a result, magnesium deposits formed and trapped paleo ocean water as they crystallized. This calcium deficiency likely created a nutrient-poor environment, fostering slow-growing photosynthetic cyanobacteria that increased oxygen levels in the atmosphere, leading to the evolution of life.
The research team conducted extensive laboratory analysis to confirm that the deposits indeed originated from ancient ocean water rather than other sources like submarine volcanic activity.
The significance of these findings lies in their potential to provide concrete information about ancient oceanic conditions, which had previously been only theoretical or modeled. Understanding the evolution of oceans and life in Earth’s history can offer valuable insights into our planet’s past and its environmental changes over time.
