Indian scientists discover ancient ocean in Himalayas
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, and the discovery could provide crucial insights into a significant oxygenation event in Earth's past.
The study, published in Precambrian Research, reveals that these mineral deposits, rich in calcium and magnesium carbonates, are akin to a "time capsule for paleo oceans," according to Prakash Chandra Arya, a Ph.D. student at the Centre for Earth Sciences (CEaS), IISc, and the study's lead author.
Scientists theorise that between 700 and 500 million years ago, the Earth underwent a prolonged period of glaciation, known as the Snowball Earth glaciation.
This was followed by the Second Great Oxygenation Event, which led to a surge in atmospheric oxygen levels and the evolution of complex life forms. However, the connection between these events has remained elusive due to the scarcity of well-preserved fossils and the disappearance of ancient oceans.
The newly discovered marine rocks in the Himalayas could provide some answers.
The team's findings suggest that during the Snowball Earth glaciation, sedimentary basins experienced a prolonged calcium deficiency, likely due to reduced riverine input. This lack of calcium led to an increase in magnesium levels, with the resulting magnesium deposits trapping ancient ocean water as they crystallised.
This calcium deprivation may have also resulted in a nutrient deficiency, creating favorable conditions for slow-growing photosynthetic cyanobacteria. These organisms could have begun releasing more oxygen into the atmosphere, contributing to the Second Great Oxygenation Event.
The researchers conducted their study across a vast stretch of the western Kumaon Himalayas, from Amritpur to the Milam glacier and Dehradun to the Gangotri glacier region.
Extensive laboratory analysis confirmed that the deposits originated from precipitation from ancient ocean water, rather than from other sources such as submarine volcanic activity.
These findings could shed light on the chemical and isotopic composition of ancient oceans, providing valuable information for climate modeling and offering insights into the evolution of oceans and life on Earth.