Tech Explorist: A team of researchers has unraveled the imprints of the sea level fluctuations and climate change that may have occurred along the coastal river of Saurashtra region in India’s west coast over the past 1.5 lakh years.
Researchers analyzed samples taken from more than six meters sedimentary sequences along the Noli River between Mangrol to Chorwad.
They carried out geomorphology, sedimentology and optical dating studies.
They found that there were four distinct significant layers.
The bottom-most layer was two meters thick and was composed of miliolite limestone with a lot of oyster shells. There was also evidence of bioturbations. This indicates that there was a marine environment around the time when the layer was formed.
Miliolite Limestone is a rock which is typically formed under shallow, warm, agitated waters of tropical sea shores and oysters are salt-water molluscs.
According to scientists, the layer perhaps represented a 3 to 5 meters higher sea level than the present days and related to the last interglacial high sea level, which was about 1.5 lakh to 1.2 lakhs years ago.
The layer above that was one-meter thick.
It had a lot of miliolitic sand, pebbles and oyster shells. It was found to be 1.14 lakh years old. The Indian summer monsoon had been the most intense during this period. The miliolitic sand seems to have been transported by what is called fluvial activity or flow of water. It was overlaid by a 1.5-meter thick layer with pebbles, cobblestone, and lithoclasts of limestone.
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