Fossilised rain drops found in India

An Indian geologist says he has discovered imprints of some of the oldest raindrops on Earth, dating back more than a billion years.

The imprints are exceptionally well preserved and are of great significance

Geologist Chirananda De

Geologist Chirananda De told the BBC that fossilised rain imprints were found on a rippled surface in primitive rocks in the lower Vindhyan range in Madhya Pradesh state.

''These imprints, which are at least 1,600 million years old, constitute one of the oldest sets of geological documents for rainfall,'' he said.

The Vindhyan mountains are formed by 4,000-metre-thick layers of sediment deposited at different periods.

Unique finding

The rain imprints were found on the exposed surface of sandstone sediment in Satna and Rewa districts in the state, according to a research article by Mr De published in the journal Current Science from the Centre for Ecological Sciences in Bangalore.

The find may give clues to past climate

The article said the rain imprints were represented by small impact craters - averaging about three to five millimetres in diameter.

These craters are circular or elliptical in shape, suggesting that the rain drops fell vertically or at a slight angle.

Balram Chatterji, a former director of the Geological Survey of India, said the finding could help in establishing the atmospheric conditions on Earth millions of years ago.

The article also said that the preservation of the rain craters suggested that ancient rainfall in the region was infrequent.