Life begun on Earth 60 million years earlier than previously thought, according to a geological survey who discovered the traces of lifeforms in the layers of ancient soils of India.
Moment at which earth’s atmosphere became oxygen-rich and suitable for life known as the “Great Oxidation Event“, is believed to have occurred around 2.4 billion years ago. But geologists from Ireland and India have recently found evidence of such event which took place 600 million years earlier.
Researchers claim that another study suggests that the first oxygen-producing lifeforms have begun to develop on Earth 60 million years earlier than thought before.
Scientists say that these lifeforms are responsible for adding oxygen in terrestrial atmosphere, a cornerstone for the evolution of life.
Indian geologists have found evidence of chemical weathering of rocks that led to the formation of very old soil, and this alteration could be done only in the presence of oxygen.
Using the naturally occurring uranium-lead isotope decay system, scientists were able to determine the age of the soil at least 3.02 billion years.
The chemical weathering of rocks found in ancient soil, or paleosol, as geologists call it, is compatible with the presence of high levels of atmospheric oxygen at that time, said researchers at Trinity College Dublin, who collaborated with specialists from Presidency University of Calcutta, India.
These high oxygen levels could only have been produced by organisms that were capable of photosynthesis., say researchers, showing that the discovery helps to fill some empty spaces in what was known about the evolution of the early Earth.
‘This paleosol from India is telling us that there was a short-lived pulse of atmospheric oxygenation and this occurred considerably earlier than previously envisaged.’ said Professor Quentin Crowley at Trinity College, who led the study.
Source: © CosmosUp.com.