Meert, the study leader, said the discrepancy between the new study and older ones is easy to explain: Initial age estimates were done in the early days of geochronology, when methods for dating rocks and sediments were not as accurate.
Even still, he noted, "in geology it's rare these days to revise the age of a large region of Earth by 500 million years."
Mired in Controversy
The findings have raised the ire of some researchers in India, "where the age of the basins has been sacrosanct," Meert added.
"Some Indian researchers think that we are wrong on the ages of the upper and lower sections, and [that] they both are only about 630 to 500 million years old," Meert said.
But the findings match with other recent work in the area, he added.
While his team focused on upper sedimentary sections of the basin, researchers in 2002 dated lower sediments at 1.8 to 1.5 billion years, older than the initial 1.4-billion-year age estimates, he said.
Bickford, who conducted a similar dating study in recent years in India's neighboring Chhattishgarh Basin, also found minerals dated at a billion years.
"There are a lot of implications to this," he said. "The one most exciting is the question of snowball Earth."
New Lease on Life
Supporters of the snowball Earth theory say evidence can be found in glacial etchings and sediment deposits that chart the ice flows long after it melted.
"One of the puzzling aspects of these basins, when they were thought to be younger, is that they contained no evidence of these severe glaciations," study leader Meert said. "If the rocks are as old as we think, then they should not contain glacial relics because they are too old."
Given the new age assessments, the basins would have been filled with sediment 500 million years ago, which explains the lack of glacial evidence, Bickford said.
And the new age estimates of the basins may potentially have a ripple effect on how life is believed to have developed on Earth, Meert said.
The new findings would mean that any verified fossils of multicellular organisms found in both the upper and lower sediments are older by hundreds of millions of years, he said.
Some researchers, for example, have made disputed claims about the discovery of multicellular creatures in the area dating to 1.6 billion years ago.
(Related: "Indian Fossil Bed Being Ground Into Cement" [February 6, 2008].)
If this speculation is verified, Meert said, "that would drastically impact our theories on the evolution of multicellularity."
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