India hosts remarkably well-preserved volcanic and sedimentary rocks as outdated as 3.5 billion years, and has similar geologic history to parts of South Africa and Australia.
| Photo Credit: Okay.R. Deepak/The Hindu
India hosts remarkably well-preserved volcanic and sedimentary rocks as outdated as 3.5 billion years, and has similar geologic history to parts of South Africa and Australia, a examine has discovered.
Researchers from the Wits University, the University of Johannesburg (UJ), each in South Africa, and the Chinese Academy of Sciences, examined volcanic and sedimentary rocks from the Daitari greenstone belt within the Singhbhum Craton in east India that had been shaped roughly 3.5 billion years in the past.
Cratons are items of historic continents that shaped a number of billions of years in the past. Their examine supplies a window into how processes inside and on the floor of Earth operated prior to now.
The workforce carried out detailed field-based research and exact Uranium-Lead (U-Pb) radiometric-age relationship to consider the geology of the traditional greenstone rocks.
The examine, revealed within the journal Precambrian Research, established key geological timelines that illustrate the tectonic evolution of the Daitari greenstones.
“The Daitari greenstone belt shares a similar geologic make-up when compared to the greenstones exposed in the Barberton and Nondweni areas of South Africa and those from the Pilbara Craton of north-western Australia,” mentioned Jaganmoy Jodder of the Wits University.
Sub-marine volcanic eruptions had been widespread between 3.5 and three.3 billion-years-ago, that are largely preserved as pillowed lava throughout the greenstones of the Singhbhum, Kaapvaal and Pilbara cratons.
More importantly, the model of volcanism decoded from the silicic rocks, that are wealthy in silica, present proof for explosive sub-marine to sub-aerial settings.
“Following silicic volcanism, sedimentary rocks that comprise sub-marine turbidity current deposits formed upon drowning of the volcanic vent,” mentioned Jodder, who led the examine.
“This provided us with an age estimate for the sub-marine sedimentary rocks that got deposited approximately 3.5 billion years ago, which was based on precise detrital U-Pb zircon data,” he added.
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Detrital zircon geochronology analyses the age of zircons deposited inside a selected sedimentary unit.
Studies of historic greenstones are necessary not solely to perceive the varied volcanic processes however well-preserved greenstones protect minor sedimentary rocks that shaped underneath sub-marine settings.
“These volcano-sedimentary rocks provide clues related to habitable environments on the young Earth and can be regarded as time capsules to help us better understand the evolutionary tale of the planet in its early stages,” mentioned Jodder.
The workforce proposes that these historic continents might have been subjected to geologically similar processes 3.5 billion years in the past.
“However, we are not certain about their palaeo-geographic positioning. And thus, cannot validate that they once formed part of a supercontinent,” Jodder added.
