· India hosts remarkably
well-preserved volcanic and sedimentary rocks as old as 3.5 billion years, and
has similar geologic history to parts of South Africa and Australia, a study
has found.
· Researchers from the
Wits University, the University of Johannesburg (UJ), both in South Africa, and
the Chinese Academy of Sciences, examined volcanic and sedimentary rocks from
the Daitari greenstone belt in the
SinghbhumCraton in east India that were formed approximately 3.5 billion
years ago.
· Cratons are pieces of
ancient continents that formed several billions of years ago. Their study
provides a window into how processes within and on the surface of Earth
operated in the past.
· The team conducted detailed
field-based studies and precise Uranium-Lead
(U-Pb) radiometric-age dating to evaluate the geology of the ancient
greenstone rocks.
· The study,
published in 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.
· Sub-marine volcanic
eruptions were common between 3.5 and 3.3 billion-years-ago, which are largely
preserved as pillowed lava within the greenstones of the Singhbhum, Kaapvaal
and Pilbara cratons.More importantly, the style
of volcanism decoded from the silicic rocks, which are rich in silica,
provide evidence for explosive sub-marine to sub-aerial settings.
· Detrital zircon
geochronology analyses the age of zircons deposited within a specific
sedimentary unit.Studies of ancient greenstones are important not only to
understand the diverse volcanic processes but well-preserved greenstones
preserve minor sedimentary rocks that formed under 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.
· The team proposes that
these ancient continents may have been subjected to geologically similar
processes 3.5 billion years ago.