South Africa, India and Australia shared similar volcanic activity 3.5
billion years ago
Ancient volcanism dating back to 3.5 billion years ago are common to
Archaean cratons of South Africa, India, and Australia

Date:
June 8, 2023
Source:
University of the Witwatersrand
Summary:
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.


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FULL STORY ========================================================================== Cratons are pieces of ancient continents that formed several billions of
years ago. Their study provides a window as to how processes within and on
the surface of Earth operated in the past. Cratons preserve relics of our
young Earth as they host a variety of rock assemblages such as greenstones
and granites. Greenstones are rock assemblages that primarily comprise of
sub- marine volcanic rocks with minor sedimentary rocks. They are the best archives to study early Earth surface processes. A new study published in Precambrian Research by a team of researchers, led by Dr Jaganmoy Jodder
of the University of the Witwatersrand's Evolutionary Studies Institute
shows that the Singhbhum Craton in India hosts remarkably well preserved volcanic and sedimentary rocks as old as 3.5 billion years, and that it
has similar geologic history to parts of South Africa and Australia.

The team that included researchers from the University of the
Witwatersrand (Wits University), University of Johannesburg (UJ) and
Chinese Academy of Sciences, Beijing, examined volcanic and sedimentary
rocks from the Daitari greenstone belt in the Singhbhum Craton of India
that were formed approximately 3.5 billion years ago. Jodder and his
co-workers conducted detailed field-based studies and precise Uranium-Lead (U-Pb) radiometric-age dating to evaluate the geology of the ancient
greenstone rocks. Based on their study, the researchers 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," says Jodder.

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 provide evidence 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. 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." 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," says Jodder.

Jodder and the team of researchers propose that these ancient continents
may have been subjected to geologically similar processes 3.5 billion
years ago.

"However, we are not certain about their palaeo-geographic
positioning. And thus, cannot validate that they once formed part of a supercontinent," says Jodder.

"The current research has led to a broader understanding of the ancient volcano-sedimentary rocks exposed in the Daitari area in India. This
study resulted in unique recognition of felsic magmatic processes that
are common to the Archaean cratons of India, South Africa and Australia respectively during the Palaeoarchaean times. It opens up newer avenues
for research on early Earth processes," says Jodder.

* RELATED_TOPICS
o Earth_&_Climate
# Geology # Volcanoes # Natural_Disasters # Geography
o Fossils_&_Ruins
# Origin_of_Life # Fossils # Ancient_Civilizations #
Human_Evolution
* RELATED_TERMS
o Gondwana o Geology_of_the_Capitol_Reef_area o Ancient_Egypt
o Mountain o Parallel_evolution o Geology_of_the_Alps o
Homo_heidelbergensis o Engineering_geology

========================================================================== Story Source: Materials provided by University_of_the_Witwatersrand. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Jaganmoy Jodder, Axel Hofmann, Hangqiang Xie, Marlina A. Elburg,
Allan
Wilson. Geochronology of the Daitari Greenstone Belt, Singhbhum
Craton, India. Precambrian Research, 2023; 388: 106997 DOI:
10.1016/ j.precamres.2023.106997 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/06/230608120950.htm

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