Date:

Study suggests Earth could have supported continental crust, life earlier than thought

The early Earth might have been habitable much earlier than thought, according to new research from a group led by University of Chicago scientists.

Counting strontium atoms in rocks from northern Canada, they found evidence that the Earth’s continental crust could have formed hundreds of millions of years earlier than previously thought. Continental crust is richer in essential minerals than younger volcanic rock, which would have made it significantly friendlier to supporting life.

- Advertisement -

“Our evidence, which squares with emerging evidence including rocks in western Australia, suggests that the early Earth was capable of forming continental crust within 350 million years of the formation of the solar system,” said Patrick Boehnke, the T.C. Chamberlin Postdoctoral Fellow in the Department of Geophysical Sciences and the first author on the paper. “This alters the classic view, that the crust was hot, dry and hellish for more than half a billion years after it formed.”

One of the open questions in geology is how and when some of the crust–originally all younger volcanic rock–changed into the continental crust we know and love, which is lighter and richer in silica. This task is made harder because the evidence keeps getting melted and reformed over millions of years. One of the few places on Earth where you can find bits of crust from the very earliest epochs of Earth is in tiny flecks of apatite imbedded in younger rocks.

Luckily for scientists, some of these “younger” minerals (still about 3.9 billion years old) are zircons–very hard, weather-resistant minerals somewhat similar to diamonds. “Zircons are a geologist’s favorite because these are the only record of the first three to four hundred million years of Earth. Diamonds aren’t forever–zircons are,” Boehnke said.

Plus, the zircons themselves can be dated. “They’re like labeled time capsules,” said Prof. Andrew Davis, chair of the Department of Geophysical Sciences and a coauthor on the study.

- Advertisement -

Scientists usually look at the different variants of elements, called isotopes, to tell a story about these rocks. They wanted to use strontium, which offers clues to how much silica was around at the time it formed. The only problem is that these flecks are absolutely tiny–about five microns across, the diameter of a strand of spider silk–and you have to count the strontium atoms one by one.

This was a task for a unique instrument that came online last year: the CHicago Instrument for Laser Ionization, or CHILI. This detector uses lasers that can be tuned to selectively pick out and ionize strontium. When they used CHILI to count strontium isotopes in rocks from Nuvvuagittuq, Canada, they found the isotope ratio suggested plenty of silica was present when it formed.

This is important because the makeup of the crust directly affects the atmosphere, the composition of seawater, and nutrients available to any budding life hoping to thrive on planet Earth. It also may imply there were fewer meteorites than thought pummeling the Earth at this time, which would have made it hard for continental crust to form.

“Having continental crust that early changes the picture of early Earth in a number of ways,” said Davis, who is also a professor with the Enrico Fermi Institute. “Now we need a way for the geologic processes that make the continents to happen much faster; you probably need water and magma that’s about 600 degrees Fahrenheit less hot.”

The study is also confluent with a recent paper by Davis and Boehnke’s colleague Nicolas Dauphas, which found evidence for rain falling on continents 2.5 billion years ago, earlier than previously thought.

UNIVERSITY OF CHICAGO

Scientists studied 3.9-billion-year-old rocks from Nuvvuagittuq, Canada, and found evidence for an earlier formation of the crust. Credit : Elizabeth Bell

- Advertisement -
spot_img
Mark Milligan
Mark Milligan
Mark Milligan is multi-award-winning journalist and the Managing Editor at HeritageDaily. His background is in archaeology and computer science, having written over 8,000 articles across several online publications. Mark is a member of the Association of British Science Writers (ABSW), the World Federation of Science Journalists, and in 2023 was the recipient of the British Citizen Award for Education, the BCA Medal of Honour, and the UK Prime Minister's Points of Light Award.
spot_img

Mobile Application

spot_img

Related Articles

Dragon sculpture found on the Jiankou section of the Great Wall of China

Archaeologists conducting restoration works on the Jiankou section of the Great Wall of China have discovered an ornate dragon sculpture.

Waters at Roman Bath may have super healing properties

A new study, published in the Microbe journal, has uncovered a diverse array of microorganisms in the geothermal waters at Roman Bath that may have super healing properties.

9,000-year-old Neolithic stone mask unveiled

A rare stone mask from the Neolithic period has been unveiled for the first time by the Israel Museum in Jerusalem.

Archaeologists recover two medieval grave slabs from submerged shipwreck

Underwater archaeologists from Bournemouth University have recovered two medieval grave slabs from a shipwreck off the coast of Dorset, England.

Study confirms palace of King Ghezo was site of voodoo blood rituals

A study, published in the journal Proteomics, presents new evidence to suggest that voodoo blood rituals were performed at the palace of King Ghezo.

Archaeologists search for home of infamous Tower of London prisoner

A team of archaeologists are searching for the home of Sir Arthur Haselrig, a leader of the Parliamentary opposition to Charles I, and whose attempted arrest sparked the English Civil War.

Tartessian plaque depicting warrior scenes found near Guareña

Archaeologists from the Institute of Archaeology of Mérida (IAM) and the CSIC have uncovered a slate plaque depicting warrior scenes at the Casas del Turuñuelo archaeological site.

Archaeologists find a necropolis of stillborn babies

Excavations by the National Institute for Preventive Archaeological Research (Inrap) have unearthed a necropolis for stillborn and young children in the historic centre of Auxerre, France.