The Earth’s oceans appeared between 4.4 and 4.2 billion years ago. At the time, they covered the entire surface of the planet. So when did the first land rise above sea level? Geologists from Utrecht, Bergen (Norway) and Münster (Germany) have recent
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Earth's Crust Emerged 500 Million Years Earlier Than Previously Thought, Research Uncovers
Scientists have devised new way to date ancient chunks of crust and as per their research, the age of the continents have been misjudged by half a billion years
Image: Unsplash
Earth’s continental crust may have emerged 3.7 billion years earlier than scientists had previously estimated. A team of scientists has devised a new way to date ancient chunks of crust and according to their latest research, the age of the continents have been misjudged by half a billion years. A research presented at the virtual European Geosciences Union (EGU) General Assembly 2021 conference, the team showed that by analyzing a mineral called barite, which is a combination of ocean salts and barium released by volcanic ocean vents, they found evidence that Earth’s continental crust was around at least 3.7 billion years ago, much older than previous estimates.
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IMAGE: An artist's conception of the early Earth, showing a surface bombarded by large impacts that result in the extrusion of magma onto the surface. At the same time, distal portions... view more
Credit: Simone Marchi/SwRI
MUNICH -- The first emergence and persistence of continental crust on Earth during the Archaean (4 billion to 2.5 billion years ago) has important implications for plate tectonics, ocean chemistry, and biological evolution, and it happened about half a billion years earlier than previously thought, according to new research being presented at the EGU General Assembly 2021.
Once land becomes established through dynamic processes like plate tectonics, it begins to weather and add crucial minerals and nutrients to the ocean. A record of these nutrients is preserved in the ancient rock record. Previous research used strontium isotopes in marine carbonates, but these rocks are usually scarce or altered in rocks older than 3 billion years.
The jury is still out about how life first formed on Earth, but nailing down when the planet’s continental crust first formed will be key to figuring out the planet’s earliest days.
An artist’s conception of the early Earth, showing a surface bombarded by large impacts that result in the extrusion of magma onto the surface. At the same time, distal portions of the planet’s surface may have retained liquid water. (Credit: Simone Marchi/SwRI)
(CN) — Don’t let their quiet modesty fool you: rocks have a lot to tell. You just need to know where to look and what to ask them.
Researchers studied rocks called barites located on three different continents
These are formed by interactions between ocean water and vents on the sea bed
However, they also capture minerals weathered into the ocean from the land
Studying these allowed the team to determine when weathering first started
This — and by extension, the emergence of land — occurred 3.7 billion years ago
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Microbes buried at bottom of sea start flourishing after 80.000 years
In otherwise energetic desserts at the bottom of the sea, researchers have found oases where microbes can harvest energy. Remarkably, the microbes first have to be buried under starving conditions for 80.000 years. An international group of researchers, amongst them José Mogollón from the Insitute of Environmental Sciences (CML) at Leiden University, has published this finding in PNAS.
The researchers studied microbes from the genus Scalindua in the Greenland/Norwegian Sea. Microbes of this species were able to reactivate and increase their population size by more than 4 orders of magnitude long after burial.