Theoretical origin of life; zircons with 4.1 byo evidence: (Introduction)

by David Turell , Tuesday, October 09, 2018, 15:29 (2020 days ago) @ David Turell

A review article:

https://www.nationalgeographic.com/science/2018/09/news-earth-rocks-sediment-first-life...

"Zircon crystals are almost indestructible; some still around today are nearly 4.4 billion years old. They're like tiny time capsules that retain the chemical fingerprints of this extremely early time. “This is basically our only window into the formative stages of our planet,” says Dustin Trail of the University of Rochester.

"By decoding these chemical clues, scientists are slowly teasing out the environments that fostered the earliest glimmers of life. But exactly what the surface looked like at that time has long remained a mystery. Now, in a new study published in Proceedings of the National Academy of Sciences, Trail and his colleagues pick apart the enigma.

***

"—no physical evidence remains from Earth's first few hundred million years. “The Earth has done a great job erasing some of that information,” Trail says. Our planet is the ultimate recycler. Plate tectonics constantly repurpose old rock into new, and lava flows harden into fresh landscapes.

"Zircon crystals, however, are so tough that they often survive the intense temperatures and pressures of this recycling process, retaining clues about the environments in which they originally formed. Using zircon oxygen isotopes, researchers previously discovered that liquid water covered parts of our planet some 4.3 billion years ago, suggesting the surface cooled just a few hundred million years after our planet’s formation. And just last year, researchers found what they believe might be hints of early life in the form of carbon-rich inclusions in 4.1-billion-year-old zircons.

***

"If we can begin to constrain the types of materials that are around at that time,” Trail says, “that perhaps pushes us one step closer to understanding how biochemical reactions, or prebiotic reactions, may have utilized the crust at that time as a substrate.”

"For answers, Trail and his colleagues turned to silicon and oxygen. Together, these elements make up roughly 75 percent of the rocks on Earth today, he explains. And both have a useful feature: they have more than one type, or isotope.

***

"More than half of the ancient zircons tested reveal early interactions between water and rock, in a range of different environments.

"Some zircons contain the chemical signatures of rocks weathered by water to form clay. Other zircons bear the signatures of dissolved minerals that crystallize to form rocks like chert or banded iron formations in lakes or oceans. Still others have the signature of a process known as serpentinization, so called for its snake-skin-like texture and color. During this process, water reacts with rocks enriched in iron and magnesium, incorporating itself into the mineral structures.

"Most importantly, each of these processes creates a new environmental niche that could foster early biochemical reactions, the glimmers of early life.

“That's a pretty cool result,” says Elizabeth Bell, a geochemist at the University of California, Los Angeles, who was not involved in the work. Many of these processes are largely indistinguishable from oxygen isotopes alone, she notes, calling the use of silicon "really significant.”

"Bell led the 2017 work that identified hints of a biosphere in 4.1-billion-year-old zircons. These latest results bolster her findings and other interpretations of early Earth. “It sort of all comes together in a nice picture,” she says.

"Everything around (and within) us once came from stardust, and the early processes that formed every molecule, mineral, and complex organism of today—from your cell phone to the food you eat to the heart pumping in your chest. And scientists are just beginning to tease out their origins."

Comment: What this means to me is that life could well have started 4.1 billion years ago and based on extremophiles in multiple places and in differing original forms, not just one cell type! Note this article re' Greg Venter:

https://uncommondescent.com/intelligent-design/zircons-are-back-as-a-possible-source-of...

"I hear a lot about the evidence that there seems to be nothing or almost nothing before the cambrian, BUT ALSO I think it is terribly important that it is pointed out that we do not note any lifeforms that show a transition between these phyla – if the main tenant of not just neo-darwinism, but common ancestry to be true, then these lifeforms could not develop independently.

"We should see a LOT of fluidity between these body plans with many, many examples in the fossil record of organisms that show a bridge between these body plans for a common ancestor to be true.

"Greg Venter and many of the greatest secular genomics researchers have stated the tree of life has actually hampered our progress in understanding the development and diversification of life and needs to be “jettisoned” – this is a HUGE shift in thinking. Ventner, to my knowledge, still leans heavily toward the idea that there were many separate ancestors and that they were anything but “common”, which is exactly my point. What he means by anything but common is saying not only are their multiple ancestors, but they are not similar to each other."

Comment: Not a single bush of life but a hedgerow.