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

by David Turell , Monday, August 20, 2018, 18:14 (2287 days ago) @ David Turell

Zircon research:

http://newsroom.ucla.edu/releases/life-on-earth-likely-started-at-least-4-1-billion-yea...

"The new research suggests that life existed prior to the massive bombardment of the inner solar system that formed the moon’s large craters 3.9 billion years ago.

“'If all life on Earth died during this bombardment, which some scientists have argued, then life must have restarted quickly,” said Patrick Boehnke, a co-author of the research and a graduate student in Harrison’s laboratory.

"Scientists had long believed the Earth was dry and desolate during that time period. Harrison’s research — including a 2008 study in Nature he co-authored with Craig Manning, a professor of geology and geochemistry at UCLA, and former UCLA graduate student Michelle Hopkins — is proving otherwise.

“'The early Earth certainly wasn’t a hellish, dry, boiling planet; we see absolutely no evidence for that,” Harrison said. “The planet was probably much more like it is today than previously thought.”

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"The scientists identified 656 zircons containing dark specks that could be revealing and closely analyzed 79 of them with Raman spectroscopy, a technique that shows the molecular and chemical structure of ancient microorganisms in three dimensions.

"Bell and Boehnke, who have pioneered chemical and mineralogical tests to determine the condition of ancient zircons, were searching for carbon, the key component for life.

"One of the 79 zircons contained graphite — pure carbon — in two locations.

“'The first time that the graphite ever got exposed in the last 4.1 billion years is when Beth Ann and Patrick made the measurements this year,” Harrison said.

"How confident are they that their zircon represents 4.1 billion-year-old graphite?

“'Very confident,” Harrison said. “There is no better case of a primary inclusion in a mineral ever documented, and nobody has offered a plausible alternative explanation for graphite of non-biological origin into a zircon.”

"The graphite is older than the zircon containing it, the researchers said. They know the zircon is 4.1 billion years old, based on its ratio of uranium to lead; they don’t know how much older the graphite is.

"The research suggests life in the universe could be abundant, Harrison said. On Earth, simple life appears to have formed quickly, but it likely took many millions of years for very simple life to evolve the ability to photosynthesize.

"The carbon contained in the zircon has a characteristic signature — a specific ratio of carbon-12 to carbon-13 — that indicates the presence of photosynthetic life.

“'We need to think differently about the early Earth,” Bell said."

Comment: Earlier and earlier.