New Oxygen research;great oxygenation event study (Introduction)

by David Turell , Monday, March 26, 2018, 20:09 (2224 days ago) @ David Turell

An other study from deep cores in Russia show the rapid increase in sulfates which demonstrates how rapidly oxygen appeared over 2.4 billion years ago:

https://www.scientificamerican.com/article/primeval-salt-shakes-up-ideas-on-how-the-atm...

"Within the three-kilometer-long, cylindrical core excavated from the Russian basin, Blättler and her colleagues identified a 600-meter-thick deposit of sulfate-rich materials, including halite (aka sodium chloride)—the crystalline progenitor of common table salt. The deposit’s immense size and various trace geochemical markers, Blättler says, both suggest it formed in ocean water rather than in any freshwater source.

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"The team’s analysis shows this ancient ocean water carried roughly 20 percent as many sulfates as are found in modern seawater. Sulfate concentration in ocean water is a key tracer of how much oxygen is the atmosphere—and how it gets there in the first place.

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"Three billion years ago Earth's atmosphere lacked the abundant molecular oxygen (O2) that makes air breathable for complex life today. It was not until the Great Oxygenation Event, a mysterious transition that occurred from 2.7 to 2.4 billion years ago, that this gas—crucial to life as we know it—began to substantially accumulate in the atmosphere.

On the way to allowing life to evolve, the rise of oxygen also transformed Earth’s rocks and thus fundamentally altered our planet’s geochemistry. As oxygen in the atmosphere reacted chemically with iron pyrite in rocks, it bonded with the pyrite's sulfur, creating sulfates and other mineral by-products that gradually washed out of the rocks and flowed into to the ocean. This is why the amount of sulfate in a well-preserved salt deposit can be used to establish the oxygen levels in ancient air.

"Previous research with carbon isotopes provided less-direct evidence of atmospheric oxygen, as did work done by Lyons’s team with trace metals and sediments. The new findings, however, provide a stronger connection to the buildup of the life-giving gas in the atmosphere, Lyons says. “Carbon isotopes suggest a lot of oxygen was released,” he notes. “But this sulfate is, in essence, the smoking gun of that process.”

"Scientists are not yet certain how all that oxygen entered the atmosphere in the first place. Some think it may have been a gradual geologic process—possibly a change in the mixtures of gases belched out by volcanoes or the atmosphere’s gradual loss of lightweight hydrogen atoms to outer space. Others prefer the idea of a more sudden mechanism such as a geologic upheaval from planet-scale volcanic eruptions or Earth-shaking asteroid impacts. Life itself may have even have caused a rapid spike, via oxygen released by newly evolved photosynthetic organisms.

"Blättler believes the new results provide a stronger case for a sudden jump than for gradual easing. “The large accumulation of sulfate that we see from our observations favors a much more dramatic transition,” Blättler says. “You have to push the system really hard to accumulate this much sulfate. It’s not a trivial amount.'”

Comment: We know cyanobacteria provided much of the oxygen and this study shows it occurred between 2.7-2.4 billion years ago. It is more evidence how God used bacteria in the controls over evolutionary processes.