A rock used as a signature for the rise of oxygen in the early earth turns out to be misleading and useless for dating.
Hematite in banded iron formations (BIFs) from Australia have been used for years as a marker for when the early earth saw a rise in oxygen in the sea. Supposedly, iron first began to be oxidized when these rocks were made. Piled on top of that assumption have been stories of the evolution of eukaryotes and photosynthesis 2.5 billion years ago, a key milestone in the progress of evolution. Now, that marker has been criticized as misleading.
In a paper in the Bulletin of the Geological Society of America, three geologists took another look at the BIFs and realized that the oxidation could have occurred much later. “The observation that at least some of the hematite in unmineralized BIF did not form directly from ferric oxyhydroxides implies that hematite is not a reliable proxy for the composition of the precursor sediment or the redox [reduction-oxidation] chemistry of the ocean,” they concluded.
Richard A. Kerr took note of this development in Science Magazine:
Geologists say the study raises serious questions about a supposedly reliable test. “People are recognizing that we have to be more careful,” says geochemist Timothy Lyons of the University of California, Riverside. “We need to increasingly focus on doing just what [these authors] did, a more careful characterization of samples.”
This raises the question of what motivated the earlier scientists to be careless. Kerr pointed out that evolutionary geologists had divined the rise of oxygen from these rocks for decades. “The ruddy mineral was thought to record the moment when photosynthesis first pushed oxygen to levels high enough to fully oxidize iron,” he said.
Let this be a warning to theistic evolutionists and other old-earthers who trust the interpretations of proxy measurements for their theories, believing that the earth maintains an incontrovertible, unbiased record of its history. If you listen to these evolutionists, ashamed as they were about trusting an unreliable method, they ended up merely replace one fallible interpretation with another. Now they think the BIFs record another imaginary date 300 million years later, “after tectonic forces crumpled the sea floor into mountains and drove oxygen-laden water down into the rock.” Anybody there to see that happen? Of course not. If reporters and other scientists leaned on a smoldering reed for decades, why should anybody lean on their next smoldering reed? In another few decades its assumptions are likely to be overturned again. Like Ken Ham tried to get Bill Nye to realize, there’s a big difference between looking at hematite in a rock in the present (operational science) and trying to figure out how it got that way in the past (origin science). Nothing about bands of iron in a rock requires the moyboy story.