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Zircons are a favorite mineral among scientists because they’re hardy. These micrometer-size crystals can withstand weathering over billions of years to preserve the geochemical secrets of their birth. They also capture uranium isotopes from the environment as they form, which serve as a timer that starts from the moment the zircons crystallize.Ebony Sex Doll

Uranium isotopes decay into lead at predictable rates. By counting the number of lead atoms that form and the uranium atoms that remain, researchers can work out how much time has passed since the zircons hardened from molten material.Lesbian Sex Doll

The study authors probed the zircons embedded in a lunar rock sample collected during Apollo 17 in 1972, and they constructed a 3D map of the atoms. Tallying the lead isotopes resulted in an age of 4.46 billion years, the oldest age for the lunar crust’s formation yet.

This age was previously determined by Greer’s collaborators led by Bidong Zhang and Audrey Bouvier in 2021, but the report drew skepticism. Critics pointed to the fact that lead atoms tend to migrate to form pockets of high or low concentrations throughout the rock. Depending on where one looked, there was a chance that they might come across these unevenly distributed lead sites and miscalculate the zircon’s age.

To assuage these concerns, Bouvier approached Greer’s team to count the atoms again, this time with an ion probe that could sample the rock at a much higher spatial resolution that was used in the previous study. A finer probe would allow the team to identify nanosized regions of enriched or depleted lead atoms, if any were present. But they found none.Melina Elden Ring Sex Doll

“In this zircon, everything was homogeneous, so we didn’t even have to worry about that,” says study author Philipp Heck, a cosmochemist at the Field Museum and the University of Chicago. The result confirmed that the previously measured age of 4.46 billion years was accurate.

“It’s a very, very nice study,” says Melanie Barboni, a geochemist at Arizona State University who wasn’t involved in the research. Barboni has studied other isotopes in lunar zircons to discover that the moon’s interior first settled into distinct layers 4.51 billion years ago, an episode that preceded the final stages of crust formation captured in the new study.

Barboni says the new research is compatible with her own findings. “A lot of papers propose that the moon formed much later than that, 4.3 billion years, for example,” she adds. “That clearly is not possible with that data.”