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Newly dated 85-million-year-old dino eggs could improve understanding of Cretaceous climateThe dating of a clutch of fossil dinosaur eggs will leave creationists scrambling for excuses to dismiss the evidence and cling to the childish notion that Earth is only 6,000–10,000 years old, created ex nihilo by magic, with all extant and extinct species brought into existence without ancestors just a few days later. In other words, this discovery is yet another small addition to the mountain of evidence showing that the biblical creation story was the work of ignorant Bronze Age people trying to make sense of the world around them, not the word of an omniscient creator god who would have known better.
An added problem for creationists is that the research team used a new method of dating the eggs based on measuring when the eggshell itself formed, rather than relying solely on dating the rock in which the eggs were embedded. The difficulty with the latter approach is that, while it gives the age of the surrounding rock, the mineral grains in that rock may predate the eggs and could have been transported there by water or wind.
The new technique is conceptually similar to the uranium–lead (U–Pb) method used to date zircon crystals in volcanic tuff. Tiny amounts of uranium, which readily substitute into the crystal lattice, are incorporated when the zircon forms, but lead is excluded. Over time, uranium isotopes decay into stable isotopes of lead. Thus, any lead present within a zircon crystal must have come from radioactive decay, and by measuring the ratio of uranium to lead isotopes, scientists can calculate the crystal’s age with high precision.
A very similar process occurs in the carbonate of dinosaur eggshells: uranium is incorporated during formation, but lead is excluded. Measuring uranium–lead isotope ratios in the shell carbonate therefore provides a direct and highly accurate age for the eggs themselves, leaving little room for error.