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"Dating the Siberian Traps is one of the more consequential precision-geochronology problems in Earth history, because the whole 'did flood basalts kill the Permian world?' argument hinges on whether the eruptions came before the extinction and by how much."

"Why it's hard: Flood basalts are the worst possible rock for high-precision dating. They're low-silica, so they crystallize almost no zircon — the mineral that makes U-Pb dating so precise — and they've been through low-grade burial metamorphism that resets or partially disturbs other systems. So geochronologists have had to hunt for datable material in unusual places."