Cambrian explosion condensed: High-precision geochronology of the lower Wood Canyon Formation, Nevada

The early Cambrian Period marks the important interval when most major groups of animals first appear in Earth's sedimentary record. The tempo of this biological diversification is still poorly defined because, globally, there are few absolute age constraints that calibrate early Cambrian fossil occurrences or the carbon isotope perturbations used to correlate the biostratigraphy of different continents. In this study, we present high-precision age constraints for strata in the southwestern United States, which suggest the early Cambrian animal radiation was significantly faster than currently recognized. Accurately constraining the timing and rates of early animal evolution is a critical step toward better understanding this milestone in Earth's history.