ARE SEPKOSKI'S EVOLUTIONARY FAUNAS EVOLUTIONARY LITHOFACIES?
To test this possibility, hiatus-bound packages of carbonate and siliciclastic sediments were compiled from the AAPG COSUNA charts. Area-weighted measures of rock quantity and rates of expansion and contraction of preserved sediments were then calculated for each lithofacies group. Carbonates decline in abundance over the Phanerozoic and there is a sharp decline, driven by a large increase in truncation rate, at the P/T boundary. Siliciclastics, by contrast, increase in abundance over the Phanerozoic and show no sharp decline at the P/T. In general, carbonates have higher mean rates of turnover and greater volatility than siliciclastics. These features reproduce quantitatively many of the same dynamics observed in the Paleozoic and Modern EFs, including selectivity at many of the major mass extinctions, suggesting that Sepkoski's EFs may reflect, at least in part, changes in the physical environment.