Accelerated Pleistocene coral extinctions in the Caribbean Basin shown by uranium-lead (U-Pb) dating

Ages of corals and shallow-marine sequences define rates of marine invertebrate evolution, tectonic uplift, and paleoclimate change, yet accurate ages are difficult to obtain prior to the late Pleistocene. We report a new approach for combining uranium-lead (U- Pb) and uranium-series dating for middle Pleistocene corals from the Caribbean side of Costa Rica. Two corals have super(230)Th/ super(238)U in secular equilibrium, small excesses in delta super(234)U, and super(206)Pb super(*)/ super(238)U ages of 1.02 plus or minus 0.07 Ma and 1.288 plus or minus 0.034 Ma. The latter coral age dates a recognized geomagnetic event to ca. 1.3 Ma, a time at which no polarity events had been identified. The new ages also show that the major coral extinction in the Caribbean Basin occurred shortly after 1.0-0.9 Ma, much more recently than previously thought. This coral extinction now coincides with the global change at 1.0-0.8 Ma to the current pattern of glacial-interglacial cycles and amplified changes in sea level. These factors may have provided a new, strong environmental mechanism for rapid habitat modification and coral extinction.