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 inverteb rate evolution, tectonic uplift, and paleoclimate change, yet accurate ages are difficult to obtain prior to the late Pleistocene, We report a new app roach for combining uranium-lead (UPb) and uranium-series dating for middle Pleistocene corals from the Caribbean side of Costa Rica. Two corals have Th-230/U-238 in secular equilibrium, small excesses in delta U-234, and Pb- 206*/U-238 ages of 1.02 +/- 0.07 Ma and 1.288 +/- 0.034 Ma. The latter cora l age dates a recognized geomagnetic event to ca, 1.3 Ma, a time at which n o polarity events had been identified. The new ages also show that the majo r coral extinction in the Caribbean Basin occurred shortly after 1.0-0.9 Ma , much more recently than previously thought. This coral extinction now coi ncides with the global change at 1.0-0.8 Ma to the current pattern of glaci al-interglacial cycles and amplified changes in sea level, These factors ma y have provided a new, strong environmental mechanism for rapid habitat mod ification and coral extinction.