Large spheroid deposits at Albion Island and Armenia in northern and
central Belize and the spherule deposits of southern Belize and eastern
Guatemala have the same glass origin based on the presence of almost
pure Cheto smectite derived from alteration of impact glass from the
Chicxulub impact on Yucatan, Mexico. The same origin has also been
determined for altered glass spherules in Mexico, Haiti and the
Caribbean. However, the spherule layers have variable ages as a result
of erosion and redeposition, with an early Danian
(Parvularugoglobigerina eugubina) zone pla(1) age in southern Belize,
Guatemala, Haiti, southern Mexico and the Caribbean, and a pre-K-T
(Plummerita hantkeninoides) zone CF1 age of 65.27 +/- 0.03 Ma in NE
Mexico. A pre-K-T age for the Chicxulub impact has now also been
determined from the new Yaxcopoil 1 core drilled in the impact crater.
These data show that Chicxulub was not the K-T impact that caused the
end-Cretaceous mass extinction, but an earlier impact event. A multiple
impact hypothesis, volcanism and climate change appears the likely
scenario for the end-Cretaceous mass extinction.