Mr. Jon Erocle - USEPA Region 9

Mr. Erocle is on assignment with NNEPA/UST & LUST Program(s)

Upper Cretaceous - Tertiary (KT) Boundary

Photograph taken in Texas along the banks of the Brazos River, 1998. Boundary is chest high between the upper dark tertiary and lighter colored cretaceous rocks. Sediment analysis indicates the contact point between the layers may have been caused by an asteroid impact which causesd the extinction of the dinosaurs.

provided by technologies.