End-Triassic Flood Basaltsat the Old Wife

The flood basalts of the Central Atlantic Magmatic Province, the most areally extensive in Earth history, attended the breakup of the supercontinent Pangea at the close of the Triassic Period. The resulting, profound global change is implicated in the end-Triassic mass extinction event that provided dinosaurs free reign to become the dominant animals on terrestrial Earth for the remainder of the Mesozoic Era, approximately 135 million years.
The basalts cooled from lava flows that erupted as North America separated from northwestern Africa, eventually giving birth to the Atlantic Ocean in the Jurassic Period. Zeolite-rich vesicular basalts occur at the western end of the section, whereas columnar structures are evident at the Old Wife headland itself. The distinctive orange-red sedimentary strata below the flood basalts were deposited within a semiarid failed rift valley in which are found fossils of the precursors to dinosaurs and their contemporary fauna. The dominant mud-rich sediments are punctuated by thin pale grey lacustrine beds that have been ascribed to climatic cyclicity of the Milankovitch band. At Red Head in the far eastern part of the cliff section, cross-bedded aeolian sandstones form part of the rift valley-fill in this classic section.