Closing of the Central American Seaway and Neogene coastal upwelling along the Pacific coast of South America

Abstract

The final closing of the Central American Seaway is estimated to have occurred at ca. 3.7–3 Ma, separating the equatorial Pacific and Atlantic oceans and the Caribbean Sea. This event greatly influenced not only areas near the seaway but also the larger Pacific Ocean. Two paleoceanographic events recorded by planktonic foraminifera on the Pacific coast of South America in Pliocene times are considered to be responses to the closing of this ocean gateway. Event 1 involves an expansion of coastal upwelling in the Southeast Pacific. Event 2 involves the abrupt cooling of surface water temperatures along the coast of Ecuador. Both events occurred around 3.5 Ma, coincident with the closing of the Central American Seaway.