Was there a flow reversal through the Panama Seaway in the early Miocene?

Abstract

We study the water exchange between the Atlantic and Pacific oceans through the Panama Seaway in the late Oligocene through early Miocene. Proxy data indicate that half of the Caribbean corals died out in the early Miocene. It has recently been suggested that this may be related to a flow reversal through the Panama Seaway from eastward to westward flow around 25 Ma. The flow reversal has indeed been found in an idealized model of the wind-driven ocean circulation. We present the physics of the flow reversal in the idealized model and use this to interpret simulation results obtained with the NCAR CCSM (version 1.4).