Geothermal Heating in the Panama Basin: 1. Hydrography of the Basin

Abstract

The Panama Basin serves as a laboratory to investigate abyssal water upwelling. The basin has only a single abyssal water inflow pathway through the narrow Ecuador Trench. The estimated critical inflow through the Trench reaches 0.34 ± 0.07 m/s, resulting in an abyssal water volume inflow of 0.29 ± 0.07 Sv. The same trench carries the return flow of basin waters that starts just 200 m above the bottom and is approximately 400-m deeper than the depth of the next possible deep water exchange pathway at the Carnegie Ridge Saddle. The curvature of temperature-salinity diagrams is used to differentiate the effect of geothermal heating on the deep Panama Basin waters that was found to reach as high as 2,200-m depth, which is about 500 m above the upper boundary of the abyssal water layer.