Export Depth of the TEX86 Signal

Abstract

AbstractTEX86 is widely used for evaluating ancient ocean temperatures. However, the debate on the export depth of the TEX86 signal in the water column has not been settled. Consequently, TEX86 has been interpreted as/calibrated to surface, shallow subsurface, or deep subsurface temperatures. Here we examine the published core top TEX86 data between 30°N and 30°S where the ocean temperatures at the surface show a clear latitudinal gradient, but not at the deep subsurface. The meridional distribution of the TEX86 data exhibits an inverted U shape with the peak near the equator, which closely resembles the surface and shallow subsurface ocean temperature profiles. And the strongest correlation was identified between TEX86 and sea surface temperatures. These results suggest that on the global scale, sedimentary TEX86 is a proxy for temperatures of the epipelagic ocean less than 200 m deep.