Santonian Cretaceous Sea Surface Temperature Record of the Southern Tethys

Sea surface temperature record of a Late Cretaceous tropical southern Tethys upwelling system

Authors:

Heiko Alsenz et al

Abstract:

Late Cretaceous sea surface temperatures (SSTs) were reconstructed based on TEX86 data from the unique high productivity upwelling system in the Southern Tethys margin, Israel. SSTs were determined from two oil shale sequences of the Santonian-early Maastrichtian (~ 85 to 68 Ma) in southern (Efe Syncline) and central (Shefela basin) Israel (paleo latitude 8–15 °N). These two sampling sites represent the inner and outer belts of the upwelling system. Our TEX86 data indicate a significant long-term SST cooling trend from 36.0 to 29.3 °C during the late Santonian and the early Campanian in the Southern Tethys margin consistent with the opening of the Equatorial Atlantic Gateway (EAG).

Based on our data from the equatorial region and literature data from the polar region we reassessed the equator to pole SST gradient to 22 °C. This value is closer to the modern ocean equator-to-pole SST gradient (30 °C) than suggested from previous studies.

Furthermore, the SST data suggests the presence of cooler surface water in the inner belt (27.7 °C) caused by the upwelling system and warmer surface water (29.2 °C) further seaward in the outer belt.