Abstract:
The TEX (sub 86) (super H) temperature proxy is a relatively new proxy based on crenarchaeotal lipids and has rarely been applied together with other temperature proxies. In this study, we applied the TEX (sub 86) (super H) on a sediment core from the Alboran Sea (western Mediterranean, core ODP-977A) covering the penultimate climate cycle, that is, from 244 to 130 ka, and compared this with previously published sea surface temperatures derived from the U (sub 37) (super k') of alkenones of haptophyta and Mg/Ca records of planktonic foraminifera. The TEX (sub 86) (super H) temperature record shows remarkably similar stadial-interstadial patterns and abrupt temperature changes to those observed with the U (sub 37) (super k') palaeothermometer. Absolute TEX (sub 86) (super H) temperature estimates are generally higher than those of U (sub 37) (super k') , though this difference (<3 degrees C in 81% of the data points) is mainly within the temperature calibration error for both proxies, suggesting that crenarchaeota and haptophyta experienced similar temperature variations. During occasional events (<5% of the analyzed time span), however, the TEX (sub 86) (super H) exhibits considerably higher absolute temperature estimates than the U (sub 37) (super k') . Comparison with Mg/Ca records of planktonic foraminifera as well as other Mediterranean TEX (sub 86) and U (sub 37) (super k') records suggests that part of this divergence may be attributed to seasonal differences, that is, with TEX (sub 86) (super H) reflecting mainly the warm summer season while U (sub 37) (super k') would show annual mean. Biases in the global calibration of both proxies or specific biases in the Mediterranean are an alternative, though less likely, explanation. Despite differences between absolute TEX (sub 86) (super H) and U (sub 37) (super k') temperatures, the correlation between the two proxies (r (super 2) = 0.59, 95% significance) provides support for the occurrence of abrupt temperature variations in the western Mediterranean during the penultimate interglacial-to-glacial cycle.