PP53C-2377
Comparison and Significance of Two Different Organic Paleotemperature Reconstructions
Abstract:
Temperature is a basic parameter in the study of paleoclimatology and paleoceanography. In the present study, two organic geochemical proxies,UK'37 and TEX86 were used for the sea surface temperature reconstruction in the site MD123434 (18°49.84’N,116°18.89’E, water depth 2995m) in
northern South China Sea. On the whole, the two reconstructed temperature correlated well with each other, reflecting low temperature in the last
glacial and high in the Holocene. Nevertheless, detailed comparison illustrated relatively higher reconstructed temperature by the UK'37 method
than that in TEX86 proxy, with a range of 23.0℃ to 27.8℃ and 18.9℃to 29.5℃ for UK'37 and TEX86 proxy respectively. The average temperature
discrepancy (ΔT) between the two temperature proxies is ~3℃ during the last glacial and ~0℃ during the Holocene, which cannot be fully attributed
to calculation errors. The offset between these two proxies may be caused by the different living water depths of the source organisms: haptophyte
and Thaumarchaeota for the UK'37 and TEX86 respectively. The terrestrial GDGTs input and the different calibration equations on the TEX86 may
possibly also contribute to the discrepancy. Meanwhile, growth seasonalities between the two source organisms cannot be ignored either.