Publication Date:
2024-01-09
Description:
Temperature reconstructions indicate that the Pliocene was ~3 °C warmer globally than today, and several recent reconstructions of Pliocene atmospheric CO2 indicate that it was above pre-industrial levels and similar to those likely to be seen this century. However, many of these reconstructions have been of relatively low temporal resolution, meaning that these records may have failed to capture variations associated with the 41 Kyr glacial-interglacial cycles thought to operate in the Pliocene. Here we present a new, high temporal resolution alkenone carbon isotope based record of pCO2 spanning 2.8 to 3.3 million years ago from ODP Site 999. Our record is of high enough resolution (~19 Kyrs) to resolve glacial-interglacial changes beyond the intrinsic uncertainty of the proxy method. The record suggests that Pliocene CO2 levels were relatively stable, exhibiting variation less than 55 ppm. We perform sensitivity studies to investigate the possible effect of changing sea surface temperature, which highlights the importance of accurate and precise SST reconstructions for alkenone palaeobarometry, but demonstrate that these uncertainties do not affect our conclusions of relatively stable pCO2 levels during this interval.
Keywords:
165-999A; AGE; Alkenone, unsaturation index UK'37; Alkenone C37:2, δ13C; Carbon dioxide, intracellular; Carbon dioxide, partial pressure; Carbon dioxide, partial pressure, standard deviation; Carbon dioxide, partial pressure maximum; Carbon dioxide, partial pressure minimum; Caribbean Sea; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Globigerinoides ruber, δ13C; Henry's law constant; Isotopic fractionation; Isotopic fractionation, during photosynthis; Joides Resolution; Leg165; Ocean Drilling Program; ODP; Sample code/label; Sea surface temperature, annual mean; δ13C, biomass; δ13C, carbonate; δ13C, carbon dioxide, aquatic; δ13C, carbon dioxide, gaseous
Type:
Dataset
Format:
text/tab-separated-values, 535 data points
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