Abstract
Global warming during the Miocene Climate Optimum(MCO,～17-14 million years ago)is associated with massive carbon emissions sourced from the flood basalt volcanism and ocean crustal production.However,the perturbation of tectonic carbon degassing on the interaction between climate change and carbon cycle remains unclear.Here,through time-evolutive phase analysis of new and published high-resolution benthic foraminiferal oxygen(δ18O)and carbon(δ13C)isotope records from the global ocean,we find that variations in the marine carbon cycle lead the climate-cryosphere system(δ13C-lead-δ18O)on 405,000-year eccentricity timescales during the MCO.This is in contrast to the previously reported climate-lead-carbon(δ18O-lead-δ13C)scenario during most of the Oligo-Miocene(～34-6 mil-lion years ago).Further sensitivity analysis and model simulations suggest that the elevated atmospheric CO2 concentrations and the resulting greenhouse effect strengthened the low-latitude hydrological cycle during the MCO,accelerating the response of marine carbon cycle to eccentricity forcing.Tropical climate processes played a more important role in regulating carbon-cycle variations when Earth's climate was in a warm regime,as opposed to the dominant influence of polar ice-sheet dynamics during the Plio-Pleistocene(after～6 million years ago).
基金项目
国家自然科学基金(42122042)
国家自然科学基金(42030403)
国家自然科学基金(42188102)
中央高校基本科研业务费专项(22120220531)
Shanghai Pilot Program for Basic Research()
Netherlands Earth System Science Centre(024.002.001)
Integrated Ocean Discovery Program(IODP)()
NETL
NSTL
万方数据