EGU21-4242, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mineral dust coupled with climate-carbon cycle on orbital timescales over the past 4 Ma

Mengmeng Cao, Zhixiang Wang, Ze Zhang, and Anguo Xiao
Mengmeng Cao et al.
  • School of Earth Sciences, China University of Geosciences, Wuhan, wuhan, China (,

Mineral dust is one of the environmental component for forcing the global climatic change, and not only influences the amount of solar radiation incoming the earth surface, but affects atmospheric CO2 concentrations in the past through wind transport to ocean and subsequent biological pumping. Mineral dust is one of the important driving factors for variations of atmospheric CO2 content in Quaternary glacial-interglacial cycles. Here, we reconstruct the interaction between the Asian dust flux (as a representative of the global dust flux), the cryosphere system (δ18Obenthic), and the global carbon cycle since 4 Ma using phase analysis, power decomposition analysis, obliquity sensitivity calculation and evolutionary spectral analysis. The evolutionary spectra show that orbital-scale variability of mineral dust, δ18Obenthic and δ13Cbenthic are very similar over the past 4 Ma, except the interval time of 3-2 Ma that shows higher obliquity energy (higher O/T values) of the δ18Obenthic and δ13Cbenthic data. Therefore, we suggest that the Asian and/or global dust is acted as a transmitter transporting the periodic signals stored in the Arctic ice sheet to deep-sea δ13Cbenthic. This is why δ13Cbenthic data have very similar changes with the Arctic ice sheets on the orbital scale. Sharp increase of global dust flux after 1.6 Ma resulted in a significant weakening of the 405 kyr long eccentricity power of δ13Cbenthic series because Arctic ice sheet signals strongly inhibit the influences of low-latitude solar insolation variations on deep-sea δ13Cbenthic system. In addition, we suggest that strengthened global drought and increases of dust fluxes since late Miocene probably forced the anti-phase relationship between δ18Obenthic and δ13Cbenthic around 6 Ma, rather than the expansion of Arctic ice sheet. Our results highlight the close coupling between dust fluxes and the global carbon cycle, with deeply influencing marine productivity and land surface processes.

Keywords: mineral dust; deep sea oxygen isotope (δ18Obenthic ); deep sea carbon isotope(δ13Cbenthic); orbital  periods ; inland Asia

How to cite: Cao, M., Wang, Z., Zhang, Z., and Xiao, A.: Mineral dust coupled with climate-carbon cycle on orbital timescales over the past 4 Ma, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4242,, 2021.

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