The Early Cretaceous Jehol Biota evolution has remarkable spatiotemporal correlation with the destruction of the North China craton though the coupling mechanism remains enigmatic. The craton destruction was accompanied by intense magmatic activity and the released volatiles and nutrients might have had climatic and environmental impacts on the biotic evolution. In this study, we investigated the mentioned hypothetical causal link by determining concentrations and total emissions of volatile elements (S, F, Cl) and bulk-rock P contents of volcanic rocks that were erupted during the pre-flourishing, flourishing and post-flourishing stages of the Jehol Biota. Our results show that the volcanism near the flourishing stage has lower S (1083-2370 ppm), Cl (1277-5608 ppm) and higher P2O5 contents (0.48-0.84 wt.%) than that in non-flourishing stages with S of 1991-3288 ppm, Cl of 7915-12315 ppm and P2O5 of 0.17-0.23 wt.%. Fluorine contents in the three stages vary from 893 to 3746 ppm. The total volatile emissions are minor in the flourishing stage (3.6-6.6 Gt S, 2.2-4.6 Gt Cl and 2.1-4.0 Gt F) but elevated in the non-flourishing stages (1-690 Gt S, 4-934 Gt Cl and 1-308 Gt F). Our data suggest that regional climatic and environmental impacts of volcanism in the non-flourishing stages probably hindered the species diversification. The high P flux released from lithospheric mantle-derived lavas during the peak time of craton destruction might enhance primary productivity and contribute to the flourishing of the Jehol Biota. Our study provides insights into the relationship between the biosphere and deep geodynamic processes driven by volcanism.

Global tomographic models have revealed the existence of two large low shear-wave velocity provinces (LLSVPs) underlying Africa and the Pacific, which are regarded as sources of most typical mantle plumes. Plume-induced basalts have the potential to imply the formation mechanisms and evolutional histories of the LLSVPs. In this study, we measured H2O contents in clinopyroxene and olivine phenocrysts from Cenozoic basalts produced by the Kerguelen and Crozet mantle plumes, which are deeply rooted in the African LLSVP. The results were used to constrain the H2O content in the source of basalts, yielding 1805 ± 579 ppm for the Kerguelen plume and 2144 ± 690 ppm for the Crozet plume. H2O contents in the mantle sources of basalts fed by other plumes rooted in these two LLSVPs were calculated from literature data. Combining these results together, we show that the African LLSVP seems to have higher H2O content and H2O/Ce (620-2144 ppm and 184-592, respectively) than the Pacific LLSVP (262-671 ppm and 89-306, respectively). These features could be ascribed to incorporation of subducted material, which had experienced variable degrees of dehydration during its downwelling, into the LLSVPs. Our results imply that the continuous incorporation of subducted oceanic crust modifies the compositions of LLSVPs and induces heterogeneous distribution of H2O within individual LLSVPs and distinct H2O contents between the African and Pacific LLSVPs. This suggests that the African and Pacific LLSVPs might have different formation and evolution histories.