EGU2020-13055
https://doi.org/10.5194/egusphere-egu2020-13055
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evolution of deep mantle sourced carbonated melt in the mantle lithosphere

Guoliang Zhang1,2
Guoliang Zhang
  • 1Institute of Oceanology, Chinese Academy of Sciences, China (zhangguoliang@qdio.ac.cn)
  • 2Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao

Deep sourced magmas play a key role in distribution of carbon in the Earth’s system. Oceanic hotspots rooted in deep mantle usually produce CO2-rich magmas. However, the association of CO2 with the origin of these magmas remains unclear. Here we report geochemical analyses of a suite of volcanic rocks from the Caroline Seamount Chain formed by the deep-rooted Caroline hotspot in the western Pacific. The most primitive magmas have depletion of SiO2 and high field strength elements and enrichment of rare earth elements that are in concert with mantle-derived primary carbonated melts. The carbonated melts show compositional variations that indicate reactive evolution within the overlying mantle lithosphere and obtained depleted components from the lithospheric mantle. The carbonated melts were de-carbonated and modified to oceanic alkali basalts by precipitation of perovskite, apatite and ilmenite that significantly decreased the concentrations of rare earth elements and high field strength elements. These magmas experienced a stage of non-reactive fractional crystallization after the reactive evolution was completed. Thus, the carbonated melts would experience two stages, reactive and un-reactive, of evolution during their transport through in thick oceanic lithospheric mantle. We suggest that the mantle lithosphere plays a key role in de-carbonation and conversion of deep-sourced carbonated melts to alkali basalts. This work was financially supported by the National Natural Science Foundation of China (91858206, 41876040).

How to cite: Zhang, G.: Evolution of deep mantle sourced carbonated melt in the mantle lithosphere, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13055, https://doi.org/10.5194/egusphere-egu2020-13055, 2020

This abstract will not be presented.