2381/11999946.v1
Thomas C Sheldrick
Thomas C
Sheldrick
Tiffany L Barry
Tiffany L
Barry
Batulzii Dash
Batulzii
Dash
Chengshi Gan
Chengshi
Gan
Ian L Millar
Ian L
Millar
Dan N Barfod
Dan N
Barfod
Alison M Halton
Alison M
Halton
Simultaneous and extensive removal of the East Asian lithospheric root.
University of Leicester
2020
Uncategorised value
Geochemistry
Geology
Petrology
Volcanology
2020-05-22 14:25:05
Journal contribution
https://figshare.le.ac.uk/articles/journal_contribution/Simultaneous_and_extensive_removal_of_the_East_Asian_lithospheric_root_/11999946
Much evidence points to a dramatic thinning of East Asian lithosphere during the Mesozoic, but with little precision on when, or over what time scale. Using geochemical constraints, we examine an extensive compilation of dated volcanic samples from Russia, Mongolia and North China to determine when the lithosphere thinned and how long that process took. Geochemical results suggest that magmatism before 107 Ma derived from metasomatised subcontinental lithospheric mantle (SCLM), whereas after 107 Ma, melt predominantly derived from an asthenospheric source. The switch to an asthenospheric magma source at ~107 Ma occurred in both Mongolia and North China (>1600 km apart), whereas in eastern Russia the switch occurred a little later (~85 Ma). Such a dramatic change to an asthenospheric contribution appears to have taken, from beginning to end, just ~30 Myrs, suggesting this is the duration for lithospheric mantle weakening and removal. Subsequent volcanism, through the Cenozoic in Mongolia and North China does not appear to include any contribution from the removed SCLM, despite melts predominantly deriving from the asthenosphere.