Triggering of episodic back-arc extensions in the northeast Asian continental margin by deep mantle flow

Back-arc extension has been well documented in subduction plate tectonic regimes. However, the reasons why back-arc extensions are associated with some systems but not others have remained elusive. Here, spatio-temporal variations composition of Cenozoic basalts northeast Asian continental margin used to constrain mechanism for episodic extensions. Using geochemical data sensitive affinity, we show that typical volcanic arc compositions located eastern Asia, whereas coeval intraplate western part and volcanism exhibit two eastward shifts, from 52 Ma 33 21 Ma. Intraplate dated at ca. 11 display a weak, arc-like signature, which suggests upwelling asthenospheric mantle resulted remelting previously melt-extracted lithospheric modified by slab-derived fluids cessation Thus, propose flow shifts led development extensive margin.