Bulk Rock and Olivine Chemistry and Isotopes of 106–58 Ma Basalts from Liaodong Peninsula and its Adjacent Areas: Implications for Secular Evolution of the Big Mantle Wedge in Eastern China.

The article focuses on the evolution of the big mantle wedge (BMW) system in East Asia from the Early Cretaceous to the present, as revealed by geochemical and isotopic analyses of 106–58 million-year-old basalts from the Liaodong Peninsula and adjacent areas (LPAA) in eastern China. These basalts exhibit oceanic island basalt (OIB)-like geochemical signatures and contain mantle sources with mixed peridotite and olivine-poor pyroxenite lithologies, incorporating three recycled components: altered lower oceanic crust, altered upper oceanic crust with young pelagic sediments, and ancient (~2.2 Ga) subducted sediments. The compositional and isotopic similarities between the LPAA basalts and modern Cenozoic basalts derived from the current BMW system suggest that the BMW structure, formed by the stagnation of the subducted Izanagi and Pacific slabs in the mantle transition zone, has existed continuously beneath East Asia for at least 120 million years, influencing mantle heterogeneity and regional geological processes.