Miocene Volcanism of the Baikal Rift Across the Boundary of the Siberian Craton: Evidence for Lithospheric Mantle Melting.

This article focuses on the geochemical and isotopic study of Miocene volcanic rocks from the Baikal Rift, specifically across the boundary between the Neoproterozoic Tuva-Mongolian massif and the Archean–Paleoproterozoic Siberian Craton, to elucidate the rift's origin. The analyzed basalts exhibit oceanic island basalt (OIB)-like geochemical signatures, with magma sources interpreted as lithospheric peridotite mantle veined by mafic lithologies rather than mantle plumes. Isotopic data (Sr–Nd–Pb–Hf–O) indicate mixing between depleted MORB mantle (DMM) and enriched mantle (EM1) components, with distinct lead isotope differences across the cratonic boundary attributed to ancient sulphides in the lithospheric mantle. The predominance of lithospheric sources and lack of plume signatures support a passive rifting model for the Baikal Rift, driven by tectonic stresses rather than active mantle upwelling.