Atlas of the underworld : Slab remnants in the mantle, their sinking history, and a new outlook on lower mantle viscosity

摘要: Abstract Across the entire mantle we interpret 94 positive seismic wave-speed anomalies as subducted lithosphere and associate these slabs with their geological record. We document this Atlas of Underworld , also accessible online at www.atlas-of-the-underworld.org a compilation comprising subduction systems active in past ~ 300 Myr. Deeper are correlated to older records, assuming no relative horizontal motions between adjacent following break-off, using knowledge global plate circuits, but without reference frame. The longest actively subducting identified reach depth ~ 2500 km some have impinged on Large Low Shear Velocity Provinces deepest mantle. Anomously fast sinking occurs regions affected by long-term plume rising. conclude that slab remnants eventually sink from upper core-mantle boundary. range subduction-age versus – lower is largely inherited history subduction. find significant variation average speed slabs. At top speeds 10 40 mm/yr, followed deceleration 10–15 mm/yr down depths around 1600–1700 km. In interval, situ time-stationary rates suggest 20 30 mm/yr 4–8 mm/yr, increasing 12–15 mm/yr below 2000 km. This corroborates existence zone do not observe (> 60 My) stagnation, excluding stagnation due compositional effects. Conversion profiles viscosity shows general trend increases which slowly decreases deep variance most published derived different observations, agrees qualitatively recent suggested material experiments.