Fig. 5: Formation of thermochemical piles in the lowermost mantle from iron-rich materials.
From: Formation of large low shear velocity provinces through the decomposition of oxidized mantle
The temperature (left column) and composition (right column) fields from the surface to the core–mantle boundary are shown at 4.5 Gyr for case 1 (a, b), case 2 (c, d), case 3 (e, f), and case 4 (g, h). In cases 1, 2, 3, and 4, the Rayleigh number is Ra = 1 × 107, 1 × 106, 1 × 108, and 1 × 107, respectively, and the iron-rich materials (shown by golden colors in the right panels) are 1.2%, 1.2%, 1.2%, and 1.5% intrinsically denser than the background mantle materials (shown by black colors in the right panels), respectively. Large thermochemical piles form after 4.5 Gyr for all cases.
