Extended Data Table 1: Plumes detected in the lower mantle in model SEMUCB-WM14, and corresponding hotspots

From: Broad plumes rooted at the base of the Earth's mantle beneath major hotspots

Table 1
  1. The numbering (column 1) and categories correspond to those in Fig. 4. Plumes are categorized as primary if the corresponding low-velocity conduit in the lower mantle has δVs/Vs less than −1.5% for most of the depth interval 1,000–2,800 km. These 11 plumes also correspond to regions of the lower mantle where the average velocity reduction over the depth range 1,000–1,800 km is significant at the 2σ level (see, for example, Supplementary Figs 3 and 4). Clearly resolved plumes correspond to vertically continuous conduits with δVs/Vs <−0.5% in the depth range 1,000–2,800 km. Somewhat resolved plumes have vertically trending conduits with δVs/Vs <−0.5% for most of the depth range 1,000−2,800 km, albeit not as clearly continuous. The only clearly resolved plume in the lower mantle that is not near a hotspot is in Indonesia, possibly because it is rising beneath a broad slab. However, it occurs close to a location where high 3He/4He ratios have been observed43. For comparison, we list the corresponding hotspot ranking (column 3)26, as well as the buoyancy flux (column 4) and 3He/4He ratios (column 5)26. Question marks indicate no value given in ref. 26. Note that in this previous ranking of hotspots, these estimates of buoyancy flux and 3He/4He ratios were used together with the velocity anomaly values in the transition zone (500-km depth) from an older tomographic shear-velocity model44. In contrast, our ranking is based entirely on the continuity of broad vertically oriented low-velocity structures across the major part of the lower mantle. Hotspots that do not have any clear expression in the lower mantle in model SEMUCB-WM1 are not listed, namely Yellowstone, Juan de Fuca/Cobb and Bowie (see also Fig. 4).