Intraplate or "hot spot" volcanic island chains, exemplified by Hawaii, play an important role in plate tectonic theory as reference points for absolute plate motions, but the origin of these volcanoes is not explained by the plate tectonic paradigm [Engebretson et al., 1985; Molnar and Stock, 1987; Morgan, 1971, 1981, 1983; Wilson, 1963]. The most widely held view is that these chains of volca...

Mantle control on planetary dynamos is often studied by imposing heterogeneous core-mantle boundary (CMB) heat flux patterns on the outer boundary of numerical dynamo simulations. These patterns typically enter two main categories: Either they are proportional to seismic tomography models of Earth’s lowermost mantle to simulate realistic conditions, or they are represented by single spherical h...

The amount of heat flowing from Earth's core critically determines the thermo-chemical evolution of both the core and the lower mantle. Consisting primarily of a polycrystalline aggregate of silicate perovskite and ferropericlase, the thermal boundary layer at the very base of Earth's lower mantle regulates the heat flow from the core, so that the thermal conductivity (k) of these mineral phase...

The South Atlantic region displays (1) a topographic gradient across the basin, with Africa elevated relative to South America, (2) a bimodal spreading history with fast spreading rates in Late Cretaceous and Eo-Oligocene, and (3) episodic regional uplift events in the adjacent continents concentrated in Late Cretaceous and Oligocene. Here we show that these observations can be linked by dynami...

Numerical simulations in both twoand three-dimensions are performed to investigate the hypothesis that D” is a thermo-chemical boundary layer. A layer of dense, compositionally-distinct material above the CMB reduces the characteristic horizontal lengthscales and interior mantle temperature. In three-dimensions, the layer forms a spoke pattern, with entrainment in upwelling cylinders, even for ...

Analyses of the relative motion using hotspot tracks, age progressions and plate circuits, and of the absolute motion using paleolatitude data indicate that three major long-lived surface hotspots geographically within a very low velocity province (VLVP) at the base of the Earth's mantle, Tristan, Marion and Kerguelen, exhibit small relative motions (b9 mm/yr) in the past 80 Ma. The geochemical...