Björn Holger Heyn

• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2018). Stabilizing effect of compositional viscosity contrasts on thermochemical piles. Geophysical Research Letters.  ISSN 0094-8276.  45(15), s 7523- 7532 . doi: 10.1029/2018GL078799 Show summary

  The large low shear velocity provinces (LLSVPs) observed in the lowermost mantle are widely accepted as chemically distinct thermochemical 'piles', but their origin and long-term evolution remain poorly understood. The survival time and shape of the LLSVPs are thought to be mainly controlled by their compositional density, while their viscosity has beeen considered less important. Based on recent constraints on chemical reactions between mantle and core, a more complex viscosity structure of the lowermost mantle, possibly including high viscosity thermochemical pile material, seems reasonable. In this study, we use numerical models to identify a trade-off between compositional viscosity and density contrasts required for long-term stability of thermochemical piles, which permits lower-density and higher-viscosity piles. Moreover, our results indicate more restrictive stability conditions during periods of strong deformation-induced entrainment, e.g. during initial pile formation, which suggests long-term pile survival.

• Reiss, Anne-Sophie; Thomas, Christine; van Driel, Jac & Heyn, Björn Holger (2017). A hot midmantle anomaly in the area of the Indian Ocean Geoid Low. Geophysical Research Letters.  ISSN 0094-8276.  44(13), s 6702- 6711 . doi: 10.1002/2017GL073440

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• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2018). Stabilization of thermochemical piles by compositional viscosity contrasts. EGU Gen. Assembly, EGU2018-12950.
• Heyn, Björn Holger; Conrad, Clinton Phillips & Trønnes, Reidar G (2017). Stabilizing effect of a chemical viscosity contrast on LLSVP structures Abstr., Gordon Res. Conf. on Chemical and dynamical evolution of Earth's deep interior, from formation to today. Mount Holyoke College, South Hadley, MA.

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