Open AccessDynamics of core formation and equilibration by negative diapirism
Author(s) -
Samuel H.,
Tackley P. J.
Publication year - 2008
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2007gc001896
Subject(s) - diapir , geology , silicate , mantle (geology) , geophysics , scaling , scaling law , mineralogy , mechanics , petrology , geometry , tectonics , paleontology , chemistry , physics , mathematics , organic chemistry
We investigate dynamically the timing and metal‐silicate equilibration processes during core formation by negative diapirism. Using numerical modeling in 3‐D axisymmetric geometry, we follow the sinking of iron‐rich diapirs through a viscous silicate mantle. We carried out a parameter study in which shear heating as well as several viscous rheologies are considered and systematically varied. General scaling laws are derived for the diapir sinking velocity as well as for the silicate melt generation and distribution around the diapir. Using these scaling laws, we show that metal diapirs of a radius ∼1–100 m, sinking through a partially molten silicate mantle can chemically equilibrate within the timescales suggested by geochemical constraints. Therefore negative diapirism can contribute significantly to metal‐silicate equilibration processes during core formation.