On Style of Mantle Convection(<Special Issue>Volcanology : It's future directions)

概要

論文の詳細を見る
Seismic tomography has demonstrated three-dimensional images of seismic velocity perturbation in the Earth, which could be a snapshot of convection in the Earth assuming that seismic velocity depends on temperature and chemical compositions. Numerical studies together with tomographic images from seismic studies may make a picture of convection in the mantle clearer. Cold materials from subduction zones flow down to the core-mantle boundary with partial trapping at the phase boundary, and a broad hot counterflow uprises due to internal heat generation. The primitive component could survive due to the partial layering of the mantle convection system. The D" layer is considered to be a reservoir of the fertile materials enriched in the slab component. Plumes generated by heat flow form the core uprise entraining primitive lower mantle materials, and reach the surface and generate hotspot magmas and LIPs (Large Igneous Provinces) magmas. These plumes have narrow conduit due to their strongly temperature dependent rheology, and are difficult to detect from geophysical observations. Dynamics of the circulation of the chemically distinct materials should be revealed based on realistic numerical models consistent with isotope data set including rare gases and heavy elements, and on secular variation of chemistry of the mantle magma sources in the history of the Earth.
特定非営利活動法人日本火山学会の論文
1995-12-25