z-logo
open-access-imgOpen Access
Origin of geochemical mantle components: Role of subduction filter
Author(s) -
Kimura JunIchi,
Gill James B.,
Skora Susanne,
van Keken Peter E.,
Kawabata Hiroshi
Publication year - 2016
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2016gc006343
Subject(s) - subduction , geology , mantle (geology) , geochemistry , seismology , earth science , geophysics , tectonics
We quantitatively explore element redistribution at subduction zones using numerical mass balance models to evaluate the roles of the subduction zone filter in the Earth's geochemical cycle. Our models of slab residues after arc magma genesis differ from previous ones by being internally consistent with geodynamic models of modern arcs that successfully explain arc magma genesis and include element fluxes from the dehydration/melting of each underlying slab component. We assume that the mantle potential temperature ( T p ) was 1400–1650°C at 3.5–1.7 Ga and gradually decreased to 1300–1350°C today. Hot subduction zones with T p ∼1650°C have a thermal structure like modern SW Japan where high‐Mg andesite is formed which is chemically like continental crust. After 2.5–1.7 Gyr of storage in the mantle, the residual igneous oceanic crust from hot subduction zones can evolve isotopically to the HIMU mantle component, the residual base of the mantle wedge to EMI, the residual sediment becomes an essential part of EMII, and the residual top of the mantle wedge can become the subcontinental lithosphere component. The Common or Focal Zone component is a stable mixture of the first three residues occasionally mixed with early depleted mantle. Slab residues that recycled earlier (∼2.5 Ga) form the DUPAL anomaly in the southern hemisphere, whereas residues of more recent recycling (∼1.7 Ga) underlie the northern hemisphere. These ages correspond to major continental crust forming events. The east‐west heterogeneity of the depleted upper mantle involves subcontinental mantle except in the Pacific.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here