Multidisciplinary constraints on the abundance of diamond and eclogite in the cratonic lithosphere - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Geochemistry, Geophysics, Geosystems Année : 2018

Multidisciplinary constraints on the abundance of diamond and eclogite in the cratonic lithosphere

Résumé

Some seismic models derived from tomographic studies indicate elevated shear-wave velocities (≥4.7 km/s) around 120-150 km depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35 mW/m2 surface heat flux) and accounting for compositional heterogeneity in cratonic peridotite xenoliths and the effects of anelasticity. We reviewed various geophysical and petrologic constraints on the nature of cratonic roots (seismic velocities, lithology/mineralogy, electrical conductivity, and gravity) and explored a range of permissible rock and mineral assemblages that can explain the high seismic velocities. These constraints suggest that diamond and eclogite are the most likely high-Vs candidates to explain the observed velocities, but matching the high shear-wave velocities requires either a large proportion of eclogite (>50 vol.%) or the presence of up to 3 vol.% diamond, with the exact values depending on peridotite and eclogite compositions and the geotherm. Both of these estimates are higher than predicted by observations made on natural samples from kimberlites. However, a combination of ≤20 vol.% eclogite and ~2 vol.% diamond may account for high shear-wave velocities, in proportions consistent with multiple geophysical observables, data from natural samples, and within mass balance constraints for global carbon. Our results further show that cratonic thermal structure need not be significantly cooler than determined from xenolith thermobarometry.

could not parse page for 10.1029/2018GC007496

Fichier principal
Vignette du fichier
Geochem Geophys Geosyst - 2018 - Garber - Multidisciplinary Constraints on the Abundance of Diamond and Eclogite in the.pdf (4.36 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

insu-03589344 , version 1 (25-02-2022)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Joshua M. Garber, Satish Maurya, Jean-Alexis Hernandez, Megan S. Duncan, Li Zeng, et al.. Multidisciplinary constraints on the abundance of diamond and eclogite in the cratonic lithosphere. Geochemistry, Geophysics, Geosystems, 2018, 19, pp.2062-2086. ⟨10.1029/2018GC007534⟩. ⟨insu-03589344⟩
63 Consultations
20 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More