Multidisciplinary Constraints on the Abundance of Diamond and Eclogite in the Cratonic Lithosphere

Autor: Hongluo L. Zhang, Barbara Romanowicz, Ulrich H. Faul, M. S. Duncan, Joshua M. Garber, Jean-Alexis Hernandez, Roberta L. Rudnick, Catherine McCammon, Lars Stixrude, Louis Moresi, Li Zeng, Jean-Paul Montagner, Satish Maurya
Přispěvatelé: Department of Earth Sciences [University of Southern California], University of Southern California (USC), Pennsylvania State University (Penn State), Penn State System, Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of California [Berkeley] (UC Berkeley), University of California (UC), Laboratoire pour l'utilisation des lasers intenses (LULI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science, Department of Earth and Planetary Sciences [Cambridge, USA] (EPS), Harvard University, University of Science and Technology of China [Hefei] (USTC), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Bayerisches Geoinstitut (BGI), Universität Bayreuth, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), School of Earth Sciences [Melbourne], Faculty of Science [Melbourne], University of Melbourne-University of Melbourne, Collège de France - Chaire Physique de l'intérieur de la Terre, Collège de France (CdF (institution)), University College of London [London] (UCL)
Rok vydání: 2018
Předmět:
Zdroj: Geochemistry Geophysics Geosystems, vol 19, iss 7
Garber, JM; Maurya, S; Hernandez, JA; Duncan, MS; Zeng, L; Zhang, HL; et al.(2018). Multidisciplinary Constraints on the Abundance of Diamond and Eclogite in the Cratonic Lithosphere. Geochemistry, Geophysics, Geosystems, 19(7), 2062-2086. doi: 10.1029/2018GC007534. UC Berkeley: Retrieved from: http://www.escholarship.org/uc/item/7pk7t2b3
Geochemistry, Geophysics, Geosystems
Geochemistry, Geophysics, Geosystems, 2018, 19, pp.2062-2086. ⟨10.1029/2018GC007534⟩
Geochemistry, Geophysics, Geosystems, vol 19, iss 7
ISSN: 1525-2027
DOI: 10.1029/2018GC007534.
Popis: Author(s): Garber, JM; Maurya, S; Hernandez, JA; Duncan, MS; Zeng, L; Zhang, HL; Faul, U; McCammon, C; Montagner, JP; Moresi, L; Romanowicz, BA; Rudnick, RL; Stixrude, L | Abstract: Some seismic models derived from tomographic studies indicate elevated shear-wave velocities (≥4.7nkm/s) around 120–150nkm depth in cratonic lithospheric mantle. These velocities are higher than those of cratonic peridotites, even assuming a cold cratonic geotherm (i.e., 35nmW/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 (g50nvol.%) or the presence of up to 3nvol.% 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 ≤20nvol.% eclogite and ~2nvol.% 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.
Databáze: OpenAIRE
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