Compositional Attributes of the Deep Continental Crust Inferred From Geochemical and Geophysical Data

dc.contributor.authorSammon, Laura G.
dc.contributor.authorMcDonough, William F.
dc.contributor.authorMooney, Walter D.
dc.date.accessioned2023-09-28T17:38:29Z
dc.date.available2023-09-28T17:38:29Z
dc.date.issued2022-08-03
dc.description.abstractThis study provides a global assessment of the abundance of the major oxides in the deep continental crust. The combination of geochemistry and seismology better constrains the composition of the middle and lower continental crust better than either discipline can achieve alone. The inaccessible nature of the deep crust (typically >15 km) forces reliance on analog samples and modeling results to interpret its bulk composition, evolution, and physical properties. A common practice relates major oxide compositions of small- to medium-scale samples (e.g., medium to high metamorphic grade terrains and xenoliths) to large scale measurements of seismic velocities (Vp, Vs, Vp/Vs) to determine the composition of the deep crust. We provide a framework for building crustal models with multidisciplinary constraints on composition. We present a global deep crustal model that documents compositional changes with depth and accounts for uncertainties in Moho depth, temperature, and physical and chemical properties. Our 3D compositional model of the deep crust uses the USGS Global Seismic Structure Catalog (Mooney, 2015) and a compilation of geochemical analyses on amphibolite and granulite facies lithologies (Sammon & McDonough, 2021, https://doi.org/10.1029/2021JB022791). We find a SiO2 gradient from 61.2 ± 7.3 to 53.3 ± 4.8 wt.% from the middle to the base of the crust, with the equivalent lithological gradient ranging from quartz monzonite to gabbronorite. In addition, we calculate trace element abundances as a function of depth from their correlations with major oxides. From here, other lithospheric properties, such as Moho heat flux (urn:x-wiley:21699313:media:jgrb55765:jgrb55765-math-0001 mW/m2), are derived.
dc.description.urihttps://doi.org/10.1029/2022JB024041
dc.identifierhttps://doi.org/10.13016/dspace/uilh-1q2x
dc.identifier.citationSammon, L. G., McDonough, W. F., & Mooney, W. D. (2022). Compositional attributes of the deep continental crust inferred from geochemical and geophysical data. Journal of Geophysical Research: Solid Earth, 127, e2022JB024041.
dc.identifier.urihttp://hdl.handle.net/1903/30605
dc.language.isoen_US
dc.publisherWiley
dc.relation.isAvailableAtDigital Repository at the University of Maryland
dc.relation.isAvailableAtGemstone Program, University of Maryland (College Park, Md)
dc.subjectcrust composition
dc.subjectmiddle crust
dc.subjectlower crust
dc.subjectgeochemical
dc.subjectgeophysical
dc.subjectseismology
dc.titleCompositional Attributes of the Deep Continental Crust Inferred From Geochemical and Geophysical Data
dc.typeArticle
local.equitableAccessSubmissionNo

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