Reassessing the Thermal Structure of Oceanic Lithosphere With Revised Global Inventories of Basement Depths and Heat Flow Measurements

Richards, FD; Hoggard, MJ; Cowton, LR; White, NJ

Reassessing the Thermal Structure of Oceanic Lithosphere With Revised Global Inventories of Basement Depths and Heat Flow Measurements

cam.issuedOnline	2018-10-09
datacite.issourceof.doi	10.17863/CAM.26215
dc.contributor.author	Richards, FD
dc.contributor.author	Hoggard, MJ
dc.contributor.author	Cowton, LR
dc.contributor.author	White, NJ
dc.contributor.orcid	Richards, FD [0000-0002-6610-4289]
dc.contributor.orcid	Hoggard, MJ [0000-0003-4310-3862]
dc.contributor.orcid	Cowton, LR [0000-0003-4301-4536]
dc.contributor.orcid	White, NJ [0000-0002-4460-299X]
dc.date.accessioned	2018-09-11T17:33:12Z
dc.date.available	2018-09-11T17:33:12Z
dc.date.issued	2018
dc.description.abstract	<jats:title>Abstract</jats:title><jats:p>Half‐space cooling and plate models of varying complexity have been proposed to account for changes in basement depth and heat flow as a function of lithospheric age in the oceanic realm. Here, we revisit this well‐known problem by exploiting a revised and augmented database of 2,028 measurements of depth to oceanic basement, corrected for sedimentary loading and variable crustal thickness, and 3,597 corrected heat flow measurements. Joint inverse modeling of both databases shows that the half‐space cooling model yields a mid‐oceanic axial temperature that is >100°C hotter than permitted by petrologic constraints. It also fails to produce the observed flattening at old ages. Then, we investigate a suite of increasingly complex plate models and conclude that the optimal model requires incorporation of experimentally determined temperature‐ and pressure‐dependent conductivity, expansivity, and specific heat capacity, as well as a low‐conductivity crustal layer. This revised model has a mantle potential temperature of 1300 ± 50°C, which honors independent geochemical constraints and has an initial ridge depth of 2.6 ± 0.3 km with a plate thickness of 135 ± 30 km. It predicts that the maximum depth of intraplate earthquakes is bounded by the 700°C isothermal contour, consistent with laboratory creep experiments on olivine aggregates. Estimates of the lithosphere‐asthenosphere boundary derived from studies of azimuthal anisotropy coincide with the 1175 ± 50°C isotherm. The model can be used to isolate residual depth and gravity anomalies generated by flexural and sub‐plate convective processes.</jats:p>
dc.description.sponsorship	Natural Environment Research Council PhD Studentship
dc.identifier.doi	10.17863/CAM.27586
dc.identifier.eissn	2169-9356
dc.identifier.issn	2169-9313
dc.identifier.uri	https://www.repository.cam.ac.uk/handle/1810/280219
dc.language.iso	eng
dc.publisher	American Geophysical Union (AGU)
dc.publisher.url	http://dx.doi.org/10.1029/2018jb015998
dc.subject	37 Earth Sciences
dc.subject	3703 Geochemistry
dc.subject	3705 Geology
dc.subject	3706 Geophysics
dc.title	Reassessing the Thermal Structure of Oceanic Lithosphere With Revised Global Inventories of Basement Depths and Heat Flow Measurements
dc.type	Article
dcterms.dateAccepted	2018-08-17
prism.endingPage	9161
prism.issueIdentifier	10
prism.publicationDate	2018
prism.publicationName	Journal of Geophysical Research: Solid Earth
prism.startingPage	9136
prism.volume	123
pubs.funder-project-id	NERC (1508951)
pubs.funder-project-id	NERC (NE/L002507/1)
rioxxterms.licenseref.startdate	2018-10-01
rioxxterms.licenseref.uri	http://www.rioxx.net/licenses/all-rights-reserved
rioxxterms.type	Journal Article/Review
rioxxterms.version	AM
rioxxterms.versionofrecord	10.1029/2018JB015998