Evidence for melting mud in Earth’s mantle from extreme oxygen isotope signatures in zircon.

Journal article


Spencer, Christopher J., Cavosie, Aaron J., Raub, Timothy D., Rollinson, Hugh, Jeon, Heejin, Searle, Michael P., Miller, Jodie A., McDonald, Bradley J. and Evans, Noreen J. 2017. Evidence for melting mud in Earth’s mantle from extreme oxygen isotope signatures in zircon. Geology. https://doi.org/10.1130/G39402.1
AuthorsSpencer, Christopher J., Cavosie, Aaron J., Raub, Timothy D., Rollinson, Hugh, Jeon, Heejin, Searle, Michael P., Miller, Jodie A., McDonald, Bradley J. and Evans, Noreen J.
Abstract

Melting of subducted sediment remains controversial, as direct observation of sediment melt generation at mantle depths is not possible. Geochemical fingerprints provide indirect evidence for subduction delivery of sediment to the mantle; however, sediment abundance in mantle-derived melt is generally low (0%–2%), and difficult to detect. Here we provide evidence for melting of subducted sediment in granite sampled from an exhumed mantle section. Peraluminous granite dikes that intrude peridotite in the Oman–United Arab Emirates ophiolite have U-Pb ages of 99.8 ± 3.3 Ma that predate obduction. The dikes have unusually high oxygen isotope (δ18O) values for whole rock (14–23‰) and quartz (20–22‰), and yield the highest δ18O zircon values known (14–28‰; values relative to Vienna standard mean ocean water [VSMOW]). The extremely high oxygen isotope ratios uniquely identify the melt source as high-δ18O marine sediment (pelitic and/or siliciceous mud), as no other source could produce granite with such anomalously high δ18O. Formation of high-δ18O sediment-derived (S-type) granite within peridotite requires subduction of sediment to the mantle, where it melted and intruded overlying mantle wedge. The granite suite described here contains the highest oxygen isotope ratios reported for igneous rocks, yet intruded mantle peridotite below the Mohorovičić seismic discontinuity, the most primitive oxygen isotope reservoir in the silicate Earth. Identifying the presence and quantifying the extent of sediment melting within the mantle has important implications for understanding subduction recycling of supracrustal material and effects on mantle heterogeneity over time.

KeywordsSedimentology; Earth science; Earth mantle; Oman
Year2017
JournalGeology
PublisherGeological Society of America
ISSN00917613
Digital Object Identifier (DOI)https://doi.org/10.1130/G39402.1
Web address (URL)http://hdl.handle.net/10545/621958
hdl:10545/621958
Publication dates02 Oct 2017
Publication process dates
Deposited24 Nov 2017, 09:31
ContributorsCurtin University, University of St Andrews, University of Derby, University of Western Australia, University of Oxford and Stellenbosch University
File
File Access Level
Open
File
Permalink -

https://repository.derby.ac.uk/item/93z50/evidence-for-melting-mud-in-earth-s-mantle-from-extreme-oxygen-isotope-signatures-in-zircon

Download files

  • 11
    total views
  • 2
    total downloads
  • 1
    views this month
  • 1
    downloads this month

Export as

Related outputs

The eastern French Pyrenees: from mountain belt to foreland basin
Satterfield, Dorothy, Rollinson, Hugh and Suthren, Roger 2019. The eastern French Pyrenees: from mountain belt to foreland basin. Geology Today. 35 (6), pp. 228-240. https://doi.org/10.1111/gto.12291
Ionic radii
Rollinson, Hugh and Adetunji, Jacob 2017. Ionic radii. in: Springer International Publishing.
Masirah – The other Oman ophiolite: A better analogue for mid-ocean ridge processes?
Rollinson, Hugh 2017. Masirah – The other Oman ophiolite: A better analogue for mid-ocean ridge processes? Geoscience Frontiers. https://doi.org/10.1016/j.gsf.2017.04.009
Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland
Szilas, Kristoffer, van Hinsberg, Vincent J., McDonald, Iain, Næraa, Tomas, Rollinson, Hugh, Adetunji, Jacob and Bird, Dennis 2017. Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland. Geoscience Frontiers. https://doi.org/10.1016/j.gsf.2017.05.003
Archaean crustal evolution in West Africa: A new synthesis of the Archaean geology in Sierra Leone, Liberia, Guinea and Ivory Coast
Rollinson, Hugh 2016. Archaean crustal evolution in West Africa: A new synthesis of the Archaean geology in Sierra Leone, Liberia, Guinea and Ivory Coast. Precambrian Research. https://doi.org/10.1016/j.precamres.2016.05.005
Surprises from the top of the mantle transition zone
Rollinson, Hugh 2016. Surprises from the top of the mantle transition zone. Geology Today. https://doi.org/10.1111/gto.12130
The geochemistry and oxidation state of podiform chromitites from the mantle section of the Oman ophiolite: A review
Rollinson, Hugh and Adetunji, Jacob 2015. The geochemistry and oxidation state of podiform chromitites from the mantle section of the Oman ophiolite: A review. Gondwana Research. https://doi.org/10.1016/j.gr.2013.07.013
Comment on ‘Podiform chromitites do form beneath mid-ocean ridges’ by Arai, S. and Miura, M.
Rollinson, Hugh and Adetunji, Jacob 2016. Comment on ‘Podiform chromitites do form beneath mid-ocean ridges’ by Arai, S. and Miura, M. Lithos. https://doi.org/10.1016/j.lithos.2015.10.023
Archaean chromitites show constant Fe 3+ /ΣFe in Earth's asthenospheric mantle since 3.8 Ga
Rollinson, Hugh, Adetunji, Jacob, Lenaz, Davide and Szilas, Kristoffer 2017. Archaean chromitites show constant Fe 3+ /ΣFe in Earth's asthenospheric mantle since 3.8 Ga. Lithos. https://doi.org/10.1016/j.lithos.2017.03.020
Chromite in the mantle section of the Oman Ophiolite: Implications for the tectonic evolution of the Oman Ophiolite
Rollinson, Hugh and Adetunji, Jacob 2015. Chromite in the mantle section of the Oman Ophiolite: Implications for the tectonic evolution of the Oman Ophiolite. Acta Geologica Sineca. https://doi.org/10.1111/1755-6724.12308_44
There were no large volumes of felsic continental crust in the early Earth
Rollinson, Hugh 2017. There were no large volumes of felsic continental crust in the early Earth. Geosphere. https://doi.org/10.1130/GES01437.1
Determination of Fe3+/ΣFe ratios in chrome spinels using a combined Mössbauer and single-crystal X-ray approach: application to chromitites from the mantle section of the Oman ophiolite
Lenaz, Davide, Adetunji, Jacob and Rollinson, Hugh 2014. Determination of Fe3+/ΣFe ratios in chrome spinels using a combined Mössbauer and single-crystal X-ray approach: application to chromitites from the mantle section of the Oman ophiolite. Contributions to Mineralogy and Petrology. https://doi.org/10.1007/s00410-013-0958-2