Disparities in oxygen isotopes of detrital and igneous zircon identify erosional bias in crustal rock record

Spencer, C.J.; Cavosie, A.J.; Morrell, T.R.; Lu, G.M.; Liebmann, J.; Roberts, N.M.W.. 2022 Disparities in oxygen isotopes of detrital and igneous zircon identify erosional bias in crustal rock record. Earth and Planetary Science Letters, 577, 117248. 10.1016/j.epsl.2021.117248

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Official URL: http://dx.doi.org/10.1016/j.epsl.2021.117248

Abstract/Summary

The detrital zircon oxygen isotope record has been used to describe 4.4 billion years of crustal evolution and maturation. Implicit in the application and use of large databases of oxygen isotope ratio (O) from detrital zircon is that such data are more representative of the history of the continental crust than are exposed rocks. Here we show that the O of igneous zircon in preserved rocks varies greatly from the detrital zircon record over time, both in terms of the magnitude of O and the secular variation. Starting from 4.0 Ga and lasting throughout the Archean, the detrital zircon record shows consistently higher O values than the rock record. In post-Archean times, detrital zircon O is conspicuously higher during periods associated with supercontinent amalgamation. Differences between detrital and igneous zircon O records imply that the igneous source rocks from which high O detrital zircon are derived have been entirely eroded and are not represented in the known geological record. We postulate that the ‘missing’ record of high O magmatic rocks consists of upper crustal sedimentary-derived melts from collisional belts, such as that found in the Himalayan orogen. The observation of higher O in Archean detrital zircon further requires a revision of the current paradigm for Archean magmatism. More broadly, recognition of a ‘missing’ component of the upper crustal rock record calls into question the degree to which the detrital zircon record accurately reflects the composition of the bulk continental crust.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.epsl.2021.117248
ISSN:	0012821X
Date made live:	25 Jan 2022 11:47 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/531818

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.epsl.2021.117248

ISSN:

0012821X

Date made live:

25 Jan 2022 11:47 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/531818