Proterozoic onset of crustal reworking and collisional tectonics : Reappraisal of the zircon oxygen isotope record
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A global U-Pb and δO zircon database shows temporal changes in the magmatic record related to changes in the degree of crustal reworking. The δO composition of bulk sediment remains relatively constant through geologic time, with a mean value of 14.9%. In contrast, the δO values in magmatic zircons vary from relatively low values averaging ̃6% in the Archean to increasingly higher and scattered values defining a series of peaks and troughs in post-Archean data. The degree of crustal reworking increases at times of supercontinent assembly. Therefore we attribute the pattern of post-Archean δO values recorded by magmatic zircons to a significant increase in the incorporation of high δO sediment in response to enhanced crustal thickening and reworking associated with the onset of collisional tectonics, especially during formation of supercontinents.
Spencer , C J , Cawood , P A , Hawkesworth , C J , Raub , T D , Prave , A R & Roberts , N M W 2014 , ' Proterozoic onset of crustal reworking and collisional tectonics : Reappraisal of the zircon oxygen isotope record ' Geology , vol 42 , no. 5 , pp. 451-454 . DOI: 10.1130/G35363.1
© 2014. Geological Society of America This is an Accepted Manuscript of an article published in the Geology May 2014, available online: http://dx.doi.org/10.1130/G35363.1
Funding: University of St Andrews and Natural Environment Research Council
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