The geochemical and oxygen-isotope affinities of Proterozoic mafic granulites from the Einasleigh Metamorphics, northern Queensland

McNaughton N.J. and Wilson A.F. (1983) The geochemical and oxygen-isotope affinities of Proterozoic mafic granulites from the Einasleigh Metamorphics, northern Queensland. Precambrian Research, 21 1-2: 21-37. doi:10.1016/0301-9268(83)90003-7


Author McNaughton N.J.
Wilson A.F.
Title The geochemical and oxygen-isotope affinities of Proterozoic mafic granulites from the Einasleigh Metamorphics, northern Queensland
Journal name Precambrian Research   Check publisher's open access policy
ISSN 0301-9268
Publication date 1983-01-01
Sub-type Article (original research)
DOI 10.1016/0301-9268(83)90003-7
Volume 21
Issue 1-2
Start page 21
End page 37
Total pages 17
Subject 1906 Geochemistry and Petrology
1907 Geology
Abstract 1.6 Ga-old layered mafic rocks from the Einasleigh Metamorphics underwent two medium-high grade metamorphisms to produce a hornblende-stable granulite facies assemblage. The concentration of the immobile elements (Ti, P, Zr, Y, Nb) in 13 selected samples consistently indicates that these mafic granulites are indistinguishable from modern MORB. Furthermore, their K contents, K/Rb ratios, FeO*MgOTiO2 signature and δ18O values are similar to modern unaltered low-K tholeiites to ocean floor basalts which show some affinities to 'plume'-type MORB. The only chemical features which separate the mafic rocks from pristine MORB are an increase in H2O+, which predates the high grade event, a lower Fe3+ ΣFe ratio, and a slight decrease in Na during the waning of the granulite facies metamorphism. These data are interpreted to indicate that the mafic rocks at Turpentine Hill underwent essentially isochemical granulite facies metamorphism, and their igneous precursors were derived from a mantle source similar to that which now underlies the mid-ocean ridges.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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