Publication Date:
2022-05-26
Description:
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008): Q04027, doi:10.1029/2007GC001876.
Description:
We report evidence for a global Ti, Ta, and Nb (TITAN) enriched reservoir sampled by ocean island basalts (OIBs) with high 3He/4He ratios, an isotopic signature associated with the deep mantle. Excesses of Ti (and to a lesser degree Nb and Ta) correlate remarkably well with 3He/4He in a data set of global OIBs, demonstrating that a major element signature is associated with the high 3He/4He mantle. Additionally, we find that OIBs with high 3He/4He ratios have moderately radiogenic 187Os/188Os (〉0.135). The TITAN enrichment and radiogenic 187Os/188Os in high 3He/4He OIBs indicate that they are melts of a mantle domain that hosts a nonprimitive (nonchondritic) component. The observation of TITAN enrichment in the high 3He/4He mantle may be important in balancing the Earth's budget for the TITAN elements. Understanding the origin of the TITAN enrichment is important for constraining the evolution of the enigmatic high 3He/4He mantle domain.
Description:
Funds for helium measurements were provided by NSF-OCE
to M.D.K. Funds for major and trace element analyses were
provided by NSF-EAR 0509891 to S.R.H.
Keywords:
He-3/He-4
;
FOZO
;
PHEM
;
C
;
OIB
;
Eclogite
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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