A deep mantle source for high He-3/He-4 ocean island basalts (OIB) inferred from Pacific near-ridge seamount lavas

Citation:
Hahm, D, Castillo PR, Hilton DR.  2009.  A deep mantle source for high He-3/He-4 ocean island basalts (OIB) inferred from Pacific near-ridge seamount lavas. Geophysical Research Letters. 36

Date Published:

Oct

Keywords:

crust, geochemistry, helium, heterogeneity, isotope systematics, neon, plumes, ratios, sr, submarine basalts

Abstract:

One of the most contentious issues in the debate on the origin of volcanic island and seamount chains is the significance of high He-3/He-4 ratios at such locations. The contemporary hotspot hypothesis calls for the high He-3/He-4 signature to be derived from a distinct source reservoir that lies deep in the mantle. The competing plate stress hypothesis claims that extreme isotopic signals, such as the high He-3/He-4, come from dispersed crustal lithologies in the upper mantle. Here, we show that lavas from the East Pacific Rise-the ridge axis and near-ridge seamounts, which have radiogenic isotope compositions overlapping with other Pacific OIB, do not have high He-3/(4) He ratios. This suggests that high He-3/He-4 is not associated with dispersed, heterogeneous lithologies embedded in the upper mantle. We conclude that the mantle source of high He-3/He-4 OIB is unique to volcanic island and seamount chains and likely resides at depth in the mantle. Citation: Hahm, D., P. R. Castillo, and D. R. Hilton (2009), A deep mantle source for high He-3/(4) He ocean island basalts (OIB) inferred from Pacific near-ridge seamount lavas, Geophys. Res. Lett., 36, L20316, doi: 10.1029/2009GL040560.

Notes:

n/a

Website

DOI:

10.1029/2009gl040560

Scripps Publication ID:

L20316