Other
Scientific paper
Sep 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993georl..20.1851l&link_type=abstract
Geophysical Research Letters (ISSN 0094-8276), vol. 20, no. 17, p. 1851-1854.
Other
8
Basalt, Helium Isotopes, Magma, Mid-Ocean Ridges, Earth Mantle, Pacific Ocean
Scientific paper
We have measured 3He/4He ratios and He and Ne concentrations on a suite of 24 basalt glasses from the neovolcanic zone of the Juan de Fuca Ridge (JdFR) from 44.6N near the Blanco Transform up to 48.0N on the Endeavour Segment. The helium isotope ratios exhibit a clear geographic variation, with relatively constant values of 7.8 RA along the southern JdFR increasing to a maximum of 8.8 RA at 46.9 deg N on the Cobb Segment, and then dropping to values of about 8.0 RA at the Cobb Offset. Ratios along the Endeavour Segment further north are somewhat higher, averaging about 8.2 RA. Basalts dredged from Axial Seamount have 3He/4He = 7.9-8.4 RA, indicating that the seamount does not have a geochemical or isotopic signature distinct from other portions of the JdFR. This confirms that while Axial Seamount is the locus of excess magma generation, it is devoid of any hotspot or ocean island basalt geochemical signature. For the whole sample set, 3He/4He ratios show a negative correlation with 87Sr/86Sr. We attribute the geographical variations in 3He/4He to broad-scale heterogeneity in the mantle source region beneath the JdFR. Beginning at Axial Seamount and further north, 3He/4He shows a positive correlation with Fea.o, suggesting that melting dynamics in the underlying mantle may exert some control on the helium isotope ratios along part of our surcey area.
Delaney John R.
Graham David W.
Johnson Howard P.
Lupton John. E.
No associations
LandOfFree
Helium isotope variations in Juan de Fuca Ridge basalts does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Helium isotope variations in Juan de Fuca Ridge basalts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Helium isotope variations in Juan de Fuca Ridge basalts will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1562685