Other
Scientific paper
Jun 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000e%26psl.179..139s&link_type=abstract
Earth and Planetary Science Letters, Volume 179, Issue 1, p. 139-152.
Other
11
Scientific paper
We present Os data for axial high-temperature and off-axial low-temperature hydrothermal solutions from the Juan de Fuca Ridge. The high-temperature, H2S-bearing axial fluids have unradiogenic Os isotopes pointing to a nearly complete domination of osmium isotopes from the basalts during hydrothermal circulation. The ridge axis fluids typically do not show large enrichment in osmium concentration over seawater although one high-temperature fluid has an Os concentration enhanced by a factor of 4 above seawater. It appears that the Os concentration of high-temperature hydrothermal fluids is typically buffered at roughly the seawater concentration. We suggest that subseafloor precipitation of pyrite from the high-temperature hydrothermal fluids controls the osmium transportation. The axial hydrothermal activity does not supply significant amounts of unradiogenic osmium to the deep oceans. In contrast, a low-temperature off-axis fluid is enriched in non-radiogenic osmium over seawater by a factor of 9, showing much less precipitation of osmium at low temperature. Because a large fraction of the cooling of oceanic lithosphere occurs on ridge flanks, Os from low-temperature, ridge-flank hydrothermal circulation may be a significant contributor to the balance of Os in the oceans. A detailed balance between Os contributions from dissolution of cosmic dust and hydrothermal fluids is still not possible. The low-temperature hydrothermal sample gives 187Os/188Os=0.110+/-0.001. This extremely unradiogenic osmium can only come from a source that underwent depletion of Re over 2.6 Ga ago. Assuming no contamination during sample collection, this result suggests that the convecting upper mantle contains ancient depleted material that imparted unradiogenic osmium to intruding basaltic melts.
Butterfield David A.
Hofmann Albrecht W.
Sharma Malti
Wasserburg Gerald J.
No associations
LandOfFree
Osmium isotopes in hydrothermal fluids from the Juan de Fuca Ridge 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 Osmium isotopes in hydrothermal fluids from the Juan de Fuca Ridge, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Osmium isotopes in hydrothermal fluids from the Juan de Fuca Ridge will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1348143