Other
Scientific paper
May 1987
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1987gecoa..51.1033s&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 51, Issue 5, pp.1033-1043
Other
51
Scientific paper
Dissolved boron in seawater from the Atlantic and Pacific is isotopically homogeneous at 39.5 per mil ( 11 B / 10 B ratios are expressed as per mil deviations from NBS SRM 951). Unaltered mid-ocean ridge basalts (MORE) from the crest of the East Pacific Rise (EPR) at 21° and 13°N have B contents of 0.39 ± 0.03 and 0.46 ± 0.03 ppm (about one order of magnitude lower than previous estimates) and 11 B of -3.6 ± 0.4 and -2.2 ± 0.6 per mil respectively. Large scale B exchange between seawater and the oceanic crust has been demonstrated at both high and low temperature. Hydrothermal solutions from nine separate vent fields at 21° and 13°N (EPR) have variable B enrichments, relative to seawater (416 moles/kg), of between 8 and 32% and have 11 B values between 30.0 ± 0.4 and 36.8 ± 0.4 per mil. Boron has been extracted from the basalts with no resolvable isotopic fractionation. High temperature water / rock ratios, based on the B concentrations, are between 0.28 and 3.0. The hydrothermal flux of B into the oceans is between 0.4 and 0.8 × 10 9 moles/yr, assuming that only pristine basalts are present in the reaction zone. Basalts altered at low temperature and serpentinites are variably enriched in B. The B content of altered whole rocks correlates strongly with 18 O, and increases with degree of alteration. Altered basalts ( n = 7) containing between 8.9 and 69 ppm B have 11 B between 0.1 and 9.2 ± 0.4 per mil. Model calculations give water / rock ratios greater than 100 for rocks recovered from DSDP Hole 418A. Serpentinized peridotites ( n = 4) with between 50 and 81 ppm B have 11 B between 8.3 ± 0.4 and 12.6 ± 0.4 per mil. The flux of B into the crust during low temperature alteration is about 13 × 10 9 moles/yr. The maximum diffusive flux of B into the crust from sediment pore waters is 0.8 × 10 9 moles/yr with a 11 B less than 43 per mil.
Edmond John M.
Spivack Arthur J.
No associations
LandOfFree
Boron isotope exchange between seawater and the oceanic crust 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 Boron isotope exchange between seawater and the oceanic crust, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Boron isotope exchange between seawater and the oceanic crust will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-858057