PL EN


Preferences help
enabled [disable] Abstract
Number of results
2016 | 71 |
Article title

The calculation of water-rock ratios using trace element (Li, B) stable isotopes

Content
Title variants
Languages of publication
EN
Abstracts
EN
The amount of aqueous fluids circulating into the oceanic crust can be estimated using mass balance equations based on stable isotope exchange between rock and water. Unlike oxygen and strontium, isotopic exchange of trace elements (such as B or Li) between fluids and rocks, operates along with a chemical evolution of the rocks (e.g. a large enrichment of B or Li) that must be integrated into any model of water-rock interaction. We propose a general dimensionless mass balance equation for single-pass open systems that describes the equilibrium elemental distribution and the isotopic composition of reacting rocks as a function of the amount of circulating water. Water-rock ratios calculated from B compositions of hydrothermally-altered basalts range from 8 to 100. They are lower than those previously published (most W/R > 300) but comparable to those inferred from Sr isotope ratios measured in the same samples (3 < W/R < 30). Similar low water-rock ratios from 2 to 20 are calculated from Li isotope compositions of altered basalts and serpentinized peridotites.
Keywords
EN
Year
Volume
71
Physical description
Dates
published
2016
online
23 - 02 - 2017
Contributors
References
  • Albarède F. (1995) Introduction to geochemical modeling. Cambridge University Press. 543 pp.
  • Albarède F., Michard A., Minster J. -F., and Michard G. (1981) 87Sr/86Sr ratios in hydrothermal waters and deposits from the East Pacific Rise at 21°N. Earth Planet. Sci. Lett. 55, 229–236.
  • Chan L.-H. and Edmond J. M. (1988) Variation of lithium isotope composition in the marine environment: a preliminary report. Geochim. Cosmochim. Acta 52, 1711–1717.
  • Chan L.-H., Edmond J. M., and Thompson G. (1993) A lithium isotope study of hot springs and metabasalts from mid-ocean ridge hydrothermal systems. J. Geophys. Res 98, 9653–9659.
  • Chan L.-H., Edmond J. M., Thompson G., and Gillis K. (1992) Lithium isotopic composition of submarine basalts: implications for the lithium cycle in the ocean. Earth Planet. Sci. Lett. 108, 151–160.
  • Chan L.-H., Gieskes J. M., You C. -F., and Edmond J. M. (1994) Lithium isotope geochemistry of sediments and hydrothermal fluids of the Guaymas Basin, Gulf of California. Geochim. Cosmochim. Acta 58, 4443--4454.
  • Criss R. E. (1999) Principles of stable isotope distribution. Oxford University Press. 254 pp.
  • Decitre S., Deloule E., Reisberg L., James R., Agrinier P., and Mével C. (2002) Behavior of Li and its isotopes during sepentinization of oceanic peridotites. Geochem. Geophys. Geosyst. 3, 10.1029/2001GC000178.
  • Donelly T. W., Thompson G., and Salisbury M. H. (1979) The chemistry of altered basalts at site 417, Deep Sea Drilling Project, Leg 51. Init. Rep. Deep Sea Drilling Project 51, 1319–1330.
  • Elderfield H. and Schultz A. (1996) Mid-ocean ridge hydrothermal fluxes and the chemical composition of the ocean. Annu. Rev. Earth Planet. Sci. 24, 191–224.
  • Elderfield H., Wheat C. G., Mottl M. J., Monnin, C., and Spiro B. (1999) Fluid and geochemical transport through oceanic crust: a transect across the eastern flank of the Juan de Fuca Ridge. Earth Planet. Sci. Lett. 172, 151–165.
  • Gregory R. T., and Taylor H. P. J. (1981) An oxygen isotope profile in a section of Cretaceous oceanic crust, Samail ophiolite, Oman: evidence for δ18O buffering of the oceans by deep ( > 5 km) seawater-hydrothermal circulation at mid-ocean ridges. J. Geophys. Res. 86, 2737–2755.
  • Palmer M. G. and Swihart G. H. (1996) Boron isotope geochemistry: An overview. In: Reviews in Mineralogy. Boron. (ed. E. S. Grew and L. M. Anovitz), 33, pp. 709 – 744. Mineral. Soc. Am., Washington, DC.
  • Sakai R., Kusakabe M., Noto M., and Ishii T. (1990) Origin of waters responsible for serpentinization of the Izu-Ogasawara-Mariana forearc seamounts in view of hydrogen and oxygen isotope ratios. Earth Planet. Sci. Lett. 100, 291–303.
  • Smith H. J., Spivack A. J., Staudigel H., and Hart S. R. (1995) The boron isotopic composition of altered oceanic crust. Chem. Geol. 126, 119–135.
  • Spivack A. J. and Edmond J. M. (1987) Boron isotopic exchange between seawater and the oceanic crust. Geochim. Cosmochim. Acta 51, 1033–1043.
  • Staudigel H., Davies G. R., Hart S. R., Marchant K. M., and Smith B. M. (1995) Large scale isotopic Sr, Nd and O isotopic anatomy of altered oceanic crust: DSDP/ODP sites 417/418. Earth Planet. Sci. Lett. 130, 169–185.
  • Taylor H. P. J. (1977) Water/rock interactions and the origin of H2O in granitic batholiths. J. Geol. Soc. London 133, 509–558.
  • Taylor H. P. J. (1978) Oxygen and hydrogen isotope studies of plutonic granitic rocks. Earth Planet. Sci. Lett. 38, 177–210.
  • You C.-F. and Chan L.-H. (1996) Precise determination of lithium isotopic composition in low concentration natural samples. Geochim. Cosmochim. Acta 60, 909–915.
Document Type
Publication order reference
Identifiers
YADDA identifier
bwmeta1.element.ojs-doi-10_17951_aaa_2016_71_79
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.