Boron Isotope Review

Boron Isotope Review

1. 13 isotopes

   • 2 stable
     • 11B/10B ratio used. 10B abundance = 19.9%. 11B abundance = 80.1%
   • Remaining isotope half-lives <1 second

2. Significant growth over the last 10 years

   • Advances in technology
     • Thermal ionization mass spectrometry (TIMS) in the early 1980s
     • Plasma-based analytical methods in early 2000s
       • ICP-MS widely used
         • NISTRM-951 STANDARD
   • Recognition of its potential as a geochemical tracer due to:
     • Relatively high abundance upper crust
     • Light mass
       • Highly mobile in fluids
     • Large difference between 10B/11B isotope masses
       • Distinct isotope ratio for different reservoirs

3. Bonded to oxygen as either tetrahedral or tetragonal complexes

   • B11 incorporated into B(OH)3
   • B10 incorporated in B(OH)4-

4. Environmental applications

   • Used as a proxy to reconstruct paleo-climate conditions (pH)
     • Composition of boron isotopes within carbonate = composition of boron isotopes associated with borate in solution
   • Groundwater Tracer
     • Unaffected by: Evaporation, oxidation-reduction, very soluble, present within almost all waters

Images and files in the map