Negative thermal ionisation mass spectrometry: a new approach to boron isotope geochemistry

Boron and Oxygen Isotope Composition of Certified Reference Materials NIST SRM 610/612 and Reference Materials JB‐2 and JR‐2

“…All analyses, including those of the chemically unprocessed standard solution of NIST SRM 951, were subject to both isotopic fractionation and, starting at the beginning of each measurement, a significant CNO interference on mass 42, which has also been reported by Hemming and Hanson (1994) and Klötzli (1992). To suppress the fractionation to an insignificant level, Hemming and Hanson (1994) chose sea water as the matrix solution.…”

Compilation of minimum and maximum isotope ratios of selected elements in naturally occurring terrestrial materials and reagents

“…It was hypothesized that non-marine borates would reflect the isotopic composition of crustal rocks and minerals, which is about 40 %o more negative than marine boron (Swihart and others, 1986). Except Klotzli, 1992Spivack and Edmond, 1987Swihart and others, 1986 Vengosh and others, 1991b Spivack, 1986 Vengosh and others, 199 la Klotzli, 1992 Agyei and McMullen, 1968Spivack and Edmond, 1987Swihart and Moore, 1989Ishikawa and Nakamura, 1993 Vanderpool and Johnson, 1992 for one value at +24 %o, the SnB of non-marine evaporites ranged between -31.3 %o (Finley andothers, 1962) and+7.3 %o (Agyei andMcMullen, 1968). Thus, non-marine borates are depleted in UB relative to marine borates (+18.2 %o to +31.7 %o) and boron isotope ratios can be used to differentiate the two evaporite borates (Swihart and others, 1986).…”

“…As sea water evaporates, salts are depleted in UB by 30 per mill in the early stages of precipitation and by 20 per mill in the latter stages of precipitation (Vengosh and others, 1992), increasing the UB content of evaporated sea water. The highest published SUB value of evaporated sea water is +58.5 %o from the Mediterranean Sea (Klotzli, 1992).…”

“…They suggest that the most negative values may be explained by leaching of boron from hydrothermally altered rhyolite. The highest SnB values in hydrothermal fluids were measured by Klotzli (1992) on Larderello geothermal field (Italy) samples (+21.8 %o to +29.1 %o). These high values were attributed to meteoric waters incorporating boron from marine sediments.…”

“…These high values were attributed to meteoric waters incorporating boron from marine sediments. The SUB value of-59 %o obtained for Sasso Pisano 6 is not included because it cannot be satisfactorily explained (Klotzli, 1992) it may be due to matrix effects during the isotopic analysis. An important source of boron to the oceans for studying global boron cycling is boron in rivers.…”