caa a22 4500 465791557 CHVBK 20180323112026.0 cr unu---uuuuu 170327e19900801xx s 000 0 eng 10.1007/BF00306542 doi (NATIONALLICENCE)springer-10.1007/BF00306542 The effect of net-transfer reactions on the isotopic composition of minerals [Elektronische Daten] [C. Chamberlain, John Ferry, Douglas Rumble III] To interpret correctly the isotopic composition of metmorphic rocks and minerals, the effect of nettransfer reactions must be quantitatively evaluated. Such evaluation requires a complete set of linearly independent, net-transfer reactions that fully describe the reacting system. The set of net-transfer reactions is then coupled with mass-balance equations for stable isotopes. Reaction spaces can be contoured with isopleths of °18O, °13C, and δD of minerals which allows evaluation of the effect of different reactions and bulk compositions on the stable isotopic composition of minerals and rocks. Using this approach, we examined the effect of fractionation of isotopes due to net-transfer reactions at the biotite and second-sillimanite isograds in northern New England. Our analysis shows that the shift in °13C and °18O at an isograd depends strongly upon the overall net-transfer reaction at the isograd and the bulk composition of the rock. The use of model isograd reactions to determine isotopic shifts, therefore, can lead to serious errors in the interpretation of isotopic data. At the second-sillimanite isograd °18O qtz (quartz), °18O kspar (K feldsdpar), and °18O wr (whole rock) decrease by ∼0.5, 1.0, and 0.8 per mil, respectively. Quantitative evaluation of the effect of fractionation of isotopes by net-transfer reactions shows that: (1) the relative changes in oxygen isotopes across the isograd could be caused by distillation of fluids during develatilization reactions; (2) the magnitude of the observed isotopic shifts often differs by a factor of 2 from the calculated shifts due to reaction progress alone. The difference between observed and calculated shifts is attributed to either, differences in bulk composition between individual rocks, or, to isotopic exchange between minerals after peak metamorphism. At the biotite isograd the shifts in carbon and oxygen isotope values are different from predicted shifts caused by net-transfer reactions alone. This discrepancy suggests that fluids infiltrated the rocks during the formation of the biotite isograd. Springer-Verlag, 1990 Chamberlain C. Department of Earth Sciences, Dartmouth College, 03755, Hanover, NH, USA aut Ferry John Department of Earth and Planetary Sciences, Johns Hopkins University, 21218, Baltimore, MD, USA aut Rumble III Douglas Geophysical Laboratory, Carnegie Institution of Washinton, 2801 Upton Street NW, 20008, Washington, DC, USA aut Contributions to Mineralogy and Petrology Springer-Verlag 105/3(1990-08-01), 322-336 0010-7999 105:3<322 1990 105 410 https://doi.org/10.1007/BF00306542 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00306542 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chamberlain C. Department of Earth Sciences, Dartmouth College, 03755, Hanover, NH, USA aut NATIONALLICENCE 700 1- Ferry John Department of Earth and Planetary Sciences, Johns Hopkins University, 21218, Baltimore, MD, USA aut NATIONALLICENCE 700 1- Rumble III Douglas Geophysical Laboratory, Carnegie Institution of Washinton, 2801 Upton Street NW, 20008, Washington, DC, USA aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 105/3(1990-08-01), 322-336 0010-7999 105:3<322 1990 105 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer