Boron isotope compositions establish the origin of marble from metamorphic complexes: Québec, New York, and Sri Lanka

Abstract

The origin of an array of marble samples found in both the Grenville Province and southwestern Sri Lanka remains uncertain, whether magmatic, sedimentary, or mixed, due to their proximity to both carbonatite bodies and carbonate-rich metasedimentary rocks. This study reports boron and trace element abundances, in addition to carbon, oxygen, boron, and strontium isotopic compositions in order to determine the petrogenesis of these carbonate-rich samples.Boron abundances for all of the samples are relatively high and variable (1.48 -71.1 ppm) compared to those for carbonatites worldwide (≤ 1 ppm), and mostly overlap those documented for sedimentary sources (up to 54 ppm). The rare earth element (REE) abundances (0.5 -1068 ppm) for the marbles studied are similar to those for local sedimentary units, and thus contain, in general, lower REE contents than both the average worldwide calcio-carbonatite and respective neighboring carbonatite bodies. The δ 13 C V-PDB and δ 18 O V-SMOW compositions for all of the This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.