| Gaia: | Inorganic calcite precipitation experiments were conducted to determine whether inducing specific orientations of calcite crystal growth can cause the enrichment of cations larger than Ca. Malonic acid (CH2(COOH)2), a di-carboxylic acid, was used to poison growth on acute kink sites, promoting growth on obtuse kink sites, causing calcite crystals elongated along their c-axes to form in a mechanism similar to that seen in the growth of E. huxleyi coccoliths. Calcite was precipitated with a range of malonic acid concentrations (0 to 10-1 M), and 9 × 10-5 M of either SrCl2 or MgCl2. The results show that calcite crystals precipitated in the presence of large malonic acid concentrations show significant elongation along the c axis, and suggest that increasing malonate concentrations corresponded with increasing DSr. Experiments with 10-1 M malonic acid caused elevated DSr comparable to that predicted for E. huxleyi coccolith calcite (Langer et al., 2006). © 2008 The Mineralogical Society.
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