Kinetic fractionation of carbon-13 during calcium carbonate precipitation
Kinetic fractionation of carbon-13 during calcium carbonate precipitation
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DOI：
10.1016/0016-7037(82)90004-7
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发表时间：
1982-07
影响因子：
5
通讯作者：
J. Turner
中科院分区：
文献类型：
--
作者：
J. Turner
本文研究了在开放体系条件下CaCO_3沉淀过程中~（13）C的动力学同位素分馏。同位素富集因子<$HCO3 −-CaCO 3在−0.35 ± 0.23和−3.37 ± 0.36%之间变化。在25°C时，根据沉淀速率和矿物学特征，13 C在固体碳酸盐相中的富集度随沉淀速率的增加而降低。平衡态HCO 3-方解石的估计值介于−1.83 ± 0.32和−2.26 ± 0.31%之间。从缓慢沉淀运行计算。采用表面扩散晶体生长模型描述了快速扩散控制晶体生长过程中动力学同位素效应对热力学同位素分馏的影响。在缓慢降水条件下，方解石-文石估计为-1.4%。然而，在快速沉淀过程中，这种分馏似乎减少，文石变得不那么富集13 C。
Kinetic isotope fractionation of13C during precipitation of CaCO3under open system conditions has been investigated. The isotope enrichment factorϵHCO3−-CaCO3varies between −0.35 ± 0.23 and −3.37 ± 0.36%. at 25°C depending on the rate of precipitation and mineralogy, the enrichment of13C in the solid carbonate phase decreasing with increasing precipitation rate. An estimate of equilibriumϵHCO3-Calciteof between −1.83 ± 0.32 and −2.26 ± 0.31%. is calculated from slow precipitation runs. A surface diffusion crystal growth model is used to describe the combination of kinetic isotope effects on thermodynamic isotope fractionation during rapid diffusion controlled crystal growth. Under slow precipitation conditionsϵCalcite-Aragonitewas estimated as −1.4%.; however, during rapid precipitation this fractionation appears to diminish and aragonite becomes less enriched in13C.