Movement of inner fluids in calcite crystallites at standard conditions
Calcite is the most abundant carbonate mineral in the lithosphere and plays a major role in CO2 balance as a geological controller of this greenhouse gas and on contaminant uptake in the environment. Here,we report evidence of migration of CO2 from fluid inclusions hosted within a calcite crystal to the surface,with subsequent renewal of the calcite surface. Spontaneous nucleation and growth of nanometre-scale hillocks,without evidence of dissolution pits, is provided by Atomic Force Microscopy observations of a freshly cleaved calcite surface. The rate of fluid transport is estimated at 5 × 10-10±0.5 m.s-1, which is about 10 orders of magnitude greater than elemental diffusion within a solid lattice under standard conditions. Surface sites of natural calcite are most likely constantly renewed by the fluid mobility that we have documented here and, as a consequence, calcites uptake capacity for contaminants in environmental systems is probably significantly higher than predicted by current models.
P.Zuddas O.Lopez S.Salvi
Institut de Physique du Globe de Paris, GME, France Université Paul Sabatier, LMTG, France
国际会议
第十二届水-岩相互作用国际研讨会(P0roceedings of the 12th International Symposium on Water-Rock Interaction)
昆明
英文
461-463
2007-07-31（万方平台首次上网日期，不代表论文的发表时间）