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Titre	Self-accelerating volumetric dolomite-for-calcite replacement: A possible mechanism for high-temperature dolomitization?
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Auteur	Morrow, D W
Source	Carbonates and Evaporites vol. 35, 2, 2020., https://doi.org/10.1007/s13146-020-00565-w
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Année	2020
Séries alt.	Ressources naturelles Canada, Contribution externe 20200175
Éditeur	Springer
Document	publication en série
Lang.	anglais
DOI	https://doi.org/10.1007/s13146-020-00565-w
Media	papier; en ligne; numérique
Formats	pdf
Sujets	dolomitisation; dolomites; solution pressurisante; solution; géochimie; Nature et environnement; Sciences et technologie
Illustrations	figures; tableaux; graphiques
Diffusé	2020 03 07
Résumé	(disponible en anglais seulement) Quantitative calculations with the geochemical program PHREEQC (c) for the replacement of calcite by dolomite in brine solutions were performed under the condition that total mineral rock volume is conserved. These simulations, using brine solutions derived from the evaporation of two "end member" compositions for Phanerozoic seawater, indicate that calcium (Ca2+) molalities in solution do not increase exponentially, but instead exhibit monotonically decreasing rates of increase. Simulated rates for calcite dolomitization also decrease monotonically. This indicates that replacement of dolomite by calcite under a stricture of rock volume conservation does not cause a rapidly increasing rate of dolomitization in a self-accelerating manner, but rather is self-limiting. Preservation of sedimentary microfabrics in dolomitized limestones, although consistent with the recently proposed mechanism of dolomite-growth-driven pressure solution mechanism for volumetric dolomitization, is not definitive, as near-surface meteoric diagenesis of Pleistocene limestones causes similar preservation of microfabrics where aragonitic paleofauna and sediments have been replaced by calcite and dolomite in open fluid-rock systems.
GEOSCAN ID	326587