Kinetically driven successive sodic and potassic alteration of feldspar.

ABSTRACT: The dynamic evolutions of fluid-mineral systems driving large-scale geochemical transformations in the Earth's crust remain poorly understood. We observed experimentally that successive sodic and potassic alterations of feldspar can occur via a single self-evolved, originally Na-only, hydrothermal fluid. At 600 °C, 2 kbar, sanidine ((K_,Na)AlSi₃O₈) reacted rapidly with a NaCl fluid to form albite (NaAlSi₃O₈); over time, some of this albite was replaced by K-feldspar (KAlSi₃O₈), in contrast to predictions from equilibrium reaction modelling. Fluorine accelerated the process, resulting in near-complete back-replacement of albite within 1 day. These findings reveal that potassic alteration can be triggered by Na-rich

SUBMITTER: Duan G 

PROVIDER: S-EPMC8295371 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature