gîte métasomatique

CONT: [...] les gîtes métasomatiques proviennent de la réaction de fluides libérés au cours de la cristallisation avec des carbonatites de formation antérieure ou avec les roches encaissantes.
CONT: Phlogopite. [...] Mica fréquent des gîtes métasomatiques de contact [...]
OBS: Le terme «gisement de substitution» est [...] plus large que celui de «gisement par métasomatose», puisqu'il peut couvrir des mécanismes par précipitation, analogues à ceux des remplissages de vides filoniens.

CONT: Metasomatic deposits ... commonly are superimposed on older rocks of the intrusive complex by continuing igneous activity or fluid transport of elements of economic interest (among other); may be crosscutting with respect to intrusive units; and commonly have associated alteration which may be a guide to ore.
CONT: Metasomatic deposits ... occur in alkalic igneous rocks or surrounding country rocks, with mineralization superimposed on pre-existing rocks. The principal commodities recoverable from deposits of this type are niobium, tantalum, beryllium, yttrium, rare earths, gallium, uranium, thorium, and zirconium. Normally only one or two commodities carry the deposit economically, with others if recovered, as byproducts. The principal Canadian example is the Highwood Resources deposit at Thor Lake, NWT ...
CONT: ... metasomatic deposits form by the reaction of fluids released during crystallization with pre-existing carbonatite or country rocks.