succession zonale

CONT: (...) la succession zonale complète n'est jamais réalisée dans un seul filon.

CONT: ... complex pegmatites may have a complex mineralogy ..., but their marked feature is the arrangement of their minerals in a zonal sequence from the contact inwards.
CONT: ... in this vein system there is present, over a very restricted vertical range, a host of minerals which in Cornwall are developed in a zonal sequence spread out vertically over hundreds of metres.