couche sous-jacente

CONT: Ce sont des gîtes d'éluvion [...] où le lessivage des couches supérieures provoque la formation d'incrustations, de concrétions ou de cimentation dans les couches sous-jacentes [...]

CONT: The orebodies occur in the sublayer which is clearly a later intrusion than the overlying norite with which it has a sharp contact. The sublayer magma was rich in sulphides and inclusions, of peridotite, pyroxenite and gabbro.
CONT: Sudbury ... possesses a sublayer rich in ultrabasic xenoliths probably derived from a hidden layered sequence.