#clay stratum
- Aquifuge — Water-repelling, impermeable; a compact geological stratum (such as dense clays, marls, or unfractured granites) that does not contain and does not allow the circulation or infiltration of water, acting as a natural insulating barrier; as an adjective, it also applies to technical materials treated for waterproofing. This structural element is essential in hydrogeology as it boundaries and protects underground aquifers.