Jersey Shale Formation
Over millions of years, the shale has been eroded away and given the shape of St Ouen’s Bay and St Aubin’s Bay.
The Jersey Shale Formation is part of the larger “Brioverian Supergroup”, which also includes rocks that can be seen outcropping in both the Baie de St Brieuc and La Manche regions of northern France.
Studies of the Jersey Shale Formation in the mid-80s concluded that these sediments were deposited in a subduction zone, where an ocean plate was being dragged down into the mantle underneath the neighbouring continent. The formation shows signs of having undergone deformation and low-grade regional metamorphism which geologists have associated with the Cadomian Orogeny and later mountain-building events.