Photo 33. Silty mudstones and marls of the Late Triassic Mercia Mudstone Group exposed in the cliffs of Ranny Bay, near Penarth, South Wales. The red colouration in the lower cliff section indicates deposition in a semi-arid or arid saline or ephemeral lake environment. The distinctive white gypsum nodules in the lower cliff section suggest periods of more extensive evaporation, leading to the deposition of evaporitic gypsum salts. The creamy grey to greenish grey rocks in the upper cliff indicate a change to restricted marine and open marine environments, produced in the Late Triassic to Early Jurassic rise in global sea levels, which resulted in widespread marine transgression.
Photo 33. Silty mudstones and marls of the Late Triassic Mercia Mudstone Group exposed in the cliffs of Ranny Bay, near Penarth, South Wales. The red colouration in the lower cliff section indicates deposition in a semi-arid or arid saline or ephemeral lake environment. The distinctive white gypsum nodules in the lower cliff section suggest periods of more extensive evaporation, leading to the deposition of evaporitic gypsum salts. The creamy grey to greenish grey rocks in the upper cliff indicate a change to restricted marine and open marine environments, produced in the Late Triassic to Early Jurassic rise in global sea levels, which resulted in widespread marine transgression.