Fossils of the Gault Clay

Dr Neale Monks (UK) The Gault Clay is an Albian (Lower Cretaceous) deposit of blue-grey clay exposed primarily in Southeast England. At the classic exposure at Copt Point, Folkestone, the Gault Clay is sandwiched between the Lower Greensand underneath and the Upper Greensand on top. Fig. 1. Folkestone is the most productive location for collecting Gault Clay fossils in the UK. It is a stiff clay that preserves fossils extremely well. In particular, aragonite is sometimes preserved on fossils such as bivalves and ammonites, resulting in much more attractive and detailed fossils than those found in limestone or chalk. As well as providing excellent preservation, the Gault Clay is highly fossiliferous at many localities. Unsurprisingly, these two factors have ensured that the Gault Clay has always been extremely popular with fossil collectors. In terms of what was going on during the Albian, the Gault Clay represents a phase of sea level rise, something known as a “marine transgression”. Compared with the preceding Lower Greensand, this clay was deposited in a deeper, less energetic environment in what is sometimes known as the “Gault Sea”. This was a shallow, warm sea with a muddy bottom. Corals were notably absent, but animals that were adapted to muddy conditions, such as clams and pelican’s foot snails, were common. The sediment particles were finer and less disturbed by water currents and benthic animals (that is, animals living on the sea bottom), resulting in the high-quality fossils so characteristic of this deposit. At this time, the … Read More

To access this post, you must purchase Annual subscription, 12 Month Subscription or Monthly subscription.
%d bloggers like this: