The Gault Clay is a formation of stiff blue clay deposited in a calm, fairly deep water marine environment during the Lower Cretaceous Period (Upper and Middle Albian). It is well exposed in the costal cliffs at Copt Point in Folkestone, Kent, England, where it overlays the Lower Greensand Formation.
The Gault Clay often contains numerous phosphatic nodules and may also contain sand as well as small grains of the mineral glauconite. Crystals of the mineral selenite are fairly common in places, as are nodules of pyrite.
The Gault Clay yields abundant marine fossils, including ammonites (such as Hoplites, Hamites, Euhoplites, Anahoplites, and Dimorphoplites), belemnites (such as Neohibolites), bivalves (such as Birostrina and Pectinucula), gastropods (such as Anchura), solitary corals, fish remains (including shark teeth), scattered crinoid remains, and crustaceans (such as the crabNotopocorystes). Occasional fragments of fossil wood may also be found.
The Gault Formation consists of both the Gault Clay and Upper Greensand.
The Gault exposure at Copt Point, which is the type locality for the formation, is 40 m in thickness.
In the south of England the Gaultclay is fairly constant in the lower part, with the Greensand above; the clay, however, passes into sand as it is followed westward and, as already pointed out, the clay and sand appear to pass into a red chalk towards the north-east.
The Gault (with Upper Greensand) passes on to the Jurassic and Rhaetic rocks near Axmouth, and oversteps farther westward, in the Haldon Hills, on to the Permian.
In the Diester and Teutoberger Wald, and in the region of Halberstadt, the clays and marls are replaced by sandstones, the so-called Gault-Quader.
Share your thoughts, questions and commentary here
Want to know more? Search encyclopedia, statistics and forums:
Press Releases |
The Wikipedia article included on this page is licensed under the
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m