Search results
Results from the WOW.Com Content Network
The Upper Greensand Formation is a Cretaceous formation of Albian to Cenomanian in age, found within the Wessex Basin and parts of the Weald Basin in southern England. [1] It overlies the Gault Clay and underlies the Chalk Group. It varies in thickness from zero to 75 m. It is predominantly a glauconitic fine-grained sandstone, locally becoming ...
Stratigraphically above the Lower Greensand Group is the Selborne Group which comprises a suite of mudstones, siltstones, sandstones and limestones laid down during the Albian age between 112 and 94 million years ago. It divides into an earlier Gault Formation and a later Upper Greensand Formation.
The formation is lithologically similar to the Ashdown Formation and comprises complex cyclic sequences of siltstones with sandstones and clays, typically fining upwards. In the western parts of the county the Tunbridge Wells Sands can be divided into three; the Lower Tunbridge Wells Sand, the Grinstead Clay, and the Upper Tunbridge Wells Sand.
This sandy bank has been exposed by the River Wey as it cuts through the Upper Greensand stratum (mid Cretaceous) near Shalford. During the Early Cretaceous epoch (from about 145 to about 100 million years ago) Surrey alternated between a fresh-to-brackish water embayment depositing Hastings Beds and Weald Clay, comprising shales and mudstones that are often finely banded.
A distinction is made between the Upper Greensand and Lower Greensand. The term greensand was originally applied by William Smith to glauconitic sandstones in the west of England and subsequently used for the similar deposits of the Weald, before it was appreciated that the latter are actually two distinct formations separated by the Gault Clay ...
Geological map of the Isle of Wight. The geology of the Isle of Wight is dominated by sedimentary rocks of Cretaceous and Paleogene age. This sequence was affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying Paleogene strata seen at The Needles, Alum Bay and Whitecliff Bay.
On top of these clays is a non-contiguous layer of Upper Greensand above which lies a rolling bed of white chalk about 200 metres thick. In the Lower Chalk and in the lower region of the Middle Chalk there are abundant fossilized shell fragments, especially Inoceramus clams. In places these form the greater part of the rock but they decrease in ...
Contact between two units of the lithostratigraphy of South England: the Chalk Group (left, white, upper unit) and the Greensand Formation (right, green, lower unit). Location: Lulworth Cove , near West Lulworth , Dorset , England.