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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 Gault Formation is a geological 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 coastal cliffs at Copt Point in Folkestone , Kent , England , where it overlays the Lower Greensand formation, and underlies the Upper ...
Fluvial terraces can be used to measure the rate at which either a stream or river is downcutting its valley. Using various dating methods, an age can be determined for the deposition of the terrace. Using the resulting date and the elevation above its current level, an approximate average rate of downcutting can be determined.
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 ...
The average flow rate at the mouth of the Amazon is sufficient to fill more than 83 such pools each second. The estimated global total for all rivers is 1.2 × 10 6 m 3 /s (43 million cu ft/s), [ 1 ] of which the Amazon would be approximately 18%.
California's Sierra Nevada snowpack is now about 200% of average at this point in the season, while the snowpack in the Upper Colorado River Basin so far stands at about 140% of the median over ...
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.