St Osyth Pit

Site of Special Scientific Interest · 51.8117, 1.0735

Also within

Essex County

Condition (Natural England)

Favourable (1)
UnitFeatureConditionArea (ha)Assessed
TM119170 Favourable 0.07 2021-11-20

Geology & landscape

Geological Period: Quaternary

Landscape processes: Glacial

Description

Description St. Osyth Pit comprises an important sequence of Pleistocene deposits related to the diversion of the Thames during the Anglian glacial period. The lower part of the succession consists of Thames gravel of the pre diversion 'Kesgrave' type i.e. deposited before the Thames was diverted by Anglian ice. This is overlain by sand and very fine gravel, the composition of the latter showing it to be distal outwash deposited by meltwater from ice which had therefore arrived in the Thames catchment. The recognition of a comparable sequence elsewhere and of its relation to the terraces of the Tendring Plateau has shown that the outwash at St. Osyth reflects a brief period when the Thames was actually blocked by ice. The site is therefore of considerable stratigraphic importance in reconstructing the events of the Anglian glacial period.