Lulworth Formation

The Lulworth Formation is a geologic formation in England. It dates from the late Tithonian to the mid Berriasian. It is a subunit of the Purbeck Group.^[1] In Dorset, it consists of three members, which are in ascending order, the Mupe Member, the Ridgway Member, and the Warbarrow Tout Member. The Mupe Member is typically 11 to 16 m thick and largely consists of marls and micrites with interbeds of calcareous mudstone.^[2] The Ridgeway Member is about 3 to 7 m thick and consists of in its western portion carbonaceous muds, marls and micrites, in the east the muds are replaced by micritic limestone.^[3] The Warbarrow Tout Member is 17 to 39 m thick and consists of limestone at the base and micrite and mudstone for the rest of the sequence,^[4] this member is the primary source of the vertebrate fossils within the formation.^[5][6] Elsewhere the unit is undifferentiated.

TypeFormation

Unit ofPurbeck Group

Sub-units

• Worbarrow Tout Member
• Ridgway Member
• Mupe Member

UnderliesDurlston Formation

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Lulworth Formation
Stratigraphic range: Tithonian - Berriasian 152–139 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Lulworth Cove, an area where the Lulworth Formation is exposed
Type	Formation
Unit of	Purbeck Group
Sub-units	Worbarrow Tout Member Ridgway Member Mupe Member
Underlies	Durlston Formation
Overlies	Portland Stone Formation
Thickness	In Dorset 27-63 metres, In Weald 86 m Vale of Wardour up to 15m
Lithology
Primary	Calcarenite, Micrite, Mudstone, Marl
Other	Gypsum
Location
Region	England
Country	United Kingdom
Type section
Named for	Lulworth
Location	West side of Worbarrow Tout

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