South-west England Chalk Group Lithostratigraphy: Jarvis & Woodroof (1984) & Jarvis & Tocher (1987) - Pounds Pool Sandy Limestone: Difference between revisions
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The Pounds Pool Sandy Limestone, named after Pounds Pool Beach [SY 227 881], Devon, where it is 3.5 m thick, broadly equates with division A1 of Jukes-Browne & Hill (1903), and comprises very coarse calcareous sandstones at the base, with common glauconitised intraclasts, overlain by pale brown, strongly indurated, sandy, bioclastic limestone with rare glauconitised intraclasts (Jarvis & Woodroof, 1984). Locally the member is attenuated or absent, but where developed can usually be recognised by common specimens of the coral-like sponge ''Acanthochaetetes ramulosus'' ( formerly ''Ceriopora ramulosa'' )'' ''(Jarvis & Woodroof, 1984). The base of the member is the indurated top of the Upper Greensand, formed by the Small Cove Hardground; fissures in the hardground locally preserve remnants of Beer Head Limestone that are absent at outcrop, including the Pounds Pool Sandy Limestone (Jarvis & Woodroof, 1984). A parting formed by the hummocky upper surface of a weakly glauconitised and limonitised hardground, named the Weston Hardground, defines the top of the member (Jarvis & Woodroof, 1984). | The Pounds Pool Sandy Limestone, named after Pounds Pool Beach [SY 227 881], Devon, where it is 3.5 m thick, broadly equates with division A1 of Jukes-Browne & Hill (1903), and comprises very coarse calcareous sandstones at the base, with common glauconitised intraclasts, overlain by pale brown, strongly indurated, sandy, bioclastic limestone with rare glauconitised intraclasts (Jarvis & Woodroof, 1984). Locally the member is attenuated or absent, but where developed can usually be recognised by common specimens of the coral-like sponge ''Acanthochaetetes ramulosus'' ( formerly ''Ceriopora ramulosa'' )'' ''(Jarvis & Woodroof, 1984). The base of the member is the indurated top of the Upper Greensand, formed by the Small Cove Hardground; fissures in the hardground locally preserve remnants of Beer Head Limestone that are absent at outcrop, including the Pounds Pool Sandy Limestone (Jarvis & Woodroof, 1984). A parting formed by the hummocky upper surface of a weakly glauconitised and limonitised hardground, named the Weston Hardground, defines the top of the member (Jarvis & Woodroof, 1984). | ||
Latest revision as of 15:05, 7 October 2013
The Pounds Pool Sandy Limestone, named after Pounds Pool Beach [SY 227 881], Devon, where it is 3.5 m thick, broadly equates with division A1 of Jukes-Browne & Hill (1903), and comprises very coarse calcareous sandstones at the base, with common glauconitised intraclasts, overlain by pale brown, strongly indurated, sandy, bioclastic limestone with rare glauconitised intraclasts (Jarvis & Woodroof, 1984). Locally the member is attenuated or absent, but where developed can usually be recognised by common specimens of the coral-like sponge Acanthochaetetes ramulosus ( formerly Ceriopora ramulosa ) (Jarvis & Woodroof, 1984). The base of the member is the indurated top of the Upper Greensand, formed by the Small Cove Hardground; fissures in the hardground locally preserve remnants of Beer Head Limestone that are absent at outcrop, including the Pounds Pool Sandy Limestone (Jarvis & Woodroof, 1984). A parting formed by the hummocky upper surface of a weakly glauconitised and limonitised hardground, named the Weston Hardground, defines the top of the member (Jarvis & Woodroof, 1984).
Macrofossil Biozonation: (see under A1 of Jukes-Browne & Hill (1903))
Correlation: see Correlation with other lithostratigraphical schemes for south-west England
see Correlation with other UK regions
References
JARVIS, I & WOODROOF, P B. 1984. Stratigraphy of the Cenomanian and basal Turonian (Upper Cretaceous) between Branscombe and Seaton, S E Devon, England. Proceedings of the Geologists' Association, Vol. 95 (3), 193-215.
JUKES-BROWNE, A J & HILL, W.1903. The Cretaceous rocks of Britain. Vol. 2 - The Lower and Middle Chalk of England. Memoir of the Geological Survey of the United Kingdom.
See: Cenomanian Limestone Bed A1