South Ferriby Chalk Pit
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| TA001201 | — | Favourable | 84.96 | 2011-10-07 |
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Mining / Industrial: Quarry · Geological Period: Cretaceous, Jurassic · Rock Type: Chalk
Landscape processes: Coastal
Description
Area, 104.9 hectares 259.2 ac Description South Ferriby Chalk Pit is of considerable importance in providing good sections of Upper Jurassic and Lower Cretaceous rocks. The lowest beds exposed are the grey clays of the Oxfordian Ampthill Clay conformably overlain by Kimmeridgian deposits. Above these Jurassic rocks there is a gap in the geological sequence, with the overlying Carstone and Red Chalk being of Lower Cretaceous age. The sequence is terminated by the Chalk of Upper Cretaceous age. The Ampthill Clay contains a rich and probably complete Amoeboceras rosenkrantzi Zoneammonite assemblage, most abundantly in the Oxytoma Cementstone, the perisphinctid ammonite fauna of which places it at the Oxfordian/ Kimmeridgian boundary. This site is probably the only locality north of Wiltshire and south of the Vale of Pickering where rocks of A. rosenkrantzi Zone age occur and nowhere else are the Upper Oxfordian clays and silt stones seen to persist so close to the Market Weighton Axis without considerable non sequence or unconformity. This is therefore a key stratigraphic locality of significance in reconstructing Upper Oxfordian palaeogeography. The Oxfordian Ampthill Clay is overlain by Kimmeridgian deposits and this is the only locality in England where the conformable contact between the Upper Oxfordian rocks and open marine Kimmeridgian deposits can be seen in entirely argillaceous facies. This exposure is of considerable stratigraphic importance in the elucidation of the Late Jurassic sequences in northern England. The quarry provides the best and clearest section through the Kimmeridgian baylei Zoneavailable between the south coast and Scotland. The stratigraphical succession for this interval is relatively thick when compared with other sites in the country and it provides one of the best opportunities to study the ammonite faunas of that zone. As well as the baylei Zone, the site exposes strata assigned to the overlying Cymodoce Zone. This large quarry provides the finest exposure of Carstone and Red Chalk in South Humberside and Lincolnshire. The thickness of both these formations is of palaeo environmental significance and their relationship to one another and the Jurassic strata below is well exhibited. South Ferriby is one of only a few localities in this country that have yielded an in situ faunafrom the Carstone and a number of rare brachiopods are described from the locality. Other Information The site is identified as being of national importance in the Geological Conservation Review.