The Jurassic-Cretaceous succession at Rifle Butts Quarry (SSSI) and its implications for sedimentation on the Market Weighton Structure

Abstract

New biostratigraphical data are presented for the Jurassic-Cretaceous succession at Rifle Butts Quarry (Goodmanham, North Yorkshire). The record of the belemnite Acrocoelites (Acrocoelites) subtenuis (Simpson) from the oolitic ironstone demonstrates that this is of early Toarcian (probably Harpoceras falciferum Zone) age. Belemnites ( Neohibolites ) and bivalves (inoceramids and Aucellina ) from the overlying Hunstanton Formation (Red Chalk) suggest an age span from the Callihoplites auritus Subzone (and possibly the late Hysteroceras varicosum Subzone) of the Mortoniceras inflalum Zone to the early Stoliczkaia dispar Zone. The marl at the base of the First Inoceramus Bed of the Ferriby Formation rests on top of the bored surface of the Hunstanton Formation. This demonstrates that both the Hunstanton and Ferriby formations onlap the Market Weighton Structure. Previous records of Carstone from Rifle Butts are incorrect as the true Carstone (as well as the lower part of the Hunstanton Formation) has been overstepped by higher parts of the Hunstanton Formation.