Stratigraphy, sedimentology and palaeontology of the Scarborough Formation (Middle Jurassic) at Hundale Point, North Yorkshire

Abstract

SUMMARY The depositional environment of the type section of the Scarborough Formation (Ravenscar Group) has been investigated through detailed sedimentological and palaeontological analyses. The lithostratigraphical framework of the formation is revised and three new members, the Helwath Beck, Hundale Sandstone and Bogmire Gill members, are introduced. The marine transgression recorded in the lower part of the Scarborough Formation (Helwath Beck Member) is attributed to the abandonment and compactional subsidence of the underlying Gristhorpe Member (Cloughton Formation) delta lobe. The overlying deepening-upward package of siliciclastic and carbonate shelf deposits (Hundale Shale — Ravenscar Shale members) reflects the extent to which eustatic sea level rise amplified the effects of the dominant tectonic and autocyclic controls within the basin. The Bogmire Gill Member has been convincingly attributed to progradation of a wave-dominated sandy shoreface. Given that recent palynological analyses fail to support the presence of a significant hiatus at the contact with the overlying Scalby Formation, it is suggested that the Bogmire Gill Member may constitute the wave-dominated coastal fringe of a Scalby Formation delta lobe.