A palynological investigation of the Lower and lowermost Middle Jurassic strata (Sinemurian to Aalenian) from North Yorkshire, UK

Abstract

SUMMARY A palynological investigation of the Lower and lowermost Middle Jurassic (Sinemurian to Aalenian) strata of North Yorkshire has been undertaken which incorporates material from the BGS Brown Moor Borehole, near Acklam and the coastal outcrops between Staithes and Robin Hood’s Bay. The resulting dataset is an additional contribution to the Jurassic dinoflagellate cyst biostratigraphy of northern England. Two distinctive variants of Liasidium variabile appear to have biostratigraphical significance in the Upper Sinemurian of North Yorkshire. Specimens of L. variabile from the Caenisites turneri Ammonite Zone, the Eparietites denotatus Ammonite Subzone and the Oxynoticeras simpsoni Ammonite Subzone have short apical and antapical horns. Forms from the overlying uppermost Oxynoticeras oxynotum Ammonite Zone, however, are characterized by elongate apical horns and rounded hypocysts. The regional dinoflagellate cyst diversity increase in the late Pliensbachian and the disappearance of many dinoflagellate cysts in the Lower Toarcian are both interpreted as being related to eustatic fluctuations. The paucity of dinoflagellate cysts close to the Dactylioceras tenuicostatum-Harpoceras falciferum Ammonite zonal transition in the Lower Toarcian was caused by the spread of widespread marine anoxia during the Lower Toarcian maximum flooding event. A new species of dinoflagellate cyst, Nannoceratopsis symmetrica , is described.

The Global Boundary Stratotype Section and Point (GSSP) for the base of the Pliensbachian Stage (Lower Jurassic), Wine Haven, Yorkshire, UK

“…In the present palynological study no dinoflagellate cysts at all have been found. This is in agreement with a previous study on the organic microplankton from the Sinemurian -Pliensbachian of Yorkshire by Bucefalo Palliani and Riding (2000), who analysed spot samples from Robin Hood's Bay and came to the same results. Their two samples from the siliceous shale (Raricostatum Zone) at Robin Hood's Bay were barren of dinoflagellate cysts, as well as the one sample from the Lower Pliensbachian (Davoei Zone) from the neighbouring Cowbar Nab section.…”

“…A critical review of the pertinent literature seems to confirm the range top of L. variabile in the Late Sinemurian Oxynotum Zone to be a reliable stratigraphical marker datum (Feist-Burkhardt, ongoing study). Similar results, with productive samples from Oxynotum Zone and barren samples from Raricostatum and earliest Jamesoni Zones, were also reported from the Brown Moor borehole, some 50 km away from Robin Hood's Bay (Bucefalo Palliani and Riding, 2000).…”

A quantitative comparison of dispersed spore/pollen and plant megafossil assemblages from a Middle Jurassic plant bed from Yorkshire, UK

“…Location and geological setting of Hasty Bank, northeast England. Modified from Milsom and Rawson (1989); Mjøs and Prestholm (1993); Cox and Sumbler (2002); Palliani and Riding (2000); Slater et al (2015). Livera and Leeder 1981;Fisher and Hancock 1985;Kantorowicz 1985;Alexander 1989Alexander , 1992Riding and Wright 1989;Gowland and Riding 1991;Rawson and Wright 2000;Powell 2010).…”

Dinosaur-plant interactions within a Middle Jurassic ecosystem—palynology of the Burniston Bay dinosaur footprint locality, Yorkshire, UK

“…1b). The Scalby Formation represents fluvio-deltaic conditions (Leeder and Nami 1979;Fisher and Milsom and Rawson (1989); Mjøs and Prestholm (1993); Palliani and Riding (2000); Rawson and Wright (2000). b Subdivision of the Middle Jurassic of Yorkshire.…”