“…Modified from Milsom and Rawson (); Mjøs and Prestholm (); Palliani and Riding (); Rawson and Wright (); Slater and Wellman (); Slater et al . ().…”
Section: Geological Settingmentioning
confidence: 97%
“…Batten and Dutta ; Slater et al . ). Thus, dispersed spore/pollen assemblages from the Jurassic of Yorkshire offer important insight into vegetation dynamics of this time period, and, when integrated with the plant megafossil record, these data sets can be used to improve local and regional‐scale palaeoenvironmental reconstructions.…”
Quantitative analysis of the distribution of dispersed spores and pollen (sporomorphs) has been used to assess temporal floral variation through the Middle Jurassic Ravenscar Group (Aalenian-Bathonian), North Yorkshire, UK. Aalenian, Bajocian and Bathonian strata possess relatively distinct sporomorph and palynofacies assemblages, which potentially reflect a dynamic history regarding the nature of parent vegetation. Specifically, Aalenian palynofloras are composed of a heterogeneous mixture of conifers, ferns, simple monosulcate pollen producers, sphenophytes and Caytoniales; Bajocian palynofloras are codominated by conifers and ferns; and Bathonian palynofloras are highly rich and contain assemblages of abundant ferns, conifers, lycophytes, pteridosperms/ conifers and Caytoniales. Individual-and sample-based rarefaction demonstrates that Bathonian samples are richer than Aalenian and Bajocian samples. Temporal variations in assemblages are a result of long-term depositional and possible climatic fluctuations through the Middle Jurassic. Ordinations of sporomorph data using non-metric multidimensional scaling (NMDS) demonstrate that short-term variations between samples are largely governed by taphonomic biases as a result of slight changes in depositional processes, which give rise to highly variable catchment areas that supply deposits with sporomorphs. Long-term compositional changes are apparent in sporomorph assemblages regardless of lithology/local depo-sitional environments, suggesting that long-term variations are more substantial than short-term variations and potentially include genuine regional temporal changes in parent vegetation. Relating sporomorph assemblages with their respective depositional environments and relative catchment area sizes using lithological and palynofacies information suggests that the basin interior was occupied by mostly low-standing species and extrabasinal vegetation was dominated by coniferous taxa. Comparisons of the dispersed sporomorph and plant megafos-sil records indicate that both fossil assemblages reflect different aspects of the palaeoflora due to a multitude of taphonomic and ecological biases. Such biases include variation in sporo-morph production levels, depositional environment and differential sporomorph and parent plant durability.
“…Modified from Milsom and Rawson (); Mjøs and Prestholm (); Palliani and Riding (); Rawson and Wright (); Slater and Wellman (); Slater et al . ().…”
Section: Geological Settingmentioning
confidence: 97%
“…Batten and Dutta ; Slater et al . ). Thus, dispersed spore/pollen assemblages from the Jurassic of Yorkshire offer important insight into vegetation dynamics of this time period, and, when integrated with the plant megafossil record, these data sets can be used to improve local and regional‐scale palaeoenvironmental reconstructions.…”
Quantitative analysis of the distribution of dispersed spores and pollen (sporomorphs) has been used to assess temporal floral variation through the Middle Jurassic Ravenscar Group (Aalenian-Bathonian), North Yorkshire, UK. Aalenian, Bajocian and Bathonian strata possess relatively distinct sporomorph and palynofacies assemblages, which potentially reflect a dynamic history regarding the nature of parent vegetation. Specifically, Aalenian palynofloras are composed of a heterogeneous mixture of conifers, ferns, simple monosulcate pollen producers, sphenophytes and Caytoniales; Bajocian palynofloras are codominated by conifers and ferns; and Bathonian palynofloras are highly rich and contain assemblages of abundant ferns, conifers, lycophytes, pteridosperms/ conifers and Caytoniales. Individual-and sample-based rarefaction demonstrates that Bathonian samples are richer than Aalenian and Bajocian samples. Temporal variations in assemblages are a result of long-term depositional and possible climatic fluctuations through the Middle Jurassic. Ordinations of sporomorph data using non-metric multidimensional scaling (NMDS) demonstrate that short-term variations between samples are largely governed by taphonomic biases as a result of slight changes in depositional processes, which give rise to highly variable catchment areas that supply deposits with sporomorphs. Long-term compositional changes are apparent in sporomorph assemblages regardless of lithology/local depo-sitional environments, suggesting that long-term variations are more substantial than short-term variations and potentially include genuine regional temporal changes in parent vegetation. Relating sporomorph assemblages with their respective depositional environments and relative catchment area sizes using lithological and palynofacies information suggests that the basin interior was occupied by mostly low-standing species and extrabasinal vegetation was dominated by coniferous taxa. Comparisons of the dispersed sporomorph and plant megafos-sil records indicate that both fossil assemblages reflect different aspects of the palaeoflora due to a multitude of taphonomic and ecological biases. Such biases include variation in sporo-morph production levels, depositional environment and differential sporomorph and parent plant durability.
“…The Ravenscar Group provides an exceptional example of extensive Middle Jurassic terrestrial sequences and the plethora of plant fossils (e.g., van Konijnenburg-van Cittert and Morgans 1999) and dinosaur footprints (Whyte and Romano 1993, 2001a,b; Romano et al 1999; Romano and Whyte 2003; Whyte et al 2006, 2007, 2010) make the Cleveland Basin an important region for paleontology.Figure 1Location 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). Figure 2Subdivision of Middle Jurassic sequences of the North Yorkshire Coast.…”
Section: Geological Settingmentioning
confidence: 99%
“…The arrow indicates the stratigraphic position of the plant bed. Modified from Rawson and Wright (2000); Slater et al (2015). …”
Section: Geological Settingmentioning
confidence: 99%
“…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). …”
Abstract.-Detailed quantitative data has previously been collected from plant megafossil assemblages from a Middle Jurassic (Aalenian) plant bed from Hasty Bank, North Yorkshire, UK. We conducted a similar analysis of palynological dispersed sporomorph (spore and pollen) assemblages collected from the same section using the same sampling regime: 67 sporomorph taxa were recorded from 50 samples taken at 10 cm intervals through the plant bed. Basic palynofacies analysis was also undertaken on each sample. Both dispersed sporomorph and plant megafossil assemblages display consistent changes in composition, diversity (richness), and abundance through time. However, the dispersed sporomorph and plant megafossil records provide conflicting evidence for the nature of parent vegetation. Specifically, conifers and ferns are underrepresented in plant megafossil assemblages, bryophytes and lycopsids are represented only in sporomorph assemblages, and sphenophytes, pteridosperms, Caytoniales, Cycadales, Ginkgoales and Bennettitales are comparatively underrepresented in sporomorph assemblages. Combined multivariate analysis (correspondence analysis and nonmetric multidimensional scaling) of sporomorph occurrence/abundance data demonstrates that temporal variation in sporomorph assemblages is the result of depositional change through the plant bed. The reproductive strategies of parent plants are considered to be a principal factor in shaping many of the major abundance and diversity irregularities between dispersed sporomorph and plant megafossil data sets that seemingly reflects different parent vegetation. Preferential occurrence/preservation of sporomorphs and equivalent parent plants is a consequence of a complex array of biological, ecological, geographical, taphonomic, and depositional factors that act inconsistently between and within fossil assemblages, which results in notable discrepancies between data sets.
Dinosaur footprints are abundant in the Middle Jurassic Ravenscar Group of North Yorkshire, UK. Footprints are particularly common within the Bathonian Long Nab Member of the Scalby Formation and more so within the socalled 'Burniston footprint bed' at Burniston Bay. The Yorkshire Jurassic is also famous for its exceptional plant macrofossil and spore-pollen assemblages. Here we investigate the spore-pollen record from the dinosaur footprint-bearing successions in order to reconstruct the vegetation and assess possible dinosaur-plant interactions. We also compare the spore-pollen assemblages with the macroflora of the Scalby Ness Plant Bed, which occurs within the same geological member as the Burniston succession. The spore-pollen assemblages are dominated by Deltoidospora spp., the majority of which were probably produced by Coniopteris. Lycophyte spores (including megaspores) are common in the Yorkshire Jurassic, but lycophyte parent plants are extremely poorly represented in the macroflora. Seed ferns, represented by Alisporites spp., are moderately abundant. Conifer pollen assemblages are dominated by Araucariacites australis (probably produced by Brachyphyllum mamillare), Perinopollenites elatoides and Classopollis spp., with additional bisaccate pollen taxa. Abundant Ginkgo huttonii in the macroflora suggests that much of the monosulcate pollen was produced by ginkgoes. The diverse vegetation of the Cleveland Basin presumably represented an attractive food source for herbivorous dinosaurs. The dinosaurs probably gathered at the flood plains for fresh-water and also used the non-vegetated plains and coastline as pathways. Although assigning specific makers to footprints is difficult, it is clear that a range of theropod, ornithopod and sauropod dinosaurs inhabited the area.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
