Biostratigraphy of selected K/T boundary sections in southwestern North Dakota, USA: toward a refinement of palynological identification criteria

Bercovici, Antoine; Pearson, Dean A.; Nichols, Douglas J.; Wood, Jacqueline N.

doi:10.1016/j.cretres.2008.12.007

Cited by 40 publications

(49 citation statements)

References 46 publications

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“…Most previous studies that incorporate dispersed sporomorphs and plant megafossils are confined to Paleozoic (e.g., Looy and Hotton 2014), Cretaceous (e.g., Lidgard and Crane 1990;Bercovici et al 2008Bercovici et al , 2009) and Cenozoic (e.g., Tinner et al 1996;Wing and Harrington 2001) floras. These floras are fundamentally different to pre-angiosperm Mesozoic communities, thus comparison of such floras with those at Hasty Bank is highly problematic.…”

Section: Discussionmentioning

confidence: 99%

“…Since sporomorph and plant megafossil assemblages undergo different transportation and depositional processes, it was expected that the respective fossil assemblages would be notably dissimilar in composition (e.g., Bercovici et al 2008Bercovici et al , 2009, with the anticipation that our analyses may shed light on the reasons behind these differences.…”

Section: Introductionmentioning

confidence: 99%

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

Slater

Wellman

2015

Paleobiology

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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.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Slater

Wellman

2015

Paleobiology

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“…These results are outlined and summarized in Hartman et al, (2002), Nichols (2002Nichols ( , 2007, Nichols and Johnson (2008) and references therein, and more recently in Bercovici et al (2009aBercovici et al ( , 2011Bercovici et al ( , 2012. Herein we analyze the palynological assemblage of a fluvial sandstone, from the lower third of the Hell Creek Formation, encasing the exceptionally well preserved specimen of Edmontosaurus annectens (specimen MRF-03) with the specific aim of reconstructing the local vegetation and paleoenvironment of this particular site.…”

Section: Introductionmentioning

confidence: 88%

A snapshot into the terrestrial ecosystem of an exceptionally well-preserved dinosaur (Hadrosauridae) from the Upper Cretaceous of North Dakota, USA

Vajda

Lyson

Bercovici

et al. 2013

Cretaceous Research

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“…First, a major decrease in Cretaceous palynomorph taxa without subsequent recovery [25] indicates the demise of Mesozoic floras. Second, the correlated development of a 'fern spike', as described from K-T boundary sections worldwide and interpreted as the recovery by pioneering plants of terrestrial ecosystems devastated by the asteroid impact [26].…”

Section: Discussionmentioning

confidence: 99%

“…Samples were sent to Global Geolabs Ltd., Alberta, Canada for preparation. A series of three palynomorph counts were performed on each sample: relative abundance, presence/absence and characterization of palynofacies (see Bercovici et al [25] for details). Individual palynomorph taxonomic count results are provided as electronic supplementary material, table S1.…”

Section: Methodsmentioning

confidence: 99%

Dinosaur extinction: closing the ‘3 m gap’

et al. 2011

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Modern debate regarding the extinction of non-avian dinosaurs was ignited by the publication of the Cretaceous–Tertiary (K–T) asteroid impact theory and has seen 30 years of dispute over the position of the stratigraphically youngest in situ dinosaur. A zone devoid of dinosaur fossils reported from the last 3 m of the Upper Cretaceous, coined the ‘3 m gap’, has helped drive controversy. Here, we report the discovery of the stratigraphically youngest in situ dinosaur specimen: a ceratopsian brow horn found in a poorly rooted, silty, mudstone floodplain deposit located no more than 13 cm below the palynologically defined boundary. The K–T boundary is identified using three criteria: (i) decrease in Cretaceous palynomorphs without subsequent recovery, (ii) the existence of a ‘fern spike’, and (iii) correlation to a nearby stratigraphic section where primary extraterrestrial impact markers are present (e.g. iridium anomaly, spherules, shocked quartz). The in situ specimen demonstrates that a gap devoid of non-avian dinosaur fossils does not exist and is inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K–T boundary impact event.

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Biostratigraphy of selected K/T boundary sections in southwestern North Dakota, USA: toward a refinement of palynological identification criteria

Cited by 40 publications

References 46 publications

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

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

A snapshot into the terrestrial ecosystem of an exceptionally well-preserved dinosaur (Hadrosauridae) from the Upper Cretaceous of North Dakota, USA

Dinosaur extinction: closing the ‘3 m gap’

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