Palynological evidence of vegetation dynamics in response to palaeoenvironmental change across the onset of the Paleocene‐Eocene Thermal Maximum at Cobham, Southern England

Flammable biomes dominated by eucalypts originated at the Cretaceous–Palaeogene boundary

“…Hence, it has been widely assumed that fire-dominated biomes became extensive only when the global climate aridified and became more seasonal after 15 Ma 1,2,14 . In other parts of the world, there is charcoal evidence that, in the lead-up to the PalaeoceneEocene thermal maximum at 55 Ma, fire frequency increased 23 , with global atmospheric oxygen levels above those of the present 24 . During this period, seasonally hot and dry climates originated both in Australia 25 and elsewhere 26 , and such climates are characterized by fires ignited by electrical storms 2 .…”

High frequency floral changes at the Paleocene–Eocene boundary revealed by comparative biomarker and palynological studies

“…The whole pollen and spore assemblage (Supplementary information) of Vasterival indicates a subtropical climate, as often reported for the Sparnacian flora of the Paris, Dieppe-Hampshire, London, Belgian and German (sub)basins (Fritel, 1910;Krutzsch, 1957;Chateauneuf and GruasCavagnetto, 1968;Gruas-Cavagnetto, 1968;Dupuis and Gruas-Cavagnetto, 1985;Roche, 1973;Krutzsch and Vanhoorne, 1977;Cavagnetto, 2000;Collinson et al, 2003Collinson et al, , 2009Roche et al, 2009;Riegel et al, 2012). Spores/pollen data depict vegetation adapted to humid conditions (Sparganiaceae, ferns, Myricaceae, Taxodiaceae).…”

“…samples 109-112, 25% and 28% respectively) and remain significant (from 5% to 15%) below and particularly above the P/E boundary (Table and Fig Cavagnetto, 1968;Roche, 1973;Krutzsch and Vanhoorne, 1977;Cavagnetto, 2000;Roche et al, 2009 and unpublished data) and in the Schöningen Fm (Early Eocene) of Northern Germany (Riegel et al, 2012). Moreover, a very high proportion (10-52%) of this taxon has been sporadically reported in all lithologies of both the Late Paleocene and the PETM interval of the Cobham section (Collinson et al, 2009). Although first tentatively ascribed to Leguminosae or Flacourtiaceae (Gruas-Cavagnetto, 1968;Roche, 1973), in situ P. macgregorii pollen was later found in some Paleogene flowers.…”

“…However, local and regional changes have been detected, such as a decrease in the abundance of gymnosperms during the PETM, observed in the Arctic (Schouten et al, 2007) and in landmasses bordering the North Sea Basin (Kender et al, 2012), as well as in Wyoming (Wing et al, 2005;Smith et al, 2007). In the London Basin, the vegetation adapted to episodic fires, which characterizes the latest Paleocene, disappears after the P-E boundary (Collinson et al, 2003(Collinson et al, , 2007(Collinson et al, 2009. At lower latitudes, a decrease in diversity has been observed in the paratropical flora of America (US Gulf Coast) during the earliest Eocene (Harrington and Jaramillo, 2007), whereas the equatorial flora of eastern Colombia and western Venezuela was subjected to an increase in diversity (Jaramillo et al, 2010).…”

“…Palynological studies have not found any global crisis among floral communities at the P-E boundary (Harrington and Kemp, 2001;Wing et al, 2003Wing et al, , 2005Collinson et al, 2009). However, local and regional changes have been detected, such as a decrease in the abundance of gymnosperms during the PETM, observed in the Arctic (Schouten et al, 2007) and in landmasses bordering the North Sea Basin (Kender et al, 2012), as well as in Wyoming (Wing et al, 2005;Smith et al, 2007).…”