Milankovitch-scale palynological turnover across the Triassic–Jurassic transition at St. Audrie's Bay, SW UK Nina R. Bonis Micha Ruhl Wolfram M. Kürschner 10.6084/m9.figshare.3454832.v1 https://geolsoc.figshare.com/articles/journal_contribution/Milankovitch-scale_palynological_turnover_across_the_Triassic_Jurassic_transition_at_St_Audrie_s_Bay_SW_UK/3454832 <p>A high-resolution palynological study of the Triassic–Jurassic boundary in the St. Audrie's Bay section revealed a palynofloral transition interval with four pronounced spore peaks in the Lilstock Formation. Regular cyclic increases in palynomorph concentrations can be linked with periods of increased runoff, and correspond to the orbital eccentricity cycle. Spore peaks can be related to precession-induced variations in monsoon strength. An implication is that the initial carbon isotope excursion lasted for at least 20 ka. Emergence during deposition of the Cotham Member had an influence on one of the peaks, which is dominated by spore-producing pioneer plants (e.g. horsetails and liverworts). There is no compelling evidence of a global end-Triassic spore spike that, by analogy with the K–T boundary fern spike, could be related to a catastrophic mass extinction event. Climate change is a more plausible mechanism to explain the increased amount of spores. </p> 2016-06-21 12:22:53 SW UK palynological study 20 ka spore peaks Lilstock Formation climate change palynomorph concentrations Cotham Member Bay section eccentricity cycle carbon isotope excursion St palynofloral transition interval Triassic monsoon strength mass extinction event Audrie Spore peaks Regular cyclic increases Geology