Sprecher
Beschreibung
A diverse and well-preserved assemblage of ~163 spore–pollen taxa from a Cretaceous–Paleogene (K/Pg) boundary interval within the marginal-marine Oyster Bay Member of the Salish Formation (OBM), Vancouver Island, Canada, reveals an attenuated terrestrial floral response to the end-Cretaceous mass extinction. Local extirpation of ~15% of Cretaceous taxa contrasts with the substantially higher turnover documented from the Western Interior Basin (WIB) of North America. Latest Maastrichtian assemblages are dominated by fern, lycophyte, and bryophyte communities occupying humid coastal lowlands, whereas Danian palynofloras record a gradual reorganization toward conifer-dominated forests with a persistent fern understory and increasing representation of anemophilous angiosperms. Several characteristic K-taxa, including Liliacidites complexus, Tricolpites microreticulatus, Tschudypollis thalmanii, and Retibrevitricolporites beccus, persist above the boundary, demonstrating diachroneity between continental-margin and interior palynofloras. Unlike most North American K/Pg successions, the OBM lacks a distinct fern-spore spike; although Cyathidites and Laevigatosporites increase within the boundary interval, assemblages remain taxonomically rich and compositionally heterogeneous, indicating ecological resilience rather than ecosystem collapse and opportunistic fern proliferation. The palynoflora is characteristic of the Continental Margin floristic province and includes numerous endemic and long-ranging taxa that reflect paleogeographic isolation of the Georgia Basin. Persistent occurrences of palm pollen, including Arecipites spp., Spinizonocolpites spp. (aff. Nypa), and Pandaniidites typicus, indicate warm, humid, frost-free subtropical conditions. Collectively, these data suggest that maritime climatic buffering ameliorated the effects of the Chicxulub impact winter along the continental margin, fostering ecological stability and sustaining coastal refugia through the K/Pg transition.