Macro- and microfossils from the Upper Cretaceous sedimentary rocks of Hornby Island, British Columbia, Canada
Date
2017-08-22
Authors
McLachlan, Sandy Melvin Stuart
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Abstract
Heteromorph ammonites and dinoflagellate cysts from the Upper Cretaceous Northumberland Formation on Hornby Island, British Columbia, Canada are examined. The collection and preparation of new material has enabled the recognition of eleven species of which only three have been reported from the locality. Of these taxa represented from three heteromorph ammonite families in the study area, five are new occurrences and three are new to science. This expansion of the Hornby Island ammonite fauna is presented alongside a pioneering taxonomic survey of dinoflagellate cysts from the same rocks. Together, these macro- and microfossils reinforce a late Campanian age for the Northumberland Formation with the upper extent of the section approaching the Campanian-Maastrichtian boundary (CMB) interval. The palaeoecology
and evolutionary relationships of these heteromorph ammonoids are considered with new insights into their ontogenetic development and neritic palaeoenvironmental circumstances. The dinoflagellate cysts and associated terrestrial palynomorphs have also allowed for enhanced palaeoenvironmental reconstruction and depositional setting inference. The scope of the studied material, and the presence of key index taxa, enables refined biostratigraphy and a stronger basis for correlation of the Hornby Island succession with neighboring coeval biotic provinces.
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Keywords
Paleontology, Invertebrate Paleontology, Micropaleontology, Paleoecology, Paleobiology, Palynology, Geology, Mesozoic, Cretaceous, Campanian, North Pacific, Nanaimo Group, Ammonites, Ammonoids, Dinoflagellates, Dinoflagellate Cysts, Dinocysts, Pollen, Biostratigraphy, Marine, Invertebrate, Fossils, Microfossils, Macrofossils