An unusual biofacies in a rocky shoreline succession of Vancouver Island, British Columbia, Canada: First record of Late Cretaceous coralline algae from the northeast Pacific region

Abstract

Three common morphotypes of Sporolithon sp., as well as the peyssonneliacean red algae Polystrata, have been identified from Cretaceous clastic strata of Departure Bay, Vancouver Island, British Columbia. While coralline algae are known from the Cretaceous of Japan, they have not been recognized previously from the Cretaceous of the Pacific coast of North America. Mollusks associated with the coralline algae indicate an age of late early to early middle Campanian, corresponding to the time of maximum paleotemperature as represented in strata of the Nanaimo Group. The coralline algae are found in conglomerate and sandstone representing a basal transgressive facies of the Upper Cretaceous Nanaimo Group succession, resting unconformably on pillow basalts of the Upper Triassic Karmutsen Formation. This rocky shoreline facies is unusual in exhibiting extensive coralline algae packstone deposits. Paleodictyon is also found with the coralline algae, the first shallow-marine example of this trace fossil from the Cretaceous of the northeast Pacific region.