Palynology of late Cretaceous mammal beds, Scollard, Alberta (Canada)

Abstract

Fossil mammal bones have been located in Upper Cretaceous (Lance or Maastrichtian) Upper Edmonton Beds above the Kneehills Tuff in the Scollard area, Alberta (Canada). Samples from the mammal-bearing beds and from above and below, have been analysed for their palynological contents. Abundant microflora representing pteridophytes, gymnosperms and angiosperms have been recorded with an abundance of Aquilapollenites in varied morphological diversity. The microflora showed five paleoecological stages. The lowest Microfloral Assemblage I, representing mid-Middle Edmonton vegetation, indicates swampy, tropical and humid climate which was replaced by stages of a sere of cooler climate shown by Microfloral Assemblage II. Cooling increased still more, possibly due to descrease in the total solar radiation reaching the earth's surface, caused by the volcanic dust in the atmosphere as the bentonitic content is high. Microfloral Assemblage III from the bentonitic beds associated with the Kneehills Tuff shows little preservation of spores and pollen although comminuted fragments are present. Microfloral Assemblage IV (including the mammal beds) shows warming up and restoration of vegetation but of a cooler climate. Climate became warmer during the deposition of Microfloral Assemblage V and a rich woodland vegetation was established representing warm subtropical climate with warm temperate aspect during mid-Upper Edmonton deposition.