Coccolith moulds in sedimentary organic matter and their use in palynofacies analysis

Abstract. Imprints of coccoliths can be expected on palynomorphs and phytoclasts in Rhaetian and younger palynofacies. They resemble the hollows left by spheroidal pyrite but may commonly be distinguished on the basis of shape and by occasional marks which reflect the arrangement of the calcite laths of which they were composed. Monospecific blooms are suggested when they are abundant and their size and form is more or less constant. Those which are larger than average and bear arcuate grooves subparallel to their margins may indicate the former presence of coccospheres. The occurrence of coccolith moulds in pre-Quaternary palynofacies both indicates marine influence on the environment of deposition and provides evidence for the affinity of amorphous organic matter in problematical preparations which are swamped with this material and contain few palynomorphs.