Small Antarctic Late Cretaceous Chorate Dinoflagellate Cysts: Biological and Palaeoenvironmental Affinities

• Published in: Palynology Vol. 38; no. 2; pp. 303 - 323
• Main Authors: Amenábar, Cecilia R, Candel, María Soledad, Guerstein, G. Raquel
• Format: Journal Article
• Language: English
• Published: Philadelphia American Association of Stratigraphic Palynologists 01-12-2014; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Algae; Antarctic regions; Antarctica; Argentina; Beagle Channel; Cape Lamb; Cenozoic; Clavus; Cretaceous; Dinoflagellata; dinoflagellate cysts; Ekelof Point; Fossils; Holocene; Impletosphaeridium clavus; James Ross Island; Late Cretaceous-Holocene; Mesozoic; microfossils; modern analogues; morphology; Neogene; palaeoenvironment; Paleobotany; Paleoclimatology; Palynology; Palynomorphs; Pleistocene; Pliocene; Pollen; Quaternary; reworking; Sanctuary Cliffs; Sediments; SEM data; Snow Hill Island; South America; Specimens; Spores; Tertiary; Tierra del Fuego; Upper Cretaceous; Vega Island; Argentina
• ISSN: 0191-6122; 1558-9188
• DOI: 10.1080/01916122.2014.907829

Small spiny marine palynomorphs have been the focus of recent palynological studies since their high proportions in Antarctic Late Cretaceous and Cenozoic assemblages were noted. These palynomorphs were assigned to the dinoflagellate cyst Impletosphaeridium clavus and they were believed to have had an affinity with some modern round brown spiny cysts (RBSCs). Our study aims to analyse there together with potential modern analogues by comparing Late Cretaceous and Cenozoic Antarctic specimens with some RBSCs recorded from the Holocene of southern Argentina. We confirm several features in common between these specimens, although differences in processes and the cyst wall are observed. The species could have been produced by dinoflagellates similar to those that generate some RBSCs. Their abundance in the Late Cretaceous may have occurred in response to short term cooling pulses without development of sea-ice cover. Cenozoic records are considered to be reworked, restricting the stratigraphical range of Impletosphaeridium clavus.