30 December 2010 Distribución de Enneadocysta (Dinoflagellata) en el Paleógeno del Atlántico Sudoccidental: implicancias paleoceanográficas
G. Raquel Guerstein, Gloria Daners
Author Affiliations +

Paleogene distribution of Enneadocysta (Dinoflagellata) in the Southwestern Atlantic Ocean: paleoceanographic implications. The study of Middle to Late Eocene dinoflagellate cyst assemblages from subtropical Southwest Atlantic basins shows the presence of species of Enneadocysta, including E. dictyostila (Menéndez) Stover and Williams emend. Fensome et al., E. brevistila Fensome et al. and E. multicornuta (Eaton) Stover and Williams. The species Enneadocysta dictyostila has been widely recorded in middle Paleogene sections from Southern Hemisphere high latitudes. High representativity of Enneadocysta spp., along with other components of the Southern Ocean endemic dinoflagellate flora, have been observed in samples from Colorado Basin (∼38°S), Argentina and Punta del Este Basin (∼36°S), Uruguay. Previous research in the Tasman area has related the presence of these endemic taxa at mid-latitudes to the formation of a strong clockwise subpolar gyre (“cold trap”) favoured by the continental blockage of the Tasman Gateway. In this paper we propose that the observed dinoflagellate cyst distribution in the Southwest Atlantic basins can be explained by a similar dynamical mechanism operating close to the present Weddell Gyre. The blockage of the Tasman Gateway and a partially open Drake Passage both contributed to the formation of a strong western-intensified clockwise gyre that may have transported the endemic flora components, mainly represented by Enneadocysta spp., from the Antarctic continent northward along the Southwest Atlantic Shelf during the Middle - Late Eocene.

©Asociación Paleontológica Argentina
G. Raquel Guerstein and Gloria Daners "Distribución de Enneadocysta (Dinoflagellata) en el Paleógeno del Atlántico Sudoccidental: implicancias paleoceanográficas," Ameghiniana 47(4), 461-478, (30 December 2010). https://doi.org/10.5710/AMGH.v47i4.5
Received: 2 August 2010; Accepted: 1 May 2010; Published: 30 December 2010
Circum-Antarctic endemic flora
Dinoflagellate cysts
Flora endémica circum-antártica
Oceanic paleocirculation
Océano Atlántico Sudoccidental
Get copyright permission
Back to Top