Dinoflagellate from the Paleogene of Punta Prat (Chile).

QUATTROCCHIO, MIRTA

PALYNOLOGY

American Association of Stratigraphic Palynologist

Año: 2008

0191-6122

Abstract The section of Punta Prat (Chile) provides a new record of the Paleogene marine microflora in the southern high latitudes. It comprises the Chorrillo Chico and Agua Fresca formations which were studied for their dinoflagellate cysts biohorizons. In view of the presence of Palaeoperidinium pyrophorum (Upper Campanian –Late Selandian), the dinoflagellate assemblages of Chorrillo Chico Formation cannot be younger than Late Selandian in this section. Through comparison with other basins and the stratigraphic ranges of characteristic taxa, a Late Danian to Middle to Late Paleocene (Late Selandian) age is proposed for the Chorrillo Chico Formation at Punta Prat. The Paleocene/Eocene (P-E) boundary is characterized by the onset of Apectodinium-dominated assemblages in mid and high latitudes and also in the Atlantic coast of Isla Grande de Tierra del Fuego (Argentina) and subsurface in Chile. The absence of this event in the present section therefore suggests the existence of a regional hiatus across the Paleocene/Eocene boundary. An Early to Middle Eocene Age is assigned to the lower Agua Fresca Formation on the basis of comparison with dinoflagellate cysts assemblages from the Southern Hemisphere. Palaeoperidinium pyrophorum (Upper Campanian –Late Selandian), the dinoflagellate assemblages of Chorrillo Chico Formation cannot be younger than Late Selandian in this section. Through comparison with other basins and the stratigraphic ranges of characteristic taxa, a Late Danian to Middle to Late Paleocene (Late Selandian) age is proposed for the Chorrillo Chico Formation at Punta Prat. The Paleocene/Eocene (P-E) boundary is characterized by the onset of Apectodinium-dominated assemblages in mid and high latitudes and also in the Atlantic coast of Isla Grande de Tierra del Fuego (Argentina) and subsurface in Chile. The absence of this event in the present section therefore suggests the existence of a regional hiatus across the Paleocene/Eocene boundary. An Early to Middle Eocene Age is assigned to the lower Agua Fresca Formation on the basis of comparison with dinoflagellate cysts assemblages from the Southern Hemisphere. Key words: Paleogene; dinoflagellates; biostratigraphy; Punta Prat locality; Chile. : Paleogene; dinoflagellates; biostratigraphy; Punta Prat locality; Chile.