Registros palinológicos en la Formación Piedra Clavada (Albiano) en su área tipo, provincia de Santa Cruz, Argentina

Resumen

Palynological data on Piedra Clavada Formación (Albian) from its type area, Santa Cruz
Province, Argentina. Two sections from the type area where Piedra Clavada Formación is found yielded pollen
assemblages in which 70 palynomorphs have been determined, including Bryophytes/Pteridophytes, Gymnosperms,
Angiosperms and terrestrial plancton. Few and badly preserved marine dinoflagellates confirm the close influence
of sea shore in a delta environement that dominate both sections. These assemblages are similar to those from La
Horqueta locality where the basal section of Piedra Clavada Formación includes ammonites of Early Albian age.
The two sections studied so far in the type area are composed of slightly younger deposits that are covered by the
Late Cretaceous Mata Amarilla Formación. The similarity of assemblages suggests that they correspond to the
same paleofloristic episode and could be united into one biozone in the near future. Comparisons with assemblages
found in the Kachaike Formación, based on presently available data, also show similarities with Piedra Clavada
palynological content, however with slight differences that point to its younger age (Early to mid Albian), as
suggested by dinoflagellate studies. Comparisons with aptian units found in the same area (Río Mayer Formación)
and in neighbouring basins (Baqueró Basin and Golfo San Jorge Basin) are briefly considered. Finally, the importance
of primitive angiosperm sporomorphs is pondered in regard to their variety and biostratigraphic significance.