Cretaceous angiosperm pollen from the Kachaike Formation, south-western Santa Cruz Province, Argentina

PEREZ LOINASE, V.; BARREDA, V.D.; ARCHANGELSKY, S.; ARCHANGELSKY, A.

Historical Biology: An International Journal of Paleobiology

Taylor & Francis

Año: 2015

0891-2963

Thirty-three angiosperm pollen species are here reported from mid-Cretaceous deposits of the KachaikeFormation, Austral Basin, southern Argentina. Clavatipollenites is the most abundant angiosperm genus,with six well-defined morphological groups recognised on the basis of their reticulum morphology andsculpture. Pollen of eudicots are scarce, represented by tricolpate (Psilatricolpites spp. and Tricolpites spp.),tricolporoidate and tricolporate morphotypes (Dryadopollis spp.). Increasing complexity in the aperturestructure is seen throughout the sequence; tricolpate and tricolporoidate forms are recorded in almost allsamples, while tricolporate pollen grains are restricted to the middle and upper levels of the unit. The highspecies richness and abundance of monocolpate-ulcerate angiosperm related to monocots or magnoliidssensu lato recorded in the unit is comparable to that previously recognised in other assemblages from theearly and middle Albian of the southern (e.g. Australia) and northern hemispheres (e.g. Western Portuguesebasin, Europe). The recorded increase in the number of angiosperm species towards the middle andupper parts of the Kachaike Formation, with the presence of monocolpate, tricolpate, tricolporoidate andtricolporate pollen, suggests an early-early middle Albian age for these parts of the unit, in agreement withthe early Albian age proposed for its basal levels on the basis of dinoflagellates.