First palynologic record of the Cretaceous La Yesera Formation (Salta Group), northwestern Argentina

Abstract

-Thirty-four taxa were documented from six palynologically productive samples of the La Yesera Formation (Brealito and Don Bartolo Members) in the Pucará locality (Salta Province, northwestern Argentina). In the Brealito Member, aquatic species (mainly freshwater algae) dominate the palynofl ora, while terrestrial species are represented by trilete spores (mainly Anemiaceae) and gymnosperm pollen grains. In the Don Bartolo Member, Classopollis spp. dominate most of the assemblages, trilete Anemiaceae spores constitute half of the total counts in one of the assemblages and a unique angiosperm species (Tricolpites variabilis) was found in two assemblages. Ephedra-type pollen grains (three genera and six species) appear in both members, although in low abundance. The results support previous sedimentology studies that indicate a perennial lake environment at the time of deposition of the Brealito Member, with evidence for dry seasonality in the Don Bartolo Member. The inferred regional paleoclimate is subtropical with arid conditions. Considering the stratigraphic ranges of selected species and the sedimentology data, an Albian/Cenomanian age is suggested for the unit.

Steppe development on the Northern Tibetan Plateau inferred from Paleogene ephedroid pollen

“…According to Song (1999), based on pollen, more than 100 species of Ephedraceae are reported for China during the late Cretaceous-Cenozoic. The relatively high diversity and abundance of polyplicate fossil pollen grains (ephedroid pollen, see later) are characteristic not only for China, but also globally during the Late Cretaceous-Cenozoic (Figure 1; Wodehouse 1933;Cookson 1956;Gray 1960;Scott 1960;Ghosh et al 1963;Muller 1968;Hochuli 1981;Chlonova et al 1994;Takahashi et al 1995;Dino et al 1999;Dilcher et al 2005;Akkiraz et al 2008;Narváez & Sabino 2008;Abubakar et al 2011).…”

Cretaceous climatic reconstruction from Argentina based on palynological data

“…At the Salta Group Basin (La Yesera Fm.) the cicatricose spores are particularly abundant reaching a peak of 54% of the total assemblage (Narváez et al, 2013(Narváez et al, , 2014. From the Albian to the end of the Cretaceous, the aquatic ferns became important components of the microfloras from South America (Prámparo, 2012).…”

“…1.a) palynologic records correspond to the Albian-Cenomanian period (La Yesera Fm. ; Narváez et al 2014) and part of the Campanian (only one sample from the Las Curtiembres Fm. ; Narváez and Sabino, 2008).…”