Paleobotanical Studies of Cretaceous Flora in Southern South America

The Cretaceous period in southern South America presents a rich archive of plant evolution and environmental change, as revealed through both macrofossil and microfossil records. Studies have documented diverse angiosperm woods, fern fronds and conifer remains in fluvial and lacustrine strata, alongside assemblages of palynomorphs that capture shifts in vegetation over millions of years. Late Cretaceous deposits in Patagonia and adjacent basins preserve aquatic macrophytes such as Salviniaceae ferns and Nelumbo, indicating the development of extensive lagoonal and deltaic systems. Palynological analyses demonstrate a marked reorganisation of flora across the Maastrichtian–Danian transition, with gymnosperm lineages like Classopollis persisting into the early Paleogene and angiosperm groups showing variable extinction and recovery dynamics. Combined sedimentological and palaeoclimatic reconstructions suggest that fluctuations in temperature and precipitation drove habitat heterogeneity, from temperate rainforests at low altitudes to alpine heathlands in upland settings. Together, these findings illuminate how southern Gondwanan regions functioned as refugia during global crises, inform models of plant resilience and guide predictions for modern biodiversity responses to environmental stress.

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Paleobotanical Studies of Cretaceous Flora in Southern South America publication trend

The graph below shows the total number of articles in paleobotanical studies of cretaceous flora in southern south america across all publications each year (not limited to Nature Index journals).

Technical terms

Palynology: The study of fossil spores and pollen to interpret past vegetation and environments.

Palynomorph: A microscopic organic fossil, such as a pollen grain or spore, used in biostratigraphy and palaeoecology.

Macrofossil: Plant remains visible without magnification, including leaves, woods and reproductive organs.

Microfossil: Tiny fossilised units, often requiring microscopy, such as spores, pollen and algal remains.

Maastrichtian: The final stage of the Late Cretaceous, spanning approximately 72 to 66 million years ago.

Biostratigraphy: The dating and correlation of rock layers by means of their fossil content.

References

1. New South American record of the Cretaceous–Paleogene boundary interval (La Colonia Formation, Patagonia, Argentina). Cretaceous Research (2021).
2. Cretaceous/Paleogene Floral Turnover in Patagonia: Drop in Diversity, Low Extinction, and a Classopollis Spike. PLOS ONE (2012).
3. Late Cretaceous Aquatic Plant World in Patagonia, Argentina. PLOS ONE (2014).