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Floristic and climatic reconstructions of two Lower Cretaceous successions from Peru

posted on 2017-10-16, 11:46 authored by Paula J. Mejia-Velasquez, Steven R. Manchester, Carlos A. Jaramillo, Luis Quiroz, Lucas Fortini

Climate during the Early Cretaceous in tropical South America has often been reconstructed as arid. However, some areas seem to have been humid. We reconstructed the floristic composition of two tropical stratigraphic successions in Peru using quantitative palynology (rarefied species richness and abundance), and used the abundance of aridity vs. humidity indicator species to infer the predominant climate conditions of this region. The Berriasian to Hauterivian La Merced succession was dominated by fern spores and was predominantly humid. The Albian Aguas Frias succession yielded rich palynofloras, with 127 species, and also indicates predominantly humid conditions. These results support the hypothesis that the west margin of South America was humid during the Early Cretaceous, thus improving the tropical climate reconstructions during the Cretaceous severe global warming episodes.


Smithsonian Tropical Research Institute; Andersen Corporate Foundation; 1923 Fund; Gregory D. and Jennifer Walston Johnson; Geological Society of America [grant number 9209-03].