Fossil plant studies from late Early Miocene of the Santa Cruz Formation: paleoecology and paleoclimatology at the passive margin of Patagonia, Argentina

BREA MARIANA; ZUCOL ALEJANDRO F.; IGLESIAS ARI

Early Miocene Paleobiology in Patagonia.

Cambridge University Press.

Lugar: Cambridge ; Año: 2012; p. 104 - 128

This chapter analyses the plant fossils including phyto- liths, carbonized wood, and leaf compressions, along with microcharcoal, chrysophycean stomatocyst, sponge spic- ules, and diatoms, recovered from the Estancia La Costa Member, Santa Cruz Formation (late Early Miocene), in the Atlantic margin of Patagonia, Argentina. The floristic composition and paleoclimatic inferences based on this fossil plants assemblage from the late Early Miocene are presented. The fossil flora is characterized by the presence of herbaceous components including chloridoid, panicoid, danthonioid, pooid, and festucoid grasses. The arboreal elements include members of the Araucariaceae, Laura- ceae, Arecaceae, Nothofagaceae, Myrtaceae, Cunoniaceae, Fabaceae (Faboideae), and ?Proteaceae. The vegetation was a mixture of open temperate semi-arid forests and humid warm-temperate forests. The integrated analysis of multiple sets of proxy data suggests that southeastern Patagonia, during late Early Miocene, was composed by a temperate to warm-temperate and semi-arid to humid climate, where seasonal low levels of precipitation served as a limiting factor for plant growth.